Fuzzy Force Compliance Control for Cleaning Processing

A special designed dual-spindle tool was assembled on the end of a Cartesian robot for purpose of cleaning up mounting holes of carbon anodes used in aluminum electrolytic production. Spiral grooves distributed around inner wall of the mounting holes lead to force compliance issues during cleaning process. Decomposing the task space into force and position control directions, the compliance movement of the scraping tools was accomplished based on hybrid force-position method. Fuzzy strategy combining with conventional PI controller was utilized to perform torque control of scraping blades of the cleaning tool while the environment stiffness is uncertain. The control algorithm was realized in a programmable logic controller based on look-up table of fuzzy rules. Cleaning tests in actual production line were also performed that indicated the validity of the force compliance controller.