Research on the performance of a novel electro-hydraulic proportional directional valve with position-feedback groove

Abstract

Accurate posture control of hydraulic roof supports, which use pressurized water as their fluid power source, is an important part and research direction of intelligent fully mechanized mining face. At present, the large flow on/off directional valve used on the hydraulic roof support cannot meet the requirement of precise posture control of the roof support. To overcome the conundrum, a novel two-position three-way electro-hydraulic proportional directional flow valve for hydraulic roof support is proposed. The new valve contains two pilot stages and two main spools. The two pilot stages cooperate with each other to control the movement of the two main valve spools, which are the inlet valve spool and the outlet valve spool. The inlet valve spool adopts the Valvistor principle. The valve can realize manual pilot control and electro-hydraulic proportional flow control of the passage P-A, which has been verified by a simulation model. In this paper, the static and dynamic mathematical models of the new proportional valve are established, and the key parameters affecting the valve performances are analyzed and verified by the simulation model. An optimization control scheme is proposed to overcome the influence of supply pressure, P-A pressure difference, and nonlinear interference force on steady-state displacement and response speed of the valve. The results show that this optimization method can significantly improve the response speed of the spool and promote the linearity of spool displacement under a slope signal. In addition, the fluctuation of chamber pressure and spool displacement caused by the discontinuous flow of a fast switching valve is systematically analyzed. The analysis shows that increasing pulse-width modulation carrier frequency is an effective way to reduce fluctuation amplitude. The research provides a new design idea and control method for an electro-hydraulic proportional directional valve of hydraulic roof support.

Characteristics Analysis of the Pilot-Operated Proportional Directional Valve by Experimental and Numerical Investigation

“…As shown in Figure 1, this product is a proportional directional valve with pilotoperated open-loop control, consisting of a main valve (4), an intermediate valve (3), and a pilot valve (2); both the pilot valve and the main valve are spool valve structures. The pilot valve, valve 2, is a three-way pressure-reducing valve driven by a proportional electromagnet.…”

“…Proportional directional control valves are widely used in industrial applications [1]. The main function of the proportional directional valve is to control the oil flow direction and flow size by controlling the displacement of the spool to be proportional to the input signal [2,3]. Their main feature is a continuous direction and flow control.…”

Multi-objective optimization design of two-dimensional proportional valve with magnetic coupling

“…where, FX nm is the magnetic component force generated along the X-axis direction between the labeled n surface and the labeled m surface. According to equation (11), the resultant force of the inner rotor in the X-axis direction can be expressed as:…”

“…Therefore, electro-hydraulic proportional valves have been widely used in many civil fields. [10][11][12][13][14] As the proportional valve is an important development direction of the electro-hydraulic servo control technology, researchers are constantly exploring the proportional valve's structural innovation. 9,[15][16][17][18][19] However, the independence of the pilot stage and the power stage makes it difficult to improve the power-toweight ratio of the proportional valve.…”

Research and Experimental Analysis of Hydraulic Cylinder Position Control Mechanism Based on Pressure Detection

“…Jiang Haiyu studied the electric and hydraulic position control system of a valve controlled cylinder based on a high-speed switch valve [23]. Zhao Ruihao proposed a novel two-position three-way electro-hydraulic proportional directional flow valve for hydraulic roof support [24]. Shi Jianpeng proposed a velocity and position combined control strategy based on mode switching control the boom and arm of hydraulic excavator [25].…”