Design and analysis of a multi-mode mobile robot based on a parallel mechanism with branch variation

Abstract

In this paper we propose the design idea of branch variation of a mobile parallel mechanism so that it can execute different locomotion modes. A novel robot is presented based on this idea, which can be reconfigured to be different equivalent mobile robots in topological structure.The robot is a four-limbed parallel mechanism in which each limb contains eight revolute joints. Based on the branch variation with topological reconfiguration of the parallel mechanism, the robot has 3 locomotion modes with 7 gaits to reply to different situations by analyzing its topological structure via adjacency matrixes and transformation equations.Tracked locomotion mode is realized by the motion of platforms as a 3-dof (degree of freedom) planar 6R closed-loop mechanism which can operate obstacles. Legged mode is realized by the deforming of four limbs to carry out trot-walking gait with 1-dof mechanism units. Wheeled mode is realized by the relative motion between each limb and platforms as a 4-dof mechanism to carry out fast moving and direction switching in this mode.To verify the locomotion modes and functionality of the robot, we present the results of a series of experiments, performed on a simulation system and a manufactured prototype.