基于扩张状态观测器的连铸结晶器振动位移系统自适应滑模控制

Adaptive sliding mode control for the oscillation displacement system of continuous casting mold based on extended state observer

针对伺服电机驱动的连铸结晶器振动位移系统中存在时变负载转矩、参数不确定性等问题,本文提出了一种基于扩张状态观测器(extended state observer, ESO)的自适应非奇异终端滑模(nonsingular terminal sliding mode,NTSM)控制方法.首先,设计ESO对系统存在的综合扰动和不可测状态进行估计.然后,采用分层设计的方法,分别对位移跟踪子系统和电流环子系统设计基于ESO的自适应NTSM控制器和滑模控制器.为削弱ESO估计误差对跟踪精度的影响,在NTSM控制器中引入了自适应增益.可以证明,所设计的控制器能够保证闭环系统所有信号有界,系统状态可渐近收敛到原点附近的小邻域内.最后,仿真结果验证了所提出控制方法的有效性.

The adaptive nonsingular terminal sliding mode(NTSM)control algorithm based on an extended state observer(ESO)is proposed for an oscillation displacement system of continuous casting mold driven by servo motor,in which there exists time-varying load torque disturbance,and parameter uncertainties,etc.Firstly,an ESO is constructed to estimate the total disturbance and the unmeasurable state.Secondly,a hierarchical control scheme is adopted,and an ESO-based adaptive NTSM controller and two sliding mode controllers are designed for the position tracking subsystem and current control subsystems,respectively.In order to reduce the effect of the ESO estimation error on the tracking accuracy,an adaptive gain is introduced in the NTSM controller.It can be proved that the all of the signals of the resulting closed-loop system are bounded,and the system states converge to a small neighborhood of the origin asymptotically.Finally,simulation results demonstrate the effectiveness of the proposed method.