© 2024, International Council of the Aeronautical Sciences. All rights reserved.Robotics is a constantly evolving field that benefits from the use of tools powerful tools for robot development and simulation. Two of these tools, widely used ROS (Robot Operating System) and CoppeliaSim (formerly known as V-REP). ROS is an open-source framework widely used in the robotics community. On the other hand, CoppeliaSim is a simulation platform for powerful and versatile 3D robots. In this paper, we distributed an F16 simulation using ROS to create tasks, combining flight visualization by Flight Gear and collision analysis of a robotic flight simulator using CoppeliaSim.

© 2024, International Council of the Aeronautical Sciences. All rights reserved.In aviation safety and performance play a pivotal role, and a critical theory part is fault detection, which can be used in subsystems that are important in ensuring the reliability of aircraft systems. This research delves into the implementation and testing of an architecture for fault detection using parity space methodology, specifically tailored to handle different maneuvers during the flight of an aircraft. The emphasis on maneuver-specific techniques aims to enhance fault detection’s overall robustness and accuracy in dynamic flight conditions. This work is intended to study two different forms of implementation for detecting faults in the actuator system of an aircraft, they will be tested using two actuator models for the elevator in a simple maneuver during the flight.

© 2024, International Council of the Aeronautical Sciences. All rights reserved.This study explores the cognitive and ergonomic aspects of military UAV operations, focusing on pilots' mental workload and interface usability using advanced eye-tracking technology. A total of 24 military pilots participated in 30-minute flight simulations, with their eye movements recorded by Tobii Pro Glasses 2 and analyzed using Tobii Pro Lab software. Pilots' subjective perceptions of workload and interface usability were assessed through NASA-TLX and SUS questionnaires. Statistical analyses, including Pearson correlation, ANOVA, and linear regression, were conducted to examine the relationships between eye-tracking metrics (fixation duration, saccade amplitude, blink rate, and pupil dilation) and subjective assessments. The findings indicate that experienced pilots rated UAV interfaces as more usable, and higher mental workload, indicated by NASA-TLX scores, was strongly correlated with increased pupil dilation and blink rate. These results demonstrate the value of integrating eye-tracking technology with subjective assessments to achieve a comprehensive understanding of UAV operator interactions. The insights gained can inform the design of more intuitive and efficient UAV interfaces and training programs, enhancing operational safety and efficiency. This study contributes significantly to military aviation training and interface design, emphasizing the necessity of incorporating technological advancements with human factors to optimize UAV operations.

© 2023 Elsevier B.V.This work presents a novel approach for 3D scanning inspection of industrial sealed parts based on data fusion from a 2D-laser beam sensor and the motion pattern of a robotic arm. The method provides as output the 3D geometrical shape and volume of the inspected part in order to allow for automatic compliance check according to process requirements. The solution is implemented and tested in sealed riveted fasteners, which are common in the automotive and aerospace industry. The effectiveness and robustness of the method is evaluated through the comparison of the obtained results with those from a 3D laser scanner system. The evaluation campaign was performed in a noisy environment (i.e., without illumination and temperature control), representative of an industrial shop floor. Statistical analyses show the system can perform geometry prediction with an overall error of 0.340 mm and is able to reject non-compliant sealed structures with a reliability of 96.6%, confirming that the proposed method is suitable to modern collaborative robotized aerospace and automotive assembly cells.

© 2023 The AuthorsPilot training has been, for decades, aided by flight simulators with different characteristics and degrees of fidelity. However, many studies indicate that, despite the recognized contribution of simulator training, actual flying practice is still necessary, depending on the trained task. This work introduces the proposal of using augmented reality for in-flight training, where elements in the environment outside the aircraft are displayed through an augmented reality headset to create a simulation scenario. The training of basic formation flight is used as an example, as it requires flying with at least two aircraft, resulting in high operational costs and risk of collision between aircraft. In this case, the augmented reality system replaces the real leader aircraft with a projection. In order to evaluate the Technology Readiness Level (TRL) of this proposal, this work presents a prototype of an augmented reality system integrated into a flight simulator to conduct an evaluation campaign. We investigate how the introduction of the augmented reality system impacts on human factors, such as stress and workload, as well as performance. Although the results obtained in a simulated environment are not equivalent to those from an in-flight campaign, the experimental campaign performed in the flight simulator provides a way of evaluating the impact on the pilot of some aspects of the proposed solution, such as the performance of occlusion routines and some ergonomic aspects of the augmented reality headset.

© 2023 IEEE.In this work, a photorealistic virtual simulator is developed to simulate the flight dynamics of an unmanned aerial vehicle (UAV - quadcopter drone) with a camera embedded, whose photographing process can be also emulated to gather image and flight data that can be further used to point cloud generation and 3D reconstruction as in digital photogrammetry process. The system is intended to simulate the UAV-based digital photogrammetry of large structures (industrial structures, small buildings, residences). To accomplish this goal, the mathematical modeling of the dynamics of a commercial-of-the-shelf drone was developed and a flight controller was designed and verified in Matlab. Finally, the simulator is verified, generating a descriptive point cloud of an inspection mission that is virtually simulated. The 3D reconstruction of the object of analysis was properly performed in the photorealistic environment.

© 2023 IEEE.This paper discusses an approach for implementing predictive and reliability displays in aircraft manufacturing processes. The aim is to support the operator to complete all operations with quality, safety, efficient resource utilization, and on schedule. This study presents the first step of the design process to assess different ways of conveying automation information to operators. The primary goal here is to propose a first iteration that aids in future display design iterations prior to behavioral studies. Additionally, this paper presents the design and testing of a representative test demonstrator for aircraft manufacturing processes, which will be used to evaluate the effectiveness of these displays. The authors used the Human Readiness Level (HLR) framework to design the test demonstrator, considering the specific needs and requirements of the aircraft manufacturing industry. The paper presents simulation and test demonstrator results and the collected feedback from participants. The findings suggest that the test demonstrator can be a valuable tool for improving the overall efficiency of the manufacturing process. The paper contributes to the body of knowledge on the use of advanced technologies in improving manufacturing processes by providing insights into the potential benefits and limitations of predictive and reliability displays and identifying areas for further research and development.

© 2023 IEEE.The paper describes the constitution of the Engineering Research Center for the Aerial Mobility of the Future (ERC-AMF) having ITA as the host institution, Embraer as the industrial partner, and researchers from the University of São Paulo and the University of Campinas. The objective of the ERC-AMF is the realization of R&D to contribute to overcoming challenges to the shaping of aerial mobility in the upcoming decades. These challenges arise from the necessity of reducing pollutant and noise emissions, and the need for increased efficiency of manufacturing processes, besides the trend of introducing in the market novel aircraft adapted for operation in urban environments and short-range travels. Five research areas are focused on the first operation phase of the Center: Machine Control for Electric Propulsion; Aeropropulsion Integration in Electric Aircraft; Methods for Decision Making in Autonomous Systems; Advanced Design for Metallic Additive Manufacturing; and Intelligent Aircraft Final Assembly. Each line will be developed by researchers from partner universities and engineers from Embraer. It is expected that the Center will contribute to the appropriation, by the Brazilian aeronautical industry, of scientific and technological knowledge generated, and, as a result, increase its preparedness to face challenges that shall be overcome in the process of shaping the aerial mobility of the upcoming decades.

© 2022, The Author(s), under exclusive licence to Springer-Verlag London Ltd., part of Springer Nature.In aeronautical manufacturing, the assembly of large structures like wings and fuselages usually uses riveting to join the primary parts. The riveting process induces deformations between parts that affect aircraft performance and increase manufacturing costs. In this work, a finite element analysis of a rivet installation is developed to predict the induce deformations as a tool for the design of the assembly process in aeronautical industry. Different from the existing literature, which focuses mainly on fatigue analysis, the method presented in this paper focuses on finding a solution for determining induced deformations that can be applicable, from an industrial perspective, to aircraft production lines. A 2D axisymmetric model represents the installation of a single rivet joining two metal sheets with a force-controlled squeezing. The simplified model is proposed to reduce computational costs. An adaptive meshing scheme is adopted to better describe the forming of the driven head and improve the accuracy of the model. When comparing with existing methods, this attribute allows to better predict the profile of the radial expansion along the thickness of the sheets because the mesh is recalculated at each iteration to prevent distorted elements. Up to 18% relative difference was observed between the mesh with and without adaptive scheme. The results indicate that the radial expansion in the rivet hole is directly related to the squeeze force. An uneven expansion occurs through the thickness of the sheets indicating bending of the material. The mean radial expansion at half-pitch of 4 diameters was used to estimate the radial expansion of a rivet line composed of two or more rivets. The obtained results show that, for a rivet line composed of 50 rivets with a 4-diameter pitch (a panel with 952.5-mm length) the mean radial expansion for a 27.4-kN squeeze force is of 0.5 mm. It was also observed that the inner sheet (closest to the driven head) expands at least three times more than the outer sheet, indicating a bending mechanism is present in the panel.

© 2021This work presents a novel approach for visual servoing of robotized aerospace manufacturing cells, based on the combined use of a camera and a 2D-beam scanner and a 1-D beam distance sensor attached to the end-effector of a collaborative robot. The proposed system can detect features associated with mechanical bounds over the aircraft structure, making possible the robot automatic online trajectory/path generation when the robot performs a target task over an aeronautical part. The effectiveness of this method is demonstrated by means of experimental evaluations carried out in unstructured environments without illumination and temperature control (simulating real shop floor conditions), evincing that the proposed approach is more robust. We also show that it is able to automatically generate and follow a target path with an accuracy of 0.40 mm and repeatability of 0.59 mm, which is roughly 2 times more accurate than the classical computer vision servoing used in the experiments. The proposed solution is suitable to applications in modern collaborative robotized aerospace assembly cells.

© 2022 ESREL2022 Organizers. Published by Research Publishing, Singapore.Air transport demand for patients increased significantly in Brazil during the COVID-19 pandemic. This occurred because hospitals were overcrowded in some regions, and patients needed to be moved over the country’s continental distances. The transport of patients with infectious diseases leads to an increased crew’s mental and physical overload due to the care provided to critically ill patients, utilization of complete personal protective equipment, and fear of contamination. To assess the mental workload levels under these conditions, health professionals involved with the air transport of patients with COVID-19 from the Brazilian Air Force were asked to answer questionnaires about flight missions performed, the patients’ clinical status, and the NASA-TLX questionnaire. Nine healthcare professionals participated in the survey. The NASA-TLX questionnaire’s outcomes were analyzed and compared according to transport time, the number of patients transported, and the patient’s clinical status. Transport with unstable patients showed the highest final weighted rating, and the most significant NASA-TLX dimensions were mental demand and reported frustration.

© 2022, International Council of the Aeronautical Sciences. All rights reserved.Helicopter rocket-firing requires continuous pilot training for mission accomplishment purposes, so measuring the mental workload involved could help to improve training effectiveness and flight safety. Physiological and flight data from two Brazilian Army pilots with distinct experience levels have shown that the aiming phase is the more mental demand, and some physiological patterns were identified. Pearson’s Correlation and Principal Component analysis, including shot stability parameters (aiming path area, perimeter, and deviation of maneuver parameters) and physiological data, have identified electrodermal activation as the more consistent human dimension related to the shooting performance.

© 2022 ICAS. All Rights Reserved.The HMI-HUFLab project is a joint Brazilian Swedish initiative in the area of human factors and design of human machine interfaces for future military concepts in Aeronautics. This paper gives a short introduction to this Brazilian Swedish collaboration. It describes the main challenges for setting up the bilateral collaboration and how challenges were tackled. We present the first projects results, which includes the definition of relevant context and scenarios for the future air domain, a review of literature and implementation of complementary simulation environments in both countries.

© 2022 ICAS. All Rights Reserved.Helicopter rocket-firing requires continuous pilot training for mission accomplishment purposes, so measuring the mental workload involved could help to improve training effectiveness and flight safety. Physiological and flight data from two Brazilian Army pilots with distinct experience levels have shown that the aiming phase is the more mental demand, and some physiological patterns were identified. Pearson's Correlation and Principal Component analysis, including shot stability parameters (aiming path area, perimeter, and deviation of maneuver parameters) and physiological data, have identified electrodermal activation as the more consistent human dimension related to the shooting performance.

© (2022) by International Council of Aeronautical Sciences (ICAS) All rights reserved.In this paper the creation and maintenance of a bilateral network is presented. Sweden and Brazil have a long standing relation stretching far beyond aeronautics. However, it was intensified with the acquisition of the Swedish Saab Gripen combat aircraft for the Brazilian Air force. This led to an intense build-up of industrial collaboration and in the wake of this, also a bilateral academic network was formed to both take advantage of this, as well as support the process and encourage spin-off effects to other parts of society. To be sustainable it is argued that a network needs the right support and encouragement to be able to grow organically in a sustainable way, based on personal relations. Once this is in place, an academic bilateral network can be formed that can be maintained effectively over time at a low cost.

© 2022 ICAS. All Rights Reserved.The problem addressed in this research is the control of a remotely piloted aircraft using a satellite communication link with communication delay. To investigate the problem, it was necessary to build and investigate a test platform where the pilot could land an aircraft outside the standard operating area. The mission mandatorily depends on communication via satellite. The dynamic model of the aircraft used for the experiment was developed in the Matlab/Simulink software, with all inertial and aerodynamic modeling arrangements. The graphical interface for displaying the scenery, 3D model of the aircraft, and items used during the experiment are generated in the FlightGear software. The Unity software is used to develop a secondary interface that receives data from Matlab/Simulink. All tests studied were monitored through performance measurements, concerning deviations from the expected trajectory, using physiological sensors. The experimental data are processed to evaluate the influence of the predictive interface during flights performed with delay in the visualization.

© 2022 ICAS. All Rights Reserved.Safety-II assumes that individuals and organizations habitually adjust their performance to match current demands, resources, and constraints to compensate the incompleteness of procedures and instructions. It suggests that everything happens basically in the same way, regardless of the outcome. This work aims to analyze the aircraft touchdown procedure through this perspective, focusing on the everyday performance and the consequent variability. The Functional Resonance Analysis Method or FRAM provides a way to explain outcomes using the idea of resonance - an activity is described through a pool of functions and the outcomes arise from their day-by-day variability. To characterize the functions' variability, Flight Data Monitoring (FDM) techniques are here used. To examine specific instantiations of the model and understand how the potential variability of each function can become resonant, the application of Monte Carlo Simulation (MCS) is proposed. To apply the MCS, a linear regression is performed in order to capture the relationship between the functions' outputs and their inputs. This method is applied to the touchdown of 288 flights. The outcome is a model to assess the risk of a long touchdown of the current sample, including the organizational, human, and technological aspects of the complex aeronautical system. Note that long touchdown is a runway overrun precursor.

© 2022 IEEE.The primary cost driver for the assembly of airframes is rooted in drilling, countersinking, and installation of fasteners. Customized automated systems, such as drilling machines and robotic platforms, are designed and built to perform these assembly processes. The operator is the closest individual to the automated system that influences its success. In addition, equipment operators must deliver quality parts within a specified cycle time in these long and repetitive processes. This work evaluates the workload of equipment operators of automated drilling processes for aerospace structures. The evaluation is carried out with experienced machine operators who work full-time in these automated drilling processes. Two different automated drilling processes are evaluated: robotic platforms and automatic drilling machines. This work evaluates workload in the different phases of the automated drilling process. This evaluation identifies phases where workload under-arousal and over-arousal may be present. Finally, recommendations to enhance human performance in automated drilling processes are presented. These results may be successfully used to improve the design of automated drilling machines and drilling processes for aerospace structures.

© 2021 IEEERobotic flight simulators have emerged as a low-cost alternative to conventional flight simulators. Despite the enormous potential, few research works have been conducted regarding the representativeness of the movement of these simulators. Thus, the present work seeks to propose an optimization of the washout filter using the genetic algorithm to obtain the parameters capable of maximizing pilot's acceleration perception during the plane's takeoff. 3 configurations were proposed: solution 1 that does not impose displacement limits for channel B of the simulator, solution 2 with a limited displacement of 15° for the channel B and solution 3 that considers the limit of 15° and a different configuration of the cost function. It was found that the solution that maximizes pilot perception is the solution 1. Solutions 2 and 3 were similar, which indicates that it is the best configuration to be obtained with the current workspace limitation. The comparison of the 3 solutions also indicates that the trail could be further explored to increase the sensation of acceleration during takeoff.

© 2021 32nd Congress of the International Council of the Aeronautical Sciences, ICAS 2021. All rights reserved.Aircraft conceptual design has mostly been characterized by sizing by the use of rather simple analytical models. Such models serve a purpose since they can be easily be manipulated for e.g. trade studies to see the effect of requirements on the design parameters and general performance of the aircraft. However, there is a trend to involve more advanced calculations, e.g. more advanced aerodynamics calculations and flight dynamics analysis, already at the conceptual design, in order to further reduce uncertainty. In the same way, it could be argued that more detailed analysis of behaviour of the aircraft in a mission should be useful. We propose the simulation of hybrid systems in the framework of transmission line modelling, TLM. We extend an existing continuous time methodology, and adopt UML Activity Diagram and Petri nets for the discrete event dynamics, to describe complex behaviour. This allows for full system simulation of a mission where a more accurate evaluation of mission performance can be obtained. In this paper the methodology is outlined and demonstrated on a UAV mission application.

© 2021 32nd Congress of the International Council of the Aeronautical Sciences, ICAS 2021. All rights reserved.Cockpit flight control interfaces have remained largely unchanged since the beginnings of Aviation (sticks, yokes, pedals and thrust levers). New technologies have emerged that have successfully been employed in other fields of technology regarding Human-Machine interaction, one such technologies is eye tracking. The pilot is a fundamental element even in modern aircraft with high levels of computerized assistance. Emergency situations or environmental factors can lead to a situation were a pilot is overwhelmed by simultaneous tasks and this can lead to the conditions for an accident. With these points into consideration, a modernized flight control interface is proposed were Eye tracking is used as a complementary input for yokes, side sticks and pedals. Review of literature and previous research suggests that this application has considerable merit for its potential benefits, this paper is in regard of early experimentation using the system in a highly realistic flight simulator. The development uses equipment available at the Instituto Tecnologico de Aeronautica (ITA) to create a prototype that enables the characterization of the proposed a system. Results from this set of experiments contributed to the further refinement of the system, error correction, obtaining of operational experience and collection of data and feedback from participants that suggest that the proposed system could have a positive impact in the controlability of an aircraft by an inexperienced pilot during a high-workload situation.

© 2021 32nd Congress of the International Council of the Aeronautical Sciences, ICAS 2021. All rights reserved.During the development of a flight control system that uses gaze as an alternative input method from the pilot, the human factors analysis is one of the most important processes. This gaze tracking system's architecture integrates three hardware elements that were not originally designed to operate with each other; the Tobii Pro Glasses 2, the HTC Vive Trackers, and the Aeronautics Institute of Technology' SIVOR flight simulator. This paper deals with an experiment that involves the visual search and acquisition of a target on a spherical screen, and the application of fitts's law to the eye tracking signal.

© 2021, Springer Nature Switzerland AG.This study evaluated the mental workload of military pilots during day and night conditions using night vision goggles (NVG) in a Flight Training Device, in order to rectify or ratify the fatigue correction factor used for flights using NVG. The experiment used basic military operational tasks measuring physiological data, specifically data on electrocardiography activity and galvanic skin response. Subjective data were gathered using NASA TLX and Psychomotor Vigilance Test methods. After collection, the data were subjected to treatment to correct possible errors during data acquisition and later analyzed in the domains of time and frequency. The analysis did not show a great change in mental workload between the day and night periods, which could be explained by the small sample, the small period between flights and the learning effect between day and night flight.

© 2021 by the authors.This work proposes a set of complementary practices to agile methodologies, aiming at adapting them to the development of critical aerospace embedded systems by distributed teams. To identify the main gaps in this context, two approaches are used. The first one confronts the main activities required by aerospace standards for the development of critical embedded systems with a set of compiled agile practices derived from a review of the most common agile methodologies. The second one confronts the same set of compiled agile practices with the main problems of distributed development. The two approaches resulted in the identification of four gaps related to software integration, software traceability, communication management, and organizational differences. One complementary practice is then proposed for each gap. Two case studies were performed to assess the gaps and evaluate the proposed practices. Both emulate the development of critical embedded systems by distributed teams using agile methodologies. The case studies were performed with and without the use of the complementary practices. The results confirmed three of the four identified gaps and pointed to a clear contribution of the complementary practices.

© 2021, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.How do people with visual impairment see the world? In this literature review based on cognitive sciences findings, we have analyzed the main concepts used in the human brain’s cognitive processes to represent our perception of the surrounding environment. One of these concepts is mental imagery, which resembles perceptual experience without external sensory stimulation. This concept plays a central role in multisensory design cognition. It can help us understand the designer’s cognition process, design better systems for people with disabilities, and open opportunities for multisensory design teams.

© 2020 IEEE.Optimization of motion cueing algorithms is a relevant topic in flight simulation industry. To achieve this goal, a representative model of the motion platform is needed. With this intent, this work presents a black-box approach to identify a model for the SIVOR flight simulator. The model receives position/orientation inputs in Cartesian space and streams out accelerations/angular speeds measured on the pilots' head. A comprehensive experimental analysis is carried out using a dataset based on isolated positional and rotational inputs. A frequency domain analysis is performed to evaluate signal measurement noise and to determine the model structure. As a result, a combination of continuous time linear transfer functions were identified to represent each of the direct and cross relations mapped throughout the process.

© 2020 IEEE.The Small Size League (SSL) is a robot soccer league of the Robot World Cup (RoboCup). A recent trend in hardware design in SSL involves multiple angles kicking mechanisms. Combining a multiple angles kicker with a dribbler, which consists of a spinning bar to manipulate the ball through friction, a robot can execute angled and curved shoots and passes. However, due to the complex physical interactions involved, determining how to control the kicking and dribbling devices in order to obtain the desired ball trajectory is not simple. The ball motion may be mathematically modelled by a nonlinear ordinary differential equation (ODE). The parameters needed to perform a desired curved kick are the solution of the inverse problem of the nonlinear ODE. Since this is hard to compute in real-time, this work proposes a neural network to solve this inverse problem. The network is trained using many simulated ball trajectories. Finally, we show simulation results to validate the proposed method.

© 2020 IEEE.The aim of this work is to implement a representative dynamics model of the SIVOR flight simulator. Two experiments were conducted and used to estimate and validate the model; the first one excites one robot channel at once and the second excites more than one robot channel. Based on a previous study, we established the model structure. Three distinct approaches of black-box identification model were employed: transfer function models, space-state models and ARX models. The results obtained were similar and satisfactory for inputs until 1 Hz.

© 2019, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.Aviation system is one of the most complex dynamical systems created. This system is subjected to the occurrence of different failures during flight. Online failure detection and identification (FDI) techniques may allow an aircraft to avoid unrecoverable post failure flight conditions and continue the mission by control laws reconfiguration. This paper focus on presenting the current FDI methods used by the aeronautical industry and by academic and research communities, discussing the gap that exists between these two domains and presenting the challenges and directions to bring them closer in order to improve flight safety.

© 2019 by Xin Ning. Published by the American Institute of Aeronautics and Astronautics, Inc.This paper aims to analyze and compare different machine learning FDI techniques to detect and identify aircraft failures using offline analysis of FDR data. We use a motion-based flight simulator (SIVOR) to perform human-in-the-loop experiments. We performed 2 experiments of a take-off maneuvre under different conditions: normal flights and flights with aircraft failures (flap, engine, aileron and elevator failures). We applied and compared different supervised machine leaning techniques to detect and identify aircraft failures: Decision Trees, Ensemble Classifiers, Support Vector Machines (SVM) and k-Nearest Neighbors (kNN). Boosted Trees algorithm, an Ensemble Classifier, presents the best result regarding overall accuracy for both flight experiments (99.5% and 97.7%).

© 2019, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.This work aims at presenting an integrated development system to a motion real-time flight simulator using a robotic device. This flight simulator is called SIVOR (Simulador de Voo Robótico – Robotic Flight Simulator). This is a multidisciplinary project since it involves different systems with different level of complexity, which by itself give some challenges in how to develop this type of flight simulator. In order to have a flight simulator with base motion upon robotic device it is necessary the domain of systems like robotic, pilot modeling, filtering design, here called by washout filter, aeronautic modeling which includes traditional systems as automatic flight control, aerodynamic, propulsion, ground handling, sensors and actuation. Therefore a considerable effort in the development is demanded to have a representative aircraft model been executed in a real-time flight simulator with robotic motion. Thus this paper presents an integrated modeling process to represents all of the system in order to give a more maturity development cycle, in order to reduce the uncertainties presented in the begin of any project and that becomes more challenging for any complex system. The real-time motion flight simulator based upon robotic environment has a nonlinear flight mechanic model of EMBRAER 190-E2, and here won’t be presented in order to protect the intellectual property and compliance policies of EMBRAER S.A., the other systems will be explained in detail and a sensitive analysis is presented in order to demonstrated that an model based approach shall be used in this kind of flight simulator in order to speed up the maturity level of the system.

� 2019 by German Aerospace Center (DLR). Published by the American Institute of Aeronautics and Astronautics, Inc.The need for an optimized aircraft development cycle imposed by market constraints, associated with airliners demands for more cost-effective and safe operations, has become a challenge for aircraft OEM in face of new aircraft ever-growing complexity. Emergent behaviors during the development phase causing project schedule oscillations and delays in the adequate time to market, associated with accident statistics after entering into service phase (especially those associated with Loss of Control in Flight), force new approaches for the development of new aircraft. Based on this scenario, this manuscript describe the efforts to develop a flight simulation-engineering center based on a robotic motion platform. This promising configuration might contribute to overcome some of the previous problems due to augmented motion platform workspace. However, the limited robot payload capacity and the need for a commercial jet representative cockpit, generate critical design constraints and technological challenges to implement this configuration. This manuscript details the design strategy to build the flight simulator assisted by a robotic motion platform and also analyses possible applications.

© 2019, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.This paper presents the SIVOR project, an anthropomorphic-robotic flight simulator under development at the Aeronautics Institute of Technology (ITA), discussing the contribution of an additional 7th degree of freedom (DOF) provided by a linear unit to improve the pilot perception inside the flight simulator. In this context, starting from a canonical washout filter (CWF) implementation, a model-based comparative evaluation – regarding the pilot sensation – is performed considering (i) models of the robotic system with and without the linear unit, (ii) modified versions of the motion-cue algorithm (MCA), (iii) and perception models of the human vestibular system. Such integrated model is used also as the first verification for a predefined flight mission. The results obtained so far suggest an improvement on the representation of the linear acceleration as a larger workspace is provided, though also highlighting the need for further developments on the MCA structure for a better usage of the near feature.

© 2019This paper presents a human factors analysis in aviation within the context of failure detection and identification (FDI) using statistical data analysis and clustering. We used data from experiments in a motion-based flight simulator (SIVOR) with 4 experienced pilots performing a take-off maneuvre under three conditions: normal, under engine failure and under flap failure. We propose two metrics based on statistical data analysis to evaluate and compare human behavior during flight. We also use k-means clustering in order to classify flights according to maneuvre conditions and misclassified flights are further analyzed according to which pilot has performed it. Results show that for the statistical data analysis the behavior of one specific pilot has higher dissimilarity with all other pilots. Moreover, for the k-means clustering, most of the misclassified flights were performed by this same pilot.

© 2019, Journal of Aerospace Technology and Management. All rights reserved.This paper presents a detailed analysis about the implementation of a washout filter on the SIVOR (Simulador de Voo Robótico – Robotic Flight Simulator) project. The main objective of this project is to develop, on an anthropomorphic robot, a flight simulator which can be used as an Engineering Development System (EDS) and a pilot training platform, capable of providing feelings the pilot would only have in more intensive maneuvers, such as losses/gains of G in aircraft flight tests. The SIVOR project also has the objective of providing a cost-efficient and flexible tool that can be used during the design phases of aircrafts. One of the demanded features of such simulator is a representative behavior of its motion system, which is achieved by an adequate implementation of the washout filter. To the best knowledge of the authors, there are no works in the literature that present a detailed discussion about the implementation of a classical washout filter in such flight simulator, especially when the translational channel is used to its limits. Experimental results to support the proposed solutions are presented herein.

© 2018 Elsevier B.V.With the purpose of making the use of model based techniques in industrial software development more efficient, this work proposes the combined application of two verification techniques: model checking with UPPAAL and CoFI (Conformance and Fault Injection) model based testing with ConData. This combination is supported by ConTEA, a software tool for automatically connecting UPPAAL to ConData, and, therefore, explore both techniques simultaneously. We present the tool and discuss the use of ConTEA in two different development processes. The first process investigates how CoFI can contribute to identify gaps in the specification and implicit assumptions made by engineers when applying model checking. The second process focuses on how model checking can improve the development and verification of the models that are used for model based testing. The proposed processes were applied to three case studies. Based on them, we compare the proposed processes to the traditional CoFI and UPPAAL stand-alone processes. The results indicate that the combined use of the two verification technique contributes to the identification of a large range of diversified errors and problems early in the development cycle.

© 2018 Elsevier LtdDue to the current pace of technological growth, the management of system safety has evolved with complex causes of accidents that are often beyond the identification of traditional safety assessment techniques. Recently, the hazard analysis tool Systems Theory Process Analysis (STPA) has emerged as an approach to improve safety of modern complex systems in concert with other hazard analysis tools. However, the effectiveness of STPA is a debatable issue in the industry and efforts towards incorporating some level of formalization in STPA steps are welcome. In this direction, this work presents a method for combining STPA and model checking, in order to provide a formal and unambiguous representation of the system under analysis and the threats identified by STPA. A practical case study of a robotic flight simulator is presented as an example of the proposed method. The results achieved with the proposed approach indicates that the merging of the two techniques improves the knowledge about the system under design and the consistence of the design changes proposed to tackle the safety constraints identified in STPA.

© 2018, The Brazilian Society of Mechanical Sciences and Engineering.This work investigates the energy consumption of industrial robots in the context of automotive industry. The purpose is to identify the most influencing parameters and variables and to propose best practices with focus on energy efficiency. The analysis approach is composed of three experiments performed in a simulation environment that test different values of programming parameters and variables, such as joint speed, acceleration, robot payload. The first experiment focuses on energy consumption of robots at standstill. The second one considers the robot moving along different paths. Finally, the third one analyses how the joint friction is affected by load, speed and temperature and how it influences the energy consumption. Results show that at standstill, it is important to reduce dwell time, select an energy efficient position and reduce the programmed value of the timer responsible for turning off the servomotors. While moving, it is important to select maximum continuous termination for intermediate points and avoid low speeds. Regarding friction variation, results show that at high motor speed, low temperatures increase energy consumption. In order to evaluate the contribution of the best practices in a real environment, they are applied to a welding robotic cell of an automotive industry.

© 2018 IEEE.The use of commercial robots in aircraft industry faces many challenges. Among them, this work approaches the problem of maintaining the robotic end-effector perpendicular to the work surface. The perpendicularity error when performing operations such as drilling and riveting affects can affect the overall aircraft drag and cause fatigue cracks. In this work, we present, compare and analyse two different solutions for the correction of the perpendicularity error of a robot. Both solutions are different from existing ones described in the literature. The first solution uses only a point distance laser sensor fixed in robot end effector. The end effector moves in its X and Y axes sequentially to determine the correct robot angle B, C. It then correct distance Z to normalize the pose and adjust the position between the effector and target. Two different point distance lasers were tested. The second solution normalizes the robot pose through a linear scan sensor and a point sensor that allows us to quickly generate the correction angles and Z distance direct without robot movements. The paper verifies if the methods are able to comply with a perpendicularity requirement of 0.5° of maximum error between the manipulator and the normal of the tested table. The results showed that only the second solution is able to achieve the required perpendicularity.

© 31st Congress of the International Council of the Aeronautical Sciences, ICAS 2018. All rights reserved.The aircraft design problem is an example of a highly integrated design, which calls for a multidisciplinary approach from the very beginning. With every generation of aircraft, it gets more difficult to make substantial improvements since so much have already been done to make aircraft as possible. Next generation civil aircraft needs to take every possibility to increase efficiency. One potential area of improvement is to reduce drag due to the requirement of positive stability. However, with the present state of the art it is difficult to get a system that can artificially stabilize an aircraft, certified. If this can be overcome, there are potential gains in drag, since all horizontal surfaces can be used for lift. Another advantage is that a wider range for center gravity can be allowed. In flight control the input signal to the aircraft are usually taken to be position of control surfaces. This is then translated to requirements on the actuation system, where the natural compliance of these systems is regarded, as something unwanted, when in fact it can also be used to tailor characteristics also at the aircraft level. This is relevant to both civil and military aircraft. The approach used here is to look at control surface actuators and different means to utilize also force control, possibly together with position control, and to introduce compliance in proper positions of the system. The pressure feedback is evaluated in a simulation environment using HOPSAN simulation package. Furthermore, an experiment is performed with the pilot in the loop to evaluate the different values of feedback gain. Statistical analysis of the results shows a significant influence of feedback level in the ability of the pilot to control the aircraft.

© 31st Congress of the International Council of the Aeronautical Sciences, ICAS 2018. All rights reserved.This paper presents a data-driven failure identification of flight control surfaces using neural networks. Experiments were performed in a motion-based flight simulator (SIVOR) that has been developed at Aeronautics Institute of Technology (ITA). We use a two-layer feed-forward network and we analyze the influence of the input parameters and the number of neurons in the hidden layer on the performance of the failure identification task. The evaluation of the neural network's performance is based on overall accuracy, training time, number of iterations, precision and recall. Best results were found for networks with 100 neurons in the hidden layer, presenting 97.2% of overall accuracy.

© 31st Congress of the International Council of the Aeronautical Sciences, ICAS 2018. All rights reserved.A great amount of aeronautical accidents and incidents in the last decades are associated with human causes, which can be related not only to the human itself, but with the human machine interface associated to a piloting task. This work presents a preliminary experiment that aims at analysing how a set of different tasks increases the workload of the pilot and how pilot's performance is affected by the increasing workload under different flight conditions (normal and abnormal). The experimental procedure considers 3 pilots executing a take-off and stabilization mission, where a group of tasks, based on the MATB-II approach, are systematically presented to the pilot. Variables such as altitude, heading, rate of climb and yaw rate, are measured. The results show that the variables measured near the pilot input command are more affected by the different levels of workload.

© 2018 Paulo Diego Barbosa da Silva et al.Operational simulators have a fundamental role in space programs. During a satellite operation, these simulators are essential for validating critical manoeuvres, testing new on-board software versions, and supporting the diagnosis of anomalies. With the purpose of reusing the operational simulators, the Brazilian National Institute for Space Research has proposed a new standard for the specification of the components that must be integrated in their in-house developed simulators. The new standard describes the behaviour of satellite subsystems using cause-effect tables that relate telecommands, electrical switches, equipment working states, energy consumption, telemetries, and operating modes of the subsystem. Using this new standard as input, this work proposes an approach that merges model-based testing and model checking to verify the correct implementation of new components in the satellite simulator. The verification approach consists of extracting state machines from the cause-effect tables and used it to automatically derive a test case suite. In order to validate the proposal, we applied it to three different satellite subsystems and assessed the results obtained from the test campaigns. In all the three cases, the proposed approach identified errors in the simulator components that were not initially detected by the traditional testing approach used at the Brazilian National Institute for Space Research.

© 2018 by University of Lavras, University of Campinas, National Institute of Space Research and Aeronautics Technological Institute. Published by the American Institute of Aeronautics and Astronautics, Inc.Problems in requirements documents are among the root cause of a number of accidents in space missions. A common approach toward the minimization of these problems is to transform the requirements into models that represent the system's behavior. However, this solution requires dealing with issues such as choosing the best modeling formalism, defining to what extent the transformation process should be automated, and assuring the quality of the requirements documents to be used as input. In space missions, requirements are frequently tailored from standard documents, such as the Packet Utilization Standard, which are composed of mandatory and optional requirements. This paper presents a semi-automatic method to transform standard requirements documents into extended finite state machines. Toevaluate it, we apply the methodtoa setofrequirements from the Packet Utilization Standard. We evaluate the method using some Packet Utilization Standard services. In light of the results, the paper discusses advantages and potential problems of each approach.

Copyright © 2017 John Wiley & Sons, Ltd.This paper discusses the applicability of agile methods to aircraft embedded software development. It presents the main results of an experiment that combines agile practices from Scrum with model-based development and distributed development. The experiment consists of the development of an aircraft cockpit display system divided in five distributed teams. Three features are analysed and quantified, using the output artefacts of each team: the artefacts' quality, the adherence to agile methods, and the adherence to standard DO-178C. The main conclusion of the experiment is that there is a high correlation between the adherence to agile methods and the artefacts' quality, motivating the use of agile methods in aircraft industry. Also, the experiment evinced that agile methods does not specifically address the integration of distributed teams and the hardware/software integration. This lacuna affects the artefacts' quality. The results of the experiment emphasize the importance of concentrating future work in the proposal of specific agile practices for these activities. Copyright © 2017 John Wiley & Sons, Ltd.

© 2017, Springer-Verlag London.Since the introduction of robots in the automotive industry for pick and place tasks, new technologies have been developed in order to adapt robots to different manufacturing processes. Among them, the use of robots as machine tools is a technological trend that demands further investigation. Industrial robots with 6 DOF (degrees of freedom) in a serial kinematic chain have larger workspace and more flexibility, when compared with CNC machines. However, robots’ stiffness is lower than that of CNC machines. Consequently, vibration problems are expected, which can have a direct impact on the quality of the machined workpieces. This work proposes a method to evaluate and customize the use of a COTS (commercial off-the-shelf) robot equipped with a spindle for machining processes. It aims at improving the machining processes based on the measurement of the workpiece waviness and explores the fact that the accuracy and rigidity of industrial robots with serial kinematic chains behave in an anisotropic way, according to the robot pose and the cutting force direction. The method is composed of a set of five experiments and is applied to the evaluation of a robot machining aluminium workpieces. The results allow the identification of the relevant factors that affect the surface quality of the workpiece and recommend the best robot configuration for meeting the waviness requirements of the workpiece. Even though the application case describes the machining of aluminium workpiece, the proposed method is generic enough to be applied to different workpiece geometries and materials.

© 2017 IEEE.Industry 4.0 brings a new productive period, in which companies that do not have its machinery updated and compatible with the precepts of the advanced manufacture will have difficulties to survive in this new competitive environment. This work proposes retrofit techniques alternatives to allow old automation and mechatronic components such as robotic arms and CNC machines to be reused in the new industrial revolution with low implementation cost, adapting them to advanced manufacturing. For the development of the techniques, the machines existent in an academic plant were used. A virtual commissioning was performed for previous validation of the plant operational layout. Then embedded computational platforms, off-the-shelf microcontrollers and programming techniques were used to modify the machinery communication interfaces, allowing the development of intelligence and remote communication. The alternatives were efficient and cost-effective.

© 2017 IEEE.New advanced traffic management solutions with fully or semi-autonomous vehicles that communicate over a wireless interface to coordinate their driving decisions create new challenges in distributed computing. In this paper we address the problem of dynamic group membership in three stages. First, we propose three criteria to specify correctness and performance of the group views created by such algorithms in terms of soundness, completeness and freshness. Second, we develop a group membership protocol tailored for vehicular coordination. Finally, we show through simulation and model-based verification that the protocol does indeed meet the criteria and provide at least 95% perfect group membership views under as adverse conditions as 70% packet loss or very high churn rate.

© 2016 IEEE.Satellite simulators are developed in the context of a space mission lifecycle to represent the real behavior of a satellite during operation and may be used for different purposes. To attend a particular purpose new functions are added or modified according to the mission phase needs, requiring models re-adaptation in a system evolving concept. The process of verification of satellite simulator software requires high-efficiency in accomplishing realistic functional and behavioral requirements. Based on the complex set of requirements the satellite behavior is represented in the simulator through software models specified by tables of cause-effect rules. Considering that the Satellite Simulator is an evolving systems and it needs to assure that the logic implemented in the simulator conforms to the requirements, the manual verification process becomes impracticable, therefore demanding a compatible verification approach. The approach suggested here unifies two techniques Conformance and Fault Inject (CoFI), constructed on Model-Based Testing and Model Checking added to a method so that it can translate the tables of cause-effect rules into finite state machines. This paper presents the verification approach illustrating it with the Data Collection Subsystem (DCS) model of the CBERS satellite simulator being developed at National Institute for Space Research (INPE).

© Emerald Group Publishing Limited.Purpose-This paper aims to propose an evaluation method to compare two different Human-Robot Interaction (HRI) solutions that can be used for on-line programming in an industrial context: a force guidance system and the traditional teach pendant operation. Design/methodology/approach-The method defines three evaluation criteria (agility, accuracy and learning) and describes an experimental approach based on the analysis of variance to verify the performance of guidance systems according to these criteria. This method is used in this paper to compare the traditional teach pendant interface with an implementation of a force guidance system based on the use of an external force/torque sensor. Findings-The application of the proposed method to an off-the-shelf industrial robot shows that the force guidance system has a better performance according to the agility criterion. Both solutions have a similar performance for the accuracy criterion, with a limit of about 2 mm in the achieved position accuracy. Regarding the learning criterion, the authors cannot affirm that any of the methods has an improved agility when the operator repeats the tasks. Practical implications-This work supports the selection of guidance systems to be used in on-line programming of industrial applications. It shows that the force guidance system is an option potentially faster than the teach pendant when the required positioning accuracy is greater than 2 mm. Originality/value-The new method proposed in this paper can be applied to a large range of robots, not being limited to commercial available collaborative robots. Furthermore, the method is appropriate to accomplish further investigations in HRI not only to compare programming methods but also to evaluate guidance systems approaches or robot control systems.

© 2014 Elsevier Inc.Poorly written requirements are a common source of software defects and, in application areas like space systems, the cost of malfunctioning software can be very high. This work proposes a benchmarking procedure for assessing the quality of software requirements that adopt the Packet Utilization Standard (PUS) defined by the European Cooperation for Space Standardization (ECSS) standards. The benchmark uses three checklists that aim at guaranteeing that the specifications comply with the PUS standard, consider faulty behaviour, and do not include errors typically found in this type of documents. The benchmark is defined for two services of the PUS standard: the telecommand verification and on board operating scheduling. A benchmark validation approach is also proposed in the paper. It uses the concept of fault injection to insert known errors in software requirements specification documents. The benchmark validation is performed through its application to three projects from different countries. Results show that our proposal provides a simple and effective way for identifying weaknesses and compare the degree of maturity of requirements documents.

© 2014, Brazilian Society for Automatics--SBA.This paper proposes a framework that combines three different environments with decreasing level of abstraction: model-in-the-loop, software-in-the-loop and hardware-in-the-loop. The purpose of the framework is to support the early detection of errors in the development of satellite control systems. Associated with the framework, the paper presents the MuSat simulator, a testbed for the development of satellite attitude controllers. MuSat is composed of a sphere that rotates with three degrees of freedom, supported by an air bearing system. The on-board computer of MuSat follows the integrated modular architecture, proposed for avionics systems. In order to illustrate both the framework and the testbed, we present the development of a non-linear control scheme. Results indicate that the designed control system fulfils the specified requirements. The example highlights the contribution of each environment of the framework for control system verification.

© 2013 The Brazilian Society of Mechanical Sciences and Engineering.This paper proposes a method to design multifunctional robot end-effectors that consider the weight as one of the main design constraint. The motivation for this work comes from aircraft industry. This sector, traditionally characterized by manual processes, has an increasing interest in the use of commercial off-the-shelf robots for the automation of their manufacturing processes. The design method proposed in this paper, named design to weight (DTW), is based on design for excellence (DFX) methodology. In order to illustrate and validate the DTW approach, it is applied to an end-effector that shall embed a set functions related to the riveting operation of aircraft fuselage barrels. The designed end-effector is compared with similar products described in the literature or available in the market. The results show that DTW is an efficient approach that not only provides low-weight solutions but also maintains a compromise with other requirements. On the other hand, the method is sensitive to the choice of relevance and quality factors that depends on the knowledge of the design team about the product under design.

The role of embedded software in the last space accidents highlights the importance of verification and validation techniques for the development of space embedded software. In this context, this work analyses the contribution of two verification techniques applied to the onboard data handling software of space products. The first technique is model checking. The system is modeled by a set of timed automata and the verification of safety and liveness properties is performed using UPPAAL model checker. The verified model is then used to generate the embedded software. The second technique analyzed in this work is model based approach for the generation of test cases. The Conformance and Fault Injection (CoFI) testing methodology is used to guide the development of a set of Finite State Machine (FSM) models from the software specification. The test suite is automatically generated from the FSM models. The contributions of the two methodologies are analyzed based on the results provided by an experiment. Two software products are used as case study, each one implementing two services of the Packet Utilization Standard (PUS). These services represent the functionalities offered by a satellite onboard data handling computer. One of the products is developed with the aid of model checking, while the other is developed according to the practices currently used at the Instituto Nacional de Pesquisas Espaciais (INPE). Both software products are tested by the CoFI methodology. The experiment highlights the advantages and vulnerable points of model checking. It also demonstrates that the main contribution of CoFI testing methodology is to highlight problems related to situations that have not been considered in the software specification, such as the occurrence of inopportune events. This analysis helps to understand how different techniques can be integrated in the design of critical embedded software. © 2012 Springer Science+Business Media, LLC.

This paper presents a probabilistic analysis of disagreement for a family of simple synchronous consensus algorithms aimed at solving the 1-of-n selection problem in presence of unrestricted communication failures. In this problem, a set of n nodes are to select one common value among n proposed values. There are two possible outcomes of each node's selection process: decide to select a value or abort. We have disagreement if some nodes select the same value while other nodes decide to abort. Previous research has shown that it is impossible to guarantee agreement among the nodes subjected to an unbounded number of message losses. Our aim is to find decision algorithms for which the probability of disagreement is as low as possible. In this paper, we investigate two different decision criteria, one optimistic and one pessimistic. We assume two communication failure models, symmetric and asymmetric. For symmetric communication failures, we present the closed-form expressions for the probability of disagreement. For asymmetric failures, we analyse the algorithm using a probabilistic model checking tool. Our results show that the choice of decision criterion significantly influences the probability of disagreement for the 1-of-n selection algorithm. The optimistic decision criterion shows a lower probability of disagreement compare to the pessimistic one when the probability of message loss is less than 30% to 70%. On the other hand, the optimistic decision criterion has in general a higher maximum probability of disagreement compared to the pessimistic criterion. © 2014 IEEE.

This work proposes the use of model checking for verifying the specification of critical embedded software of university satellites. The motivation for this work comes from two features commonly found in university satellite projects. The first one is the limited budget of the project. It usually results in a design of the on-board computer that relies on the software for detecting and treating hardware faults, instead of using radiation hard components. The second one is the lack of experience of the development team, which may compromise the quality of specification documents, jeopardizing the mission. In order to identify the advantages and limitations of model checking for university satellites, we used the software of the communication module of ITASAT satellite as a case study. The verification is performed with UPPAAL model checker. In order to avoid the state space explosion problem, similar non-deterministic events are simplified. The results show that the model checking process significantly contributed to identify and remove completeness problems in the software requirement specification documents. © Brazilian Society for Automatics-SBA 2013.

This paper addresses the problem of leader election in virtual traffic lights. A virtual traffic light (VTL) is a self-organizing traffic control system that allows road vehicles equipped with vehicle-to-vehicle communication facilities to implement the function of a traffic light without the support of a roadside installation. Previous research has shown that it is impossible to construct a leader election protocol that guarantees agreement among the participating vehicles in the presence of massive communication failures. The paper addresses the problem of calculating the probability of disagreement in situations where a large number of protocol messages are lost due to communication interference, so-called communication grey-outs. To this end, we present a probabilistic analysis of a family of simple round-based consensus algorithms that solve the 1-of-n selection problem. We propose to use these algorithms for the core logic of a VTL leader election protocol (LEP). Our analysis shows that the probability of disagreement depends on: i) the number of vehicles involved in the leader election, ii) the number of rounds of message exchange, iii) the probability of message loss, and iv) the decision criterion used by the LEP. We propose an optimistic and a pessimistic decision criteria for the proposed 1-of-n selection algorithms. The analysis encompass two probabilistic failure models, one for symmetric communication failures and one for asymmetric communication failures. © 2013 IEEE.

Functional safety is becoming increasingly important in the automotive industry to deal with the growing reliance on the electrical and/or electronic (E/E) systems and the associated complexities. The introduction of ISO 26262, a new standard for functional safety in road vehicles, has made it even more important to adopt a systematic approach of evaluating functional safety. However, standard assessment methods of benchmarking functional safety of automotive systems are not available as of today. This is where the BeSafe (Benchmarking of Functional Safety) project comes into the picture. BeSafe project aims to lay the foundation for benchmarking functional safety of automotive E/E systems. In this paper, we present a brief overview of the project along with the benchmark targets that we have identified as relevant for the automotive industry, assuming three abstraction layers (model, software, hardware). We then define and discuss a set of benchmark measures. Next, we propose a benchmark framework encompassing fault/error models, methods and the required tool support. This paper primarily focuses on functional safety benchmarking from the Safety Element out of Context (SEooC) viewpoint. Finally, we present some preliminary results and highlight potential future works. © 2013 Springer-Verlag.

In this paper we are concerned with the fundamental problem of reaching agreement among a set of distributed processes in presence of an unbounded number of communication failures. We present a probabilistic analysis of a family of synchronous consensus algorithms that aim to solve the 1-ofn selection problem. In this problem, a set of n nodes are to select one common value among a set of n proposed values. There are two possible outcomes of each node's selection process: it can decide either to select a value, or to abort. Agreement implies that all nodes select the same value, or all nodes decide to abort. We know from previous research that it is impossible to guarantee agreement if there is no upper bound on the number of communication failures that can occur. Our aim is to study how the probability of disagreement varies for different decision criteria. The decision criterion consists of the logical expressions that determine whether a process will select a value or decide to abort based on its view of the system state. In this paper we propose and analyse a moderately pessimistic decision criterion. We compared this decision criterion with an optimistic and a pessimistic decision criterion, which we have investigated in our previous work. Our results show that the moderately pessimistic decision criterion for most configurations has a lower maximum probability of disagreement compared with the two other decision criteria. Furthermore, it provides a compromise between the optimistic and the pessimistic approaches since it reduces the probability of disagreement without increasing excessively the probability of agreeing to abort. © 2013 IEEE.

This paper proposes a software architecture based on LabVIEW for controlling discrete event systems. The proposed architecture is an adaptation of the producer-consumer design pattern. This work uses the control software of a multifunctional robotic end-effector as a test-bed for analyzing the applicability of the software architecture and its limitations and advantages. This case study demonstrates the effectiveness of the architecture for dealing with the integration of multiple functionalities in the control system. For this case study, the validation of the architecture is performed using two verification techniques: (1) a formal verification using timed automata and the UPPAAL model checker and (2) the CoFI (Conformance and Fault Injection) method for defining the set of test cases to check the software product. Both verification techniques identified errors that were introduced into the control system during the programming phase. © 2012 Elsevier Ltd. All rights reserved.

This work presents the use of a temporal filter, named Dynamic Retina, instead of spatial-neighborhood operators to process the image. Originally, this kind of filter has been proposed for use in mobile robot platforms for analyzing sequences of images [1]. The use of this filter could be adapted to enhance the defects on the aluminum surfaces by taking advantage of the intrinsic vibration of the industrial robot arm that drives the vision system to acquire images. This vibration generates small differences on each image that are sufficient to detect scratches. Mostly, the finishing process of aluminum surfaces in the aeronautic industries is currently carried out manually by trained operators; nevertheless certain steps can be automated using this technology. © 2012 CZECH TECH UNIV.

The alignment of aircraft fuselages in the aerospace sector is currently done either manually or by complex, expensive automated systems. The manual process introduces a significant production delay and the automated systems are purpose-built and have limited flexibility, apart from its financial drawback. This work proposes a low-cost, high-flexibility system and, as part of it, evaluates the performance of a Rotary-Laser Automatic Theodolite (R-LAT) as a feedback source for the adaptive robot control of an anthropomorphic manipulator. In the proposed solution the robot carries a fuselage barrel and aligns it with respect to a second barrel. A high accuracy, frequency-modulated laser equipment is used to generate the reference system for the procedure. The measurements of the R-LAT are then verified with the frequency-modulated laser equipment in order to determine the linear and angular alignment tolerances achieved by the robot/R-LAT closed loop in a predefined work envelope. A throughout, step-by-step analysis of the measuring procedure is carried out to allow the recognition of error sources and thus the determination of an optimized method. These results identify the operation boundaries of the R-LAT within the process and yield its best configuration for the intended purpose. Using the EN ISO 9283 robot evaluation standard, the closed loop system was found to attain the nominal position with an average accuracy of 0.38 mm and 0.01°, contrasting with an average accuracy of 4.53 mm and 0.21° when the robot was operating in an open loop configuration. © 2012 Elsevier Ltd. All rights reserved.

This work presents the EFIP project (Efetuador de Furação e Inserção de Prendedores, Portuguese for "Effector of Drilling and Fasteners Inserter"), a robot end-effector design for implementing an automatic riveting process used in manufacturing aircraft fuselage components. The EFIP is mounted in an industrial anthropomorphic robot, with a seven-meter (7m) linear unit able to range over the entire side of an aircraft fuselage section. The end-effector has several modules that allows for a one-step-drilling process, including a special drill with chamfer; automatic rivet delivery; automatic rivet insertion; sealant applicator for each rivet; perpendicular drilling correction mechanism; clamp force control loop, and means for visual inspection. Each module can work independently or in integration with others, controlled by a graphical interface in a remote station. Other support devices complete the system, managing chip aspiration, tool cleaning and lubrication, liquid cooling of the spindle, and sub-systems to ensure safety. Integration of the end-effector and robot controllers are described in detail. Full functionality of the EFIP has been demonstrated in experiments testing its operational performance. The results have shown high stability in the drilling process, with the capability index (Cp) for the holes created nearing sigma 4. Copyright © 2012 SAE International.

This paper proposes a mixed validation approach based on coloured Petri nets and 3D graphic simulation for the design of supervisory systems in manufacturing cells with multiple robots. The coloured Petri net is used to model the cell behaviour at a high level of abstraction. It models the activities of each cell component and its coordination by a supervisory system. The graphical simulation is used to analyse and validate the cell behaviour in a 3D environment, allowing the detection of collisions and the calculation of process times. The motivation for this work comes from the aeronautic industry. The automation of a fuselage assembly process requires the integration of robots with other cell components such as metrological or vision systems. In this cell, the robot trajectories are defined by the supervisory system and results from the coordination of the cell components. The paper presents the application of the approach for an aircraft assembly cell under integration in Brazil. This case study shows the feasibility of the approach and supports the discussion of its main advantages and limits. © 2011 Elsevier Ltd.

This paper presents a benchmark aimed to provide an unbiased basis for characterizing OBDH software of different satellites with regards to dependability attributes. Instead of considering only the delivered product, the proposed benchmark covers a set of criteria for accepting or not OBDH artifacts created along the lifecycle development. The benchmark is based on the ECSS European standards that guide both the development lifecycle and the services to be provided by OBDH software. © 2010 by the American Institute of Aeronautics and Astronautics, Inc.

The aircraft fuselage assembly process is too labor intensive and highly manual within the Brazilian aircraft industry. Foreign companies of this industrial segment started the adoption of automated solutions in the last two decades. Their automated solutions are very product dependent as well as very expensive. This kind of solution is inadequate for the Brazilian aircraft industry. This paper shows the preliminary results of a flexible, low cost automated system specially designed to fit the Brazilian requirements. This is based upon the usage of industrial robots for general purposes. In order to check the feasibility of such a solution, the process requirements are expressed in terms of accuracy, repeatability and resolution of the robots. These characteristics are measured by two independent, state-of-art measurement systems, namely, Indoor GPS and photogrammetry device. The initial results allow one to conclude that the robot can be used for the purpose described herein as long as it is assisted by correction process based upon the very measurement systems used to acquire its operational characteristics.

Poorly written requirements are a common source of software defects. In application areas like space systems, the cost of malfunctioning software can be very high. This way, assessing the quality of software requirements before coding is of utmost importance. This work proposes a systematic procedure for assessing software requirements for space systems that adopt the European Cooperation for Space Standardization (ECSS) standards. The main goal is to provide a low-cost, easy-to-use benchmarking procedure that can be applied during the software requirements review to guarantee that the requirements specifications comply with the ECSS standards. The benchmark includes two checklists that are composed by a set of questions to be applied to the requirements specification. It was applied to the software requirements specification for one of the services described in the ECSS Packet Utilization Standard (PUS). Results show that the proposed benchmark allows finding more with a low effort. © 2010 Springer-Verlag Berlin Heidelberg.

Aerospace systems software is developed taking into account some precautions to avoid dangerous situations. Usually the controllers of these systems are critical embedded real-time controllers and the respective software programs are developed in the C programming language. This paper is developed on the context of developing embedded critical real-time systems software, for aerospace systems applications, based on formalisms commonly used in the industrial automation field. More precisely, the approach proposed, in this paper, consists in translating a SFC specification to C programming language code considering also the behaviour of the controller device, where the specification will be implemented. An illustrative case study is presented in the end of the paper in order to facilitate the understanding of the proposed approach.

This paper presents a field study on real errors found in space software requirements documents. The goal is to understand and characterize the most frequent types of requirement problems in this critical application domain. To classify the software requirement errors analyzed we initially used a well-known existing taxonomy that was later extended in order to allow a more thorough analysis. The results of the study show a high rate of requirement errors (9.5 errors per each 100 requirements), which is surprising if we consider that the focus of the work is critical embedded software. Besides the characterization of the most frequent types of errors, the paper also proposes a set of operators that define how to inject realistic errors in requirement documents. This may be used in several scenarios, including: evaluating and training reviewers, estimating the number of requirement errors in real specifications, defining checklists for quick requirement verification, and defining benchmarks for requirements specifications. © 2010 IEEE.

This paper presents a comparative analysis of two verification techniques: (1) formal verification of the system specification and (2) execution of FSM-derived test cases on the delivered product. It uses as a testbench a didactic example of a coffee machine and a work team composed of post-graduation students. The purpose is to analyze the advantages and drawbacks of each technique, define the kind of errors detect by each one and highlight the contributions to the development process.

This paper presents the development of a remote monitoring and control system for a CIM plant. It discusses the main steps for the system specification. The purpose of the remote access system is to provide the user with facilities necessary to understand the system behavior, propose supervisory control strategies and test them. Copyright; © 2006 International Federation for Information Processing.

One of the most important activities of control system design is its verification. Verification ensures that the controlled system will behave as expected under any circumstances it may operate. In this context, the purpose of this paper is to introduce a new method for the verification of aircraft control systems. The focus of this method is on aircraft systems that are characterized as hybrid, i.e., that merge continuous and discrete dynamics. The method proposed is divided into two main parts: the system modeling and the verification of behavioral properties. In the first part, Petri net, differential equation systems, and object oriented concepts are used concurrently in order to model complex hybrid systems. In the second part, the distributed nature of the model is explored in order to decompose a complex verification problem into series of simple local problems. Linear logic is used as a basis of a theorem-proving approach for the verification from the discrete-event point of view. The verification method has been applied to a number of case studies. Among them is the landing system of a military aircraft, which is described in this paper. © 2006 IEEE.

This paper approaches the problem of analysing control strategies for Fire Safety Systems. The components of Fire Safety Systems present behaviours of different nature and therefore the use of a hybrid modelling formalism is necessary. Petri net is used to model the discrete dynamics. Algebraic and differential equations are used for the continuous one. In order to realistically evaluate the performance of Fire Safety Systems, failures and other uncertainties, such as people's behaviour, should be included in the model. Due to the model complexity, results are obtained by Monte Carlo simulation. © 2005 Elsevier Ltd. All rights reserved.

Safeness is one of the major concerns in the design of aircraft systems. Most of the aircraft components are provided with redundancy. The degree of redundancy of each component depends on a number of factors such as the kind and probability of fault, per hour of flight. Usually, in order to estimate how safe an aircraft system is, the probabilities of fault in each one of the system components are combined in a static approach using methods such as fault-tree analysis. These methods derive the total probability of fault in the system, which must be within predefined limits. The maximum allowed probability of fault depends on how the system deteriorates the level of flight quality and how it affects the aircraft operation and functionality. © 2006 Elsevier Ltd All rights reserved.

This paper introduces the use of a hybrid modelling and simulation approach for the analysis of safety issues in aircraft systems. Traditionally, safety analysis in aircraft industry is performed without considering the system dynamics. In this paper the dynamics of the aircraft components are modelled using Petri nets and differential equations. Faults are incorporated in the model using probabilistic distributions functions. The reliability of the system under fault is then estimated by simulation. The approach is applied to the landing system of a military aircraft in order to compare two different control strategies for detecting and processing faults. Copyright © 2006 IFAC.

The increasing complexity of productive systems associated with the geographical dispersion of industries motivates new demands and the adoption of new design tools. In this context the purpose of this work is to introduce a new platform for distributed modeling and analyses of productive systems. The platform is based on Petri net as a modeling formalism and on the label-ring protocol for managing the distributed simulation. The focus of this paper is on the platform communication algorithm. An example is presented in order to illustrate the proposal. © 2005 IEEE.

This paper introduces a new approach for the modelling of hybrid productive systems. This approach is based on Petri net to represent the discrete part, differential equations to describe the continuous part and object-oriented paradigm to deal with the complexity problem in real systems. During the modelling process, the Unified Modelling Language (UML) is used in order to support the description of different aspects and identify different hybrid characteristics of the system. The proposed approach is illustrated using as an example the design of supervisory systems for air-conditioning systems. © 2005 Elsevier Ltd. All rights reserved.

This paper approaches the problem of analysing control strategies in the case of fire in a building. The elements of this problem present behaviours of different nature and therefore the use of a hybrid modelling formalism is necessary. Petri nets are used to model the discrete aspects and differential equation systems are used for the continuous ones. in order to realistically evaluate the safeness provided by the fire management system, faults, failures and other uncertainties, such as people behaviour, should be included in the model. Due to the model complexity, results are obtained using Monte Carlo simulation. Copyright © 2005 IFAC.

This paper introduces a new approach for the modelling and verification of behaviour properties in complex industrial plants that are hybrid in nature. It is based on Petri nets to represent the discrete view and differential equations to describe the continuous part. The object-oriented concepts are used to provide modularity and handle system complexity. With respect to the system analysis, the object-oriented structure allows a global analysis problem with a number of objects to be divided, into a set of local problems involving one or a few objects only. The proposed approach is applied to a cane sugar factory. © 2004 Elsevier Ltd. All rights reserved.

In this work, a novel hybrid modeling approach for HVAC control system design in Intelligent Buildings is introduced. In order to achieve building system integration, a characterization of HVAC system as hybrid is required. The proposed approach is a top-down modeling method based on Petri net. Starting from abstract models designed using the Production Flow Schema, Petri net based models are built by successive refinements. The discrete part of the system is modeled using Place-Transition Petri nets and the continuous part is modeled using differential equation systems. The interface between these two parts is provided by Differential Predicate Transition Petri nets.

© 2003 IEEE.The design of supervisory system for automated environments can be seen as a task involving techniques and methods of two main areas: software and control engineering. In this context, the purpose of this work is to introduce a new approach for open distributed supervisory system design based on the merging of traditional techniques of software engineering (such as object-oriented concepts) with formal models of discrete events dynamic systems- (such as Petri nets). In this first level of abstraction, the reference model of open distributed processing (RM-ODP) is used as a standard architectural framework for the construction of open distributed system. Based on the RM-ODP, the unified modeling language (UML) diagrams are built as a second level of abstraction. Finally, the Petri nets (the third level of abstraction) are used throughout the process in order to guarantee the coherence among the UML models from requirement analysis to implementation, and to provide formal models of the system.

Copyright © 2002 IFAC.This paper presents a novel modelling approach for hybrid industrial plants. It is based on the introduction of object-oriented concepts to the Differential Predicate Transition nets. To handle the system complexity a top-down methodology is considered, where class models are successively refined and decomposed. The UML language is also used to represent different views of the modelled system. A cane sugar factory is used as an example to illustrate the proposed approach.

In this paper, a Petri Net approach is introduced for modelling and simulation of control strategies in Intelligent Building. In this context, it is claimed that integration with other building systems can be achieved in a more systematic way considering a mechatronic approach (i.e. multidisciplinary concepts applied to the development of systems). The case study is the Ambulatory Building of Medical School Hospital of University of Sao Paulo. Particularly, the developed methodology is applied to the elevator system and to the HVAC (Heating, Ventilation and Air Conditioning) system. It is shown that using this approach, the control systems could be integrated, improving performance.

In this work, a new approach for the design of supervisory systems is introduced. It focuses on how supervisory systems can improve global system performance through the use of efficient local controller switching configuration policies. For this purpose, a modeling approach that can represent the integration of different hierarchical levels of the control architecture and different dynamic behavior is developed. UML, Petri nets and differential equation systems are merged in order to provide a framework with flexibility for representing the abstractions that emerge when considering supervisory system design.