双电机同步驱动伺服系统故障诊断与容错控制

本文针对双电机同步驱动伺服系统中执行器失效会导致系统性能下降甚至失稳的情况,提出了一种基于自适应滑模的故障诊断和容错控制策略.该方法通过设计各电机转速的自适应滑模状态观测器,在线估计各执行器的失效因子:当单个执行器部分失效时,通过自适应的方法调整控制器增益;当单个执行器全部失效时,重构系统的控制律.对于系统中存在非匹配不确定项的情况,提出在期望虚拟信号中引入基于扩张状态观测器的补偿项抑制方案;利用Lyapunov理论证明了闭环系统在正常和故障状况下的稳定性以及观测器的收敛性;仿真结果表明,所设计的控制策略能保证系统稳定跟踪指令信号,在单个执行器失效的情况下系统跟踪性能基本不下降.

Fault diagnosis and fault tolerant control for the servo system driven by two motors synchronously

In the servo system driven by two motors synchronously, actuator failures deteriorate the tracking performance or even result in system instability. To deal with this problem, we propose a fault diagnosis and fault tolerant control scheme based on adaptive sliding mode method. In this control scheme, the adaptive sliding mode observers for motor speed are designed, and the actuator failure factors are estimated online. When an actuator partly fails to work, the controller gains will be adjusted automatically. When an actuator fully breaks down, the control law of the system willbe reconstructed. Considering that there are unmatched uncertainties in the system, we introduce compensations based on extended state observer (ESO) to the desired virtual signals. The stability of the servo system under normal and fault conditions are analyzed by Lyapunov theory, the convergence of the observers are also analyzed. It is shown by simulation results that the control strategy can assure the stable tracking of the command signals. The tracking performance almost remains unchanged when an actuator partly or fully fails to work.