本文为加拿大康科迪亚大学(作者:Iman Sadeghzadeh)的博士论文,共138页。
动态控制系统的安全性、可靠性和可接受的性能水平是所有控制系统特别是安全控制系统的关键。控制器应能处理施加在受控过程中的噪声和不确定性。容错控制器不仅在正常运行条件下,而且在系统部件可能发生部分故障或全部故障的情况下,都应该能够以保证的稳定性和良好或可接受的性能来控制系统。当系统发生故障时,它突然开始以一种意想不到的方式运行。因此,容错控制器的设计应能在故障/损坏情况下处理故障,保证系统的稳定性和可接受的性能。这说明了容错控制(FTC)对安全关键系统的重要性和必要性,甚至在当今一些新的和非安全关键系统中也是如此。
近年来,无人机在军事和民用领域发挥着重要的作用。无人机在不同任务中的成功保证了未来无人机数量的不断增长。无人机及其部件的故障可靠性是包括有人驾驶飞机和无人机在内的安全关键系统的重要目标之一。国防部办公室在《2005-2030年无人机路线图》中表示,“提高无人机的可靠性是确保其成功的最直接和最长远的需要”,这一点暗示了无人机可靠性的重要。这为无人机的安全性、可靠性和容错飞行控制(FTFC)系统提供了广阔的前景。
本文的主要目的是研究和比较无人机容错飞行控制技术的性能、鲁棒性和故障处理能力。在康科迪亚大学的两个主要平台上开发和测试了几种控制技术,用于容错控制技术的开发、实施和飞行试验目的:四旋翼和固定翼无人机。FTC技术包括:增益调度比例积分微分(GS-PID)、控制分配与重分配(CA/RA)、模型参考自适应控制(MRAC),最后是线性变参数(LPV)控制。作为一种替代的、理论上更全面的基于增益调度的控制技术,采用LPV技术对四旋翼直升机进行无故障控制。采用GS-PID控制器作为容错控制器,并在某固定翼无人机舵卡住的故障情况下实现。
Safety, reliability and acceptable level of performance of dynamic control systems are the major keys in all control systems especially in safety-critical control systems. A controller should be capable of handling noises and uncertainties imposed to the controlled process. A fault-tolerant controller should be able to control a system with guaranteed stability and good or acceptable performance not only in normal operation conditions but also in the presence of partial faults or total failures that can be occurred in the components of the system. When a fault occurs in a system, it suddenly starts to behave in an unanticipated manner. Thereby, a fault-tolerant controller should be designed for being able to handle the fault and guarantee system stability and acceptable performance in the presence of faults/damages. This shows the importance and necessity of Fault-Tolerant Control (FTC) to safety-critical and even nowadays for some new and non-safety-critical systems. During recent years, Unmanned Aerial Vehicles (UAVs) have proved to play a significant role in military and civil applications. The success of UAVs in different missions guarantees the growing number of UAVs to be considerable in future. Reliability of UAVs and their components against faults and failures is one of the most important objectives for safety-critical systems including manned airplanes and UAVs. The reliability importance of UAVs is implied in the acknowledgement of the Office of the Secretary of Defense in the UAV Roadmap 2005-2030 by stating that, ”Improving UA [unmanned aircraft] reliability is the single most immediate and long-reaching need to ensure their success”. This statement gives a wide future scenery of safety, reliability and Fault-Tolerant Flight Control (FTFC) systems of UAVs. The main objective of this thesis is to investigate and compare some aspects of faulttolerant flight control techniques such as performance, robustness and capability of handling the faults and failures during the flight of UAVs. Several control techniques have been developed and tested on two main platforms at Concordia University for fault-tolerant control techniques development, implementation and flight test purposes: quadrotor and fixedwing UAVs. The FTC techniques developed are: Gain-Scheduled Proportional-IntegralDerivative (GS-PID), Control Allocation and Re-allocation (CA/RA), Model Reference Adaptive Control (MRAC), and finally the Linear Parameter Varying (LPV) control as an alternative and theoretically more comprehensive gain-scheduling based control technique. The LPV technique is used to control the quadrotor helicopter for fault-free conditions. Also a GS-PID controller is used as a fault-tolerant controller and implemented on a fixedwing UAV in the presence of a stuck rudder failure case.
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引言
- 项目背景、基础知识与定义
- 固定翼无人机的容错飞行控制
- 四旋翼直升机无人机的容错飞行控制
- 四旋翼直升机无人机的线性参数可变控制
- 结论与展望
附录无人机测试平台的开发
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