基于速度观测器的GMS摩擦模型辨识与补偿

GMS friction model identification and compensation based on velocity observer

摩擦是伺服系统在低速运动时精度降低的主要非线性因素之一。采用基于模型的摩擦补偿可以有效地预测摩擦力,并实现误差补偿,因此利用可全面描述系统摩擦力的GMS摩擦模型预测伺服系统的摩擦力。为提高此模型参数的辨识精度,设计了全维速度观测器提供反馈速度信息,克服低速时速度测量误差带来的影响;并基于此观测器,给出了GMS摩擦模型的参数辨识的实验方法。为验证所提出的摩擦补偿及辨识方法的有效性,在一新型的空间大型末端执行器的拖动系统进行了拖动实验。实验结果表明,通过此摩擦模型补偿,可使拖动系统的位置跟踪精度优于0.02 mm,与具有固定参数的Stribeck摩擦模型相比,位置跟踪精度提高超过30%。

Friction is a kind of strong nonlinear factor that severely degrades accuracy of servo system.The fiction compensation based on model can effectively predict the friction amplitude and compensate the dynamic error.The friction is predicted by the generalized Maxwell-slip model（GMS）.In order to improve the parameters identification accuracy of friction model,and overcome the error effects of the low speed velocity measurement,the full-order speed observer was designed as feedback speed information.Based on this observer,an experimental parameter identification method of GMS friction model was implemented.In order to verify the proposed identification method effectiveness for friction compensation,some dragging experiments on a late-model space large end-effector were done.Results of experiments show that the precision of the position tracking can reach 0.02 mm by this friction compensation,increased more than 30% compared with Stribeck friction model which has fixed parameters.