Development of a real-time force-controlled compliant polishing tool system with online tuning neural proportional–integral–derivative controller

Abstract

This article presents a real-time force-controlled pneumatic compliant polishing tool with self-supplied abrasives making the abrasives added to the contact area between the polishing pad and workpiece, which can lead to good polishing performance. And a force–position decoupling pneumatic servo system for polishing force control is presented to solve the problem of force–position coupling in the traditional polishing process. However, it is difficult to realize satisfactory control performance due to the problems of time variance, compliance, hysteresis and nonlinearity in pneumatic servo system. This article proposes an online tuning neural proportional–integral–derivative controller to improve force control performance. The real-time polishing force control results of pneumatic servo control system are investigated by adopting proposed neural proportional–integral–derivative control strategies with data acquisition card and RTW toolbox in MATLAB/Simulink. The real-time experimental results of polishing force control indicate that the excellent control performance can be achieved by the proposed neural proportional–integral–derivative controller no matter the reference force is constant or varied. Compared with those by traditional proportional–integral–derivative controller, the duration for stabilizing the polishing force is shorter and the error between the output force and the reference is smaller by the proposed neural proportional–integral–derivative controller.