| Throughout the domestic and foreign existing automatic polishing technology research and equipment development we could find that either the robot or CNC machine tool for polishing process of motion control technology were mature, but the core technology of the hybrid force / position servo control of the surface polishing- active compliance control technology were still in the phase of study and simulation with no substantive breakthrough, partial published research, although it has been supported by advanced computational methods and modern control theory, it is still difficult to competent for the hybrid force / position servo control of the surface polishing due to its control strategy is complex.In order to solve the problem, this paper developed a complaint polishing tool system based on the pneumatic transmission device with CNC milling machine, through the CNC milling machine obtaining accurate position for movements of free-form surface. It could control polishing pressure between the tool head and the work-piece surface with the pneumatic transmission device, realized the polishing process of force- position- orientation decoupling control.This paper established the mathematical model of polishing head swinging angle by analyzing the structure of the tool system, after determining the design variables, objective function and constraint conditions obtained the optimization design model of polishing head swing angle, used MATLAB to write program to solve the optimization and calculation, then adaptive angle solution was obtained, so that the tool system had better adaptive ability.This paper identified polishing force control system through the identification tool of MATLAB, deduced the transfer function of the system, established the transfer function model of the control system with MATLAB/Simulink, designed PID control by analysis of the performance of the control system with the critical ratio method and trial and error method, simulated the experiment on the step response performance of the system with PID control and without PID control by Simulink to significantly improve the control performance.This paper established a tool system experimental research platform based on LabVIEW data acquisition system, measured the normal force, tangential force of polishing process, studied on the change of friction coefficient under different parameter condition, re-deduced the polishing removal mechanism based on Preston equation. |
PDF Full Text Request