An identification procedure for rate-dependency of friction in robotic joints with limited motion ranges. (June 2016)

• Record Type: Journal Article
• Authors: Iwatani, Masayoshi; Kikuuwe, Ryo
• Is Part Of: Mechatronics. Volume 36(2016)
• Page Start: 36
• Page End: 44
• Publication Date: 2016-06
• Subjects: Rate-dependent friction -- Identification -- Compensation -- Robotic manipulator; Computer integrated manufacturing systems -- Periodicals; Flexible manufacturing systems -- Periodicals; Mechatronics -- Periodicals; Productique -- Périodiques; Fabrication, Systèmes flexibles de -- Périodiques; Mécatronique -- Périodiques; Computer integrated manufacturing systems; Flexible manufacturing systems; Mechatronics; Periodicals; 629.89
• DOI: 10.1016/j.mechatronics.2016.04.002
• Languages: English
• ISSNs: 0957-4158

Abstract

Abstract: This paper proposes a procedure for identifying rate-dependent friction of robotic manipulators of which the motion is limited due to the configuration or the environment. The procedure is characterized by the following three features: (i) the rate dependency is represented by line sections connecting sampled velocity-force pairs, (ii) the robot is position-controlled to track desired trajectories that are some cycles of sinusoidal motion with different frequencies, and (iii) each velocity-force pair is sampled from one cycle of the motion with subtracting the effects of the gravity and the inertia. The procedure was validated with a six-axis industrial robotic manipulator YASKAWA MOTOMAN-HP3J, of which the joints are equipped with harmonic-drive transmissions of the reduction ratios of 81.5–224. The experimental results show that the identification is achieved with a sufficient accuracy with the 20 degrees of motion of each joint. In addition, the results were utilized for friction compensation, successfully reducing the effect of the friction by 60–80%.