Analysis And Design Of The Control System For A Bonnet Polishing Hybrid Machine Tool

Bonnet polishing has been used for manufacturing increasingly as a new method,it can make the polishing tool fits the workpiece better,and then maintain the same polishing force to ensure the material removal rate at the same level.Due to its high precision and high load capacity,parallel structure has been widely used in precision manufacturing industry.Taking advantage of series structure,parallel structure and bonnet polishing method,this thesis presented a bonnet polishing hybrid machine tool.Based on the machine structural analysis,kinematics and dynamics modeling have been derived,motion planning and error compensation algorithms also have been developed.First,this thesis starts from the structural analysis,separating the machine tool into two parts,polishing series part and parallel part,then according to the principle of the bonnet polishing,the kinematics modeling of this part was established.And forward and inverse kinematic of parallel part,the Jacobin matrix and the speed control model also have been derived.These models have been verified by Matlab programs.Moreover,a control system has been designed,and many important components have been selected such as servo actuators,motion controller and PC.Based on the PID principle,debugging the motion controller by the integral separation PID control and feedforward control.An integrated software which includes many multifunction modules has been developed through the Visual Studio.Finally,for motion control algorithms,the speed control algorithm for polishing head has been developed.The multi-phase velocity curve has been used based on the S-shaped curve.By the multi-phase S-curve control model,the acceleration and deceleration process become more smooth.At the same time,a contour error compensation algorithm for mobile platform has been designed to reduce the contour error,and the effect of compensation algorithm has been verified by simulation results.This thesis lays the foundation of hybrid force/position control of the polishing hybrid machine and the development of a multisensor in-situ metrology system.