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Companies are gradually developing: 1) complex and/or highly integrated systems including vehicles (as satellites, airplanes, cars, etc.) or equipment (as computers, cell phones, no breaks, etc.) to use under 2) increasingly varied or inhospitable environments, and to survive under 3) increasingly long life cycles and unavoidable changes in staff & facilities & technologies. The overall decision to use (by time, cost, quality, of functions, services, etc.) such end systems under 2 require 4) high Dependability (Reliability, Maintainability, Availability, Correction, Safety, Security, etc.) of them. The overall survival in use (by health monitoring, housekeeping, retrofit, upgrade, etc.) of such end systems under 3 require 5) high Suportability (Maintainability, Adaptability, Availability, Robustness, etc.) of them coupled with the support systems.

This works presents the generation and customization of real time code for embedded controllers using a modeling and simulation environment. When the controller model is considered satisfactory, the developers can use a code generation tool to build a real time source code capable to be migrated to an embedded target processor. The code generation tool used is capable to generate real time code in ANSI C or ADA 95 languages. This process can be customized to adequate to a target processor and/or a Real Time Operating System (RTOS). The code customization can be achieved using a specific Template Programming Language (TPL) that specifies how the code will be generated. This technique makes it possible the instantiation of real time embedded controllers code using the same controller model to a wide variety of target processors and/or RTOSs.

This paper presents the first of four parts of the academic design of an Attitude Control System (ACS) for the Multi-Mission Platform (MMP) and its migration to a Real Time Operating System. The MMP is a three axis stabilized artificial satellite now under development at the National Institute for Space Research (INPE). Such design applied some software engineering concepts as: 1)visual modeling; 2)automatic code generation; 3)automatic code migration; 4)soft real time simulation; and 5)hard real time simulation. A block diagram based modeling and a virtual time simulation of the MMP ACS in its nominal operational mode were built in the MatrixX 7.1 environment satisfying the three axis pointing and stabilization requirements. After that, its AutoCode module was used to generate C ANSI code representing the block diagram model. Time characteristics were added to the ACS generated code to make it the real time control software of MMP nominal operational mode.

One challenge that the space, aeronautical and automotive industries are facing today is the fast growing number of vehicles versus the slowly growing number of useful orbits, routes, and speedways. Furthermore, the adoption of “free-flight”, “speed-drive”, etc. policies in the near future will only aggravate it. All these factors increase the risk of collisions and the frequency of deviation maneuvers to avoid them. But they also create the opportunity to devise policies to mitigate such problems, including algorithms to propagate the uncertainties in vehicle motions and to predict the risk of their collisions. This work discusses the development and simulation of an algorithm for the propagation of navigation uncertainties in the trajectory of aerospace vehicles, to minimize the risk of collisions. The scenario of Satellites Formation Flying shall be used for the simulations, with focus on the prediction of the collision probability.

The purpose of this work is Fault Detection and Diagnosis (FDD) on a Knock Sensor because some of the modern petrol engines operate on the efficient four-stroke cycle, where each cylinder of the engine contains an intake and exhaust poppet valve that is operated at the appropriate time. The ECM (Engine Control Module) uses the Knock Sensor signal to control timing. The Knock Sensor detects engine knock and sends voltage signal to the ECM. These signals can be sufficient to detect abnormal combustion, like ‘spark knock’ and ‘surface ignition’. Engine knock occurs within a specified range. The Knock Sensor, located in the engine block, cylinder head, or intake manifold is tuned to detect that frequency, which motivates the use of signal models for detection. But this sensor is a wide-band accelerometer of the piezoelectric type too. Analogy with a general seismic mass system is possible since it is a general damped second order vibrating system which is forced into oscillatory motion.

This paper presents the automatic code generation process of the academic design of an Attitude Control System (ACS) for the Multi-Mission Platform (MMP). The MMP is a three axis stabilized artificial satellite now under development at the National Institute for Space Research (INPE). Such design applied some software engineering concepts as: 1)visual modeling; 2)automatic code generation; 3)automatic code migration; 4)soft real time simulation; and 5)hard real time simulation. A block diagram based modeling and a virtual time simulation of the MMP ACS in its nominal operational mode were built in the MatrixX 7.1 environment satisfying the three axis pointing and stabilization requirements. After that, its AutoCode module was used to generate C ANSI code representing the block diagram model. Four operating systems were used for code migration: 1)Windows 2000; 2)Mandrake Linux 10.1; 3)RedHawk Linux 2.1; and 4)RTEMS 4.6.2.

A constant challenge for the mobility engineering is to build correctly, the right product at the right time, cost and quality. This challenge gives opportunities to adopt new paradigms in system development, especially in generation, migration and tests of controller codes. This work presents the automatic generation, migration, and tests of real time code to an embedded controller. This is part of the Attitude and Orbit Control System (AOCS) for the Multi-Mission Platform (MMP) of the National Institute for Space Research (INPE). The modeling and simulation paradigm associated with automatic code generation makes possible the migration of a real time embedded controller code to a wide variety of target processors and/or Real Time Operating Systems (RTOS) using the same controller model. The MATRIXx (XMath/SystemBuild/AutoCode/DocumentIt) modeling and simulation environment was used to analyze and design the controller and generate its real time code.

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.

In this work, still under development, we study the stability degradation due to delays in a networked control system. Our networked system is composed by: 1) a computer with Rate Monotonic Scheduler policy and, 2) a communication network based on TDMA access. Under this scenario, we analyze an integrated communication-computing delay and define the worst delay. The simulations shows that the presence of a worst delay can be determined only with an extensive analysis. The simulations were done in Matlab/Simulink with the help of Truetime toolbox.

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.

Complex systems such as satellites, aircrafts, automobiles and air traffic controls are becoming increasingly complex and highly integrated as prescribed by the SAE ARP 4754 Standard. They integrate many technologies and they work in very demanding environments sometimes with little or no maintenance due to the severe conditions of operation. To survive such harsh operating conditions, they require very high levels of reliability, to be reached by a diversity of approaches, processes, components, etc. By their turn, the processes of analysis and decision making shall be improved progressively, as experience accumulates and suggests modifications and adaptations. According to this philosophy, in this work, we discuss a proposal for improving the results of the Reliability Analysis and FMEA/FMECA of the CBERS Satellite Program, conducted at the National Institute for Space Research-INPE, since 1987.

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

This paper presents some techniques for fault diagnosis in aerospace and automotive systems. A diagnosis technique is an algorithm to detect and isolate fault components in a dynamic process, such as sensor biases, actuator malfunctions, leaks and equipment deterioration. Fault diagnosis is the first step to achieve fault tolerance, but the redundancy has to be included in the system. This redundancy can be either by hardware or software. In situations in which it is not possible to use hardware redundancy only the analytical redundancy approach can be used to design fault diagnosis systems. Methods based on analytical redundancy need no extra hardware, since they are based on mathematical models of the system.

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 critical real-time computer systems, whether aircraft, automotive and industrial products it is very common the use of a fixed priority scheduler. The fixed priority scheduler has shown a good performance in control applications even in different applications where it was adopted. But nowadays, to go forward with the technology, be it in hardware and software, schedulers with dynamic priority can be a better alternative in certain situations. The present work aims to show that a variable priority scheduler can improve the performance of a control system obtained with a fixed priority scheduler, even when it was bad conditioned. This study is based on a four motor position control system. For this, the study will make use of a specialized simulation tool. In the future, we intend to extend this study to schedulers that use random and sporadic tasks.

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.

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.

Systems such as satellites, aircrafts, automobiles and air traffic controls are becoming increasingly complex and highly integrated, as prescribed by the SAE ARP 4754 Standard. They integrate many technologies and they work in very demanding environments, sometimes with little or no maintenance, due to the severe conditions of operation. To survive such harsh operating conditions, they require very high levels of reliability, to be reached by a diversity of approaches, processes, components, etc. By their turn, the processes of analysis and decision making shall be improved progressively, as experience accumulates and suggests modifications. Most of this can be translated in models. According to this philosophy, in this work, we discuss the use of Model Based Reliability for improving the results of the Reliability Analysis and FMEA/FMECA of a satellite program, as those conducted at the National Institute for Space Research-INPE, since 1979.