Hybrid Force/Position Control Method for Robotic Polishing Based onPassive Compliance Structure

In order to realize the position control and contact force control of the polishing robot end-point, a hybrid control strategy based on passive compliant device is proposed. By installing a compliant device at the end of the robot, the force control and position control of the tool end are decoupled. One end of the compliant device is mounted at the end of the robot and the other end is connected with the polishing tool. The robot controller is used to control the position and orientation of the robot end, so as to control and compensate the position and orientation of the tool end indirectly, while the compliant device controller is used to control the contact force between the tool and the workpiece directly. Through modeling and analysis, nonlinear PD (proportional-differential) control is adopted to improve the dynamic performance of the compliant device. The simulation results show that the method can track and compensate the target trajectory, and realize rapid adjustment of the desired force. Nonlinear PD control improves the regulating time from 220 ms to 60 ms after the compliant device is disturbed. The simulation results are further verified by experiments, and good surface quality is obtained through polishing the aviation blades. The results show that the proposed control method is feasible.