Prediction and prevention of losing steps in a helical teethed linear actuator

This paper describes the prediction and prevention of losing steps in helical teethed linear actuator (HTLA) for artificial muscle. When the rapid external force is applied to the HTLA, it becomes a state of losing steps. Therefore, it is important to predict and prevent this phenomenon. First, we clarified the phenomenon of losing steps in the HTLA by using numerical simulation with 3-D FEM. Next, we improved the force controller of the HTLA by adjusting of maximum current limit and two-degree-of-freedom PID control. As the results, the mover of the HTLA under the proposed controller was less likely to lose steps with respect to rapid external force and it was possible to improve the robustness for losing steps.