Electro-hydraulic proportional flow control valve assembly, method, medium, controller and system

Abstract

This invention relates to the field of hydraulic control, and discloses an electro-hydraulic proportional flow control valve assembly, method, medium, controller, and system. The electro-hydraulic proportional flow control valve assembly includes an inlet flow restrictor, a proportional throttle valve as a pilot valve, and a flow control valve as a main valve. The flow control valve is configured to generate valve core displacement under the action of the spring chamber pressure and the load chamber pressure from the actuator. The inlet flow restrictor and the proportional throttle valve together form a pressure divider on the spring chamber pressure, and the spring chamber pressure changes according to the opening degree of the proportional throttle valve. This invention avoids the flow error caused by the scheme of compensating for load pressure by displacement changes in the flow control valve.

Description

Technical Field

[0001] This invention relates to the field of hydraulic control, specifically to an electro-hydraulic proportional flow control valve assembly, method, medium, controller, and system. Background Technology

[0002] Flow control valves are one of the main components of hydraulic systems, controlling the flow rate to control the speed of actuators. In existing technology, to ensure that the flow control process is unaffected by load interference, flow control valves typically employ methods such as... Figure 1 The flow control structure shown is a "valve throttling + pressure compensation" configuration. It adjusts the throttling opening by regulating the pressure compensation valve in a force-balanced manner, so as to control the differential pressure at the throttling orifice and keep the differential pressure across the throttling orifice constant, thereby achieving the purpose of flow control.

[0003] However, the "valve throttling + pressure compensation" configuration relies on the pressure compensation valve, and the force balance of the pressure compensation valve itself is easily disturbed by load fluctuations. When the pressure in the load chamber changes rapidly, it will cause the pressure compensation valve to become unbalanced and be in the extreme position, resulting in uncontrolled flow control. Summary of the Invention

[0004] The purpose of this invention is to provide an electro-hydraulic proportional flow control valve assembly, method, medium, controller, and system to at least partially solve the above-mentioned technical problems.

[0005] To achieve the above objectives, the present invention provides an electro-hydraulic proportional flow control valve assembly, comprising an inlet flow restrictor, a proportional throttle valve as a pilot valve, and a flow control valve as a main valve, wherein the flow control valve is configured to generate valve core displacement under the action of the spring chamber pressure and the load chamber pressure from the actuator end, the inlet flow restrictor and the proportional throttle valve together form a pressure divider effect on the spring chamber pressure, and the spring chamber pressure changes according to the opening degree of the proportional throttle valve.

[0006] Preferably, the inlet flow restrictor is a cone valve or a sensing piston. The cone valve is a cone-shaped throttle valve whose oil flow rate is affected by the pressure difference between its inlet and outlet. The sensing piston is a sensing throttle element whose spring chamber pressure and pump outlet pressure are linearly related to affect the oil flow rate of the sensing piston.

[0007] The present invention also provides an electro-hydraulic proportional flow control method, applied to any of the above-mentioned electro-hydraulic proportional flow control valve assemblies, and the electro-hydraulic proportional flow control method includes: determining a desired spring chamber pressure for the flow control valve based on a desired flow rate and a pump outlet pressure, wherein the desired spring chamber pressure makes the output flow rate of the flow control valve consistent with the desired flow rate; and executing a preset closed-loop control algorithm to output a control quantity for the opening of the proportional throttle valve based on the deviation between the desired spring chamber pressure and the current actual spring chamber pressure, so as to adapt to the change of the actual spring chamber pressure by changing the opening of the proportional throttle valve.

[0008] Preferably, determining the desired spring chamber pressure for the flow control valve includes: inputting the desired flow rate and the pump outlet pressure into a primary control model to output the desired spring chamber pressure, wherein the primary control model is a computational model pre-constructed based on the flow equation and force balance equation of the flow control valve to illustrate the relationship between the desired flow rate, the pump outlet pressure and the desired spring chamber pressure.

[0009] Preferably, the master-level control model is described as determining the desired spring chamber pressure P using the following formula. e :

[0010]

[0011] Among them, A p It is the working area of ​​the oil inlet chamber of the flow control valve; A e It is the working area of ​​the spring chamber of the flow control valve; A c It is the effective area of ​​the load chamber of the flow control valve; k e It refers to the spring stiffness of the flow control valve; K a It is the flow gain of the flow control valve; K b F1 is the pressure gain of the flow control valve; F1 is the spring preload of the flow control valve; P p It is the pump outlet pressure; Q e k1 is the expected flow; k1 is P e The proportionality constant, k2 is P p The proportionality coefficient, k3 is the offset of the load chamber pressure.

[0012] Preferably, when the inlet flow restrictor is a cone valve, the electro-hydraulic proportional flow control method further includes obtaining the current actual spring chamber pressure through the following steps: obtaining the current load chamber pressure and the historical spring chamber pressure; determining the current oil flow rate of the proportional throttle valve based on the current load chamber pressure and the current output current of the proportional throttle valve; determining the current oil flow rate of the inlet flow restrictor based on the historical actual spring chamber pressure and the pump outlet pressure; and determining the current actual spring chamber pressure by combining the current oil flow rate of the proportional throttle valve and the current oil flow rate of the inlet flow restrictor.

[0013] Preferably, the current load chamber pressure is obtained by any of the following methods: determining the current load chamber pressure based on the force balance equation of the flow control valve, according to the historical actual spring chamber pressure and the pump outlet pressure; or, detecting the current load chamber pressure in real time using a pressure sensor.

[0014] Preferably, the current oil flow rate Q of the proportional throttle valve is determined using the following formula. i :

[0015] Q i =K l x l -K c P c

[0016] x l =k*I

[0017] Where, x l k is the proportional throttle valve displacement, and k is the proportional throttle valve current I - displacement x. l Gain coefficient, K l It is the flow gain of the proportional throttle valve, K c It is the pressure gain of the proportional throttle valve, P c I is the current load chamber pressure, and I is the current output current of the proportional throttle valve detected in real time.

[0018] Preferably, the current oil flow rate Q of the inlet flow restrictor is determined using the following formula. v :

[0019]

[0020] Among them, A i A is the working area of ​​the oil inlet chamber of the cone valve. d F0 is the working area of ​​the cone valve spring cavity, and K is the preload force of the cone valve spring. e It is the cone valve pressure gain, K q It is the flow gain of the cone valve, K v It is the spring stiffness of the cone valve, P pre_ei It is the historical spring cavity pressure.

[0021] Preferably, the current actual spring chamber pressure P is determined using the following formula. ei :

[0022] dtQ=Q v -Q i

[0023]

[0024] Among them, Q i Q is the current oil flow rate of the proportional throttle valve. v dtQ is the current oil flow rate of the inlet flow restrictor, dtQ is the flow rate difference of the spring cavity, E is the oil elasticity model, and V is the volume of the spring cavity.

[0025] Preferably, when the inlet flow restrictor is a sensing piston, the electro-hydraulic proportional flow control method further includes determining the current actual spring chamber pressure P by the following formula. ei :

[0026]

[0027] In the formula, A i A is the working area of ​​the piston oil inlet chamber. d P is the effective area of ​​the piston spring cavity, F0 is the piston spring preload, and P is the piston spring preload. p It is the pump outlet pressure.

[0028] The present invention also provides a machine-readable storage medium storing instructions for causing a machine to perform any of the above-described electro-hydraulic proportional flow control methods.

[0029] The present invention also provides an electro-hydraulic proportional flow controller, comprising: a memory storing a program capable of running on a processor; and the processor configured to implement any of the above-described electro-hydraulic proportional flow control methods when executing the program.

[0030] The present invention also provides an electro-hydraulic proportional flow control system, comprising: any of the above-described electro-hydraulic proportional flow control valve groups; and any of the above-described electro-hydraulic proportional flow controllers, for controlling the output flow of the flow control valve to be consistent with the desired flow by controlling the spring chamber pressure of the flow control valve in the electro-hydraulic proportional flow control valve group.

[0031] Through the above technical solution, the present invention designs a flow control valve group with a load pressure feedback mechanism, which enables the flow control valve to compensate for the pressure difference before and after its throttling orifice caused by the load pressure by displacement change, and further enables the controlled flow to be consistent with the desired flow by designing a control strategy for the spring cavity pressure, thereby avoiding the flow error caused by the flow control valve compensating for the load pressure by displacement change.

[0032] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0033] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the following detailed description to explain the invention, but do not constitute a limitation thereof. In the drawings:

[0034] Figure 1 This is a schematic diagram of a conventional flow control structure with a "valve orifice throttling + pressure compensation" configuration.

[0035] Figure 2 This is a schematic diagram of the electro-hydraulic proportional flow control valve assembly according to Embodiment 1 of the present invention;

[0036] Figure 3 This is a schematic flowchart of the electro-hydraulic proportional flow control method according to Embodiment 2 of the present invention;

[0037] Figure 4 This is an example of the overall control strategy block diagram of Embodiment 2 of the present invention.

[0038] Figure 5 This is a schematic diagram of the process for obtaining the current actual spring chamber pressure in Embodiment 2 of the present invention when the inlet flow restrictor is a cone valve;

[0039] Figure 6 This is a schematic diagram of the flow control structure according to Embodiment 3 of the present invention;

[0040] Figure 7 This is an example of the overall control strategy block diagram of Embodiment 3 of the present invention;

[0041] Figure 8 This is a schematic diagram of the example flow control structure of Embodiment 4 of the present invention; and

[0042] Figure 9 This is a schematic diagram of the electro-hydraulic proportional flow control system according to Embodiment Six of the present invention.

[0043] Explanation of reference numerals in the attached figures

[0044] 100. Flow control valve assembly; 200. Electro-hydraulic proportional flow controller;

[0045] 110. Inlet flow restrictor; 120. Proportional throttle valve; 130. Flow control valve; 140. First pressure sensor; 150. Second pressure sensor; 160. Main relief valve; 170. Main pump. Detailed Implementation

[0046] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0047] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the directional terms "left" and "right" are exemplary and intended to facilitate the description of relative relationships. Those skilled in the art can understand the specific meaning of the above directional terms in this invention according to the specific circumstances.

[0048] It should also be noted that, for those skilled in the art, after understanding the hydraulic connection relationships shown in the accompanying drawings, simple replacements can be made to the oil circuit or valve body to achieve the function of the flow control structure of the present invention, which also falls within the protection scope of the present invention. Related hydraulic components (e.g., cone valves, proportional throttle valves, sensing pistons, flow control valves, main pumps, etc.), the cavity design within components (e.g., the valve core, spring chamber, and load chamber of a flow control valve), and the connection relationships between some conventional components (e.g., the connection between the pilot valve and the main valve in a valve group) are all well-known to those skilled in the art. Therefore, the following description is only brief, focusing instead on the original flow control scheme of the present invention.

[0049] As stated in the background section, Figure 1 The "valve throttling + pressure compensation" configuration shown is prone to causing uncontrolled flow, specifically manifested as follows:

[0050] 1) The differential pressure control of the throttling orifice and the throttling opening control are decoupled. They are controlled by the throttling orifice and the pressure compensation valve, respectively. As mentioned above, when the load chamber pressure changes rapidly, the pressure compensation valve will become unbalanced and reach its limit position. At this time, the flow control is out of control and is prone to phenomena such as sudden flow changes, oscillations, and obvious nonlinear characteristics. It is not suitable for dynamic operating conditions.

[0051] 2) When the oil flow rate of the pressure compensation valve increases, its pressure regulation deviation will also increase, causing the controlled flow rate to deviate from the target value, thus limiting the controllable flow range. It is barely suitable for small flow conditions, while it will cause a significant drop in flow rate under large flow conditions.

[0052] Accordingly, embodiments of the present invention provide the following original flow control scheme.

[0053] Example 1

[0054] Figure 2 This is a schematic diagram of an electro-hydraulic proportional flow control valve assembly 100 (hereinafter referred to as the flow control valve assembly) according to Embodiment 1 of the present invention, including an inlet flow restrictor 110, a proportional throttle valve 120 as a pilot valve, and a flow control valve 130 as a main valve. The flow control valve 130 is configured to generate a valve core displacement under the action of a spring chamber pressure that changes according to the opening change of the proportional throttle valve 120 and a load chamber pressure fed back from the actuator, and to change the oil flow rate according to the valve core displacement. The inlet flow restrictor 110 and the proportional throttle valve 120 together exert a pressure divider effect on the spring chamber pressure. That is, the valve core displacement of the flow control valve 130 is changed by the pressure in its spring chamber and the pressure in its load chamber to change the oil flow through the flow control valve. The inlet flow restrictor 110 and the proportional throttle valve 120 together form a pressure divider on the spring chamber pressure. The pressure divider relationship can be changed by controlling the opening of the proportional throttle valve 120, thereby changing the spring chamber pressure. The load chamber pressure is the pressure fed back to the flow control valve by the load at the actuator driven by the flow control valve 130.

[0055] In addition, the flow control valve assembly 100 may be equipped with a first pressure sensor 140 for detecting the pump outlet pressure, and the inlet flow restrictor 110, in addition to the above-mentioned pressure dividing function, may also be used to restrict the flow of fluid pumped by the main pump in order to control the flow rate entering the proportional throttle valve 120.

[0056] For example, the inlet flow restrictor 110 uses a cone valve, the proportional throttle valve 120 uses a conventional proportional throttle valve, and the flow control valve 130 uses a two-position two-way valve. The cone valve is a cone-shaped throttle valve whose oil flow rate is affected by the pressure difference between its inlet and outlet. The load pressure and outlet pressure act on the right side of the valve core of the two-position two-way valve. At the same time, the pumped inlet flow passes through the cone valve and then flows out to the load port through the proportional throttle valve. Under the combined action of the cone valve and the proportional throttle valve, a spring chamber pressure is formed and acts on the left side of the valve core of the two-position two-way valve. Thus, the spring chamber pressure can be controlled by the proportional throttle valve. Furthermore, the two-position two-way valve drives the actuator to move. When the actuator is subjected to external load interference, causing the load chamber pressure to rise, the pressure difference of the two-position two-way valve decreases. At this time, the oil flow rate decreases. Because the load chamber pressure acts on the right side of the valve core of the two-position two-way valve, the flow valve core moves to the left, the throttling opening increases, and the oil flow rate increases. Thus, the flow difference caused by the load interference is compensated. Since the proportional throttle valve maintains its original opening, the spring chamber pressure increases until the two-position two-way valve maintains a new equilibrium state.

[0057] Accordingly, the electro-hydraulic proportional flow control threshold group of Embodiment 1 of the present invention has a load pressure feedback mechanism, which enables the flow control valve to compensate for the pressure difference before and after its throttling orifice caused by the load pressure by displacement change.

[0058] Example 2

[0059] Known Figure 2 Under load disturbances, the flow control valve compensates for the flow error caused by the pressure difference across its throttling orifice due to the load-induced change in valve core displacement, maintaining a balanced state. However, in this balanced state, the oil flow through the flow control valve is not the required flow. Based on this, Embodiment 2 of the present invention further calculates the spring chamber pressure under the current required flow and controls the spring chamber pressure to ensure that the controlled flow is consistent with the actual flow.

[0060] Figure 3 This is a schematic flowchart of the electro-hydraulic proportional flow control method according to Embodiment 2 of the present invention. This electro-hydraulic proportional flow control method is applied to... Figure 2 The electro-hydraulic proportional flow control valve assembly shown is... Figure 4 This is an example of the overall control strategy block diagram of Embodiment 1 of the present invention, which will be described below. Figure 3 During the steps, it will be combined Figure 4 Examples will be provided to make each step clearer.

[0061] like Figure 3 As shown, the steps S100 and S200 may be included:

[0062] Step S100: Determine the desired spring chamber pressure for the flow control valve based on the desired flow rate and pump outlet pressure. This desired spring chamber pressure ensures that the output flow rate of the flow control valve matches the desired flow rate.

[0063] Step S200: For the deviation between the desired spring chamber pressure and the current actual spring chamber pressure, a preset closed-loop control algorithm is executed to output a control quantity for the opening of the proportional throttle valve, so as to adapt to the change of the actual spring chamber pressure by changing the opening of the proportional throttle valve.

[0064] Accordingly, the method of this invention solves the spring cavity pressure under the desired flow rate and performs closed-loop control on it. Then, when the flow control valve is in a balanced state and the flow error is caused by the change in pressure difference before and after the throttling orifice due to the load caused by the change in valve core displacement, the output flow rate of the flow control valve is kept consistent with the desired flow rate by controlling the actual spring cavity pressure.

[0065] For step S100, determining the desired spring chamber pressure for the flow control valve preferably includes: inputting the desired flow rate and the pump outlet pressure to the master control model to output the desired spring chamber pressure.

[0066] The primary control model is a computational model pre-constructed based on the flow equation and force balance equation of the flow control valve, used to illustrate the relationship between the desired flow rate, pump outlet pressure, and desired spring chamber pressure.

[0067] The following examples illustrate the construction and application of the master-level control model.

[0068] First, the flow equation for the flow control valve is as follows:

[0069] Q e =K a x e -K b P c (1)

[0070] Among them, Q e It is the expected traffic, K a It is the flow gain of the flow control valve; K b It is the pressure gain of the flow control valve, x e It is the valve core displacement of the flow control valve, P c It is the pressure in the load chamber.

[0071] Secondly, the force balance equation for the flow control valve is:

[0072] P p A p -P e A e +P c A c -F1=k e x e (2)

[0073] In the formula, A p It is the working area of ​​the oil inlet chamber of the flow control valve; A e It is the working area of ​​the spring chamber of the flow control valve; A c It is the effective area of ​​the load chamber of the flow control valve; k e F1 is the spring stiffness of the flow control valve; P is the spring preload of the flow control valve; p It is the pump outlet pressure; P e This is the desired spring cavity pressure; x e It is the valve core displacement of the flow control valve, P c It is the pressure in the load chamber.

[0074] Furthermore, by setting the primary spring as a weak spring, the change in spring force caused by the change in spring displacement can be approximately ignored. P can be obtained through testing and fitting. c Regarding P e P p The linear equation is shown in equation (3):

[0075] Pc =k1P e -k2P p +k3 (3)

[0076] In the formula, k1 is P e The proportionality constant, k2 is P p The proportionality coefficient, k3 is P c The offset.

[0077] Combining equations (1), (2), and (3), the master-level control model is described as calculating the desired spring cavity pressure P using the following equation (4). e :

[0078]

[0079] Accordingly, step S100 yields the desired spring chamber pressure of the flow control valve at the desired flow rate, which ensures that the output flow rate of the flow control valve matches the desired flow rate. Step 200 further maintains the actual spring chamber pressure at this desired spring chamber pressure.

[0080] Returning to step S200, Figure 5 This is a schematic diagram illustrating the process of obtaining the current actual spring chamber pressure when the inlet flow restrictor is a cone valve. For example... Figure 5 As shown, the steps S310-S340 may be included:

[0081] S310, obtain the current load chamber pressure and historical spring chamber pressure.

[0082] Preferably, the current load chamber pressure can be calculated based on the force balance equation of the flow control valve shown in equation (3) above, according to the historical spring chamber pressure and the pump outlet pressure. The historical spring chamber pressure can be controlled using the closed-loop control algorithm to obtain the previous actual spring chamber pressure in the previous step, and can be denoted as P. pre_ei If this is the first calculation of the closed-loop control algorithm, then P pre_ei This can be a pre-set initial value. Based on this, according to equation (3), the load chamber pressure P can be determined. c The value is then used to proceed to step S320.

[0083] Step S320: Determine the current oil flow rate of the proportional throttle valve based on the current load chamber pressure and the current output current of the proportional throttle valve.

[0084] Following the example above, the current oil flow rate Q of the proportional throttle valve is calculated using the following formula. i :

[0085] Q i =Kl x l -K c P c (5)

[0086] x l =k*I (6)

[0087] Where, x l k is the proportional throttle valve displacement, and k is the proportional throttle valve current I - displacement x. l Gain coefficient, K l It is the flow gain of the proportional throttle valve, K c It is the pressure gain of the proportional throttle valve, P c I is the current load chamber pressure, and I is the current output current of the proportional throttle valve detected in real time.

[0088] Equation (5) is the proportional throttle valve flow linearization equation, which is a polynomial equation about displacement and load pressure obtained by linearizing the conventional pressure-flow characteristic equation and expanding it using Taylor. l Specifically, K is the magnitude of the change in load flow rate caused by a unit displacement when the load pressure is constant. c The slope of the pressure-flow curve obtained from the specific test has the physical meaning of the gain of valve load flow change caused by pressure change. Based on this, the proportional throttle valve K can be obtained under certain test data using equations (5) and (6). l K c The parameter curves are used, and a multi-dimensional map table composed of load pressure and valve core opening is used to characterize the pressure-flow characteristics of the proportional throttle valve.

[0089] Therefore, based on equations (5) and (6), the current oil flow rate Q of the proportional throttle valve can be determined. i This will be used in step S340.

[0090] Step S330: Based on the previous actual spring chamber pressure and the pump outlet pressure, determine the current oil flow rate of the inlet flow restrictor.

[0091] Following the example above, step S330 utilizes the following cone valve force balance equation (7) and cone valve flow linearization equation (8):

[0092] P p A i -P ei A d -F0=k v x v (7)

[0093] Q V =K q x v -Ke P ei (8)

[0094] The specific meaning of the cone valve flow linearization equation in equation (8) can be found in the above explanation of the proportional throttle valve flow linearization equation in equation (5), and will not be repeated here.

[0095] Based on equations (7) and (8), the current oil flow rate Q of the inlet flow restrictor can be calculated using equation (9) below. v :

[0096]

[0097] Among them, A i A is the working area of ​​the oil inlet chamber of the cone valve. d F0 is the working area of ​​the cone valve spring cavity, and K is the preload force of the cone valve spring. e It is the cone valve pressure gain, K q It is the flow gain of the cone valve, K v It is the spring stiffness of the cone valve, P ei It is the historical spring cavity pressure.

[0098] Therefore, according to equation (9), the current oil flow rate Q of the cone valve can be determined. v Proceed to step S340 for use.

[0099] Step S340: Combine the current oil flow rate of the proportional throttle valve and the current oil flow rate of the inlet flow restrictor to determine the current actual spring chamber pressure.

[0100] Following the example above, the current actual spring chamber pressure P is calculated using the following formula. ei :

[0101] dtQ=Q v -Q i (10)

[0102]

[0103] Among them, Q i Q is the current oil flow rate of the proportional throttle valve. v dtQ is the current oil flow rate of the inlet flow restrictor, dtQ is the flow rate difference of the spring cavity, E is the oil elasticity model, and V is the volume of the spring cavity.

[0104] Based on this, the current actual spring chamber pressure P was calculated. ei Returning to step S200, and combining the expected spring cavity pressure P calculated in step S100... e A closed-loop control algorithm is set up to calculate and process the deviation between the two pressures, so as to output a control quantity for the opening of the proportional throttle valve.

[0105] Following the example above, the closed-loop control algorithm can be described as the discrete PI algorithm shown in the following equation:

[0106] Δu(k)=K p [e(k)-e(k-1)]+K i e(k) (12)

[0107] e(k)=P e (k)-P ei (k) (13)

[0108] Where Δu(k) is the control quantity for the opening degree of the proportional throttle valve, P e (k) is the expected spring cavity pressure P at the k-th step size. e P ei (k) is the actual spring cavity pressure P at the k-th step size. ei K p It is the proportional gain coefficient, K i Δu(k) is the integral gain coefficient, and e(k) is the deviation between the desired spring chamber pressure and the current actual spring chamber pressure at the k-th step. Δu(k) is the control variable, which is, for example, the control current for a proportional throttle valve. It controls the opening of the proportional throttle valve to ensure that the flow control valve has sufficient spring chamber pressure. Thus, even when the flow control valve adapts to differential pressure shift due to load chamber pressure, the spring chamber pressure can still ensure that the flow control valve has an appropriate opening so that the output flow rate matches the desired flow rate.

[0109] It should be noted that, in addition to the discrete PI method mentioned above, the conventional PID algorithm can also be used.

[0110] In summary, the electro-hydraulic proportional flow control method of Embodiment 1 of the present invention has at least the following advantages:

[0111] 1) A flow control valve assembly with a load pressure feedback mechanism was designed, which enables the flow control valve to compensate for the pressure difference before and after its throttling orifice caused by the load pressure by displacement change. Furthermore, a control method for the spring chamber pressure was designed to ensure that the controlled flow rate is consistent with the desired flow rate, thus avoiding the flow error caused by the flow control valve's scheme of compensating for the load pressure by displacement change.

[0112] 2) The flow control structure of this invention is based on a flow-displacement-hydraulic feedback configuration. It uses load pressure feedback to adaptively adjust the opening of the flow control valve, thereby achieving flow compensation under load disturbances and no large flow change under load fluctuations. It has good adaptability to flow control under multiple load composite and drastic load conditions.

[0113] 3) The electro-hydraulic proportional flow control method of this invention is based on a master-level control model and a closed-loop control strategy. By constructing a master-level control model, for example, a two-position two-way valve, the spring chamber pressure under the required flow rate is solved and closed-loop control is performed to achieve the flow control objective. During the flow control process, the opening degree and pressure difference of the flow control valve are not decoupled, the hydraulic force has a low impact, the flow controllable range is large, the flow control characteristics are programmable and not limited by structure.

[0114] 4) The method in this embodiment of the invention does not require the use of a pressure sensor to detect the pressure in the load chamber, which reduces the number of pressure sensors required to work with the flow control valve assembly and simplifies the structure.

[0115] Example 3

[0116] Embodiment 3 of the present invention provides an electro-hydraulic proportional flow control method, which, based on Embodiment 1, uses Equation (3) to determine the load chamber pressure P in Embodiment 1. c The proposed method is a simpler and more effective one: real-time detection of the current load chamber pressure using a pressure sensor. Specifically, Figure 6 This is a schematic diagram of the flow control structure of Embodiment 2 of the present invention, which is relative to... Figure 2 An additional second pressure sensor 150 was installed to collect the pressure in the load chamber. Based on this, Figure 7 This is an example of the overall control strategy block diagram of Embodiment 2 of the present invention, compared to Embodiment 1. Figure 4 The pressure P in the load chamber is directly collected using pressure sensor 150. c Participating in the master-level control model Q e -P e Solving for the proportional throttle valve Q i Flow calculation is performed to complete the subsequent flow control process in Example 1.

[0117] For more details on the implementation and effects of this third embodiment, please refer to embodiment two, which will not be repeated here.

[0118] Example 4

[0119] Embodiment 4 of the present invention provides an electro-hydraulic proportional flow control method, which, based on Embodiment 2, replaces the cone valve used as the inlet flow restrictor 110 in Embodiment 2 with a sensing piston as the inlet flow restrictor 110. Accordingly, Figure 8 This is a schematic diagram of an example flow control structure according to Embodiment 3 of the present invention, wherein the inlet flow restrictor is replaced by a sensing piston. Figure 2 The cone valve.

[0120] The sensing piston is a sensing-type throttling element whose oil flow rate is affected by the linear correlation between the spring chamber pressure and the pump outlet pressure. It can be understood as a component whose forces at both ends affect the effective area of ​​the internal oil inlet chamber and spring chamber, thereby changing the throttling opening. The forces at both ends can be determined according to the scenario and requirements. For example, in Embodiment 3 of this invention, the pump outlet pressure and spring chamber pressure are applied to both ends of the sensing piston, thereby adjusting the throttling opening of the sensing piston under the interaction of the pressures at both ends, ensuring the balance between the spring chamber pressure and the pump outlet pressure. Since the effective area ratio of the sensing piston is fixed, the pump outlet pressure P... p Same spring chamber pressure P ei The relationship is linear, therefore the sensing piston can serve as the sensing element for Pp-Pei.

[0121] Thus, when the sensing piston of Embodiment 4 of the present invention is configured to be in a non-limit position, the pressure P in the spring chamber is such that... ei With pump outlet pressure P p It exhibits a linear correlation, meaning it is P. p -P ei Sensing equation. The electro-hydraulic proportional flow control method of Embodiment 4 of the present invention, compared to Embodiment 2, calculates the current actual spring chamber pressure P using the following formula. ei :

[0122]

[0123] In the formula, A i A is the working area of ​​the piston oil inlet chamber. d P is the effective area of ​​the piston spring cavity, F0 is the piston spring preload, and P is the piston spring preload. p This refers to the pump outlet pressure of the main pump 170.

[0124] It is easy to see that, compared to Example 2, the actual spring chamber pressure P is calculated using equations (3)-(11). ei The fourth embodiment simplifies the calculation process by using a sensing piston, achieving flow control with fewer components.

[0125] In addition, compared to Figure 2 The flow control valve 130 of Embodiment 4 of the present invention is... Figure 8 Taking the three-position four-way valve shown as an example, it can also achieve very good control results. Additionally, as... Figure 8 As shown, the flow control structure may further include a main relief valve 160 located on the oil inlet side, which serves a safety venting function. When the pressure in the oil inlet pipe reaches a set pressure, it automatically opens to vent, ensuring the stability of the pump outlet pressure. Similarly, a main relief valve may also be located on the oil return side. It should be noted that other embodiments of the present invention may also include a main relief valve accordingly.

[0126] For more details on the implementation and effects of this fourth embodiment, please refer to embodiment two, which will not be repeated here.

[0127] Example 5

[0128] Embodiment 5 of the present invention provides an electro-hydraulic proportional flow controller, comprising: a memory storing a program capable of running on a processor; and the processor configured to implement the electro-hydraulic proportional flow control method described in any one of Embodiments 2 to 4 when executing the program.

[0129] The electro-hydraulic proportional flow controller can be implemented using a conventional controller with computing and data transmission capabilities, such as the controller built into engineering machinery (e.g., fire trucks, cranes, etc.) that uses the electro-hydraulic proportional flow control method.

[0130] The processor contains a kernel, which retrieves the corresponding program units from memory. One or more kernels can be configured, and the flow control described in this embodiment of the invention can be implemented by adjusting kernel parameters.

[0131] The memory may include non-permanent memory in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM. Additionally, the memory may include at least one memory chip.

[0132] For more details on the implementation and effects of the electro-hydraulic proportional flow controller in Embodiment 4, please refer to Embodiment 1, which will not be repeated here.

[0133] Example 6

[0134] Embodiment 6 of the present invention provides an electro-hydraulic proportional flow control system, which is based on the same inventive concept as Embodiment 2. Figure 9 This is a schematic diagram of the electro-hydraulic proportional flow control system according to Embodiment Six of the present invention. It includes: a flow control structure 100, comprising an inlet flow restrictor 110, a proportional throttle valve 120 as a pilot valve, and a flow control valve 130 as a main valve. The flow control valve 130 is configured to generate a valve core displacement under the action of a spring chamber pressure that changes according to the opening change of the proportional throttle valve 120 and a load chamber pressure from load feedback at the actuator end, and to adapt the change in oil flow rate to the valve core displacement. The inlet flow restrictor 110 and the proportional throttle valve 120 together provide a pressure divider effect on the spring chamber pressure. It also includes the electro-hydraulic proportional flow controller 200 described in Embodiment Four, used to control the output flow rate of the flow control valve to be consistent with the desired flow rate by controlling the spring chamber pressure of the flow control valve.

[0135] Furthermore, referring to Embodiments 2 and 4, the inlet flow restrictor is a cone valve or a sensing piston.

[0136] Furthermore, referring to Embodiment 2, it can be seen that the corresponding control method mainly includes the calculation of the desired spring pressure achieved by the master-level control strategy and the control of the spring cavity pressure achieved by the closed-loop control strategy. Accordingly, Figure 9 As shown, the electro-hydraulic proportional flow controller 200 can be divided into two parts: the master-level control model and the spring chamber pressure control strategy. Furthermore, in... Figure 9 The signal association between this part and the components of the flow control structure 100 is shown by dashed lines. For example, the first pressure sensor 140 is used to transmit the detected pump outlet pressure to the main control model and the spring chamber pressure control strategy. It should be noted that, for Embodiment 2, the second pressure sensor 150 also transmits the detected load chamber pressure to the main control model and the spring chamber pressure control strategy, which will not be described in detail here. In addition, the main control model can be signal-connected to a handle, which is operated to control the desired flow rate delivered by the pump. At the same time, the handle operation signal is transmitted to the main control model to inform it of the specific value of the desired flow rate. Accordingly, the electro-hydraulic proportional flow controller 200, which has a main control model and a spring chamber pressure control strategy, executes the relevant control process of Embodiment 1 based on the received desired flow rate, pump outlet pressure, and load chamber pressure, realizing flow control based on a flow-displacement-hydraulic feedback configuration.

[0137] For more details on the implementation and effects of this sixth embodiment, please refer to the second embodiment, which will not be repeated here.

[0138] Another embodiment of the present invention provides a machine-readable storage medium storing instructions for causing a machine to execute the electro-hydraulic proportional flow control method described in any of the above embodiments. The machine may be, for example, a separately configured controller or a controller integrated into engineering machinery. Furthermore, the machine-readable storage medium includes, but is not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic disk storage or other magnetic storage devices, and various other media capable of storing program code.

[0139] For further implementation details and effects of the machine-readable storage medium in this embodiment, please refer to the embodiments of the corresponding methods described above, which will not be repeated here.

[0140] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0141] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0142] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0143] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0144] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0145] Memory may include non-persistent memory in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM. Memory is an example of computer-readable media.

[0146] Computer-readable media includes both permanent and non-permanent, removable and non-removable media that can store information using any method or technology. Information can be computer-readable instructions, data structures, modules of programs, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic magnetic disk storage or other magnetic storage devices, or any other non-transferable medium that can be used to store information accessible by a computing device. As defined herein, computer-readable media does not include transient computer-readable media, such as modulated data signals and carrier waves.

[0147] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0148] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

[0149] It should also be noted that the specific technical features described in the above embodiments can be combined in any suitable manner, without contradiction, such as by exchanging the execution order of some steps. To avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0150] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. An electro-hydraulic proportional flow control valve assembly, characterized in that, The system includes an inlet flow restrictor, a proportional throttle valve as a pilot valve, and a flow control valve as a main valve. The inlet of the flow control valve is connected to the inlet of the inlet flow restrictor and the pump outlet, respectively. The outlet of the inlet flow restrictor is connected to the inlet of the proportional throttle valve and the spring chamber of the flow control valve, respectively. The outlet of the flow control valve is connected to the outlet of the proportional throttle valve and the actuator. The flow control valve is configured to generate valve core displacement under the action of the spring chamber pressure, the pump outlet pressure, and the load chamber pressure from the actuator. The change in valve core displacement of the flow control valve changes the flow rate through the flow control valve. The inlet flow restrictor and the proportional throttle valve together form a pressure divider effect on the spring chamber pressure, and the spring chamber pressure changes according to the opening degree of the proportional throttle valve. The load chamber pressure and the pump outlet pressure act on one side of the valve core of the flow control valve, and the spring chamber pressure acts on the other side of the valve core of the flow control valve.

2. The electro-hydraulic proportional flow control valve assembly according to claim 1, characterized in that, The inlet flow restrictor is a cone valve or a sensing piston. The cone valve is a cone-shaped throttle valve whose oil flow rate is affected by the pressure difference between its inlet and outlet. The sensing piston is a sensing throttle element whose oil flow rate is affected by the linear relationship between the spring chamber pressure and the pump outlet pressure.

3. An electro-hydraulic proportional flow control method, characterized in that, The method is applied to the electro-hydraulic proportional flow control valve assembly of claim 1 or 2, and the electro-hydraulic proportional flow control method includes: Based on the desired flow rate and pump outlet pressure, determine the desired spring chamber pressure for the flow control valve, such that the output flow rate of the flow control valve matches the desired flow rate; and For the deviation between the desired spring chamber pressure and the current actual spring chamber pressure, a preset closed-loop control algorithm is executed to output a control quantity for the opening of the proportional throttle valve, so as to adapt to the change of the actual spring chamber pressure by changing the opening of the proportional throttle valve.

4. The electro-hydraulic proportional flow control method according to claim 3, characterized in that, Determining the desired spring chamber pressure for the flow control valve includes: The desired flow rate and the pump outlet pressure are input to the master stage control model to output the desired spring chamber pressure, wherein the master stage control model is a computational model pre-constructed based on the flow equation and force balance equation of the flow control valve to show the relationship between the desired flow rate, the pump outlet pressure and the desired spring chamber pressure.

5. The electro-hydraulic proportional flow control method according to claim 4, characterized in that, The master-level control model is described as determining the desired spring cavity pressure using the following formula. P e : in, It is the working area of ​​the oil inlet chamber of the flow control valve; The working area of ​​the spring chamber in the flow control valve; The effective area of ​​the load chamber of the flow control valve; Flow control valve spring stiffness; Flow control valve flow gain; Pressure gain of flow control valve; Flow control valve spring preload; Pump outlet pressure; Expected traffic; The proportionality coefficient, The proportionality coefficient, It is the offset of the load chamber pressure.

6. The electro-hydraulic proportional flow control method according to claim 3, characterized in that, When the inlet flow restrictor is a cone valve, and the electro-hydraulic proportional flow control method further includes obtaining the current actual spring chamber pressure through the following steps: Obtain the current load chamber pressure and historical spring chamber pressure; The current oil flow rate of the proportional throttle valve is determined based on the current load chamber pressure and the current output current of the proportional throttle valve. Based on the historical spring chamber pressure and the pump outlet pressure, the current oil flow rate of the inlet flow restrictor is determined; as well as The current actual spring chamber pressure is determined by combining the current oil flow rate of the proportional throttle valve and the current oil flow rate of the inlet flow restrictor.

7. The electro-hydraulic proportional flow control method according to claim 6, characterized in that, The current load chamber pressure is obtained using any of the following methods: Based on the force balance equation of the flow control valve, the current load chamber pressure is determined according to the historical spring chamber pressure and the pump outlet pressure; or... The current load chamber pressure is detected in real time by a pressure sensor.

8. The electro-hydraulic proportional flow control method according to claim 6, characterized in that, The current oil flow rate of the proportional throttle valve is determined using the following formula. Q i : in, proportional throttle valve displacement Proportional throttle valve current I-displacement Gain coefficient, It is the flow gain of the proportional throttle valve. It is the pressure gain of the proportional throttle valve. This is the current load chamber pressure. I It is the current output current of the proportional throttle valve that is detected in real time.

9. The electro-hydraulic proportional flow control method according to claim 6, characterized in that, The current oil flow rate of the inlet flow restrictor is determined using the following formula. Q v : in, It is the working area of ​​the oil inlet chamber of the cone valve. It is the working area of ​​the spring chamber of the cone valve. It is the preload of the cone valve spring. It is the pressure gain of the cone valve. It is the flow gain of the cone valve. It is the spring stiffness of the cone valve. P pre_ei It is the historical spring cavity pressure.

10. The electro-hydraulic proportional flow control method according to claim 6, characterized in that, The actual spring chamber pressure is determined using the following formula. P ei : in, Q i This is the current oil flow rate of the proportional throttle valve. Q v This is the current oil flow rate of the inlet flow restrictor. It is the difference in flow rate of the spring cavity. It is an oil elasticity model. It is the volume of the spring cavity.

11. A machine-readable storage medium storing instructions for causing a machine to perform the electro-hydraulic proportional flow control method according to any one of claims 3 to 10.

12. An electro-hydraulic proportional flow controller, characterized in that, include: Memory, which stores programs that can run on a processor; as well as The processor is configured to implement the electro-hydraulic proportional flow control method according to any one of claims 3 to 10 when executing the program.

13. An electro-hydraulic proportional flow control system, characterized in that, include: The electro-hydraulic proportional flow control valve assembly according to claim 1 or 2; as well as The electro-hydraulic proportional flow controller of claim 12 is used to control the output flow of the flow control valve to be consistent with the desired flow by controlling the spring chamber pressure of the flow control valve in the electro-hydraulic proportional flow control valve assembly.

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