Research On Fault-tolerant Technology Of Embedded Computer Control System

Computer control technology applied in many fields, such as space navigation* aviation, process control, engineering design, management, military, etc. Because computer use widely, its reliability is becoming an important problem. Fault-tolerant design of computer control system includes all kinds of method that can reduce effect of fault, such as fault detect and diagnose (FDD), dependable hardware technique, and dependable software technique, degrade run when hardware cannot resume or there is no redundant part, etc. The thesis study mainly on computer control system of satellite, and the central issue is how to improve the reliability of control system by software techniques.The operation of control system needs correct data that come from sensors, then the research focus on sensor fault detection and diagnose at first. The incorrect data root in two ways, one is come from all kinds of disturbances, and another is sensor fault. For fault detection of sensors, the thesis predicts the next output data of sensor by numeric algorithm, and then gets the fault probability of sensor by compared the predict data with actual data which sensor acquire. Because the case is observed frequency that sensor output data jump sharply, so the probability can't estimate the sensor is fault indeed, it need multi-source data fusion to judge fault DS evidence theory is the appropriate method, so we can judge sensor fault by multi-source data fusion, but the traditional DS evidence theory cannot accord with the truth in some case. After the analysis to the bug of DS evidence theory, the thesis put forward RDS reliable evidence theory that based on DS theory, RDS theory introduce reliability weight coefficient and correlation coefficient, and then RDS theory can get correct output by this means.Fault-tolerant software is important to implement the high reliability of computer control system, we can apply some methods to avoid disturbance and implement fault-tolerance, such as instruction redundancy, software trap, watch timer dog of software, etc. and then system can resume. Designers may produce all kinds of error, and then the software of satellite computer should be reconfigurable. The thesis provide the reconfigurable technique which base on component for embedded software, on the basis of module technique, we can achieve the reconfiguration of embedded software by some way, such as recovery block, N-version and software injection, etc. The main problem that satellite computer system encounters is the SEUs that result from radiation, so the thesis provides a design method that can tolerate temporal hardware error. The method based on data copy, at any point that program produce new data, the method reproduce and compare the source data and output data, the last output is the consensus data mat produced by every algorithm. For rinding the consensus data, the thesis put forward a method which base on dynamic fuzzy cluster algorithm.The validity of fault-tolerance need verify. The thesis verified the fault-tolerance of power control system with the method that injects error of software and hardware. The method build fault analysis tree, and analyze the fault mode, then produce fault by simulator and emulator to verify the fault-tolerance. At last, the thesis introduce the design of computer software and hardware of ChuangXin-1 micro-satellite which author is one of the designer, and the test in orbit of ChuangXin-1.The main contribution of the thesis include several parts. The first, the thesis predict the output of sensor by numeric algorithm, and then analyze the probability of sensor. The second, the thesis improve the Dempster-Shafer evidence theory, and put forward reliable DS theory (RDS), and then prove the correct of RDS theory by a case. The third, the thesis provide the flow for the reconfiguration of embedded software. The fourth, the thesis implement fault-tolerance of hardware error with software by data copy, integrate with software EDAC, the method can achieve reliable satellite computer with COTS. The fifth,...