关键词: 摩擦模型, 非线性干扰观测器, 曲面加工机器人, PD控制器

Abstract:

In order to reduce the machining accuracy caused by friction in a special-shaped surface grinding robot, an improved non-linear disturbance observer is proposed to observe and compensate it. The dynamic model of high-precision industrial manipulator is established. The nonlinear disturbance observer is designed based on the model and the stability analysis of the system is given by applying Lyapunov function stability theory. A typical friction model is introduced, and the observer is used to estimate the unmeasurable internal friction state, and the estimated value is applied to the friction compensation portion of the PD controller. Through simulation and experimental verification, the experimental results show that the observer can greatly improve the control precision of the system and reduce the tracking error of the simulation experiment. The control accuracy of the experimental platform is improved by more than 30%. The observer can greatly compensate the friction of the two-joint manipulator and track the joint position.

Key words: friction model, non-linear disturbance observer, curved surface processing robot, PD controller