Installing force-controlled end-effectors on the end of industrial robots has become the mainstream method for robot force control. Additionally, during the polishing process, contact force stability has an important impact on polishing quality. However, due to the difference between the robot structure and the force-controlled end-effector, in the polishing operation, direct force control will have impact during the transition from noncontact to contact between the tool and the workpiece. Although impedance control can solve this problem, industrial robots still produce vibrations with high inertia and low stiffness. Therefore, this research proposes an impedance matching control strategy based on traditional direct force control and impedance control methods to improve this problem. This method’s primary purpose is to avoid force vibration in the contact phase and maintain force–tracking performance during the dynamic tracking phase. Simulation and experimental results show that this method can smoothly track the contact force and reduce vibration compared with traditional force control and impedance control.

This paper aims to reduce vibration of end-effectors caused by low stiffness and large inertia of industrial robots during grinding and polishing, and to further improve the performance of force control. The proposed method to solve this problem is impedance matching. An additional impedance is introduced to match coupling impedance with industrial robots and end-effectors. The results obtained in simulations and experiments prove that the proposed approach can achieve minor vibration than traditional force control.