A hybrid control strategy for grinding and polishing robot based on adaptive impedance control

Haibo Zhou,Guilian Wang,Shitai Ma,Zhenzhong Liu,Yuxin Deng

doi:10.1177/16878140211004034

Haibo Zhou, Guilian Wang + Show 3 more

Open Access

https://doi.org/10.1177/16878140211004034

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Abstract

In order to realize the active and compliant motion of the robot, it is necessary to eliminate the impact caused by processing contact. A hybrid control strategy for grinding and polishing robot is proposed based on adaptive impedance control. Firstly, an electrically driven linear end effector is designed for the robot system. The macro and micro motions control model of the robot is established, by using impedance control method, which based on the contact model of the robot system and the environment. Secondly, the active compliance method is adopted to establish adaptive force control and position tracking control strategies under impact conditions. Finally, the algorithm is verified by Simulink simulation and experiment. The simulation results are as follows: The position tracking error does not exceed 0.009 m, and the steady-state error of the force is less than 1 N. The experimental results show that the motion curve coincides with the surface morphology of the workpiece, and the contact force is stable at 10 ± 3 N. The algorithm can realize more accurate position tracking and force tracking, and provide a reference for the grinding and polishing robot to realize surface processing.

Highlights

With the development of large fan blades, aircraft turbine blades, and propellers, the surface quality requirements of complex curved workpieces are constantly increasing, and the machining process requires higher precision
In order to solve the shortcomings of manual polishing and the advantages of applying industrial robots, the development of grinding and polishing robot systems and other types of automatic polishing equipment has received extensive attention.[2]
The compliant motion control considers the process of stable contact between the grinding and polishing robot and the workpiece

Summary

Introduction

With the development of large fan blades, aircraft turbine blades, and propellers, the surface quality requirements of complex curved workpieces are constantly increasing, and the machining process requires higher precision. The force sensor measures the actual contact force signal of the polishing module and converts it into the driving signal of the voice coil motor module and the posture adjustment signal of the industrial robot It is used for real-time adjustment of the end effector to realize the closed-loop control of the contact stress of the workpiece. The compliant motion control considers the process of stable contact between the grinding and polishing robot and the workpiece It includes industrial robot pose control and end effector force control. After the end of the grinding and polishing robot adjusts its posture and makes stable contact with the inclined surface, the end effector sends its displacement information to the industrial robot during the force control process. It can be seen from the average value of the two errors in Table 3 that the adaptive impedance control can achieve a smaller error tracking of the environmental position when the environmental position and stiffness are unchanged

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