Passive arbitration in adaptive shared control of robots with variable force and stiffness scaling. (April 2023)

• Record Type: Journal Article
• Authors: Balachandran, Ribin; De Stefano, Marco; Mishra, Hrishik; Ott, Christian; Albu-Schaeffer, Alin
• Is Part Of: Mechatronics. Volume 90(2023)
• Publication Date: 2023-04
• Subjects: Human–robot interaction -- Shared control -- Adaptive arbitration -- Teleoperation -- Passivity -- Stability; 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.2022.102930
• Languages: English
• ISSNs: 0957-4158

Abstract

Abstract: In mixed-initiative shared control, the final control command to the robot is a weighted sum of the commands from two or more agents (human operators or automatic control systems). In force controlled robots, scaling of forces without power-consistent scaling of velocities leads to loss of passivity of the overall system. In this work, we first pose the problem statement related to position drift, while using a state-of-the-art, passivity ensuring method for scaling of forces. We then formulate adaptive mixed-initiative shared control as an adaptive stiffness control approach. We ensure passivity of the adaptive stiffness controller with a novel, model-independent method. The salient features, benefits and limitations of the approach are emphasized through analyses, simulations and hardware experiments. The proposed approach is finally validated with a practical shared control task. Highlights: A passivity-based method for adaptive arbitration in shared control of robots. Arbitration formulated as adaptive stiffness problem, which is not done earlier. A novel model-free, gain-gradient limitation method for passivity. Compared to state-of-the-art method with analyses, simulations and experiments. Validated with a practical task requiring precision in both position and force.