The workspace analysis of quadruped robot regarded as a parallel manipulator under different configurations

The quadruped mammal is one kind of animal that has the excellent motion performances (i.e. walking stability, running speed and body flexibility). Lots of attentions have focused on imitating structure/characteristic of these quadruped animals to promote the development in quadruped robot in recent years. Most of the researches are concentrated on the motion capability analysis of the quadruped robots, However, the workspace variation, which is an important characteristic to scale the static manipulation ability when the quadruped is standing with the four feet fixed on the ground, is ignored by the most of researchers. In this paper, the workspace variation of quadruped robot, when regarded as a parallel manipulator with for foot fixed on ground as a case, is studied using the first generation of MANA robot to explore feet configuration on the influence of workspace variation. This quadruped robot is designed based on the mammal skeleton, which can realize the motion of robot body by alternating the motions in four legs. Firstly, the performance indicators of the MANA are given. Then, the MANA robot is regarded as a parallel platform with four feet fixed on the ground, thus, the corresponding inverse kinematic equations are used to calculate the workspace under the given configuration. After that, variables (i.e. positions of the feet and body posture) are defined to analyze the influence on the workspace variation. At last, four cases are studied to research the overall influence of foot configurations on the workspace variation. The workspace variation analysis of the quadruped can help to optimize the feet configuration for the getting the better manipulator ability, which expands the static performance for quadruped robot.