隔膜分切机放卷张力串级控制器设计

Design of a cascade controller for unwinding tension of diaphragm slitting machine

以锂电池隔膜分切机中的放卷张力为研究对象,针对放卷系统非线性、强耦合与参数时变特性对张力控制提出的挑战,提出一种基于扰动补偿的串级控制方法。通过分层控制的思路,对放卷张力和速度2个相互耦合的变量进行串级控制,增加对速度环的扰动补偿与鲁棒控制,提升张力控制的稳定性。考虑到张力滞后于速度,张力外环使用积分滑模控制(ISMC),得到放卷辊最优速度期望值。速度内环使用鲁棒反演滑模控制(BSMC),实现放卷速度的稳定跟踪。针对系统的扰动及未建模因素,设计了扩张状态观测器(ESO)进行实时补偿。仿真和实验结果表明,提出的控制方法相较于传统PID控制具有良好的鲁棒性和抗干扰性,能够很好地适应隔膜分切机不同工况下的张力控制要求。

Aiming at the control of unwinding tension in slitting machine for diaphragm used in lithium batteries,a cascade control method based on disturbance compensation is proposed to accommodate the challenge due to the system nonlinearity,strong coupling and time-variant characteristics in the unwinding section of the slitting machine.Via the idea of hierarchical control,two coupled variables of unwinding tension and unwinding velocity were put in cascade manner in the control schema,which enhanced the disturbance compensation and robust control of the speed-loop in the unwinding section and improved the stability of the control system.Considering time lag nature of tension behind speed,the outer tension-loop was designed with integral sliding mode control to obtain the optimal value of the speed expectation of the unwinding roll,while the inner speed-loop was designed with robust backstepping sliding mode control to achieve unwinding speed tracking.An extended state observer was designed to compensate the disturbances and unmodel dynamics of the system.Simulation and experiments show that the proposed cascade controller has good performance in robustness and anti-disturbance compared with PID control,which is applicable to different working conditions of the diaphragm slitting machine.