著者

Kyo Kutsuzawa Sho Sakaino 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.9, no.5, pp.505-514, 2020-09-01 (Released:2020-09-01)

参考文献数

22

被引用文献数

4

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The robots used in our daily lives come in contact with the environment not only directly, but also through grasped objects and tools. In such cases, the shape of the grasped objects could be unknown or uncertain; thus, the shape must be estimated using information about the contact. However, previous studies could not estimate the shape of the grasped objects without knowledge about the contact environment. In this study, unscented particle filters were used to estimate the contact positions, contact forces, and shape of the tools, simultaneously. In addition, we verified that the proposed method can estimate these characteristics by measuring the force and torque in the robots.

著者

Tetsuro Akagawa Sho Sakaino

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.12, no.1, pp.26-32, 2023-01-01 (Released:2023-01-01)

参考文献数

27

被引用文献数

2

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Recent research in the field of robotics has primarily focused on motion generation methods using imitation learning to adapt to various environments. Human-level speed motion can be imitated by combining imitation learning with bilateral control. In this approach, prediction errors accumulate in the leader because this method requires a leader state that does not exist during autonomous operation. This issue is caused by the low-frequency prediction error of the leader's responses during autonomous operation. Therefore, this paper describes a training model for predicting a leader's state by eliminating low-frequency prediction errors during autonomous operations. The proposed training model predicts the high-frequency state of the leader-follower differential. Because the low-frequency of the leader is not included in the information input and output of the proposed training model, the low frequency prediction error of the leader does not occur during autonomous operation. During our analysis, while writing letters on a paper on a slope, the previous training model failed to write letters when the paper position moved away from the robot. By contrast, only the proposed training model achieved writing at all positions in the experiment.

著者

Sho Sakaino Tomoya Kitamura Naoto Mizukami 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.10, no.2, pp.124-133, 2021-03-01 (Released:2021-03-01)

参考文献数

47

被引用文献数

4

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In functional electrical stimulation, the time delay between an input voltage and the corresponding muscle force is a significant issue. This study revealed that the joint angle/voltage relationship can be modeled as a fourth-order system. This enables the inclusion of a time delay in the high-order phase delay of the force/voltage relationship, which may lead to delay recovery using a suitable controller. Accordingly, a full state feedback controller is proposed in this study, to recover the phase delays. Jerk measurement is mandatory for full state feedback controllers owing to the joint the fourth-order joint angle/voltage relationship. This issue can be solved by the recent development of high-resolution encoders. Finally, the validity of the proposed method was verified experimentally.

著者

Tetsuro Akagawa Sho Sakaino

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

pp.22002155, (Released:2022-09-09)

被引用文献数

2

---

Recent research in the field of robotics has primarily focused on motion generation methods using imitation learning to adapt to various environments. Human-level speed motion can be imitated by combining imitation learning with bilateral control. In this approach, prediction errors accumulate in the leader because this method requires a leader state that does not exist during autonomous operation. This issue is caused by the low-frequency prediction error of the leader's responses during autonomous operation. Therefore, this paper describes a training model for predicting a leader's state by eliminating low-frequency prediction errors during autonomous operations. The proposed training model predicts the high-frequency state of the leader-follower differential. Because the low-frequency of the leader is not included in the information input and output of the proposed training model, the low frequency prediction error of the leader does not occur during autonomous operation. During our analysis, while writing letters on a paper on a slope, the previous training model failed to write letters when the paper position moved away from the robot. By contrast, only the proposed training model achieved writing at all positions in the experiment.

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.