A Three-Finger Gripper Prototype for Autonomous Free-Flying Manipulation of On-Orbit Logistics

Astrobee is a free-flying robot aboard the International Space Station (ISS) that performs autonomous microgravity manipulation tasks such as anchoring onto smooth surfaces and perching onto ISS handrails. Autonomous free-flying intra-vehicular robots that transport cargo could help manage on-orbit logistics for future crewed and uncrewed space stations. However, cargo transport in microgravity presents novel challenges in ensuring contact-rich free-flying manipulation. The authors propose a novel prototype of a three-finger underactuated tendon-driven gripper for Astrobee to manipulate cargo logistics in microgravity. By leveraging Astrobee's reconfigurable perching arm payload, this prototype is capable of contact-rich grasping and transport of a single-size ISS cargo transfer bag (CTB). This article presents the hardware design, gripper prototype, and payload testing at Astrobee's Granite Lab testing facility.