Research on force-position decoupling control technology of bonnet polishing of robotic arm

Among complex curved surface polishing technologies, bonnet polishing has developed rapidly due to its superior polishing performance, but the force-position coupling problem is still a major problem in the polishing process. This study proposes a bonnet polishing system based on a torque servo. First, the force-position coupling problem was theoretically analyzed, and a dual-disc torque servo based on magnetorheological fluid was designed. On this basis, the output-damping torque model was established. Based on the Preston equation, the complex surface grinding and polishing removal function was modeled, and a force-position decoupling model based on the torque servo was further established. Then relevant performance simulation and performance testing were performed on the torque servo to verify the feasibility of its structural design. Finally, a robotic arm bonnet polishing system based on a torque servo was built, and a series of polishing experiments were conducted on complex curved surface workpieces. The results show that the surface quality Sa and Sz values of the workpiece before and after polishing dropped from 902.75 nm to 10.74λ to 32.75 nm and 0.96λ respectively, which significantly improved the surface quality of the processed parts. In order to improve the processing accuracy of complex curved surface workpieces, a reliable polishing solution is provided.