Sensing, identification, fault detection and diagnosis, and performance recovery of systems

磨损、设计缺陷以及外部影响和干扰（如过载）会导致许多系统逐渐恶化，从而导致性能下降和/或灾难性故障。对系统进行满意的控制和监测需要关于系统及其各个部件以及操作特性的准确信息。全面的信息往往不容易获得，特别是在系统运行时。此外，由于设备/机械制造商通常不预见确定和提供此类信息的需要，因此它们不提供将来提取此类数据的内置手段。在过去几年中，申请人一直从事在线系统/参数识别、故障检测、隔离和恢复。包括神经网络、模糊逻辑、遗传算法和小波分析等技术在内的系统建模与仿真技术已经得到了成功的探索和应用。 目前正在研究的和未来感兴趣的具体平台（或故障情况）是“爆震”，或内燃机中的自燃现象，以及航天器中的致动器和传感器故障检测。在敲击的情况下，除了导致低效的操作和污染外，它们还产生高于设计规格的压力和力，这可能导致机械损坏和故障。本文成功地将小波变换作为一种处理非平稳信号的方法应用于发动机故障检测。我们建议开发互补的分析工具，以提高准确性和故障检测率，并将目前的结果从单缸案例扩展到更实际的多缸应用。在航天器致动器/传感器故障的情况下，我们正在开发的技术，为单个和多个组件故障检测和设计方案，系统的重新配置和恢复。我们将研究新的软件/控制和硬件冗余，重点是航天器中致动器和传感器的最佳空间放置，以提高系统的全局第一级故障安全特性，以实现强大的恢复。

Wear, design flaws, and external influences and disturbances, such as overload, cause gradual deterioration in many systems, which can lead to inferior performance and/or catastrophic failure. Satisfactory control and monitoring of a system require accurate information about both the system and its individual components, and operational characteristics. Comprehensive information is often not readily available, particularly when the system is in operation. In addition, since equipment/machinery manufacturers do not generally foresee a need to determine and supply such information, they do not provide a built-in means to extract such data in the future. Over the past several years the applicant has been engaged in online system/parameter identification, fault detection, isolation and recovery. Systems modeling and simulation including such techniques as neural networks, fuzzy logic, genetic algorithms and wavelet analysis have been successfully explored and used.  Specific platforms (or fault cases) currently under study and of future interest are "knock", or the autoignition phenomenon in internal combustion engines, and actuator and sensor failure detection in spacecraft. In the case of knocks, in addition to causing inefficient operation and pollution, they also create pressures and forces above the design specifications, which could lead to mechanical damage and failure. We have successfully used wavelet transform, as a method of processing unsteady signals, in engine fault detection. We are proposing to develop complementary analysis tools to improve accuracy and the fault detection rate and extend the current results from single cylinder cases to more practical multi-cylinder applications. In the case of spacecraft actuator/senor failures, we are developing techniques for single and multiple component failures detection and devising schemes for system reconfiguration and recovery. We will examine new software/control and hardware redundancies with emphasis on optimal spatial placement of actuators and sensors in the spacecraft to improve the global first-level fail-safe characteristics of the system for robust recovery.