S2MBot: A Spherical Self-Reconfigurable Modular Robot with High Torque Output Capability - Design and Simulation

This paper presents the design of a spherical self-reconfigurable modular robot for in-orbit servicing applications that meets the requirements of high torque, high-precision force, and position transmission, as well as robust and reliable communication transmission. First, the morphology of the modular robot (including the number and arrangement of DOF, the number and arrangement of interfaces) is designed based on the geometric morphology design method, and based on the morphology design results, the main structure including three rotary joints, transmission parts and support parts is designed. Then, considering that the modular robots need to realize the transmission of large torque and large amount of current and information, a four-taper rod/taper hole type mechanical docking interface and a multi-contact type electronic control interface are designed, and a plug-and-play mechatronic docking interface with large torque locking and strong stable locking retention capability is also designed. In addition, considering the needs of sensing, transmission and data processing of the modular robot, an electronic control system including a sensor unit, a communication unit and a control unit is designed. Finally, to ensure the reliability and safety of the modular robot during task execution, the key components are subjected to stress analysis and stress-strain simulation. The simulation results demonstrate that the structural strength safety factor is greater than 1.5, which meets the design requirements.