Modeling, motion planning, and control of one-legged hopping robot actuated by two arms

A new underactuated one-legged hoping robot model is proposed for researching the utilization of the elastic energy of underactuated flexible mechanical system repeatedly, and researching the motion control method for underactuated hopping robots with dynamic balance. Only two arms actuate the hopping robot, the single elastic leg of the robot has no actuator, thus the coupling between the arms and the unactuated leg controls the hopping motion. The modeling, motion planning, and control method are investigated for this kind of hopping robot. A new time-varying feedback control algorithm is suggested based on the nonlinear transformation of inputs locally. It is shown that controlling the orientation and vibration of the leg would be essential for hoping stably, and controlling the motion of center of mass of the system can control the moving speed in horizontal direction. Some numerical simulations verified some aspects of the feasibility of the proposed model and control method. (C) 2007 Elsevier Ltd. All rights reserved.