A New Aspheric Surfaces Polishing by Parallel Orthogonality Movement/Force Servomechanism

Abstract

According to the all-pervading theory, the best strategy for multiaxis compliant control system is the famous hybrid movement/force control. Until now, the typical way to get it inclines to integrate force control with movement control into one numerical control (NC) interpolator. The more axes being taken for the interpolator, the lower calculating and computerizing speed and the greater errors are. Furthermore, the errors of movement control, including the position errors and pose errors, would inevitably disturb the processing of force control for their coupling relationship. In this paper, the orthogonal movement/force servo strategy is brought forward based on the orthogonality relation of force control and movement control. Combining with the processing of aspheric surfaces polishing, the paper develops a new three-axis computer numerical control (CNC) compliant polishing method and system by the hybrid orthogonal movement/force servomechanism, in which the force controlling and movement controlling are taken in its orthogonal complement space, respectively. Experiments show that this new polishing system is of great robustness for the change of slope and curvature of the aspheric surfaces and it can polish aspheric surfaces to get ultrasmooth surfaces at nanoscale.