Application of feedback elements in proportional electrohydraulic directional control valve with independent flows control

This study presents the static and dynamic characteristics of load-sensing and pressure-compensated directional control valve under the working conditions. A mathematical model is developed, two types of working conditions are presented through the static work point calculation. The static characteristic is analyzed by simulation, and the conclusion is validated by experiments. Solution procedure of the flow gain transfer function and flow-pressure coefficient transfer function is detailed introduced based on the above static computation, and their dynamic characteristic is analyzed by using Bode diagram. Finally, three types of compensatory modes are proposed, which provides very useful value and significance for the hydraulic component or system design and parameters optimization.

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Transient Phenomena Caused by Directional Control Valve in a Hydraulic Pipeline

Bulletin of JSME ◽

10.1299/jsme1958.16.1911 ◽

1973 ◽

Vol 16 (102) ◽

pp. 1911-1917 ◽

Cited By ~ 1

Author(s):

Koji TAKAHASHI ◽

Shigeru IKEO ◽

Yoneaki TAKAHASHI

Keyword(s):

Control Valve ◽

Transient Phenomena ◽

Directional Control ◽

Directional Control Valve

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Positioning control of hydraulic cylinder with unknown friction using on/off directional control valve

Proceedings of the Institution of Mechanical Engineers Part I Journal of Systems and Control Engineering ◽

10.1177/0959651818771522 ◽

2018 ◽

Vol 232 (8) ◽

pp. 983-993 ◽

Cited By ~ 2

Author(s):

Liyang Jin ◽

Qingfeng Wang

Keyword(s):

Predictive Models ◽

Control Valve ◽

Hydraulic Cylinder ◽

Switching Frequency ◽

Control Input ◽

Positioning Control ◽

Switching Law ◽

Directional Control ◽

Control Scheme ◽

Directional Control Valve

In this study, a prediction-based positioning control scheme is proposed for the hydraulic cylinder controlled by a solenoid operated on/off directional control valve. The discrete-valued input, low switching frequency and significant delay of directional control valve make the control problem very complex. Only a discrete-valued control input can be used here; meanwhile, the input has switching frequency constraint and time-delay. Existing methods such as pulse-width modulation control and sliding-mode control are not suitable for this problem, because chattering may arise due to the control input restrictions. The newly proposed prediction-based positioning control scheme consists of two parts: a switching law based on predictions of future states and learning algorithms which learn required predictive models online. According to accurate predictions, the switching law can control the hydraulic cylinder to target position in an optimal way, and chattering is avoided. Meanwhile, the required predictive models are identified by a generalized growing and pruning for radial basis function network and a recursive least square estimation algorithm in real time. Essentially, the problems caused by input restrictions, time-delay and model uncertainty are solved by the accurate identifications to some well-designed models. The control scheme is verified by physical experiments. Fast and accurate positioning control can be achieved for the hydraulic cylinder with unknown nonlinear friction.

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DYNAMICS OF PROPORTIONAL SPEED CONTROL VERSUS SERVO SPEED CONTROL OF A HOSE / CABLE SPOOLING DEVICE FOR WINCH

INMATEH Agricultural Engineering ◽

10.35633/inmateh-61-37 ◽

2020 ◽

Vol 61 (2) ◽

pp. 350-359

Author(s):

Alexandru-Polifron Chirita ◽

Marian Blejan ◽

Teodor-Costinel Popescu ◽

Ana-Maria Popescu

Keyword(s):

Closed Loop ◽

Dynamic Performance ◽

Control Valve ◽

Speed Control ◽

Hydraulic Cylinder ◽

Directional Control ◽

First Case ◽

Control Versus ◽

And Control ◽

Directional Control Valve

This article presents and analyses in two cases the dynamic performance of regulation and control of the linear speed of an electro-hydraulically driven mechatronic axis. In the first case, the flow control is performed with a proportional hydraulic directional control valve, while in the second case the control is performed with a servo-valve. The linear mechatronic axis is part of a complex subsystem used in both agriculture and industry, that allows the precise winding of a hose / cable on a drum with the help of a spooling device, which conditions the positioning of the hose. The speed control of the hydraulic cylinder with bilateral rod on whose liner the spooling device is fixed is performed in a closed loop with the help of transducers and a programmable controller (PLC).

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Development and Control of an Electro-Hydraulic Actuator System for an Exoskeleton Robot

Applied Sciences ◽

10.3390/app9204295 ◽

2019 ◽

Vol 9 (20) ◽

pp. 4295 ◽

Cited By ~ 1

Author(s):

Dongyoung Lee ◽

Buchun Song ◽

Sang Yong Park ◽

Yoon Su Baek

Keyword(s):

Gait Cycle ◽

Sliding Mode ◽

Control Valve ◽

Hydraulic Cylinder ◽

Hydraulic Actuator ◽

Directional Control ◽

Robot Systems ◽

Actuator System ◽

And Control ◽

Directional Control Valve

Exoskeleton robots have been developed in various fields and are divided into electric and hydraulic exoskeletons according to the actuator type. In the case of hydraulic robots, because a unidirectional pump is applied, there are limitations to the wearer’s walking. In addition, robot systems are complicated, because a directional control valve is required to change the direction of the actuator. To solve these problems, we designed the electro-hydraulic actuator (EHA) system which has both the hydraulic and electric advantages. The EHA system consists of a hydraulic bidirectional pump, a motor, a hydraulic cylinder, and various valves. For the development of the piston pump, we analyzed the gait cycle and considered the flow rate and pulsation rate. In order to reduce the size and weight of the EHA system, the valves were made from one manifold, and the hydraulic circuit was simplified. We verified that the developed EHA system is applicable to robots through position and force control experiments. Because the hydraulic system is nonlinear, we designed a sliding mode control (SMC) and compared it with the proportional integral derivative (PID) controller.

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