Optimal Design, Modeling and Force Control of Tension Generator Driven by Parallel Elastic Actuator

Abstract

This paper proposes a novel actuator that can generate desired tension by torque control to provide the necessary load for physical exercise. In order to reduce the required torque level of the motor, a spring is incorporated in this actuator design such that the torque (and thus tension) can be generated not only by the motor but also from the spring. The proposed mechanism is a type of Parallel Elastic Actuator (PEA), which consists of the motor, the spring, and the reduction gear. Dynamic model and analysis of PEA are developed in this paper to properly understand the working principle of PEA. The precise analysis of the proposed mechanism is conducted based on the developed model. The optimal characteristic of the spring and the gear ratio are determined to generate large torque while utilizing motor torque efficiently. In addition to this optimal design, the force controller is developed for the proposed actuator module, considering the dynamic characteristic of PEA. Finally, the performance of the proposed PEA and controller is verified through experiments. © 2021 IEEE.