Adaptive Fault Accommodation Based Resilient Control Techniques

研究的目标是为设计具有弹性的控制系统奠定技术基础，这些系统能够在执行器故障、结构损伤和传感器故障等不确定系统故障存在的情况下保持期望的性能。这项研究的目的是开发新的故障检测算法和新的自适应和鲁棒控制方法和判据，以处理大而多的系统故障不确定性。它将创造适用于飞机、航天器、风力涡轮机、喷气发动机和智能机器人等性能关键型系统的新的弹性控制理论和技术，以增强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，飞机失控的先兆条件，如机身损坏、部件故障、结冰和湍流效应，可能会导致大的和可变的系统不确定性，而现有的反馈控制器对这些不确定性的处理能力不够。本研究旨在推动反馈控制理论和技术的发展，以适应新兴应用对控制系统故障的弹性要求，即具有适应不确定和大系统故障的能力。本研究研究了控制系统弹性的独特度量、弹性控制问题的显著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，以确保多变量非线性系统在不确定的多故障条件下具有期望的控制系统弹性。它解决了不稳定系统的故障检测、结构不确定系统的控制、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。这些问题的关键特征是被控系统具有故障引起的参数、结构和功能的不确定性，这是现有的大多数控制方案难以处理的(确保系统的稳定性和渐近跟踪)。例如，可能存在不确定的故障模式、不确定的欠驱动、不确定的系统无限零结构、不确定的动态变化、由不确定的故障引起的。这项研究的一个主要目标是建立一个新的控制系统设计框架，其中包含特定的控制方案，能够处理弹性控制系统技术所需的未解决的系统不确定性问题。几种新的反馈控制方法将被开发出来，包括：自适应多层多模型设计(以确保故障处理能力和性能改善能力)、自适应多设计集成(以处理多个故障)、基于自适应反馈的故障检测(以具有自稳定能力)、自适应结构不确定性调节(以处理较大的系统结构损伤)和基于特征参数的非正则型非线性系统的自适应逼近控制(以设计自适应且稳定的控制器结构)。发展直接控制自适应技术，以快速、平稳地补偿大的、多故障的不确定性。新的弹性控制设计，用于性能保证的容错控制，将在一些基准应用系统模型上进行测试。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.