Design of a rendezvous robotic capture arm for DockSat

• A novel manipulator design is developed to enhance docking between nanosatellites. • A full kinematic and mechanical design of the space manipulator is presented. • The proposed manipulator stows within a 1U volume and has a reach of 660mm. This paper presents the development of a robotic capture arm designed for the DockSat mission, aimed at enhancing docking capabilities for nano-satellites. Due to the limited instantaneous thrust of small-scale thrusters on nano-satellites, their close-range manoeuvrability is restricted. To address this challenge, a capture arm with a 660 mm reach and a 1U stowed volume is designed to assist in capturing targets at close proximity. The design process follows a logical progression: first, a kinematic analysis is conducted, followed by mechanical design, and concluded with prototype testing to validate novel joint designs and characterise joint performance. Three distinct kinematic configurations are compared, and the superior design is selected. Building on this, a mechanical design is developed, with a focus on key constraints such as space limitations and motor selection. A novel cable-sheath joint is incorporated into the design, alongside a passive deployment wrist for the docking adapter end-effector. To validate the design, a prototype of a single joint is fabricated and tested, characterising its performance under different loading conditions and motion sequences.