Design principle of two mass jumping system

Abstract

In our previous research, we developed a jumping legged robot aiming at expansion of mobile robot's activities. In jumping motion, the velocity and mass of robot have large effect on jumping height and motion. In order to analyze the jumping motion, one-mass or two-mass models are proposed. At the moment of jumping, the velocity of the robot in two-mass model changes rapidly because the top mass of robot lifts up the foot mass together. The balance of two masses, upper and lower bodies, is one of the important parameters to have enough jumping height. For designing a real robot, we must estimate/design the robot function, total weight, actuator type, motor power, etc, however, it is difficult to find optimal design under ill-defined constraints. It is known that relative proportion of the body and length in animals follows the elastic similarity law. One reason for the relationship is supposed that animals keep safety and robustness in the strength of body. In this paper, we propose index parameters for jumping robot by taking into account the elastic similarity law in animals, and the mass of the robot and necessary actuator power are estimated.