A Novel Force-Controlled Spherical Polishing Tool Combined With Self-Rotation and Co-Rotation Motion

Xiang Wu,Zhi Huang,Haitao Liu,Xiang Chen,Yongjian Wan

doi:10.1109/access.2020.2997968

Abstract

In order to improve the polishing efficiency and aim at the problem that the positioning error of industrial robot will cause the fluctuation of polishing force and the instability of removal function, a novel force-controlled spherical polishing tool combined with self-rotation and co-rotation motion for automatic polishing process is presented. The spherical polishing tool, which is integrated into the end of arm of an industrial robot for workpiece profile polishing has a linear voice coil motor to provide compliance and polishing force in the polishing process. The fluctuation of the polishing force caused by the positioning error of the robot can be effectively reduced, and a stable symmetric Gaussian removal function can be obtained by optimizing the ratio of co-rotation to self-rotation speed of the end-effector. The main advantage of the polishing method is that the polishing force can be actively controlled according to the pre-planned polishing requirements. By measuring the responsiveness and the stability of the polishing force using the proposed end-effector, it is verified that the polishing method can better adapt to the fluctuation of the polishing force and has a good performance in achieving remarkable polishing force tracking. The effectiveness of the proposed polishing method in ensuring the stability of removal function and surface convergence efficiency is verified through polishing experiments. The robotic flexible polishing method has great application prospect in processing large-sized optical components. It significantly improves the precision of polishing force and the surface convergence efficiency of the workpiece.

Highlights

Polishing is frequently used as a precision machining process to improve the surface precision of workpieces
THE STABILITY OF MATERIAL REMOVAL FUNCTION According to the Preston theory and the constructed material removal modeling as described above, the polishing force error will directly affect the polishing process
In order to verify the effectiveness of the proposed end-effector on polishing force control, five sets of fixed spot polishing experiments were conducted on a SiC specimen with a diameter of 130 mm

Summary

INTRODUCTION

Polishing is frequently used as a precision machining process to improve the surface precision of workpieces. To obtain the removal function modeling, we established the instantaneous geometric motion relationship of the contact area between the workpiece and the proposed polishing tool. In order to obtain a symmetrical Gaussian removal function and have a high material removal efficiency, the angular velocity ratio (ωz : ωy) of the polishing tool designed in this paper was selected as 1: 4. B. STRUCTURAL DESIGN Figure 4 shows the three-dimensional assembly drawing of the mechanical structure of the proposed force-controlled spherical polishing tool combined with self-rotation and corotation motion. STRUCTURAL DESIGN Figure 4 shows the three-dimensional assembly drawing of the mechanical structure of the proposed force-controlled spherical polishing tool combined with self-rotation and corotation motion It is mainly composed of a rotating mechanism and an electric control mechanism. In order to reduce the polishing force tracking error from the modeling error, the controller is proposed as u=

Kd def dt

La dia dt

CONCLUSION AND FUTURE WORKS