为建立具有良好动态性能的开放式伺服系统,针对自适应摩擦补偿对未知建模误差和扰动抑制能力较弱的问题,提出了一种基于修正黏性摩擦Lu Gre模型的自适应滑模摩擦补偿方法.建立开放式伺服系统的动力学方程,并结合修正黏性摩擦Lu Gre模型,提出伺服系统的状态方程.根据反演设计的思想,设计自适应滑模摩擦控制器以及相应的自适应律和切换函数,并分析了其全局渐进稳定性.通过可编程多轴控制器(PMAC)实现了该补偿控制方案在开放式伺服平台的应用,并通过实验验证了其有效性.实验结果表明:与自适应摩擦补偿相比,该自适应滑模摩擦补偿方案在输入信号为正弦信号时,伺服系统的跟踪误差由±6.9,μm降低到±4.1,μm.采用该补偿方案可有效地抑制摩擦及其他不确定干扰对伺服系统的不利影响,进一步提高伺服系统的跟踪性能.
In order to establish an open-servo system with good dynamic performance, this paper proposes a adaptive sliding mode compensation method based on modified viscous friction LuGre model. It is applied to solve the problem of adaptive friction compensation in unknown modeling errors and disturbance rejection. Firstly, a dynamic equation of an open-servo system is given and a servo system equation of state based on modified LuGre friction model is es- tablished. Secondly, according to the inversion design, an adaptive sliding friction controller, the corresponding adaptive laws and switching functions are given. Besides, its global asymptotic stability is analyzed by this method. In the last, a programmable multi-axis controller is utilized to realize the compensation applied to the open-servo platform and demonstrate the validity of the method. Results show that the tracking error of servo system is reduced from ~6.9 ~tm to ~4.1 pan compared with the conventional adaptive friction compensation, when the input signal is a sinusoidal signal. The proposed method effectively suppresses the adverse effects of friction and other uncertainties on the servo system and improves the tracking performance of the servo system.