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

2019 ◽  
Vol 9 (20) ◽  
pp. 4295 ◽  
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.

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

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).

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

2020 ◽  
pp. 379-388
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).

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

2018 ◽  
Vol 232 (8) ◽  
pp. 983-993 ◽  
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.

Impact of Long Hydraulic Pipeline upon Performance of Hydraulic Control System

2011 ◽  
Vol 328-330 ◽  
pp. 2148-2151
Author(s):  
Ya Nan Zhao ◽  
Hong Wang Du ◽  
Yu Mei Li ◽  
Xiang Luo ◽  
Gang Liu
Keyword(s):  
Pressure Sensors ◽  
Control Valve ◽  
Hydraulic Cylinder ◽  
Hydraulic Control ◽  
Relief Valve ◽  
Supply Pressure ◽  
Directional Control ◽  
Cylinder Piston ◽  
The Impact ◽  
Directional Control Valve

In ocean exploitation, long hydraulic pipelines are usually applied. Using SimHydraulic software, the model of hydraulic system including hydraulic fluid, pump, hydraulic cylinder, directional control valve, relief valve, accumulator, long supply pipeline and return pipeline, is established. The position of the cylinder piston is measured by position sensor, while the supply pressure of the cylinder and the system supply pressure are measured by pressure sensors, the directional control valve is controlled by an on-off signal. The simulation was carried out, the impact of long hydraulic pipeline on system performance is also analyzed.

Experimental Test of Magneto-Rheological Directional Control Valve

2011 ◽  
Vol 383-390 ◽  
pp. 5409-5413 ◽  
Author(s):  
Maher Yahya Salloom ◽  
Z. Samad
Keyword(s):  
Experimental Test ◽  
Performance Test ◽  
Control Valve ◽  
Experimental Result ◽  
Hydraulic Actuator ◽  
Hydraulic Actuators ◽  
Directional Control ◽  
Fluid Properties ◽  
And Performance ◽  
Directional Control Valve

Directional control valve is the main part in hydraulic system which has complex construction, such as moving spool to control the direction of actuator for required speed. Utilizing MR fluid properties, direct interface can be realized between magnetic field and fluid power without the need for moving parts like spool in directional control valves. This paper dedicates the experimental test of four ways, three position MR directional control valve. The experimental methods were done by connecting the MR directional control valve with hydraulic actuators. The experiment was conducted to show the principle work of the valve functionally and performance test for valve was done. The valve works proportionally to control the direction and speed of hydraulic actuators. As a result, the experimental result demonstrates the operation of MR directional control valve using two configurations. The experimental about ON-OFF and proportional operations is discussed. The MR directional control valve can replace many types of the spool directional control valve for controlling hydraulic actuator.

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