A high-speed high-precision oil cylinder control system and method

Abstract

The application discloses a high-speed and high-precision oil cylinder control system and method, and the control system comprises a control valve group, wherein the control valve group comprises a first cartridge valve, a second cartridge valve, a solenoid valve, a solenoid proportional valve, an A oil inlet, a T oil return, a Pst pilot oil inlet and an A1 oil return; a first oil port of the first cartridge valve is communicated with a rodless cavity of an oil cylinder, a second oil port of the first cartridge valve is communicated with a first oil port of the second cartridge valve, and a second oil port of the second cartridge valve is communicated with the A1 oil return; a control cavity of the first cartridge valve is communicated with a control port of the solenoid valve, an oil inlet of the solenoid valve is respectively communicated with the first oil port of the first cartridge valve and the rodless cavity of the oil cylinder, an oil return of the solenoid valve and an oil return of the solenoid proportional valve are respectively communicated with the T oil return, a control cavity of the second cartridge valve is communicated with a control port of the solenoid proportional valve, and an oil inlet of the solenoid proportional valve is communicated with the Pst pilot oil inlet. The application improves the oil cylinder retraction rate and solves the problem of inaccurate retraction speed control.

Description

Technical Field

[0001] This invention belongs to the field of hydraulic control technology and relates to a high-speed, high-precision hydraulic cylinder control system and method. Background Technology

[0002] Existing lifting equipment primarily utilizes hydraulic cylinder lifting mechanisms to convert energy and achieve its designed functions during operation. Examples include the luffing mechanism of telescopic boom cranes and the lifting mechanisms of some dynamic compaction machines. In telescopic boom cranes, the luffing mechanism uses cylinders to control the telescopic boom's working radius, thereby controlling the boom system's amplitude and thus the working radius of the main unit. In dynamic compaction machines, the lifting mechanism uses cylinders to extend and retract, driving a wire rope pulley system to raise and lower the load. To control the descent speed of the boom or load, ensuring smooth descent and proper clamping, a balance valve is installed on the hydraulic system's oil circuit outside the hydraulic cylinders. The balance valve's opening and throttling action control the smooth descent of the boom or load.

[0003] In construction machinery, many lifting mechanisms using hydraulic cylinders employ balance valves to limit and lock the descent speed of the lifted object. The descent power of the hydraulic cylinder comes from the weight of the lifted object itself and the hydraulic pressure provided by the hydraulic system. The balance valves used are typically spool valves or cone valves, and due to manufacturing limitations, the flow rate is restricted, which in turn limits the speed of this system.

[0004] The working mechanism of the balance valve and the effect of the weight of the lifted object, as well as the changes in force during operation, cause the speed limiting effect of the balance valve to be inaccurate and unstable, and it is significantly affected by the load size. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a high-speed, high-precision hydraulic cylinder control system and method, which improves the hydraulic cylinder retraction rate and solves the problem of inaccurate retraction speed control.

[0006] To achieve the above objectives, the present invention is implemented using the following technical solution:

[0007] A high-speed, high-precision hydraulic cylinder control system includes a control valve assembly. The control valve assembly includes a first cartridge valve, a second cartridge valve, a solenoid valve, a solenoid proportional valve, an A inlet, a T return port, a Pst pilot inlet, and an A1 return port. The first port of the first cartridge valve is connected to the rodless chamber of the hydraulic cylinder. The second port of the first cartridge valve is connected to the first port of the second cartridge valve. The second port of the second cartridge valve is connected to the A1 return port. The A inlet is located in an oil passage connecting the second port of the first cartridge valve and the first port of the second cartridge valve. The control chamber of the first cartridge valve is connected to the control port of the solenoid valve. The inlet of the solenoid valve is connected to both the first port of the first cartridge valve and the rodless chamber of the hydraulic cylinder. The return ports of the solenoid valve and the solenoid proportional valve are connected to the T return port. The control chamber of the second cartridge valve is connected to the control port of the solenoid proportional valve. The inlet of the solenoid proportional valve is connected to the Pst pilot inlet.

[0008] Optionally, it also includes an overflow valve, which is located in the oil passage between the oil inlet and the oil return port of the solenoid valve. One end of the overflow valve is connected to the oil inlet of the solenoid valve, and the other end of the overflow valve is connected to the oil return port of the solenoid valve, the oil return port of the electromagnetic proportional valve, and the T-return port.

[0009] Optionally, the control chamber of the second cartridge valve is provided with a displacement sensor for detecting the displacement of the valve core, and the displacement sensor is connected to the valve core of the second cartridge valve.

[0010] Optionally, a controller may also be included, configured to control the opening degree of the second cartridge valve based on the spool position of the second cartridge valve.

[0011] Optionally, a directional valve is connected to the oil inlet A.

[0012] Optionally, the first cartridge valve and the second cartridge valve are both two-way cartridge valves.

[0013] Optionally, the solenoid valve is a two-position three-way solenoid valve.

[0014] A control method for a high-speed, high-precision hydraulic cylinder control system includes:

[0015] With the cylinder stationary, the solenoid valve and the solenoid proportional valve are de-energized, and the first cartridge valve and the second cartridge valve are closed. The control chamber of the first cartridge valve is connected to the rodless chamber of the cylinder through the oil inlet of the solenoid valve, and the control chamber of the second cartridge valve is connected to the pilot oil inlet of the Pst through the oil inlet of the solenoid proportional valve. The hydraulic oil is sealed inside the rodless chamber of the cylinder.

[0016] When the hydraulic cylinder is lifted, the solenoid valve is energized, the control chamber of the first cartridge valve is connected to the return port of the solenoid valve, the control chamber of the first cartridge valve is depressurized, the first cartridge valve is opened, and hydraulic oil enters the rodless chamber of the hydraulic cylinder through the A inlet, the second port and the first port of the first cartridge valve, and the piston rod of the hydraulic cylinder extends out of the cylinder barrel.

[0017] When the hydraulic cylinder descends, the solenoid valve is energized, and the control chamber of the first cartridge valve is connected to the return port of the solenoid valve. The control chamber of the first cartridge valve is depressurized, and the first cartridge valve opens. When the electromagnetic proportional valve is energized, the control chamber of the second cartridge valve is connected to the return port of the electromagnetic proportional valve. The control chamber of the second cartridge valve is depressurized, and the second cartridge valve opens. Hydraulic oil enters the A1 return port from the rodless chamber of the hydraulic cylinder through the first and second ports of the first and second cartridge valves, and the piston rod retracts into the cylinder barrel.

[0018] Optionally, the controller outputs a command displacement signal to control the electromagnetic proportional valve and the electromagnetic valve. The pressure difference generated by the action of the electromagnetic proportional valve drives the main valve core of the second cartridge valve to move. The actual displacement of the main valve core of the second cartridge valve monitored by the displacement sensor is fed back to the controller. The controller compares the feedback signal with the original output command signal. Based on the comparison result, it outputs the command displacement signal again until the actual displacement is equal to the original command displacement.

[0019] Optionally, the output flow rate of the solenoid valve and the solenoid proportional valve is related to the input displacement command signal and the valve pressure difference, and the load flow rate is proportional to the square root of the valve port pressure difference, as shown in the following formula:

[0020]

[0021] Where Q is the actual flow rate of the valve; Q N The valve's rated output flow rate, ΔP is the valve's actual pressure difference, ΔP N This is the valve's rated differential pressure.

[0022] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0023] This invention provides a high-speed, high-precision hydraulic cylinder control system and method, which controls the falling speed of the hydraulic cylinder through a first cartridge valve and a second cartridge valve, and locks it when it stops; compared with the balance valve, the first cartridge valve and the second cartridge valve have the characteristics of large flow capacity, low hydraulic resistance, fast action, low leakage, low internal resistance and fast response, which solves the original problems of slow falling speed, slow response and inaccurate control.

[0024] The first cartridge valve and the second cartridge valve are controlled by solenoid valve and solenoid proportional valve respectively, so that the flow rate of hydraulic oil can be controlled more precisely. Attached Figure Description

[0025] Figure 1 The diagram shown is a schematic diagram of a high-speed, high-precision hydraulic cylinder control system and method according to an embodiment of the present invention.

[0026] In the diagram: 1. First cartridge valve; 2. Second cartridge valve; 3. Solenoid valve; 4. Solenoid proportional valve; 5. Relief valve; 6. Displacement sensor. Detailed Implementation

[0027] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0028] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0029] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0030] Example 1

[0031] like Figure 1As shown, a high-speed, high-precision hydraulic cylinder control system includes a control valve assembly. The control valve assembly includes a first cartridge valve 1, a second cartridge valve 2, a solenoid valve 3, a relief valve 5, an A inlet, a T return port, a solenoid proportional valve 4, a Pst pilot inlet, and an A1 return port. The Pst inlet is connected to an external control oil source. The first port of the first cartridge valve 1 is connected to the rodless chamber of the cylinder. The second port of the first cartridge valve 1 is connected to the first port of the second cartridge valve 2. The second port of the second cartridge valve 2 is connected to a hydraulic oil tank. The A inlet is located between the second port of the first cartridge valve 1 and the first port of the second cartridge valve 2. On the oil passages connected by oil ports, the A inlet is externally connected to a directional valve and connected to the hydraulic oil source; the control chamber of the first cartridge valve 1 is connected to the control port of the solenoid valve 3, the inlet of the solenoid valve 3 is connected to the first oil port of the first cartridge valve 1 and the rodless chamber of the cylinder, the return port of the solenoid valve 3 and the return port of the solenoid proportional valve 4 are connected to the T return port, the control chamber of the second cartridge valve 2 is connected to the control port of the solenoid proportional valve 4, and the inlet of the solenoid proportional valve 4 is connected to the Pst pilot inlet; the first cartridge valve 1 and the second cartridge valve 2 are both two-way cartridge valves; the solenoid valve 3 is a two-position three-way solenoid valve;

[0032] The overflow valve 5 is located in the oil passage between the oil inlet and the oil return port of the solenoid valve 3. One end of the overflow valve 5 is connected to the oil inlet of the solenoid valve 3, and the other end of the overflow valve 5 is connected to the oil return port of the solenoid valve 3, the oil return port of the solenoid proportional valve 4, and the T oil return port.

[0033] The control chamber of the second cartridge valve 2 is equipped with a displacement sensor 6 for detecting the displacement of the valve core. The displacement sensor 6 is connected to the valve core of the second cartridge valve 2.

[0034] The control system also includes a controller configured to control the opening degree of the second cartridge valve 2 based on the valve core position of the second cartridge valve 2.

[0035] Example 2

[0036] like Figure 1 As shown, a high-speed, high-precision hydraulic cylinder control method includes:

[0037] When the cylinder is stationary, solenoid valve 3 and solenoid proportional valve 4 are de-energized, and the first cartridge valve 1 and the second cartridge valve 2 are closed. The control chamber of the first cartridge valve 1 is connected to the rodless chamber of the cylinder through the oil inlet of solenoid valve 3, and the control chamber of the second cartridge valve 2 is connected to the pilot oil inlet of Pst through the oil inlet of solenoid proportional valve 4. The hydraulic oil is sealed in the rodless chamber of the cylinder.

[0038] When the cylinder is lifted, the solenoid valve 3 is energized, the control chamber of the first cartridge valve 1 is connected to the return port of the solenoid valve 3, the control chamber of the first cartridge valve 1 is depressurized, the first cartridge valve 1 is opened, and the hydraulic oil enters the rodless chamber of the cylinder through the A inlet, the second port and the first port of the first cartridge valve 1, and the cylinder piston rod extends out of the cylinder barrel.

[0039] As the cylinder descends, solenoid valve 3 is energized, connecting the control chamber of the first cartridge valve 1 with the return port of solenoid valve 3. The control chamber of the first cartridge valve 1 is depressurized, and the first cartridge valve 1 opens. Solenoid proportional valve 4 is energized, connecting the control chamber of the second cartridge valve 2 with the return port of solenoid proportional valve 4. The control chamber of the second cartridge valve 2 is depressurized, and the second cartridge valve 2 opens. Hydraulic oil flows from the rodless chamber of the cylinder through the first and second ports of the first cartridge valve 1 and the second port of the second cartridge valve 2 into the A1 return port, causing the piston rod to retract into the cylinder barrel.

[0040] The controller outputs a command displacement signal to control the electromagnetic proportional valve 4 and the electromagnetic valve 3. The pressure difference generated by the action of the electromagnetic proportional valve 4 drives the main valve core of the second cartridge valve 2 to move. The actual displacement of the main valve core of the second cartridge valve 2 monitored by the displacement sensor 6 is fed back to the controller. The controller compares the feedback signal with the original output command signal. Based on the comparison result, it outputs the command displacement signal again until the actual displacement is equal to the original command displacement.

[0041] The output flow rates of solenoid valve 3 and solenoid proportional valve 4 are related to the input displacement command signal and the valve pressure difference. The load flow rate is proportional to the square root of the valve port pressure difference, as shown in the following formula:

[0042]

[0043] Where Q is the actual flow rate of the valve; Q N The valve's rated output flow rate, ΔP is the valve's actual pressure difference, ΔP N This is the valve's rated differential pressure.

[0044] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A high-speed, high-precision hydraulic cylinder control system, characterized in that: The system includes a control valve assembly comprising a first cartridge valve, a second cartridge valve, a solenoid valve, a solenoid proportional valve, an A inlet, a T return port, a Pst pilot inlet, and an A1 return port. The first port of the first cartridge valve is connected to the rodless chamber of the cylinder; the second port of the first cartridge valve is connected to the first port of the second cartridge valve; the second port of the second cartridge valve is connected to the A1 return port; the A inlet is located in the oil passage connecting the second port of the first cartridge valve and the first port of the second cartridge valve; the control chamber of the first cartridge valve is connected to the control port of the solenoid valve; the inlet of the solenoid valve is connected to both the first port of the first cartridge valve and the rodless chamber of the cylinder; the return ports of the solenoid valve and the solenoid proportional valve are connected to the T return port; the control chamber of the second cartridge valve is connected to the control port of the solenoid proportional valve; and the inlet of the solenoid proportional valve is connected to the Pst pilot inlet.

2. The high-speed, high-precision hydraulic cylinder control system according to claim 1, characterized in that: It also includes an overflow valve, which is located in the oil passage between the oil inlet and the oil return port of the solenoid valve. One end of the overflow valve is connected to the oil inlet of the solenoid valve, and the other end of the overflow valve is connected to the oil return port of the solenoid valve, the oil return port of the electromagnetic proportional valve, and the T-return port.

3. The high-speed, high-precision hydraulic cylinder control system according to claim 1, characterized in that: The control chamber of the second cartridge valve is equipped with a displacement sensor for detecting the displacement of the valve core, and the displacement sensor is connected to the valve core of the second cartridge valve.

4. The high-speed, high-precision hydraulic cylinder control system according to claim 1, characterized in that: It also includes a controller configured to control the opening degree of the second cartridge valve based on the spool position of the second cartridge valve.

5. The high-speed, high-precision hydraulic cylinder control system according to claim 1, characterized in that: The A inlet is connected to an external reversing valve.

6. The high-speed, high-precision hydraulic cylinder control system according to claim 1, characterized in that: The first cartridge valve and the second cartridge valve are both two-way cartridge valves.

7. The high-speed, high-precision hydraulic cylinder control system according to claim 1, characterized in that: The solenoid valve is a two-position three-way solenoid valve.

8. A control method for a high-speed, high-precision hydraulic cylinder control system according to any one of claims 1-7, characterized in that, include: With the cylinder stationary, the solenoid valve and the solenoid proportional valve are de-energized, and the first cartridge valve and the second cartridge valve are closed. The control chamber of the first cartridge valve is connected to the rodless chamber of the cylinder through the oil inlet of the solenoid valve, and the control chamber of the second cartridge valve is connected to the pilot oil inlet of the Pst through the oil inlet of the solenoid proportional valve. The hydraulic oil is sealed inside the rodless chamber of the cylinder. When the hydraulic cylinder is lifted, the solenoid valve is energized, the control chamber of the first cartridge valve is connected to the return port of the solenoid valve, the control chamber of the first cartridge valve is depressurized, the first cartridge valve is opened, and hydraulic oil enters the rodless chamber of the hydraulic cylinder through the A inlet, the second port and the first port of the first cartridge valve, and the piston rod of the hydraulic cylinder extends out of the cylinder barrel. When the hydraulic cylinder descends, the solenoid valve is energized, and the control chamber of the first cartridge valve is connected to the return port of the solenoid valve. The control chamber of the first cartridge valve is depressurized, and the first cartridge valve opens. When the electromagnetic proportional valve is energized, the control chamber of the second cartridge valve is connected to the return port of the electromagnetic proportional valve. The control chamber of the second cartridge valve is depressurized, and the second cartridge valve opens. Hydraulic oil enters the A1 return port from the rodless chamber of the hydraulic cylinder through the first and second ports of the first and second cartridge valves, and the piston rod retracts into the cylinder barrel.

9. The control method of the high-speed, high-precision hydraulic cylinder control system according to claim 8, characterized in that: The controller outputs a command displacement signal to control the electromagnetic proportional valve and the electromagnetic valve. The pressure difference generated by the action of the electromagnetic proportional valve drives the main valve core of the second cartridge valve to move. The actual displacement of the main valve core of the second cartridge valve monitored by the displacement sensor is fed back to the controller. The controller compares the feedback signal with the original output command signal. Based on the comparison result, it outputs a command displacement signal again until the actual displacement is equal to the original command displacement.

10. The control method of the high-speed, high-precision hydraulic cylinder control system according to claim 8, characterized in that: The output flow rate of the solenoid valve and the solenoid proportional valve is related to the input displacement command signal and the valve pressure difference. The load flow rate is proportional to the square root of the valve port pressure difference, as shown in the following formula: ； Where Q is the actual flow rate of the valve; Q N The valve's rated output flow rate, ΔP is the valve's actual pressure difference, ΔP N This is the valve's rated differential pressure.

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