Investigations On Compliance Control Technology Oriented For Robot Surface Polishing And Grinding

In the environmental contact tasks such as robot assembly,deburring and polishing,the operation requirements cannot meet by robot position control.On the one hand,the conventional position control appears as rigid contact,which is easy to damage the operation object;on the other hand,the insufficient rigidity of the robot caused the end vibration,which is reduced the operation accuracy.By improving the flexibility of the robot,the compliance control is well suited to the operation requirements.On the one hand,the accuracy of the operation is improved by controlling the end contact force;on the other hand,the operation strategy is simplified by the hybrid of the force/position information.The contact force has the primary effect on the polishing quality.In order to improve the efficiency and precision of the surface polishing,robot compliance polishing is researched in this paper.The main contents are as follows:(1)In order to choose a good compliance control carrier,a comparative study about the series elastic actuators was conducted.The theoretical model of the mainstream series elastic actuators have been established,and the main evaluation standards are summarized: the force sensitivity,the compliance,and the transferability.The influencing factors of each index are analyzed based on the derived mathematical form.(2)In order to reduce the control difficulty of the SEA,the control strategy based on position is designed,which is aimed at parameter identification and disturbance compensation.The system model is established,the influence of each variable on system performance is analyzed.For the problem of unknown friction coefficient,the reference model adaptive control is used.For the problem of external disturbance,the sliding mode control based on disturbance observer is adopted.(3)In order to improve the real-time performance of the SEA,the fuzzy controller based on torque is designed,which is aimed at control the high-order system.The control model is established,the effects of different variables on the dynamic response characteristics of the system are studied.The fuzzy PID controller of the system was designed and simulated.(4)In order to verify the feasibility and effectiveness of the SEA,an experimental study was conducted on the designed force control system.The mechanical device,software and hardware platform of the system are designed.Based on the built force test platform,the tracking effect of constant force and variable force under static and dynamic conditions is tested,and the causes of error are analyzed.A robotic force-controlled polishing platform was built,Contrast experiments of the concave-convex surface parts have been done,besides,the polishing effects were comparatively analyzed.