Dynamic gait transition between walking, running and hopping for push recovery

Re-planning of gait trajectory is a crucial ability to compensate for external disturbances. To date, a large number of methods for re-planning footsteps and timing have been proposed. However, robots with the ability to change locomotion from walking to running or from walking to hopping were never proposed. In this paper, we propose a method for replanning not only for footsteps and timing but also locomotion mode which consists of walking, running and hopping. The re-planning method of locomotion mode consists of parallel computing and a ranking system with a novel cost function. To validate the method, we conducted push recovery experiments which were pushing in the forward direction when walking on the spot and pushing in the lateral direction when walking in the forward direction. Results of experiments showed that the proposed algorithm effectively compensated for external disturbances by making a locomotion transition.