| As the deeper research into the earth and planet exploration, designing novel mobile robots with higher motion performances becomes a leading research area. Traditional mobile robots including wheeled robot, legged robot, tracked robot and so on have the limitations in explorations caused by their structural properties. Right now, planet exploration robots are mainly designed as the wheeled robots, of which the repositioning performances are usually bad when overturned. To design deformable tetrahedral mobile mechanisms based on URU chain by researching the geometeic tetrahedron is the goal of this thesis.Firstly, the configuration of URU chain is discussed, the motion restriction supplied by the configurations whose R joint axis and U joint axis are parallel and orthogonal is analyzed. Then, comparative analysis of tetrahedral configuration based on different URU chains is conducted, including the initial installation angle of the Hooke hinge, the degree of freedom and the motion model of the configuration, the study object is defined. In order to verify the feasibility of this mechanism, the motion principle is analyzed, the theoretical calculation of kinematics is done.Secondly, the virtual prototype model of the mobile mechanism is made and the kinematics and dynamic simulation is performed. The theoretical analysis can be proved by this result.Finally, the control scheme is designed according to the characteristics of the mechanism. The main parts of the mobile mechanism are chosen in market and designed to manufacture, at the same time, modular URU chains are designed. The prototype is manufactured and the experimental research is conducted, achieving the expected mobile function to verify the proposed conception. The performance of the mechanism is judged preliminarily by comparing to the planetary robot TET-walker made by NASA.This paper will provide theoretical and designing foundations of the researches and developments on polyhedral mobile mechanisms. |
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