Design and Reflex Control for a Series Elastic Actuator Based Ankle Joint Emulator

Human body is a highly efficient stable system, although the center of mass is high. While quiet standing ankle joint has the function of resisting disturbance to maintain balance of human body. Studying the control mechanism of ankle joint helps to improve relative technologies such as bipedal robot, powered prosthesis and exoskeleton. In this paper, a series elastic actuator (SEA) based ankle joint emulator and reflex-like control algorithm are purposed to test human push-recovery mechanism. The SEA element provides an easy way for ankle joint torque control. Proportion-Derivative (PD) based reflex-like control algorithm calculates reference torque for SEA element. Experimental results indicate that this proposed emulator has the ability to mimic human ankle joint quiet standing push-recovery performance. The emulator is a useful platform to test further human ankle joint torque control function.