Kinematics of a quadruped/biped reconfigurable walking robot with parallel leg mechanisms

In recent years, the research of life assistive walking robot has become a new study hotspot in the robot research area and a great development has been made. This paper introduces a quadruped/biped reconfigurable walking robot used for the elderly and disabled people. By using the parallel leg mechanism, the walking robot can improve the payload-weight ratio, save the battery energy and prolong the walking time. The quadruped walking robot has the features of good stability and high safety. In smooth road, the robot walks with four legs, so that the fearful feeling of user during disabled people riding the biped walking robot can be eliminated. Since the seat has a steep slope, when going up and down stairs/steps, if the robot walks with two legs, the body slope caused by the quadruped walking robot can be remedied. The implementation of mechanism for the reconfigurable quadruped/biped walking robot is described. The 3-UPU PM (parallel mechanism) with 3-DOF (degrees of freedom) and the 6-SPU PM consisting of two 3-SPU are synthesized and analyzed. The application of the parallel mechanism to the reconfigurable quadruped/biped walking robot and the workspace of 3-UPU and 6-SPU parallel leg mechanisms are discussed. The mobility of the reconfigurable quadruped/biped walking robot is analyzed by the calculation of DOF. This research provides a theoretical basis for further investigate of the walking robot with quadruped/biped reconfigurable parallel leg mechanisms.