A control of underactuated hopping gait systems: acrobot example

While many researchers have been working on hopping gait systems, most of the previous works have focused on the mechanism designed by Raibert (1986) which has two actuators. We consider the acrobot, which has only one actuator as our model of a hopping gait system. In spite of the difficulty of realizing the acrobot´s hopping gait, it produces more interesting and attractive control problems than Raibert´s model. Furthermore, the hopping principle of legged systems can be understood by treating the system which is difficult to control by intuition like the acrobot