Generation of Joint Trajectories Using Hybrid Automate-Based Model: A Rocking Block-Based Approach

Human walk is the combination of seven different discrete subphases. It is difficult to express the one gait cycle as a whole. To develop the human like bipedal robot, the walk cycle is divided into seven discrete subphases. Each subphases has its own continuous dynamics. To express this discrete behavior for the development of the more accurate bipedal robot, the hybrid automata are proposed. The bipedal walk is configured as the rocking block model. It is the first attempt to express the bipedal walk as a rocking block. During double support phases, it is configured as a vertical rectangular plane, and during the left and right leg swing, it is configured as the tilt of the rectangular rocking block in the left and right direction. In this paper, we have configured the bipedal robot as the rocking block before and after impact. The novelty of work is the configuration of bipedal walk as the rocking block and the development of hybrid automata. We configured the hybrid automata dynamic walk model for individual subjects. The trajectory generated by the model is compared with the two models of OpenSim bipedal Gait2354 and normal walk. This paper presents a new modeling technique of bipedal locomotion using hybrid automata. The hip, knee, and ankle trajectories have been synthesized from the model. The stability margin has been defined analytically. Similarly, these trajectories have been fed to a real humanoid robot HOAP2, which were able to perform the stable walking with these trajectories.