Design of Autonomous Coupling Mechanism for Modular Reconfigurable Lunar Rovers

Modular reconfigurable robotics consist of modules that can join together to form larger entities capable of changing their morphologies for improved versatility, robustness, and cost. Coupling mechanisms play a key role in these systems, as they are the component connecting the modules and enabling the robot to change shape. Coupling mechanisms also define the structure, rigidity, and function of modular systems. This paper details the development of the autonomous coupling mechanism for SHREWs, a modular reconfigurable system of rovers designed to explore the permanently shadowed regions of the Moon. The coupling mechanism allows the modules to connect and form collaborative caravan formations, providing enhanced mobility in uncertain terrain and enabling the rovers to self-rescue when immobilized. The coupling system must withstand operational loads while the SHREWs are driving, and is designed to minimize cost, mass, and energy consumption. Other considerations include misalignment tolerance, power transmission, roll and yaw DOFs, ease of fabrication, and the ability to dock in darkness. The full design approach of the mechanism will be presented, including the development of initial concepts and the detailed design of the mechanical, electrical, and software components. The final prototype uses a computer vision algorithm to guide a robotic boom toward the opposite rover, where it docks by placing a spring-loaded plug connector into a funnel-shaped receptacle. Testing of the system and recommendations for further iterations will be discussed, as well as potential future applications of autonomous coupling in the context of NASA’s Artemis program