Characteristics analysis of a helical teethed linear actuator

This paper presents a helical teethed linear actuator (HTLA) for artificial muscles of human coexistence robots. The HTLA has small number of simple-shaped permanent magnets and coils. The advantages of this actuator are a high force constant and capability of accurate assembly. The performances of the HTLA were investigated by using 3-D finite element method (FEM). As a result, it was found that the maximum thrust force was 23.1 N, and the efficacy of the PID position control for the HTLA was confirmed. In addition, by the force control using encoder signals, the detent force was decreased to 0.56 N and the force constant was 34.9 N/A. Moreover, the control of the stiffness for flexible motions was implemented by using compliance control.