Impedance-based contact control of a free-flying space robot with a compliant wrist for non-cooperative satellite capture

This paper presents the impedance-based contact control of a free-flying space robot utilizing a compliant wrist for non-cooperative satellite capture operation. An open loop impedance control law based on contact dynamics model is introduced to realize a desired coefficient of restitution defined between a manipulator hand of a space robot and a contact point on a free-flying target. The coefficient of restitution and the damping ratio are expressed as a function of contact and impedance parameters; and hence, the impedance parameters are tuned by setting a desired coefficient of restitution and a desired damping ratio. The collision experiment using twodimensional microgravity emulator, called air-floating test bed, verifies that the proposed open loop control law is capable of realizing a desired coefficient of restitution with fairly small errors.