Exploiting human walking speed transitions using a dynamic bipedal walking robot with controllable stiffness and limb coordination

In this paper, we employ a two-dimensional dynamic bipedal walking robot to investigate the effects of controllable stiffness and limb coordination on speed transition of bipedal walking. The robot is equipped with a variable stiffness actuator at each joint. We proposed a central pattern generatorbased control method to implement limb coordination and realize independent control of torque and stiffness for the robot. Then we carry out human motion experiments on speed transitions. The comparison of hip joint kinematics and ground reaction forces between human and the robot during speed transitions shows that variable stiffness and limb coordination are important for adaptive human walking and can improve the performance of bipedal walking robot. The results may be used to exploit possible principles of complex human gaits.