Numerical Analysis of an Exoskeleton Crank Slider Series Elastic Actuator with Clearance Joints

Series elastic actuator is a very effective actuation method, which is suitable for force control applications inter-acting with ambient intelligence. The actuator is distinguished by an elastomer which placed in the transmission system. However, due to spring fatigue and joint friction, there are clearances in the actuator transmission, which will greatly affect its output performance. Therefore, we firstly developed an exoskeleton crank-slider series elastic actuator, and then established a simplified mathematical model of the actuator with clearance joints. Finally, the impact of clearance on the dynamic behavior and nonlinear response of the mechanism is explored by numerical simulation. The results show that the output of the mechanism lags behind due to the clearance, and with the increase of the hysteresis effect, the mechanism will appear chaotic behavior.