Passive Compliance Control of Redundant Serial Manipulators

Document Type

Article

Publication Date

8-2018

Publisher

American Society of Mechanical Engineers (ASME)

Source Publication

Journal of Mechanisms and Robotics

Source ISSN

1942-4302

Original Item ID

DOI: 10.1115/1.4039591

Abstract

Passive compliance control is an approach for controlling the contact forces between a robotic manipulator and a stiff environment. This paper considers passive compliance control using redundant serial manipulators with real-time adjustable joint stiffness. Such manipulators can control the elastic behavior of the end-effector by adjusting the manipulator configuration and by adjusting the intrinsic joint stiffness. The end-effector's time-varying elastic behavior is a beneficial quality for constrained manipulation tasks such as opening doors, turning cranks, and assembling parts. The challenge in passive compliance control is finding suitable joint commands for producing the desired time-varying end-effector position and compliance (task manipulation plan). This problem is addressed by extending the redundant inverse kinematics (RIK) problem to include compliance. This paper presents an effective method for simultaneously attaining the desired end-effector position and end-effector elastic behavior by tracking a desired variation in both the position and the compliance. The set of suitable joint commands is not unique; the method resolves the redundancy by minimizing the actuator velocity norm. The method also compensates for joint deflection due to known external loads, e.g., gravity.

Comments

Journal of Mechanisms and Robotics, Vol. 10, No. 4 (August 2018). DOI.

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