带摩擦补偿的滚珠丝杠副进给系统自适应滑模控制
Adaptive sliding mode control of ball screw drives with friction compensation

为了提高滚珠丝杠副进给系统的跟踪性能,采用了带摩擦补偿的自适应滑模控制方法.基于滚珠丝杠副进给系统轴向振动特性建立了两自由度的质量模型,根据模型的状态方程设计了系统的反演滑模控制器,考虑到外界干扰的影响设计了带自适应律的自适应滑模控制器.采用基于Stribeck摩擦模型的摩擦补偿方法和遗传算法对滚珠丝杠副进给实验台的Stribeck摩擦模型进行了参数辨识.采用建立的控制方法在实验台上进行了轨迹跟踪实验.实验结果表明:在没有使用摩擦补偿情况下自适应滑模控制器最大跟踪误差为31.85 μm;使用带摩擦补偿的自适应滑模控制器,其最大跟踪误差减小为15.55 μm.实验结果证明了针对滚珠丝杠副进给系统轴向振动特性模型设计的自适应滑模控制器具有较高的跟踪性能,并且采用带摩擦补偿的自适应滑模控制方法显著提高了滚珠丝杠进给系统的跟踪精度.
In order to improve the tracking performance of ball screw drives, the adaptive sliding mode control with friction compensation was adopted. A two degrees of freedom mass model was established based on the axial vibration characteristics of ball screw drives, and a backstepping sliding mode controller was designed according to the state equation of the model. Then an adaptive sliding mode controller with adaptive law was designed considering the influence of the external disturbance. The friction compensation method based on the Stribeck friction model was used, and the Stribeck friction model parameters of ball screw feed test bench were identified by the genetic algorithm. The trajectory tracking experiments were conducted on test bench with the proposed control method. The results show that the maximum tracking error is 31.85 μm by using the adaptive sliding mode controller without friction compensation, while it decreases to 15.55 μm when using the adaptive sliding mode controller with friction compensation. It is proved that the adaptive sliding mode controller designed for the axial vibration characteristics model of ball screw drives has a high tracking performance, and the tracking accuracy of ball screw drives is improved considerably by using the adaptive sliding mode control with friction compensation