Water Hydraulic Proportional Valve Research Articles

Modeling and Dynamic Characteristics of a Novel High-Pressure and Large-Flow Water Hydraulic Proportional Valve

In the field of fully mechanized coal mining equipment, the hydraulic valve used in the hydraulic support is an on/off directional valve. There are many problems caused by the valve such as large pressure shock and discontinuous flow control. Therefore, a novel two-position three-way hydraulic proportional valve suitable for high-pressure and large-flow conditions is proposed to overcome the above problems. The novel valve utilizes a two-stage structure and the displacement follow-up principle is adopted between the pilot stage and the main stage to meet proportional control. In this paper, a simulation model of the novel proportional valve was established after a simplified analysis of the structural principle. Its reliability and the feasibility of the design were verified by the test results under different working conditions. Then, the step response characteristics of the proportional valve under different strokes were predicted and analyzed. Nonlinear characteristics were presented, and the closing time was shorter than the opening time because of the influence of nonlinear flow force. Under different ramp signals, the displacement of the main inlet spool was always approximately equal to the displacement of the pilot stage. Then, the motion relationship between the pilot stage and the main stage was studied, and the influence of the structural parameters on the stability was analyzed.

Investigation on the Modeling and Dynamic Characteristics of a Novel Hydraulic Proportional Valve Driven by a Voice Coil Motor

As the key control component of the water hydraulic systems, the water hydraulic proportional valve has a significant influence on the control performance of the systems. Due to the poor viscosity and lubricity of water, the valve spool resistance is large and non-linear. In this study, a novel fast-response water hydraulic proportional valve is presented. The actuator of the valve adopts a voice coil motor (VCM), which has the advantages of fast response, high control precision and small volume. In order to realize the fast control of the valve, a lever amplifier is designed to obtain enough actuation force. A detailed and precise non-linear mathematical model of the valve considering both the valve’s structural parameters and VCM electromagnetic characteristics is developed. A comprehensive performance simulation analysis has been carried out, mainly divided into an electromagnetic simulation, an analysis of the characteristics of the lever magnifier, and a dynamic performance simulation of the valve. The simulation results show that the adjusting time is about 28ms, and the maximum overshoot is about 5 %. The step response rise time is about 15 ms. The test rig of the valve and VCM have been built. The test results of the prototype show that the optimal stroke range of VCM is 4 mm to 15 mm. The maximum overshoot of the valve is around 10 %; the adjusting time is about 30 ms in the opening process and 35 ms in the closing process. The test results prove that the valve has good static and dynamic control performance.

Investigation on the modeling and dynamic characteristics of a fast-response and large-flow water hydraulic proportional cartridge valve

In large-power and high-pressure hydraulic systems, the maximum instantaneous flow rate is often several thousand liters per minute. Normal proportional valves are often difficult to meet their requirements for large flow rate and fast response at the same time. And the leakage of hydraulic oil will seriously pollute the environment. Therefore, a novel water hydraulic proportional valve with fast response and high flow capacity is presented for the large transient power hydraulic system in this paper. The valve utilizes a two-stage structure with two 2/2-way water hydraulic proportional valves as the pilot stage and a cartridge poppet valve as the main stage to achieve fast-response and large-flow capacity simultaneously. A detailed and precise nonlinear mathematical model of the valve considering both structural parameters and flow force is developed. A comprehensive performance optimization has been carried out, which can be mainly divided into computational fluid dynamics simulation optimization based on reducing flow force and multi-objective optimization based on genetic algorithm. The effects of double U-grooves' parameters on the flow force (flow-induced loads) have been studied in detail by numerical simulation. Through the grooves geometry optimization, the maximum flow force can be reduced by 10%. Then, the influences of structure parameters on the performance of step response have been studied, and the optimal parameters of the valve have been obtained by multi-objective optimization based on genetic algorithm. The maximum overshoot has been reduced from 15% to 6% (about 60%) and the adjusting time has been reduced from 58 ms to 48 ms. The dynamic characteristics of the valve have been improved effectively. Finally, a test apparatus which has the ability to provide transient large flow is built. The accuracy of simulation model and optimization design method is verified by test results.

21101 水圧用比例弁を用いた水圧シリンダの位置決め(OS10-3【ロボティクス・メカトロニクス(3)】)

This study is concerned with position control of a water hydraulic cylinder using the water hydraulic proportional valve. Modelling was made about the water hydraulic proportional valve that the authors have developed, and the water hydraulic cylinder connected to it The simulation was carried out by MATLAB/Simulink. The proportional control system was built, in which the cylinder displacement was detected by LVDT and fed back to the controller. The simulation and experimental results were compared for the step response and the response to a sinusoidal input. Since the indefinite parameters remained, the responses did not quite agree, but the settling time agreed well comparatively.

J112022 水圧駆動用90°回転型アクチュエータの開発([J11202]次世代アクチュエータシステム(2))

This paper describes design of a semi-rotary actuator of quarter-turn type for water hydraulic robotic arm that will be mounted on the deep submergence research vehicle. This actuator is vane-type, by which oscillating motion can be obtained directly. Also, the actuator is double vane-type that excessive force is not applied to bearings. Rotation angle of the actuator is 90 degrees. Metal components of the actuator is made of stainless steel. The bearings used are made of plastic. To reduce internal leakage and eliminate metal contact, plastic (UHMW-PE) plates are inserted between the sliding parts as seal material. To design the structure and dimension of the actuator, strength of the parts are analyzed by finite element method. The assembled actuator is driven by water hydraulic proportional valve. Smooth oscillating motion is obtained without any stick-slip. However, internal leakage is relatively large. Therefore, countermeasures to reduce the internal leakage are required.

COMPARISON OF VIBRATION AND PRESSURE SIGNALS FOR FAULT DETECTION ON WATER HYDRAULIC PROPORTIONAL VALVE

The goal of this paper is to detect internal leakages created by seal faults and also identify which seal is damaged from water hydraulic proportional valve using vibration and pressure signals which are analyzed using different data analysis methods. In this study water hydraulic spool valve is studied in a test system during extending and retracting strokes of cylinder while vibration and pressure signals from the valve are measured in normal and different fault situations. Feature extraction is performed using descriptive statistics and wavelet analysis to identify the most influential variables from the measured signals which are then used to classify the state of the system using Self-Organizing Maps (SOM).

Steady State and Dynamic Characteristics of Water Hydraulic Proportional Ceramic Spool Valve

AbstractWater hydraulics is both old and new technology area. The first fluid power applications were using water as pressure medium already in 18th-century, but the modern water hydraulics has been rapidly growing just recently in 1980's and 1990's. The main reasons for the comeback are environmental and safety aspects. Water hydraulics offers a significant alternative to establish motion control systems in environments, where possible oil leakage can cause serious problems.One of the major tasks to solve in modern water hydraulics is to achieve more accurate control systems than today`s technology provides. The present water hydraulic control valves are not yet at the same technology level as that of oil hydraulics. This means that a lot of effort has to be put to develop better and more accurate valve constructions and on the other hand more intelligent control methods has to be developed to achieve reasonable valve characteristics.This paper concentrates on a study of water hydraulic proportional valv...