Thomas Battista, Michael Andonian, Jake Singh, Ashtin Cheng, Kevin Chow
The Aerospace Corporation, El Segundo, CA, 90245
We study a scenario where a principal spacecraft, outfitted with a three-link robotic arm, looks to mitigate contact-induced disturbance forces when capturing a nearby object. This effort is motivated by the increased role that spacecraft robotics is expected to play as applications like on-orbit servicing and manufacturing, as well as debris capture and deorbit, become more prevalent. Stiffness control, impedance control, and admittance control are three chosen
schemes for controlling the robotic arm, which are analyzed using internally developed contact simulation capabilities. The simulation uses a generic contact model for the collision between the contacting object and the robotic arm. For the chosen contact model, we observe that robot arm controllers designed to be compliant during contact – low stiffness, impedance, and admittance control - performed better throughout the scenario with respect to our metrics, which asses the controller’s ability to mitigate the contact effects felt by the spacecraft bus. Admittance control in particular appears to have properties that make it the best overall performer in our scenario.