带饱和约束非线性系统的鲁棒自适应容错控制

Robust adaptive active fault tolerant control for nonlinear system with saturation constraint

针对发生执行器故障的饱和非线性系统提出一种主动容错控制方法.考虑系统存在的外界干扰情形,运用H∞控制结合饱和约束设计了自适应容错控制器.首先,引入饱和幅值以确保控制输入始终在界范围之内,设计包含故障估计值的自适应状态反馈控制输入;其次,为实现系统具有鲁棒稳定性,同时具有最大容错椭球体稳定域的控制目标,采用李雅普诺夫理论结合H∞控制方法,并运用不变集理论估计最大椭球体稳定域,将自适应容错控制器的设计方法转化为求解线性矩阵不等式约束下的多目标优化问题;最后,通过一数值算例将自适应与固定增益控制器设计方法进行对比分析.研究结果表明:自适应控制器的性能更优,更适合用于受饱和约束非线性系统的容错控制.

A novel scheme of active fault tolerant control was proposed for the saturated nonlinear system with actuator fault.Considering the disturbances contained in the system,an adaptive fault tolerant controller was designed in this paper.First the control input was limited in the upper bound of saturation to make the control input avoid the saturation,and an adaptive fault tolerant controller combining fault estimation and adaptation law was provided.Then considering the control performance of robust and stability region,the H∞control combind with Lyapunov theory was adopted to design the parameters of controller,meanwhile the set of invariance conditions was introduced to determine the largest ellipsoid stability region,then an issue of multi objectives optimization under linear matrix equalities constraints was put forward to realize the two control objectives.Finally an example was included to illustrate the control performance of adaptive controller compared with the fixed gain controller.The results show that the adaptive controller has better control performance which is more suitable for the fault tolerant controller design of saturated nonlinear system.