Optimization of jumping motion of a legged robot for different take-off postures

This paper deals with an optimal jumping motion of a four-link legged robot that minimizes the necessary joint torques during the motion. A fixed amount of translational energy is supplied to the robot from joint torques by the take-off time when the foot leaves the ground, and the rotations of joints are stopped in the air by the time when the robot reaches the maximum height with the joints fully extended. Numerical optimization results for different take-off postures show that the take-off posture that is close to a singular configuration has an advantage in supplying translational energy efficiently in ground phase, and is also useful for reducing the rotational energy that has to be eliminated in aerial phase.