Adaptive Fault Accommodation Based Resilient Control Techniques

研究目标是为设计弹性控制系统建立技术基础，使其能够在存在不确定系统故障（如执行器故障、结构损坏和传感器故障）的情况下保持期望的性能。该研究旨在开发新的故障检测算法和新的自适应鲁棒控制方法和准则，以处理大而多的系统故障不确定性。它将创造新的弹性控制理论和技术，适用于飞机、航天器、风力涡轮机、喷气发动机和智能机器人等性能关键系统，以提高它们在不确定故障条件下的安全性。它将对现有控制设计不适用的各种故障条件下的系统建模和控制进行新的研究。例如，飞机失去控制的前兆条件，如机身损坏、部件故障、结冰和湍流效应，可能会导致现有反馈控制器不够强大的大而多变的系统不确定性。该研究有望推动反馈控制理论和技术的发展，以满足新兴应用的需求，这些应用要求控制系统对故障具有弹性，即具有适应不确定和大型系统故障的期望能力。本文研究了控制系统弹性的独特度量、弹性控制问题的独特特征以及性能关键系统的关键控制理论要求。它发展了新的控制理论和设计技术，以保证在不确定多故障条件下多变量非线性系统所需的控制系统弹性。它解决了不稳定系统的故障检测、结构特征不确定系统的控制、欠驱动或非最小相位系统的自适应容错控制等新的控制问题。这些问题的主要特征是被控系统具有故障引起的参数、结构和功能不确定性，大多数现有控制方案难以处理（既保证系统稳定性又保证系统渐近跟踪）。例如，由不确定故障引起的不确定失效模式、不确定欠驱动、不确定系统无穷零结构、不确定动态变化。本研究的主要目标是建立一个具有特定控制方案的新的控制系统设计框架，该框架能够处理弹性控制系统技术所需要的未解决的系统不确定性问题。将开发几种新的反馈控制方法，包括：自适应多层多模型设计（保证故障处理和性能改进能力）、自适应多设计集成（处理多个故障）、自适应基于反馈的故障检测（具有自稳定能力）、自适应结构不确定性调节（处理大系统结构损伤）、基于特征参数化的非规范非线性系统自适应逼近控制（设计自适应稳定的控制器结构）。直接控制自适应技术将用于快速、平稳地补偿大而多的故障不确定性。本文将在一些基准应用系统模型上对新的弹性控制设计进行性能保证容错控制的测试。弹性控制系统的新概念、理论和技术将用于学生培训和知识传播。

The research goal is to build technical foundations for designing resilient control systems which are capable of maintaining desired performance in the presence of uncertain system faults such as actuator failures, structural damage and sensor failures. The research is aimed at developing new fault detection algorithms and new adaptive and robust control methods and criteria to handle large and multiple system fault uncertainties. It will create new resilient control theory and techniques applicable to performance-critical systems such as aircraft, spacecraft, wind turbines, jet engines and intelligent robots, to enhance their safety under uncertain fault conditions. It will conduct new studies on modeling and control of systems under various fault conditions for which existing control designs are not applicable. For example, aircraft loss-of-control precursor conditions such as airframe damage, component failures, icing and turbulence effects may cause large and variant system uncertainties for which existing feedback controllers are not powerful enough. The research is expected to advance feedback control theory and technology for the need of emerging applications which require control systems to be resilient to faults, that is, have desired capabilities to accommodate uncertain and large system faults.This research studies unique metrics of control system resilience, distinct features of resilient control problems, and key control theory requirements of performance-critical systems. It develops new control theory and design techniques to ensure desired control system resilience for multivariable nonlinear systems under uncertain multi-fault conditions. It solves new control problems such as fault detection for unstable systems, control of systems with uncertain structural characterizations, adaptive and fault-tolerant control of systems with under-actuation or non-minimum phase. These problems have the key feature that the controlled systems have fault-induced parametric, structural and functional uncertainties, difficult for most existing control schemes to deal with (to ensure both system stability and asymptotic tracking). For example, there can be uncertain failure patterns, uncertain under-actuation, uncertain system infinite zero structures, uncertain dynamic variations, caused by uncertain faults. A main goal of this research is to build a new control system design framework with specific control schemes which are capable of dealing with such unsolved system uncertainty problems, needed for resilient control systems technology. Several new feedback control methods will be developed, including: adaptive multi-layer multiple-model design (to ensure both fault handling and performance improvement abilities), adaptive multi-design integration (to deal with multiple faults), adaptive feedback-based fault detection (to have self-stabilization capacity), adaptive structural uncertainty accommodation (to deal large system structural damage), and characteristic parametrization based adaptive approximation control for non-canonical form nonlinear systems (to design an adaptable and stable controller structure). Direct control adaptation techniques will be developed for fast and smooth compensation of large and multiple fault uncertainties. New resilient control designs, for performance-guarantee fault-tolerant control, will be tested on some benchmark application system models. New concepts, theory and techniques for resilient control systems will be used for student training and knowledge dissemination.