Hybrid head mechanism of the groundhog-like mine rescue robot

Since mining accidents severely threaten production safety, robotic assistant systems can play an important role by searching and rescuing survivors in hostile underground environments. Accordingly, this paper focuses on the design, modeling and optimization of a 4UPS+PU spatial hybrid manipulator, which serves as the dexterous head section of a quadrupedal, groundhog-like mine rescue robot. This biologically inspired mechanism has three degrees of freedom (DOF), one translation and two rotations. Additionally, a passive leg is connected to both centers of the base and the moving platform in order to constrain undesirable motion. In order to evaluate the operational capacity, an analysis of the mobility and the inverse kinematics are conducted. The reachable workspace is generated with a boundary-searching discretization approach, and the local and global performance atlas, including stiffness and dexterity, are investigated. The multi-population evolution of structural and behavioral parameters is implemented to seek the optimal dexterity of the hybrid head mechanism.