외란 관측기를 이용한 반력 측정 직렬탄성구동기의 정교한 출력 토크 추정기 설계

Abstract

Series elastic actuator (SEA) which has a spring between an actuator and a load are mainly used in human-robot interaction applications. Reaction-force-sensing SEA (RFSEA) has been developed because of its compact design. The output torque of an RFSEA was estimated by the spring torque. However, when a load has low impedance, the conventional output torque estimation method is inaccurate. To solve this problem, a novel output torque estimator of an RFSEA is proposed in this paper. The proposed torque estimator observes angular velocity using a disturbance observer and obtains model parameters through system identifications to estimate torque. The performance of the proposed torque estimator is verified and confirmed that it is significantly more accurate than conventional output torque estimator when the load has low impedance.