Kinematics and Interfacing of ModRED: A Self Healing Capable, 4DOF Modular Self Reconfigurable Robot

Abstract

Modular selfreconfigurable robots (MSRs) are systems which rely on modularity for maneuvering over unstructured terrains, while having the ability to complete multiple assigned functions in a distributed way. An MSR should be equipped with robust and efficient docking interfaces to ensure enhanced autonomy and selfreconfiguration ability. Genderless docking is a necessary criterion to maintain homogeneity of the robot modules. This also enables selfhealing of a modular robot system in the case of a failed module. The mechanism needs to be compact and lightweight and at the same time have sufficient strength to transfer loads from other connected modules. This research focuses on the design of a modular robot with four degrees of freedom (4DOF) per module and with the goal of achieving higher workspace flexibility and selfhealing capability. To explain the working principle of the robot, forward kinematic transformations were derived and workspace and singularity analysis were performed. In addition, to address the issues of interfacing, a rotary plate genderless singlesided docking mechanism—RoGenSiD—was developed. The design methodology included considerations for minimal space and weight as well as for fault tolerance. As a result, this docking mechanism is applicable for multifaceted docking in latticetype, chaintype, or hybridtype MSR systems. Several locomotion gaits were proposed and benchtop testing validated the system performance in terms of selfhealing capability and generation of locomotion gaits.