| Curved surface parts have been applied widely in aerospace,ship,automobile,mold and etc.At present,the curved surface polishing is mainly performed manually,in order to solve the problems such as unstable quality of artificial polishing,more dust and low efficiency,the research on automatic polishing of curved surface is of great significance.In this paper,the robot polishing system based on compliance control is set up for theoretical and experimental research.The main contents are as follows:(1)Based on the analysis of the polishing process of curved surface parts,the influence factors of industrial robot polishing on the surface quality of the workpiece are studied by Preston model.A automatic polishing platform of the KUKA robot with force feedback is built and introduced.The overall framework of the polishing control software is designed.(2)The Jacobi matrix of 6 DOF robot is solved.The dynamic model of the robot is established with Lagrange method,and the important parameters of the dynamic equation are solved,such as the pseudo inertia matrix and gravity factor.The derived dynamic model is analyzed by MATLAB program,and the ADAMS simulation analysis of the dynamic model of the robot is carried out.The simulation results are in good agreement with the MATLAB solution results,which demonstrates that the model has a high accuracy.(3)Based on the theory of compliant control,the inner loop adopts the position PD control,and the external loop adopts single force feedback control,impedance control and admittance control to compare and analyze each other.Through the system simulation technology based on MATLAB/Simulink,the influences,advantages and disadvantages of each parameter of the three control algorithms are simulated respectively.Finally,the admittance control is used in this paper.According to the shortcomings of admittance control,a time-based dynamic factor is proposed to improve the admittance control algorithm,which can meet the requirements of smaller overshoot and steady-state errors at the same time.The improved algorithm is veri-fied by simulation,and the ideal control effect is obtained.(4)The compliant control software of the polishing system is designed based on VC++6.0 and LabVIEW software platform,collection of force is finished on the LabVIEW software platform,the communication between the host computer and the controlle,the development of the KUKA RSI communication protocol and its control program are finished on the VC++6.0 platform.The robot polishing system completes the correction of the track position by calling the admittance control algorithm subroutine based on the dynamic correction factor,and the feasibility of the system is verified by conducting a polishing experiment on the curved workpiece.In this paper,the KUKA robot polishing platform is built to explore the dynamic characteristics of the polishing robot.A modified admittance control algorithm based on time dynamic factor is proposed and the control algorithm is verified by experiments.The research results of this paper are of great significance for the theory and engineering application of robot surface polishing. |
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