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A major trend in modern aerospace and automotive systems is to integrate computing, communication and control into different levels of the vehicle and/or its supervision. A well fitted architecture adopted by this trend is the common bus network architecture. A Networked Control System (NCS) is called when the control loop is closed through a communication network. The presence of this communication network introduces new characteristics (sharing bus, delays, jitter,etc) to be considered at design time of a control system. This work focuses on the effect of sharing bus between the control system and the other devices connected to the bus foreigner to control. These last devices are called interferences. We intented to show, through simulations, the influence of sharing bus on real time control systems performance. To compare effects, we choose the CanBus protocol where the medium access control is event driven; and the TTP protocol where the medium access control is time driven.

This work presents the first part of the analysis, design and simulation of the reconfigurable control architecture for the Multi-Mission Platform (MMP), a generic service module currently under design at INPE. Its control system can be switched among nine main Modes of Operation. The implementation followed the specifications when they were found, otherwise it was designed. The manager block of the control system was implemented as a finite state machine. The tests were based in simulations with the MatriX/SystemBuild software. They focused mainly on the worst cases that the satellite is supposed to endure in its mission.

In this work we discuss some types of simulation architectures and standards, their characteristics and applications to the simulation and control of aerospace vehicles. This includes: the basic definitions, types and characteristics of simulators and simulations (physical, computational, hybrid, etc.; discrete events, discrete time, continuous time, etc; deterministic, stochastic, etc.) their basic compromise (simplicity x fidelity), their man-machine interfaces and interactions (virtual, constructive, live, etc.), their evolution law (time, events, mixed, etc.), their architectures (“stand-alone”, PIL, HIL, MIL, DIS, HLA, etc.), their standards (OMBA, SIMNET, ALSP, DIS, HLA 1.3, HLA 1516, ASIA, AP2633, etc.) and their applications to the simulation and control of aerospace vehicles. This is illustrated by some examples driven from the aerospace industry

This work presents the distributed simulation of the longitudinal mode of an aircraft by using the DoD High Level Architecture (HLA). The HLA is a general-purpose architecture for simulation reuse and interoperability. This architecture was developed under the leadership of the Defense Modeling and Simulation Office (DMSO) to support reuse and interoperability across the large numbers of different types of simulations developed and maintained by the DoD. To do this, the transfer function of the longitudinal mode of a hypothetical aircraft was implemented by means of a SystemBuild/MATRIXx model. The output of this model was connected to a Run-Time Infrastructure (RTI) and monitored on a remote computer. The connection between the model and the RTI was implemented by using a wrapper which was developed in C++. The HLA RTI implementation used in this work was the poRTIco.

Computer systems aboard aerospace vehicles have become more and more distributed in an attempt to solve “real-life” problems such as commonality and longevity of components and subsystems. On the other hand, distributed systems pose a much bigger challenge in system design than traditional, “monolithic” systems, whereby functions are performed by a single component combining hardware and software. “Determinism” (predictability in the occurrence of events), “causality” (temporal ordination of occurrence of events) and “synchronism” (simultaneousness in the occurrence of events) can be pointed out as major challenges in system design. This paper shall survey methods of analyzing determinism in network communications in distributed computer systems aboard aerospace vehicles in different network topologies using a representative model.

This paper aims at discussing the use of dissimilar hardware architecture to mitigate DESIGN ERRORS in a flight control system application, as one of the possible design techniques that, combined with the usage of development processes, will satisfy the safety objectives for airborne systems. To accomplish its purpose, the paper starts by understanding the origins of DESIGN ERRORS in micro-coded devices and the concerns of airworthiness certification authorities (or simply certification authorities from now on). After that, an overview of the aeronautical industry efforts in terms of development processes and certification requirements to mitigate DESIGN ERRORS will be presented. At this point, the dissimilar architecture is proposed as an effective mean to mitigate the problem of DESIGN ERRORS. Finally, a Flight Control System application using dissimilar architecture is proposed as a case study.

A major trend in modern aerospace and automotive systems is to integrate computing, communication and control into different levels of the vehicle and/or its supervision. A well-fitted architecture adopted by this trend is the common bus network architecture. A Networked Control System (NCS) is called when the control loop is closed through a communication network. The presence of this communication network introduces new characteristics that must be considered at the design time of a control system. This work, still in development, focuses on a worst case formula for a communication (TDMA) plus computation (RMS) on a NCS. This formula, in a first instance, agrees with the simulated cases under the hypotheses and conditions when the NCS is composed by 1 actuator - 1 sensor and when is composed by 2 actuators - 2 sensors. In the future, we intend to generalize this formula and extend this study to NCS that uses other communication protocols or others computer schedulers.

On several engineering applications high Reliability is one of the most wanted features. The aspects of Reliability play a key role in design projects of aircraft, spacecraft, automotive, medical, bank systems, and so, avoiding loss of life, property, or costly recalls. The highly reliable systems are designed to work continuously, even upon external threats and internal Failures. Very convenient is the fact that the term 'Failure' may have its meaning tailored to the context of interesting, as its general definition refers to it as "any deviation from the specified behavior of a system". The above-mentioned 'deviation' may refer to: performance degradation, operational misbehavior, deviation of environmental qualification levels, Safety hazards, etc. Nevertheless, Reliability is not the only requirement for a modern system. Other features as Availability, Integrity, Security and Safety are always part of the same technical specification, in a same level of importance.

This work presents the analysis, design and simulation of the reconfigurable control architecture for the contingency mode of the MultiMission Platform (MMP). The MMP is a generic service module currently under design at INPE. Its control system can be switched among nine main Modes of Operation and other Sub-Modes, according to ground command or information coming from the control system, mainly alarms. The implementation followed the specifications when they were found, otherwise it was designed. They cover operations from detumbling after launcher separation and solar acquisition, to achieving payload nominal attitude and orbital corrections maneuvers. The manager block of the control system was implemented as a finite state machine. The tests are based in simulations with the MatriX/SystemBuild software. They focused mainly on the worst cases that the satellite is supposed to endure in its mission, be it during modes or transitions between modes and submodes.

In this work we discuss some types of simulators and simulations, their characteristics and applications to the simulation and control of aerospace vehicles. This includes: the basic definitions, types and characteristics of simulators and simulations (physical, computational, hybrid, etc.; discrete events, discrete time, continuous time, etc; deterministic, stochastic, etc.) their basic compromise (simplicity × fidelity), their man-machine interfaces and interactions (virtual, constructive, live, etc.), their evolution law (time, events, mixed, etc.), their architectures (“standalone”, PIL, HIL, MIL, DIS, HLA, etc.), their environments (discrete, continuous, hybrid, etc.) and their applications to the simulation and control of aerospace vehicles. This is illustrated by some examples driven from the aerospace industry

Cyber-physical systems are joint instances of growing complexity and high integration of elements in the information and physical domains reaching high levels of difficulty to engineer an operate them. This happens with satellites, aircraft, automobiles, smart grids and others. Current technologies as computation, communication and control integrate those domains to communicate, synchronize and operate together. However, the integration of different domains brings new challenges and adds new issues, mainly in real time distributed control systems, beginning with time synchronization. In this paper, we present a discussion on time synchronization and their effects in distributed cyber-physical control systems. To do that, we review the literature, discuss some time synchronization techniques used in cyber-physical systems, and illustrate them via model and simulation of a system representative of the aerospace area.

Switching controls are those that can switch between control or plant modes to perform their functions. They have the advantage of being simpler to design than an equivalent control system with a single mode. However, the transients between those modes can introduce steps or overshootings in the state variables, and this can degrade the performance or even damage the control or the plant. So, the smoothing of such transients is vital for their reliability and mantainability. This is can be of extreme importance in the aerospace and automotive fields, plenty of switchings between manual and autopilot modes via relays, or among gears via clutches, for example. In this work, we present a first strategy for smoothing transients in switching controls of aerospace and automotive systems.

In this work we discuss current trends driving the aerospace and automotive systems architectures. This includes trends as: 1) pos-globalization and regionalization; 2) the formation of knowledge oligopolies; 3) commonality, standardization and even synergy (of components, tools, development process, certification agents, standards); 4) reuse and scalability; 5) synergy of knowledge and tools convergence; 6) time, cost and quality pressures and innovation speed; 7) environmental and safety issues; and 8) abundance of new technologies versus scarcity of skilled manpower to apply them.

Many control systems switch between control modes according to necessity. That is often simpler than designing a full control to all situations. However, this creates new problems, as determining the composed system stability and the transient during switching. The latter, while temporary, may introduce overshooting that degrade performance and damage the plant. This is particularly true for the MultiMission Platform (MMP), a generic service module currently under design at INPE. Its control system can be switched among nine main Modes of Operation and other submodes, according to ground command or information coming from the control system, mainly alarms. It can acquire one and three axis stabilization in generic attitudes, with actuators including magnetotorquers, thrusters and reaction wheels.

Systems are becoming increasingly more complex. To follow this increasingly complexity, systems engineering must evolve rapidly with the introduction of new methodologies, processes, tools, etc. Due to this rapid evolution, little attention is dedicated to the study of the history of its evolution. Currently there is the initiative of installation of a chapter of INCOSE (International Council on Systems Engineering) in Brazil and from this initiative emerged the interest of recovering the history of systems engineering in the country. There are indications that the introduction of systems engineering into Brazil occurred in the late 1960's, directly from NASA and that its first applications in Brazil were in Space Systems Engineering. This paper recovers the origins of systems engineering, of its introduction into Brazil, and of its use in space systems engineering.

In this work, the problem of fault detection, isolation, and reconfiguration (FDIR) for Networked-Control Systems (NCS) of aerospace vehicles is discussed. The concept of fault-tolerance is introduced from a generic structure, and a review on quantitative and qualitative methods (state estimation, parameter estimation, parity space, statistic testing, neural networks, etc.) for FDIR is then performed. Afterwards, the use of networks as loop-closing elements is introduced, followed by a discussion on advantages (flexibility, energy demand, etc.) and challenges (networks effects on performance, closed-loop fault-effects on safety, etc.) represented thereby. Finally, examples of applications on aerospace vehicles illustrate the importance of the discussion herein exposed.

Internet of Things (IoT) for real-time applications are demanding more and more high performance, precision, accuracy, modularity, integration, dependability and other attributes in a complex and/or highly integrated environment. Such systems need to provide coordination among the integrated components (e.g. sensors, computer, controller and networks) for enabling the application to take real-time measurements and to translate into controllable, observable and smart actions with strict timing requirements. Therefore, coordination and synchronization are required to ensure the controllable, observable and smart actions of real-time IoT systems. This paper shows the design issues about the coordination and synchronization in the internet of things applied to real-time applications. We also show the current coordination and synchronization techniques and their design issues when applied to IoT systems.

Current systems such as satellites, aircrafts, automobiles, turbines, power controls and traffic controls are becoming increasingly complex and/or highly integrated as prescribed by the SAE-ARP-4754a Standard. Such systems operate in a real time distributed environment which frequently requires a common knowledge of time among different devices, levels and granularities. So, temporal correctness is mostly needed, besides logical correctness. It can be achieved by hardware clocks and devices, software clocks and algorithms, or both, to avoid or tolerate, within appropriate margins, the time faults or failures that may occur in aerospace and automotive systems. This paper presents an overview of clock synchronization algorithms and their uses in aerospace and automotive systems. It is based on a review of the literature, discussion and comparison of some clock synchronization algorithms with different policies.

The aerospace and automotive electronic systems are getting more complex and/or highly integrated, as defined by ARP 4754A, making extensive use of microelectronics and digital memories which, in turn, operates in higher frequencies and lower voltages. In addition, the aircraft are flying in higher altitudes, and polar routes are getting more frequent. These factors raise the probability of occurrence of hazardous effects like the Single Event Upsets in their embedded electronic systems. These must be designed in a way to tolerate and assure the immunity to the Single Event Upsets, based upon criteria such as reliability, availability and criticality. This paper proposes an overview of an assurance process of immunity of embedded electronic systems to Single Event Upsets caused by ionizing particles by means of a review of literature and an analysis of standards as ECSS-E-ST-10-1, NASA Single Event Effects Criticality Analysis and IEC TS 62396-1.

Current systems such as: satellites, aircrafts, automobiles, turbines, power controls and traffic controls are becoming increasingly complex and/or highly integrated as prescribed by the SAE-ARP-4754 Standard. Such systems and their control systems use many modes of operation and many forms of redundancy to achieve high levels of performance and high levels of reliability under changing environments and phases of their lifecycle. The environment disturbances, environment variability, plant non-linear dynamics, plant wear, plant faults, or the non-symmetric plant operation may cause de-synchronization in phase or time among: 1) simultaneous units in the same normal mode of operation; 2) successive units in successive normal modes of operation; 3) main and spare units from normal to faulty modes of operation. So, techniques to reduce those causes or their effects are becoming important aspects to consider in the design of such systems.