基于Backstepping-L1自适应控制的旋翼飞行器容错控制

针对旋翼飞行器控制过程中存在侧风等外界干扰、飞机本身存在未建模动态等不确定性,提出了一种基于Backstepping-L1自适应控制的旋翼飞行器容错控制方法。首先,在不考虑不确定性的情况下,根据旋翼飞行器的动力学方程和运动学方程,利用Lyapunov函数方法设计了基于Backstepping控制的姿态控制律,实现了闭环系统的稳定控制,且响应快速精确。其次,考虑不确定性对系统的影响,在Backstepping控制器的基础上,通过引入自适应律和状态观测器,实现对不确定性的实时估计和系统状态的在线观测,进而设计出具有鲁棒性的L1自适应控制器,消除了不确定性的影响,实现了旋翼姿态的容错控制。再次,通过引入一个闭环稳定的自治参考系统,对所设计的L1控制器进行稳定性分析,分析表明:设计的状态观测器跟踪误差有界并收敛到0,能够准确实时地估计被控系统状态;自适应律可快速自适应于系统存在的干扰及未建模动态等不确定性;控制律可以保证系统在正常状态及存在不确定性的情况下实时跟踪引入的参考系统,且跟踪误差趋近于0,从而保证系统稳定。最后,通过MATLAB仿真对比验证了该方法的有效性。

A Fault Tolerant Control of Multi-rotors Based on Backstepping-L1 Adaptive Controller

This paper presents a Backstepping-L1 adaptive control method aimed at the problems that there are outside interferences such as crosswind, etc., and non modeling dynamic uncertainties exist in aircraft itself in the process of flight for attitude control of multi rotors. Firstly, according to the kinematics and dynamics equations of multi rotors, the paper designs a Backstepping control law by a Lyapunov function under no consideration of uncertainties to realize a fast, accurate and stable control target. Then, under consideration of the influence of uncertainties, the paper introduces adaptive law and state predictor into the system on the basis of Backstepping controller. With the augmentations of adaptive law and state predictor, the real time estimation of uncertainties and online state prediction are realized. A L1 adaptive controller is designed to compensate the influence of uncertainties and make the system robustness and fault tolerant. And its stability analysis is realized by introducing a stable reference system. The analysis result shows that the state predictor, adaptive law and control law can ensure the system stable. MATLAB simulator is provided to demonstrate the performance of the presented control scheme.