Abstract: The research of biomimetic robot has become one of the hottest spots of robotics. As living beings evolving for many years, it is difficulty that kinematics features of organisms can completely be realized by man-made mechanisms. In order to overcome the disadvantages of low stiffness and weak function of hind limbs, which widely exist in biomimetic robot, robot dog is studied as an example to propose the rule of importance/weight so as to simplify movement joints. In other words, by considering the base behavioral characteristics and the physical construction of each joint, main functions are put in order according their importance so that each movement joint can be easily designed with mechanical structure. Based on the work mentioned above, 24-DOF robot dog is designed by using 2-DOF parallel rotation machines (RGRR-I and RGRR-II), as well as 1-DOF joint structure. It has many advantages such as simple structure, easy manufacture, high stiffness, convenient control, agile movement, etc. This method may be useful to design other kinds of biomimetic robot.

Key words: Biomimetic robot, Degree of freedom, Design, Parallel mechanisms, Rotation