Pressure feedback effects of electro-hydraulic actuator system

Choi, Jong Yoon; Lee, Kyung Ha; Baek, Seung Guk; Park, Sung Chul; Moon, Hyungpil; Choi, Hyouk Ryeol; Koo, Ja Choon

doi:10.1109/urai.2014.7057454

Cited by 2 publications

(3 citation statements)

References 2 publications

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“…This work can be effectively used with Brito 27 which addressed issues such as impulsive surging pressure measurement and scale factor determination which set it aloof from the issues, 28 which proposed a backstepping algorithm for the position control of nonlinear electro-hydrostatic actuators (EHAs) involving uncertainties and Choi et al 29 which ascertained the dynamic characteristics of EHA through pressure feedback having the role of damping to tackle resonance problem, which have not been considered in this proposed setup.…”

Section: Resultsmentioning

confidence: 99%

Actuation dynamic modeling and characterization of an electrohydraulic system

Das

Mishra

Saha

et al. 2016

Proceedings of the Institution of Mechanical Engineers, Part I:

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The physical model of an electrohydraulic actuation system with pressure-reducing cylinder end cushioning has been obtained. In order to arrive at the closure of the model, experimental models for actuator friction and the characteristics of the relief, non-return and proportional valves have been constructed. The variation in discharge through the proportional valve with both pressure and command signal has been modeled by training a neural network with experimental data. For the characterization of the discharge through the proportional valve, besides square root of the pressure drop in each metered orifice, polynomial forms of command signal for the discharge coefficients have been used. Such a direct characterization of the discharge with the command signal eliminates the orifice opening as an intermediate variable. A simple friction model that retains all the features of the existing complex models has been developed. Parameters such as maximum dynamic friction and the corresponding velocity have been introduced for this purpose. All these nonlinear subsystem models have been integrated together in MATLAB/Simulink frame to predict the actuation dynamics. The variations in the predicted and experimental displacements of the piston against different command signals have been found to be quite close to each other.

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Section: Resultsmentioning

confidence: 99%

Actuation dynamic modeling and characterization of an electrohydraulic system

Das

Mishra

Saha

et al. 2016

Proceedings of the Institution of Mechanical Engineers, Part I:

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show abstract

“…As a result, the pump-controlled EHA has higher energy efficiency than the conventional hydraulic actuator and the valve-controlled type of EHA [5,9]. However, most EHA studies conducted thus far have focused on valve-controlled EHAs [11][12][13][14][15][16][17][18]; these types offer a quick response, but their energy efficiency is low due to the supply of constant pressure [5]. Due to this constant pressure supply, leakage from the valves increases gradually.…”

Section: Introductionmentioning

confidence: 99%

“…In addition, backstepping control, adaptive robust control, adaptive sliding mode control, and pressure feedback have been utilized in experimental efforts to address the nonlinearity issue of valve-controlled EHAs. However, with the valve-controlled method, the double-rod cylinder and single-rod cylinder used are dynamically different and applying the load to the robot leg with the single-rod cylinder was found to be challenging [12][13][14][15][16]. Although non-linear control methods have been demonstrated with valve-controlled EHAs, these systems remain associated with low energy efficiency levels due to leakage problems stemming from the valve characteristics [5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Design and Performance of Nonlinear Control for an Electro-Hydraulic Actuator Considering a Wearable Robot

et al. 2019

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In the development of a wearable robot, compact volume size, high energy efficiency, and a high load capacity linear actuator system are necessary. However, conventional hydraulic actuator systems are difficult to apply to wearable robots. Also, they have nonlinearities because of the presence of hydraulic fluid in a single rod cylinder. Electric linear actuators resolve the problems of hydraulic systems. However, due to their low load capacity, they are not easy to apply to wearable robots. In this paper, a pump-controlled electro-hydraulic actuator (EHA) system that considers the disadvantages of the hydraulic actuator and electric actuator is proposed for a wearable robot. Initially, a locking circuit design is considered for the EHA to give the system load holding capacity. Based on the developed model, the adaptive sliding mode control (ASMC) scheme is designed to resolve the nonlinearity problem of changes in the dynamic system. The ASMC scheme is then modeled and verified with Simulink. In order to verify the performance of the proposed adaptive control with the model, experiments are conducted. The proposed EHA verifies that the ASMC reaches the target value well despite the existence of many model uncertainties.

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Pressure feedback effects of electro-hydraulic actuator system

Cited by 2 publications

References 2 publications

Actuation dynamic modeling and characterization of an electrohydraulic system

Actuation dynamic modeling and characterization of an electrohydraulic system

Design and Performance of Nonlinear Control for an Electro-Hydraulic Actuator Considering a Wearable Robot

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