Achieving Jumping Functions of a Bipedal Robot with Knee and Toe Spring Mechanisms

Abstract

This paper proposes a model for characterizing the jumping motion of a bipedal robot with knee and toe spring mechanisms. The bipedal robot has seven active DoFs for its body and legs, and two passive DoFs for its toes. The mathematical model of the robot is based on the ZMP (zero moment point) method and Newton's laws of motion to obtain the trajectory of the center of mass, the velocity of the center of mass and the flight height. The results show that the knee and toe spring mechanisms play important roles for the jumping motion. The calculated ZMP trajectory before take-off agrees with the experimental observations. In addition, the predicted flight height with the proposed model is about 8% in error compared with the measured value. That is, the models developed are in close agreement with the experimental results and are useful for analyzing the characteristics of the jumping robot.