A flexible opening and closing control method of an electromagnetic valve based on speed feedback

Abstract

The application discloses a flexible opening and closing control method of an electromagnetic valve based on speed feedback and belongs to the field of electromagnetic valve control. Different driving voltages are respectively used to drive each stage of the controlled electromagnetic valve, and each driving voltage is connected to the controlled electromagnetic valve through switching of a switching switch. A magneto-electric vibration speed sensor is installed on the controlled electromagnetic valve, and the magneto-electric vibration speed sensor converts the vibration signal of the controlled electromagnetic valve into an electric signal reflecting the moving speed of the valve core. The moving speed of the valve core is detected in real time through the magneto-electric vibration speed sensor, and the speed feedback controller is fed back, so that the starting time and the ending time of the negative voltage loading of the opening movement and the starting time and the ending time of the high voltage loading of the closing movement can be accurately controlled, the deceleration of the opening and closing movement of the electromagnetic switch valve is realized, and flexible opening and closing are realized.

Description

Technical Field

[0001] This invention belongs to the field of solenoid valve control, specifically relating to a flexible opening and closing control method for solenoid valves based on speed feedback. Background Technology

[0002] Solenoid valves offer advantages such as high precision, small size, high reliability, contamination resistance, and low cost, making them a fundamental control element in digital hydraulics. The discrete fluid generated by their high-frequency continuous opening and closing can simulate the behavior of continuous fluid. However, during this process, the valve core impacts the valve body at a high speed each time, resulting in significant noise and vibration, as well as wear on component surfaces. These factors not only greatly affect the lifespan of the solenoid valve but also damage its sealing performance, impacting its control accuracy.

[0003] The best way to solve the above problem is to propose a method to reduce the impact speed between the valve core and the valve body during the opening and closing of the electromagnetic switch valve.

[0004] Existing research on addressing the aforementioned problems mainly falls into two categories: structural optimization and control strategy adjustment. Regarding structural optimization, research involves adding a squeeze film damper to reduce the impact velocity during the opening and closing of the solenoid valve; however, this method can only be used in the early stages of solenoid valve design. As for control strategy adjustment, research focuses on designing closed-loop controllers based on measured or estimated valve spool positions; however, closed-loop controllers that estimate valve spool positions using measured parameters suffer from significant positional errors. Therefore, the best approach to solving these problems is to propose a flexible opening and closing control method for the solenoid valve based on velocity feedback. Summary of the Invention

[0005] To address the problems in the prior art, this invention proposes a flexible opening and closing control method for electromagnetic valves based on speed feedback.

[0006] The technical solution of the present invention is as follows:

[0007] The present invention first provides a flexible opening and closing control method for a solenoid valve based on speed feedback, wherein one opening and closing cycle of the solenoid valve includes at least an opening phase, an opening maintenance phase, a closing phase, and a closing maintenance phase;

[0008] The control method includes the following steps:

[0009] 1) Each stage of the controlled solenoid valve is driven by a different driving voltage, and each driving voltage is connected to the controlled solenoid valve through switching of a switch; a magnetoelectric vibration velocity sensor is installed on the controlled solenoid valve; the magnetoelectric vibration velocity sensor converts the vibration signal of the controlled solenoid valve into an electrical signal reflecting the speed of the valve core movement.

[0010] 2) During the opening phase, the speed detected by the magnetoelectric vibration speed sensor is compared with the set speed value V1 input by the user in the speed feedback controller. If the detected speed is greater than V1, the speed feedback controller causes the voltage output controller to output a negative voltage to the controlled solenoid valve to reduce the valve core movement speed during the opening phase.

[0011] 3) During the closing phase, the speed detected by the magnetoelectric vibration speed sensor is compared with the user-inputted speed value V2 in the speed feedback controller. If the detected speed is greater than V2, the speed feedback controller causes the voltage output controller to output a positive voltage to the controlled solenoid valve to reduce the valve core movement speed during the opening phase.

[0012] As a preferred embodiment of the present invention, in step 1), the magnetoelectric vibration velocity sensor is installed on the valve body of the controlled solenoid valve, and the magnetoelectric vibration velocity sensor and the controlled solenoid valve are installed on the same axis.

[0013] As a preferred embodiment of the present invention, in step 2), the loading time t1 when the negative voltage is applied to the controlled solenoid valve is the moment when the speed is detected to be greater than V1, the loading time t2 when the negative voltage ends is the moment when the valve core is fully opened, and the loading duration of the negative voltage is t2-t1.

[0014] As a preferred embodiment of the present invention, in step 3), the loading time t3 when the positive voltage is applied to the controlled solenoid valve is the moment when the speed is detected to be greater than V2, the loading time t4 when the positive voltage ends is the moment when the valve core is completely closed, and the loading duration of the positive voltage is t4-t3.

[0015] As a preferred embodiment of the present invention, the positive voltage is 24V and the negative voltage is -24V. The negative sign indicates that when the negative voltage is applied, the direction of the current in the coil of the controlled solenoid valve is opposite to that when the positive voltage is applied.

[0016] As a preferred embodiment of the present invention, the frequency of the vibration signal of the controlled solenoid valve is more than five times greater than the natural frequency of the magnetoelectric vibration velocity sensor.

[0017] Compared with existing technologies, this invention uses a magnetoelectric vibration velocity sensor to detect the valve core movement speed in real time and feeds it back to the speed feedback controller. This enables precise control of the negative voltage loading and termination times for the opening movement, and the high voltage loading and termination times for the closing movement. This achieves deceleration of the opening and closing movement of the electromagnetic switch valve, reduces vibration and noise during the opening and closing of the electromagnetic switch valve, extends the life of the electromagnetic switch valve, and further improves the accuracy and reliability of the electromagnetic switch valve-controlled hydraulic system. Attached Figure Description

[0018] Figure 1This is a schematic diagram of the mechanical model of a magnetoelectric vibration velocity sensor.

[0019] Figure 2 This is the amplitude-frequency curve.

[0020] Figure 3 This is the phase frequency curve.

[0021] Figure 4 This is a diagram showing the connection between the electromagnetic switch valve and the sensor.

[0022] Figure 5 This is a schematic diagram illustrating a flexible opening and closing control device for a solenoid valve, as shown in the embodiment.

[0023] Figure 6 The diagram shows the deceleration effect during the initial phase (V1 = 0.27 m / s);

[0024] Figure 7 The diagram shows the deceleration effect during the initial phase (V1 = 0.28 m / s).

[0025] Figure 8 The diagram shows the deceleration effect during the closing phase (V1 = 0.42 m / s);

[0026] Figure 9 The diagram shows the deceleration effect during the closing phase (V1 = 0.5 m / s). Detailed Implementation

[0027] The present invention will be further described and illustrated below with reference to specific embodiments. The embodiments described are merely examples of the content of this disclosure and do not limit the scope of the invention. The technical features of each embodiment in the present invention can be combined accordingly, provided that there is no mutual conflict.

[0028] This invention uses a magnetoelectric vibration velocity sensor to detect the valve core's movement speed in real time, such as... Figure 1 The figure shows the mechanical model of a magnetoelectric vibration velocity sensor, where m is the coil mass, k is the spring stiffness, and c is the damping coefficient. Let x1 be the absolute displacement of the valve body being measured, used as the sensor input; x0 be the absolute displacement of the coil; and x be the relative displacement of the coil relative to the housing. 01 Therefore, we have:

[0029] x 01 (t)=x0(t)-x1(t) (1)

[0030] The mechanical expression of the coil throughout the entire motion is:

[0031]

[0032] If we consider the relative displacement of the coil with respect to the housing, equation (2) can be rewritten as:

[0033]

[0034] The transfer function of the output to the input is:

[0035]

[0036] Among them, natural frequency Damping ratio

[0037] Substituting s = jω into the equation, we obtain the frequency response function:

[0038]

[0039] Therefore, the expressions for the amplitude-frequency response and phase-frequency response can be obtained as follows:

[0040]

[0041]

[0042] The resulting amplitude-frequency and phase-frequency curves are as follows: Figure 2 , 3 As shown in the curve, when the frequency of the measured signal is much higher than the sensor's natural frequency, the relative motion of the coil with respect to the housing can be used to replace the absolute velocity of the housing, i.e., the velocity of the valve body. Furthermore, since the forces between the valve core and the valve body during the opening and closing of the electromagnetic switching valve are interaction forces, the velocity of the valve core can be calculated from the velocity of the valve body. Therefore, a magnetoelectric vibration velocity sensor can be used to collect the velocity of the valve core in real time.

[0043] like Figure 4 As shown, the present invention connects a magnetoelectric vibration velocity sensor to an electromagnetic switching valve, and requires that the magnetoelectric vibration velocity sensor and the electromagnetic switching valve be installed coaxially. Figure 5 The medium-magnetic vibration velocity sensor is installed on the valve cover of the electromagnetic switch valve.

[0044] For a solenoid valve, a complete cycle of opening and closing includes at least an opening phase, an opening holding phase, a closing phase, and a closing holding phase. To improve the dynamic characteristics of the opening phase, a pre-loading phase can be set before the opening phase. In the pre-loading phase, the coil current is increased to a pre-load current value, which is slightly lower than the valve core opening current. By setting the pre-load current value, once the opening phase begins, the coil current can quickly reach the opening current, thereby improving the dynamic characteristics of the opening phase. Similarly, a pre-closing phase can be set before the closing phase to reduce the coil current value in advance, improving the dynamic characteristics of the closing phase. The above describes the existing technology of solenoid valves and will not be elaborated further here.

[0045] like Figure 5 The diagram illustrates a flexible opening and closing control device for a solenoid valve. This device uses seven different voltage sources to power each stage of the solenoid valve, with a high-speed switching switch connecting to each voltage source. The seven voltage sources are: preload voltage source 1, opening stage voltage source 2, negative voltage source 3 (for deceleration during the opening stage), opening sustaining voltage source 4, closing stage voltage source 5, high voltage source 6 (for closing if necessary), and closing sustaining voltage source 7.

[0046] The system comprises the following voltage sources: Preload voltage source 1 operates during the preload phase to increase the coil current to a level slightly below the opening current (typically 90%-95% of the opening current); Opening phase voltage source 2 operates during the opening phase to open the solenoid valve; negative voltage source 3 decelerates the valve core during the opening phase; Opening sustaining voltage source 4 maintains the solenoid valve in the opening phase. Closing phase voltage source 5 triggers the solenoid valve into the opening / closing phase and closes it; high voltage source 6 decelerates the valve core during the closing phase; Closing sustaining voltage source 7 keeps the solenoid valve closed, awaiting the next opening / closing cycle. The output voltage values ​​of each voltage source can be selected based on the specific parameters of the controlled solenoid valve and the actual situation. Specifically, the voltage values ​​of opening phase voltage source 2 and high voltage source 6 can be 24V, and the voltage values ​​of closing phase voltage source 5 and negative voltage source 3 can be -24V. The negative sign indicates that when negative voltage is applied, the direction of the current in the coil of the controlled solenoid valve is opposite to that when positive voltage is applied.

[0047] Correspondingly, the high-speed switching switch 8 of the present invention includes 8 contacts for connecting the electromagnetic switching valve to the above-mentioned 7 voltage sources, wherein the first contact 8-1 is connected to the preloaded voltage source, the second contact 8-2 is connected to the turn-on voltage source, the third contact 8-3 is connected to the turn-on negative voltage source, the fourth contact 8-4 is connected to the turn-on sustaining voltage source, the sixth contact 8-6 is connected to the turn-off voltage source, the seventh contact 8-7 is connected to the turn-off high voltage source, and the eighth contact 8-8 is connected to the turn-off sustaining voltage source; the fifth contact 8-5 is connected to the coil of the electromagnetic switching valve.

[0048] The speed feedback control 11 acquires the speed detection value and controls the voltage output controller based on the comparison result. The voltage output controller acts on the high-speed switching switch 8, connecting it to the corresponding voltage source. The host computer 13 can regulate the voltage output controller to enable different working states of the high-speed switching valve. That is, the host computer 13 outputs the opening and closing signal of the solenoid valve to the voltage output controller, causing it to operate according to the normal opening and closing cycle.

[0049] During the opening phase, the velocity value collected by the magnetoelectric vibration velocity sensor is compared with the user-input velocity value V1 in the velocity feedback controller. If the detected velocity is greater than V1, the velocity feedback controller immediately causes the voltage output controller to output a negative voltage. The loading time of this negative voltage is t1, and the loading time of this negative voltage is t2. Time t1 is the moment when the opening velocity is detected to be greater than V1, and time t2 is the moment when the valve core is fully open. By loading the negative voltage, the electromagnetic force during the opening phase of the solenoid valve is reduced, thereby slowing down the movement of the valve core and reducing the impact force of the valve core on the valve seat at the moment of opening. During the closing phase, the velocity value collected by the magnetoelectric vibration velocity sensor is compared with the user-input velocity value V2 in the velocity feedback controller. If the detected velocity is greater than V2, the velocity feedback controller immediately causes the voltage output controller to output a positive voltage. The loading time of this positive voltage is t3, and the loading time of this positive voltage is t4. Time t3 is the moment when the closing velocity is detected to be greater than V2, and time t4 is the moment when the valve core is fully closed. By reducing the positive voltage load, the electromagnetic force during the closing phase of the solenoid valve is increased to counteract the spring return force during closing, thereby slowing down the movement of the valve core and reducing the impact force of the valve core on the valve seat at the moment of closing.

[0050] During the opening phase, the effect of the method for decelerating the opening and closing of the electromagnetic switching valve based on a speed sensor is as follows: Figure 6 , Figure 7 As shown, in Figure 6 With V1 = 0.27 m / s, after implementing a deceleration method for the opening and closing of the electromagnetic switch valve based on a speed sensor, the impact velocity of the valve core at the moment of opening is only 0.16 m / s. Figure 7 With V1 = 0.28 m / s, after implementing the deceleration method for opening and closing the electromagnetic switch valve based on the speed sensor, the impact velocity of the valve core at the moment of opening is 0.22 m / s, indicating that the deceleration effect of this method is quite obvious.

[0051] During the closing phase, the effect of the speed sensor-based method for decelerating the opening and closing of the electromagnetic switching valve is as follows: Figure 8 , Figure 9 As shown, in Figure 8 With V2 = 0.42 m / s, after implementing a deceleration method for opening and closing the electromagnetic switch valve based on a speed sensor, the impact velocity of the valve core at the moment of opening is 0.28 m / s. Figure 9 With V1 = 0.5 m / s, after implementing the deceleration method for opening and closing the electromagnetic switch valve based on the speed sensor, the impact velocity of the valve core at the moment of opening is 0.39 m / s. It can be found that the deceleration effect of this method is still quite obvious during the closing process.

[0052] The above-described embodiments are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. Those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A flexible opening and closing control method for a solenoid valve based on speed feedback, wherein one opening and closing cycle of the solenoid valve includes at least an opening phase, an opening maintenance phase, a closing phase, and a closing maintenance phase; Its features are, The control method includes the following steps: 1) Each stage of the controlled solenoid valve is driven by a different driving voltage, and each driving voltage is connected to the controlled solenoid valve through a switching switch; a magnetoelectric vibration velocity sensor is installed on the controlled solenoid valve; the magnetoelectric vibration velocity sensor converts the vibration signal of the controlled solenoid valve into an electrical signal reflecting the speed of the valve core movement; the magnetoelectric vibration velocity sensor is installed on the valve body of the controlled solenoid valve, and the magnetoelectric vibration velocity sensor and the controlled solenoid valve are installed on the same axis; the frequency of the vibration signal of the controlled solenoid valve is more than five times the natural frequency of the magnetoelectric vibration velocity sensor. 2) During the opening phase, the speed detected by the magnetoelectric vibration speed sensor is compared with the user-inputted set speed value V1 in the speed feedback controller. If the detected speed is greater than V1, the speed feedback controller causes the voltage output controller to output a negative voltage to the controlled solenoid valve to reduce the valve core movement speed during the opening phase. The loading time t1 when the negative voltage is applied to the controlled solenoid valve is the moment when the detected speed is greater than V1, and the loading time t2 when the negative voltage ends is the moment when the valve core is fully opened. The loading duration of the negative voltage is t2 - t1. 3) During the closing phase, the speed detected by the magnetoelectric vibration speed sensor is compared with the user-input set speed value V2 in the speed feedback controller. If the detected speed is greater than V2, the speed feedback controller causes the voltage output controller to output a positive voltage to the controlled solenoid valve to reduce the valve core movement speed during the closing phase. The loading time t3 when the positive voltage is applied to the controlled solenoid valve is the moment when the detected speed is greater than V2, and the loading time t4 when the positive voltage ends is the moment when the valve core is completely closed. The loading duration of the positive voltage is t4 - t3.

2. The method for flexible opening and closing control of a solenoid valve based on speed feedback according to claim 1, characterized in that, The positive voltage is 24V, and the negative voltage is -24V. The negative sign indicates that when a negative voltage is applied, the direction of the current in the coil of the controlled solenoid valve is opposite to that when a positive voltage is applied.

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