基于预滑—动态摩擦力矩估计模型的自适应前馈补偿方法

根据数控交流伺服工作台进给系统从静止到宏观运动的过渡时间，和零速度时刻的指令加速度大小呈反比关系，区分摩擦力矩的预滑动区和滑动区，由此提出基于力矩值估计的摩擦补偿方法；在设定指令加速度后，基于命令力矩值的摩擦力矩模型，不需要测量速度就可以补偿工作台进给系统中的摩擦。同时，考虑到参数的不确定性，设计非线性摩擦自适应控制方案，对其稳定性进行理论证明。在交流伺服工作台进给系统上对基于摩擦力矩值估计的自适应前馈补偿方法进行验证。试验结果表明，基于预滑—动态摩擦力矩估计模型的自适应前馈补偿方法能实现在不同指令加速度下对期望轨迹的跟踪，并能大大提高系统的跟踪精度。

ADAPTIVE FEEDFORWARD COMPENSATION METHOD BASED ON PRESLIDING-DYNAMIC FRICTION TORQUE ESTIMATION MODEL

According to the inverse relationship between the command acceleration at zero-velocity and transition time from rest to macroscopic motion of a CNC alternating current servo worktable feed system,the pre-sliding regime of friction is distinguished form sliding regime,hence a method of friction compensation is put forward based on the estimated value of the torque value.After command acceleration is given,friction in the worktable feed system is compensated without measurement of velocity with friction torque model based on command torque value.Meanwhile,in consideration of pararn-eter uncertainty, nonlinear friction adaptive control scheme is designed and its stability is theoretically proven.Experimental study verifies the effectiveness of the adaptive compensation scheme based on the estimated value of the friction torque value,and shows that this adaptive compensation method based on presliding-dynamic friction torque estimation model can implement tracking of expected locus at different command acceleration and greatly improve the tracking precision of the system.