Premium
Torque control of a series elastic actuator using an ultrasonic motor with angular‐velocity saturation
Author(s) -
Nakamura Toshiya,
Yashiro Daisuke,
Yubai Kazuhiro,
Komada Satoshi
Publication year - 2021
Publication title -
electrical engineering in japan
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.136
H-Index - 28
eISSN - 1520-6416
pISSN - 0424-7760
DOI - 10.1002/eej.23297
Subject(s) - control theory (sociology) , torque , actuator , overshoot (microwave communication) , vibration , ultrasonic motor , controller (irrigation) , integrator , angular velocity , physics , saturation (graph theory) , mechanics , engineering , acoustics , mathematics , computer science , classical mechanics , control (management) , agronomy , quantum mechanics , voltage , artificial intelligence , combinatorics , biology , electrical engineering , thermodynamics
A series elastic actuator (SEA) using an ultrasonic motor (USM) and an elastic element has attracted attention as a compact actuator with high torque–weight ratio and high force control performance. However, an elastic element in a SEA often causes mechanical vibrations. To suppress these vibrations, studies implemented the state feedback of the motor‐ and load‐side angles. However, as the controller has many integrators, the control system becomes unstable when the angular‐velocity of the USM is saturated. Therefore, in this study, integrators in the controller were reduced in number. Furthermore, a limit error feedback controller was designed to suppress the windup phenomenon caused by the integrators. The frequency analysis using a describing function showed that stability is guaranteed even if the angular‐velocity is saturated. In addition, the experimental results indicate that an overshoot of the torque response is suppressed.