Research On Gasbag Plishing Contact Force Control System

Gasbag polishing is considered as a new technique of ultra-precision machining, which is particularly useful for the curved surface polishing. During the gasbag polishing, the contact force will be varying because of the mould surface morphology error, polishing trajectory error and the mould surface curvature change. The varying contact force will affect the final polishing effect and reduce the polishing quality.A gasbag polishing contact force control system is proposed based on the research of the gasbag polishing technology and the analysis of the relationship between downward depth, inflation pressure and contact force. The detail work is shown as follows:1) The relationship between the downward depth, inflation pressure and contact force is analisysed based on the experimental study. Given the fitting formula and the adjustable range of the contact force. The experimental study of contact area is made on mould curved surfaces with different radius of curvature, and the study shows that the Hertz contact theory can be used on the calculation of the contact area.2) Design the gasbag polishing natural network control system, include gasbag pressure predictor and natural network PID controller. The control system realized the prediction of input inflation pressure and the control of contact force.3) The gasbag polishing contact force control platform is designed, the structure, working principle and the hardware is introduced and The control procedures are designed on LabVIEW.4) The tracking characteristic of the gasbag polishing contact force control platform is verified by the tracking simulation and experiment of the contact force, the contrast of simulation results and experimental results prove the correctness of gasbag contact force model.5) The polishing experiments, which is used the contact force control way and the common mode on the mould surface, show that it can effectively restrain gasbag press quantity on the influence of polishing contact force by control way. In the polishing process, it can maintain the contact force steady to improve uniformity and quality of polishing.This study realizes the controllability of polishing contact force in the polishing process and has some significant theoretical guidance for improving the automation degree of the gasbag polishing technology.