Development of friction free controller for electro-hydrostatic actuator using feedback modulator and disturbance observer

Sakaino, Sho; Tsuji, Toshiaki

doi:10.1186/s40648-016-0070-2

Cited by 14 publications

(5 citation statements)

References 16 publications

(21 reference statements)

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“…According to this figure, an EHA can be seen as a two-inertia system, as shown in Fig. 5 (4) . Here, the disturbance force applied to the servomotor τ dis m corresponds to the reaction force caused on the hydraulic actuator.…”

Section: Ehamentioning

confidence: 99%

“…These ratios result from the separation of the driving units and actuators. Hydraulic actuators also allow considerable freedom in the system design (4) . The driving units of hydraulic actuators include electric motors, oil tanks, servo units, and hydraulic pumps in addition to power sources.…”

Section: Introductionmentioning

confidence: 99%

“…Hydraulic closed-loop circuits have smaller and more * Graduate School of Science and Engineering, Saitama University 255, Shimo-ohkubo, Sakura-ku, Saitama 338-8570, Japan efficient systems than open-loop circuits as driving units are closed within servo units and actuators (4) . Electro-hydrostatic actuators (EHAs), which are hydraulic actuators comprising closed-loop circuits with displacement volume-controlled systems, have been developed (6) (7) .…”

Section: Introductionmentioning

confidence: 99%

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Resonance-suppression Control for Electro-hydrostatic Actuator as Two-inertia System

et al. 2017

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Electro-hydrostatic actuators (EHAs) are hydraulic actuators with high power-to-weight ratios that exhibit low energy loss. Thus far, methods for determining the characteristics and parameters of EHAs have not been fully established. Therefore, modeling methods for EHA are in demand. EHAs are driven by servomotors on the motor-side and hydraulic motors on the load-side, and therefore, the actuators are expected to experience sympathetic vibrations. Thus, EHAs can be considered as systems in which two rigid objects are connected to one another with a low-rigidity shaft such as a spring. The occurrence of resonance in EHAs has not yet been discussed because of difficulties with hydraulic systems. One major problem is the large friction in hydraulic motors. We apply a feedback modulator for friction compensation to enable the experimental identification of characteristics. Assuming that EHAs experience two-inertia resonance, the parameters of the motors can be calculated. In addition, vibration-suppression techniques for two-inertia systems can be applied to EHAs. This study proposes the application of a two-inertia model to suppress vibrations in EHAs and verify their dynamic characteristics.

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Section: Ehamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Resonance-suppression Control for Electro-hydrostatic Actuator as Two-inertia System

et al. 2017

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“…It should be noted that using this method, the reference torque is only quantized when the motor's speed is low. Note that FMs do not affect the stability of the entire control system so that interference between FMs and the other controllers does not need to be considered (19) .…”

Section: Feedback Modulatormentioning

confidence: 99%

“…However, these methods are not suitable for EHAs because they rely on the response performance of servo-valves (17) . In order to overcome the problem of the dead zone, Sakaino et al implemented feedback modulators (FMs) to control the hydraulic actuators (18) (19) . Consequently, FMs are considered to be suitable for the practical implementation of EHAs.…”

Section: Introductionmentioning

confidence: 99%

Reaction Force Estimation of Electro-hydrostatic Actuator Using Reaction Force Observer

et al. 2018

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Electro-hydrostatic actuators (EHAs) are hydraulic actuators that are flexible and exhibit high backdrivability. Flexible operation and accurate detection of reaction forces are required for robots to be able to perform in environments in which they will be cohabiting with humans. However, nonlinear elements that degrade detection accuracy, such as static friction, backlash, and oil leakage, are present in hydraulic systems. In addition, pressure sensors in hydraulic systems are not very accurate at estimating reaction forces, because they cannot estimate internal forces and viscous friction. In this study, we propose a combination of control algorithms for accurately estimating reaction forces. Static friction is compensated by using feedback modulators. In addition, we use a backlash and oil leakage compensator, which do not require any models, to suppress the relative velocity between the motor-side and load-side. Then, the use of a reaction force observer (RFOB) that exploits both pressure sensors and encoders is proposed. The RFOB can be implemented because disturbances are linearized by the compensators. Experimental results show that reaction forces can be estimated with very high accuracy using the proposed RFOB. In addition, we implemented force control using the RFOB and evaluate the force tracking performances by improving the estimation accuracy.

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A Review of Single‐Cell Pose Adjustment and Puncture

Guo

Zhang

Jin

et al. 2022

Advanced Intelligent Systems

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Single‐cell manipulation technology is an essential method of cell research, with wide applications in biological engineering, medical engineering, agricultural engineering, and other precise manipulation fields. Cell pose adjustment and cell puncture are considered as two basic operations of single‐cell manipulation. Cell pose adjustment can be used for cell sorting, cell trapping, cell orientation, cell transportation, etc. It consists of direct contact manipulation methods and noncontact manipulation methods (e.g., mechanical contact method, electric field, optical field, magnetic field, acoustic field, and hydrodynamic methods). Cell puncture consists of ordinary glass needle puncture methods, piezoelectric‐assisted puncture methods, and rotational oscillatory drill puncture methods. It aims to achieve directional and quantified injection or sampling with minimal damage. Herein, the recent research progress on single‐cell pose adjustment and puncture methods is systematically summarized and discussed, which involves the basic mechanism, characteristics, limitations, and applications. Some potential directions for future research are proposed in accordance with the above analysis. It is hoped that this review can provide a reference for academic research and industrial applications of single‐cell manipulation technology.

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Development of friction free controller for electro-hydrostatic actuator using feedback modulator and disturbance observer

Cited by 14 publications

References 16 publications

Resonance-suppression Control for Electro-hydrostatic Actuator as Two-inertia System

Resonance-suppression Control for Electro-hydrostatic Actuator as Two-inertia System

Reaction Force Estimation of Electro-hydrostatic Actuator Using Reaction Force Observer

A Review of Single‐Cell Pose Adjustment and Puncture

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