基于线性扩张状态观测器的挖掘机电液系统滑模控制

Sliding mode control of excavator electro-hydraulic system based on linear extended state observer

无人驾驶挖掘机器人实际工作环境恶劣,为提高铲斗在负载扰动下的轨迹跟踪精度,建立了挖掘机电液系统非线性数学模型,设计了基于线性扩张状态观测器的滑模控制器(Sliding mode controller based on linear extended state observer,SMC-LESO)。根据铲斗油缸活塞杆位移信号,利用设计的线性扩张状态观测器对系统的速度、加速度及负载扰动和不确定因素进行估计,解决了系统参数难以测量的问题。在此基础上,设计了滑模控制器,并证明了该控制器的Lyapunov稳定性。为进一步验证该控制器的有效性,建立了挖掘机电液比例控制系统的联合仿真模型,并与PID控制器、滑模控制器的轨迹跟踪精度进行对比。仿真结果表明,该控制器可以有效抑制扰动,位移跟踪精度高、鲁棒性强。

The actual working environment of unmanned excavation robot is harsh.In order to improve the trajectory tracking accuracy of bucket under load disturbance,a nonlinear mathematical model of electro-hydraulic system of digging robot was established,and a sliding mode controller(SMC)based on linear extended state observer(LESO),called SMC-LESO,was designed.Based on the displacement signal of the piston rod of the bucket cylinder,the velocity,the acceleration,the load disturbance and uncertain factors of the system were estimated by the LESO.On this basis,SMC-LESO was completed,and the Lyapunov stability of the controller was proved.The cosimulation model of electro-hydraulic proportional control system of the excavator was established.Compared with proportional-integralderivative(PID)controller and SMC,the simulation results show that the designed controller can effectively suppress the disturbance,and has high displacement tracking accuracy and robustness.