Adaptive friction compensation control of robotic pneumatic end-effector based on LuGre model

Abstract

Purpose Considering the response lag and viscous slip oscillation of the system caused by cylinder piston friction during automatic polishing of aero-engine blades by a robotic pneumatic end-effector, the purpose of this study is to propose a constant force control method with adaptive friction compensation. Design/methodology/approach First, the mathematical model of the pneumatic end-effector is established based on the continuous LuGre model, and the static parameters of the LuGre model are identified to verify the necessity of friction compensation. Second, aiming at the problems of difficult identification of dynamic parameters and unmeasurable internal states in the LuGre model, the parameter adaptive law and friction state observer are designed to estimate these parameters online. Finally, an adaptive friction compensation backstepping controller is designed to improve the response speed and polishing force control accuracy of the system. Findings Simulation and experimental results show that, compared with proportion integration differentiation, extended state observer-based active disturbance rejection controller and integral sliding mode controller, the proposed method can quickly and effectively suppress the polishing force fluctuation caused by nonlinear friction and significantly improve the blade quality. Originality/value The pneumatic force control method combining backstepping control with the friction adaptive compensation based on LuGre friction model is studied, which effectively suppresses the fluctuation of normal polishing force.

Design of Backstepping Sliding Mode Control for a Polishing Robot Pneumatic System Based on the Extended State Observer

“…where q i (i = 1, 2, 3, 4) are all positive numbers. 3,4) as the ESO estimation error. The observer error equation can be obtained by subtracting Equation (12) from Equation (11):…”

“…Polishing is a surface finishing process that aims to enhance the appearance or the functionality of a workpiece through material removal or shape modification [1]. It is widely applied in various fields, including metal processing, mold manufacturing, aerospace engineering, and biomedical engineering [2,3]. However, the traditional manual polishing process heavily depends on skilled labor, resulting in inconsistent quality and low productivity.…”

“…Among the popular methods for automated polishing, pneumatic polishing systems integrated with robotic arms have emerged as a preferred approach. An essential aspect of automatic polishing is the precise control of the end effector within the pneumatic system of the polishing robot [3,6].…”

An Investigation of Real-Time Robotic Polishing Motion Planning Using a Dynamical System

“…The use of polishing robots to address the demand for smallbatch, customized production significantly enhances efficiency and precision. However, as the complexity of workpiece surfaces increases, higher demands are being placed on the polishing quality and applicability of polishing robots [2,3]. Sometimes, it is necessary to polish specific areas of a workpiece, such as automotive parts.…”