著者

Sho Sakaino Tomoki Sakuma Toshiaki Tsuji

出版者

The Institute of Electrical Engineers of Japan

雑誌

IEEJ Journal of Industry Applications (ISSN:21871094)

巻号頁・発行日

vol.8, no.2, pp.279-286, 2019-03-01 (Released:2019-03-01)

参考文献数

34

被引用文献数

3

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Electro-hydrostatic actuators (EHAs) are hydraulic systems that operate without control valves, making them a compact, cheap, and highly energy efficient system. However, resonance, static friction, and oil leakage degrade their control performance. Three controllers are integrated to overcome these issues. First, static friction is suppressed by a feedback modulator (FM). Input torque is quantized to exceed the maximum static friction force, and quantization errors are suppressed by the FM. Second, resonance is canceled out by a self resonance cancellation (SRC) technique. In the SRC, both angle responses of a hydraulic pump and a hydraulic motor are measured, and the rigid body mode is extracted. Then, resonance becomes unobservable, changing the system as a second-order system. Third, modeling errors, including oil leakage, are suppressed by a self resonance cancellation disturbance observer (SRCDOB). As the SRCDOB is implemented in the rigid body mode, the cut-off frequency of the SRCDOB can be greater than that of most common disturbance observers. This combination of controllers drastically improves the control performance, and it enables control system design based on frequency.