Hydraulic counterweight system and method

Abstract

According to the hydraulic counterweight system and method, the main hydraulic pump and the auxiliary hydraulic pump are arranged, when a hydraulic lifting mechanism needs larger oil flow, the hydraulic pump and the auxiliary hydraulic pump can work together to provide pressure oil, and therefore the overall adaptability of the system is improved. And in addition, control dead zone compensation is carried out on the electro-hydraulic proportional reversing valve by using the PID regulator, so that the control stability of the whole system is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of hydraulic lifts, and in particular to a hydraulic counterweight system; in addition, the present invention also relates to a hydraulic counterweight method. Background Art

[0002] The hydraulic lifting system is a device that drives the load up or down by the movement of a hydraulic cylinder or a hydraulic motor. It has the advantages of large load capacity, safe and stable operation, and simple structure. However, the existing hydraulic counterweight system cannot adapt to the flow specifications of various hydraulic lifting mechanisms, and there is a certain control dead zone when controlling the output pressure oil, which causes deviations when controlling the electro-hydraulic proportional reversing valve, resulting in unstable control. Summary of the invention

[0003] In order to solve the problems existing in the prior art, at least one embodiment of the present invention provides a hydraulic counterweight system, which greatly improves the adaptability and control stability. To this end, at least one embodiment of the present invention also provides a hydraulic counterweight method.

[0004] In the first aspect, an embodiment of the present invention proposes a hydraulic counterweight system, which is installed on a hydraulic lifting mechanism, and includes a main hydraulic pump, an auxiliary hydraulic pump, an electro-hydraulic proportional reversing valve, an accumulator, an oil replenishing pump, an electromagnetic valve, and an oil tank; the input ends of the main hydraulic pump and the auxiliary hydraulic pump are respectively connected to the oil tank through pipelines, and the output ends of the main hydraulic pump and the auxiliary hydraulic pump are respectively connected to the electro-hydraulic proportional reversing valve, and the output ends of the main hydraulic pump and the auxiliary hydraulic pump are provided with a first pressure sensor; the signal input end of the electro-hydraulic proportional reversing valve is connected to a PID regulator, the electro-hydraulic proportional reversing valve is connected to the hydraulic lifting mechanism through a pipeline, and the liquid inlet end of the hydraulic lifting mechanism is provided with a second pressure sensor; the input end of the oil replenishing pump is connected to the oil tank through a pipeline, the output end of the oil replenishing pump is connected to the accumulator through a pipeline, the accumulator is connected to one end of the electromagnetic valve through a pipeline, and the other end of the electromagnetic valve is connected to the hydraulic lifting mechanism through a pipeline.

[0005] In some embodiments, the present invention provides a hydraulic counterweight system, wherein an oil suction filter is provided on the pipelines between the main hydraulic pump, the auxiliary hydraulic pump, the oil replenishment pump and the oil tank, and a manual stop valve is provided at the output end of the accumulator.

[0006] In some embodiments, the present invention provides a hydraulic counterweight system, in which a fine filter is provided on the pipeline between the output ends of the main hydraulic pump and the auxiliary hydraulic pump and the electro-hydraulic proportional reversing valve.

[0007] In some embodiments, the present invention provides a hydraulic counterweight system, wherein the output ends of the main hydraulic pump and the auxiliary hydraulic pump are provided with a first pressure gauge.

[0008] In some embodiments, the present invention provides a hydraulic counterweight system, wherein a cooler is provided at one end of the electro-hydraulic proportional reversing valve.

[0009] In some embodiments, the present invention provides a hydraulic counterweight system, wherein the output end of the oil replenishment pump is respectively provided with a third pressure sensor and a second pressure gauge.

[0010] In some embodiments, a hydraulic counterweight system provided by the present invention also includes a first safety valve and a second safety valve, one end of the first safety valve is connected to the output ends of the main hydraulic pump and the auxiliary hydraulic pump through a pipeline, and the other end of the first safety valve is connected to the oil tank through a pipeline; one end of the second safety valve is connected to the output end of the oil replenishment pump through a pipeline, and the other end of the second safety valve is connected to the oil tank through a pipeline.

[0011] In some embodiments, a hydraulic counterweight system provided by the present invention also includes a manual pump, a first ball valve and a second ball valve; the input end of the manual pump is connected to the oil tank, the output end of the manual pump is connected to one end of the first ball valve, and the other end of the first ball valve is connected to the hydraulic lifting mechanism; one end of the second ball valve is connected to the electro-hydraulic proportional reversing valve, and the other end of the second ball valve is connected to the hydraulic lifting mechanism.

[0012] In a second aspect, an embodiment of the present invention further provides a hydraulic counterweight method, including the hydraulic counterweight system of any one of the first aspects, the method comprising: Determine whether the oil flow rate required by the hydraulic lifting mechanism is greater than the oil flow rate range of the main hydraulic pump. If the oil flow rate required by the hydraulic lifting mechanism is not greater than the oil flow rate range of the main hydraulic pump, the pressure oil is output through the main hydraulic pump; if the oil flow rate required by the hydraulic lifting mechanism is greater than the oil flow rate range of the main hydraulic pump, the pressure oil is output through the auxiliary hydraulic pump and the main hydraulic pump together; Real-time detection of the oil pressure at the output end of the main hydraulic pump through the first pressure sensor and detection of the oil pressure in the hydraulic lifting mechanism through the second pressure sensor; When the oil pressure at the output end of the main hydraulic pump is equal to the oil pressure in the hydraulic lifting mechanism, the electro-hydraulic proportional reversing valve is controlled to open, and the output pressure oil drives the hydraulic lifting mechanism to move up and down; When the electro-hydraulic proportional reversing valve is controlled, the zero dead zone compensation is performed on the electro-hydraulic proportional reversing valve through a PID regulator, and the PID is expressed by the following formula 1: Formula 1 Among them, U(k) is the output value of the regulator at the kth sampling, T i is the integration time constant, T D is the differential time constant, T is the sampling control period, k is the sampling number, E(k) is the deviation value at the kth sampling, and E(k-1) is the deviation value at the k-1th sampling.

[0013] In some embodiments, the present invention provides a hydraulic counterweight method, the method further comprising: When a failure occurs during the output of the pressure oil, the hydraulic lifting mechanism is driven by a manual pump to perform lifting motion.

[0014] It can be seen that the hydraulic counterweight system and method of the embodiment of the present invention, by setting up a main hydraulic pump and an auxiliary hydraulic pump, can work together to provide pressure oil when the hydraulic lifting mechanism requires a larger oil flow, thereby increasing the overall adaptability of the system. Furthermore, by using a PID regulator to control the dead zone compensation of the electro-hydraulic proportional reversing valve, the control stability of the entire system is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0016] Figure 1 Shown is a structural schematic diagram of a hydraulic counterweight system in an embodiment of the present invention; Figure 2 Shown is a flow chart of a hydraulic counterweight method in an embodiment of the present invention.

[0017] The reference numerals in the accompanying drawings of the specification are as follows: Main hydraulic pump 1, auxiliary hydraulic pump 2, electro-hydraulic proportional reversing valve 3, accumulator 4, oil replenishment pump 5, solenoid valve 6, oil tank 7, first pressure sensor 8, PID regulator 9, hydraulic lifting mechanism 10, second pressure sensor 11, oil suction filter 12, fine filter 13, manual pump 14, first pressure gauge 15, first safety valve 16 and second safety valve 17, cooler 18, third pressure sensor 19, second pressure gauge 20, first ball valve 21, second ball valve 22, manual stop valve 23. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] It should be noted that, in this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. In this article, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element.

[0020] [Example 1] In the prior art, the hydraulic counterweight system cannot adapt to the flow specifications of various hydraulic lifting mechanisms, and there is also a certain control dead zone when controlling the output pressure oil, which causes deviations when controlling the electro-hydraulic proportional reversing valve, resulting in unstable control. The embodiment of the present invention provides the following solution: like Figure 1 As shown, an embodiment of the present invention provides a hydraulic counterweight system, which is installed on a hydraulic lifting mechanism 10, and includes a main hydraulic pump 1, an auxiliary hydraulic pump 2, an electro-hydraulic proportional reversing valve 3, an accumulator 4, an oil replenishing pump 5, an electromagnetic valve 6, and an oil tank 7. The input ends of the main hydraulic pump 1 and the auxiliary hydraulic pump 2 are respectively connected to the oil tank 7 through pipelines, and the output ends of the main hydraulic pump 1 and the auxiliary hydraulic pump 2 are respectively connected to the electro-hydraulic proportional reversing valve 3. The output ends of the main hydraulic pump 1 and the auxiliary hydraulic pump 2 are provided with a first pressure sensor 8. The signal input end of the electro-hydraulic proportional reversing valve 3 is connected to a PID regulator 9, and the electro-hydraulic proportional reversing valve 3 is connected to the hydraulic lifting mechanism 10 through a pipeline. The liquid inlet end of the hydraulic lifting mechanism 10 is provided with a second pressure sensor 11. The input end of the oil replenishing pump 5 is connected to the oil tank 7 through a pipeline, and the output end of the oil replenishing pump 5 is connected to the accumulator 4 through a pipeline. The accumulator 4 is connected to one end of the electromagnetic valve 6 through a pipeline, and the other end of the electromagnetic valve 6 is connected to the hydraulic lifting mechanism 10 through a pipeline.

[0021] It should be noted that the oil pressure at the output end of the main hydraulic pump 1 and the auxiliary hydraulic pump 2 is detected by the first pressure sensor 8, the oil pressure at the inlet end of the hydraulic lifting mechanism 10 is detected by the second pressure sensor 11, and the zero dead zone compensation is performed on the electro-hydraulic proportional reversing valve 3 by the PID regulator 9. Before the operation, it is first determined whether the oil flow required by the hydraulic lifting mechanism 10 is greater than the oil flow range of the main hydraulic pump 1. If the oil flow required by the hydraulic lifting mechanism 10 is not greater than the oil flow range of the main hydraulic pump, the pressure oil is output through the main hydraulic pump 1; if the oil flow required by the hydraulic lifting mechanism 10 is greater than the oil flow range of the main hydraulic pump 1, the pressure oil is output through the auxiliary hydraulic pump 2 and the main hydraulic pump 1. It can be understood that the oil flow required by the hydraulic lifting mechanism 10 is the oil flow required by the hydraulic cylinder or hydraulic motor in the hydraulic lifting mechanism 10.

[0022] Open the solenoid valve 6 so that the accumulator 4 is connected to the hydraulic lifting mechanism 10. The accumulator 4 can collect and store energy during the lifting process of the hydraulic lifting mechanism 10 to help balance the load of the system, reduce vibration, and maintain the stability of the system. When the pressure oil is output through the main hydraulic pump 1 or the main hydraulic pump 1 and the auxiliary hydraulic pump 2, when the oil pressure at the output end of the main hydraulic pump 1 is equal to the oil pressure in the hydraulic lifting mechanism 10, the electro-hydraulic proportional reversing valve 3 is controlled to open, and the pressure oil is output to drive the hydraulic lifting mechanism 10 to move up and down. When the hydraulic lifting mechanism 10 rises or falls to the specified position, the solenoid valve 6 and the electro-hydraulic proportional reversing valve 3 are closed.

[0023] In some embodiments, an oil suction filter 12 is provided on the pipelines between the main hydraulic pump 1 , the auxiliary hydraulic pump 2 , the supplementary oil pump 5 and the oil tank 7 , and a manual stop valve 23 is provided at the output end of the accumulator 4 .

[0024] It should be noted that the oil suction filter 12 ensures the cleanliness of the sucked oil and has the function of protecting the main hydraulic pump 1, the auxiliary hydraulic pump 2 and the replenishing pump 5. When the accumulator 4 fails or is not used for a long time, the accumulator 4 is closed by the manual shut-off valve 23, so as to be compatible with various usage scenarios.

[0025] In some embodiments, a fine filter 13 is provided on the pipeline between the output ends of the main hydraulic pump 1 and the auxiliary hydraulic pump 2 and the electro-hydraulic proportional reversing valve 3 .

[0026] It should be noted that the fine filter 13 can perform precise filtration on the oil to a level of 10 um, thus meeting the requirements of the electro-hydraulic proportional reversing valve 3 for oil cleanliness.

[0027] In some embodiments, a first pressure gauge 15 is provided at the output ends of the main hydraulic pump 1 and the auxiliary hydraulic pump 2 , and a third pressure sensor 19 and a second pressure gauge 20 are provided at the output ends of the supplementary oil pump 5 .

[0028] It should be noted that the first pressure gauge 15 can display the pressure value of the output end of the main hydraulic pump 1 and the auxiliary hydraulic pump 2 in real time, and the second pressure gauge 20 can display the pressure value of the output end of the oil replenishment pump 5 in real time. The third pressure sensor 19 is used to detect the pressure value of the output end of the oil replenishment pump 5. If a pressure drop is detected, the oil replenishment pump 5 can be used to replenish oil to restore it to a stable pressure state.

[0029] In some embodiments, a cooler 18 is provided at one end of the electro-hydraulic proportional reversing valve 3, and the cooler 18 is used to cool the oil to prevent the failure of the seal due to excessively high oil temperature.

[0030] In some embodiments, the system further includes a first safety valve 16 and a second safety valve 17, one end of the first safety valve 16 is connected to the output ends of the main hydraulic pump 1 and the auxiliary hydraulic pump 2 through a pipeline, and the other end of the first safety valve 16 is connected to the oil tank 7 through a pipeline. One end of the second safety valve 17 is connected to the output end of the oil replenishment pump 5 through a pipeline, and the other end of the second safety valve 17 is connected to the oil tank 7 through a pipeline.

[0031] It should be noted that when the pressure of the main hydraulic pump 1 and the auxiliary hydraulic pump 2 is overloaded, the first safety valve 16 can be opened to ensure the safety of the system. When the pressure of the charge pump 5 is overloaded, the second safety valve 17 can be opened to ensure the safety of the system.

[0032] In some embodiments, the system further includes a manual pump 14, a first ball valve 21, and a second ball valve 22; the input end of the manual pump 14 is connected to the oil tank 7, the output end of the manual pump 14 is connected to one end of the first ball valve 21, and the other end of the first ball valve 21 is connected to the hydraulic lifting mechanism 10. One end of the second ball valve 22 is connected to the electro-hydraulic proportional reversing valve 3, and the other end of the second ball valve 22 is connected to the hydraulic lifting mechanism 10.

[0033] It should be noted that when the system cannot work normally, for example, when the main hydraulic pump 1 and the auxiliary hydraulic pump 2 fail and cannot output the pressure oil normally, the manual pump 14 can continue to drive the hydraulic lifting mechanism 10 to perform lifting and lowering movements, thereby increasing the fault tolerance rate and improving the stability of the entire system.

[0034] [Example 2] like Figure 2 As shown, the embodiment of the present invention further provides a hydraulic counterweight method, including the hydraulic counterweight system in embodiment 1, the method comprising: Determine whether the oil flow rate required by the hydraulic lifting mechanism is greater than the oil flow rate range of the main hydraulic pump. If the oil flow rate required by the hydraulic lifting mechanism is not greater than the oil flow rate range of the main hydraulic pump, the pressure oil is output through the main hydraulic pump. If the oil flow rate required by the hydraulic lifting mechanism is greater than the oil flow rate range of the main hydraulic pump, the pressure oil is output through the auxiliary hydraulic pump and the main hydraulic pump.

[0035] The oil pressure at the output end of the main hydraulic pump is detected in real time through the first pressure sensor, and the oil pressure in the hydraulic lifting mechanism is detected through the second pressure sensor.

[0036] When the oil pressure at the output end of the main hydraulic pump is equal to the oil pressure in the hydraulic lifting mechanism, the electro-hydraulic proportional reversing valve is controlled to open, and the output pressure oil drives the hydraulic lifting mechanism to perform lifting and lowering movements.

[0037] When the electro-hydraulic proportional reversing valve is controlled, the zero dead zone compensation is performed on the electro-hydraulic proportional reversing valve through a PID regulator, and the PID is expressed by the following formula 1: Formula 1 Among them, U(k) is the output value of the regulator at the kth sampling, T i is the integration time constant, T D is the differential time constant, T is the sampling control period, k is the sampling number, E(k) is the deviation value at the kth sampling, and E(k-1) is the deviation value at the k-1th sampling.

[0038] It should be noted that the oil pressure at the output end of the main hydraulic pump 1 and the auxiliary hydraulic pump 2 is detected by the first pressure sensor 8, the oil pressure at the inlet end of the hydraulic lifting mechanism 10 is detected by the second pressure sensor 11, and the zero dead zone compensation is performed on the electro-hydraulic proportional reversing valve 3 by the PID regulator 9. Before the operation, it is first determined whether the oil flow required by the hydraulic lifting mechanism 10 is greater than the oil flow range of the main hydraulic pump 1. If the oil flow required by the hydraulic lifting mechanism 10 is not greater than the oil flow range of the main hydraulic pump, the pressure oil is output through the main hydraulic pump 1; if the oil flow required by the hydraulic lifting mechanism 10 is greater than the oil flow range of the main hydraulic pump 1, the pressure oil is output through the auxiliary hydraulic pump 2 and the main hydraulic pump 1. It can be understood that the oil flow required by the hydraulic lifting mechanism 10 is the oil flow required by the hydraulic cylinder or hydraulic motor in the hydraulic lifting mechanism 10.

[0039] Open the solenoid valve 6 so that the accumulator 4 is connected to the hydraulic lifting mechanism 10. The accumulator 4 can collect and store energy during the lifting process of the hydraulic lifting mechanism 10 to help balance the load of the system, reduce vibration, and maintain the stability of the system. When the pressure oil is output through the main hydraulic pump 1 or the main hydraulic pump 1 and the auxiliary hydraulic pump 2, when the oil pressure at the output end of the main hydraulic pump 1 is equal to the oil pressure in the hydraulic lifting mechanism 10, the electro-hydraulic proportional reversing valve 3 is controlled to open, and the pressure oil is output to drive the hydraulic lifting mechanism 10 to move up and down. When the hydraulic lifting mechanism 10 rises or falls to the specified position, the solenoid valve 6 and the electro-hydraulic proportional reversing valve 3 are closed.

[0040] In some embodiments, when a failure occurs during the output of the pressure oil, the hydraulic lifting mechanism 10 is driven by the manual pump 14 to perform lifting motion.

[0041] It should be noted that when the system cannot work normally, for example, when the main hydraulic pump 1 and the auxiliary hydraulic pump 2 fail and cannot output the pressure oil normally, the manual pump 14 can continue to drive the hydraulic lifting mechanism 10 to perform lifting and lowering movements, thereby increasing the fault tolerance rate and improving the stability of the entire system.

[0042] In summary, embodiments 1-2 of the present invention provide a hydraulic counterweight system and method, by providing a main hydraulic pump and an auxiliary hydraulic pump, when the hydraulic lifting mechanism requires a larger oil flow, the hydraulic pump and the auxiliary hydraulic pump can work together to provide pressure oil, thereby increasing the overall adaptability of the system. Furthermore, by using a PID regulator to control the dead zone compensation of the electro-hydraulic proportional reversing valve, the control stability of the entire system is improved.

[0043] The above contents are only specific implementation methods of the present application, and the protection scope of the present application is not limited thereto. Those skilled in the art may make changes or substitutions within the technical scope disclosed in the present application, and these changes or substitutions shall be within the protection scope of the present application.

[0044] Those skilled in the art will appreciate that although some embodiments described herein include certain features included in other embodiments but not other features, the combination of features from different embodiments is meant to be within the scope of the present invention and to form different embodiments.

[0045] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A hydraulic counterweight system, installed on a hydraulic lifting mechanism (10), characterized in that: The invention comprises a main hydraulic pump (1), an auxiliary hydraulic pump (2), an electro-hydraulic proportional reversing valve (3), an accumulator (4), an oil replenishing pump (5), an electromagnetic valve (6), and an oil tank (7); the input ends of the main hydraulic pump (1) and the auxiliary hydraulic pump (2) are respectively connected to the oil tank (7) through pipelines, the output ends of the main hydraulic pump (1) and the auxiliary hydraulic pump (2) are respectively connected to the electro-hydraulic proportional reversing valve (3), and the output ends of the main hydraulic pump (1) and the auxiliary hydraulic pump (2) are provided with a first pressure sensor (8); the signal input end of the electro-hydraulic proportional reversing valve (3) is ... A PID regulator (9) is provided, the electro-hydraulic proportional reversing valve (3) is connected to the hydraulic lifting mechanism (10) through a pipeline, and a second pressure sensor (11) is provided at the liquid inlet end of the hydraulic lifting mechanism (10); the input end of the oil replenishment pump (5) is connected to the oil tank (7) through a pipeline, the output end of the oil replenishment pump (5) is connected to the energy accumulator (4) through a pipeline, the energy accumulator (4) is connected to one end of the solenoid valve (6) through a pipeline, and the other end of the solenoid valve (6) is connected to the hydraulic lifting mechanism (10) through a pipeline.

2. The hydraulic counterweight system according to claim 1, characterized in that: An oil suction filter (12) is provided on the pipelines between the main hydraulic pump (1), the auxiliary hydraulic pump (2), the oil replenishment pump (5) and the oil tank (7), and a manual stop valve (23) is provided at the output end of the energy accumulator (4).

3. The hydraulic counterweight system according to claim 1, characterized in that: A fine filter (13) is provided on the pipeline between the output ends of the main hydraulic pump (1) and the auxiliary hydraulic pump (2) and the electro-hydraulic proportional reversing valve (3).

4. The hydraulic counterweight system according to claim 1, characterized in that: The output ends of the main hydraulic pump (1) and the auxiliary hydraulic pump (2) are provided with a first pressure gauge (15).

5. The hydraulic counterweight system according to claim 1, characterized in that: A cooler (18) is provided at one end of the electro-hydraulic proportional reversing valve (3).

6. The hydraulic counterweight system according to claim 1, characterized in that: A third pressure sensor (19) and a second pressure gauge (20) are respectively provided at the output end of the oil replenishment pump.

7. The hydraulic counterweight system according to claim 1, characterized in that: The invention also comprises a first safety valve (16) and a second safety valve (17), wherein one end of the first safety valve (16) is connected to the output ends of the main hydraulic pump (1) and the auxiliary hydraulic pump (2) through a pipeline, and the other end of the first safety valve (16) is connected to the oil tank (7) through a pipeline; one end of the second safety valve (17) is connected to the output end of the oil replenishment pump (5) through a pipeline, and the other end of the second safety valve (17) is connected to the oil tank (7) through a pipeline.

8. The hydraulic counterweight system according to claim 1, characterized in that: It also comprises a manual pump (14), a first ball valve (21) and a second ball valve (22); the input end of the manual pump (14) is connected to the oil tank (7), the output end of the manual pump (14) is connected to one end of the first ball valve (21), and the other end of the first ball valve (21) is connected to the hydraulic lifting mechanism (10); one end of the second ball valve (22) is connected to the electro-hydraulic proportional reversing valve (3), and the other end of the second ball valve (22) is connected to the hydraulic lifting mechanism (10).

9. A hydraulic counterweight method, characterized in that: Comprising a plurality of hydraulic counterweight systems according to any one of claims 1 to 8, the method comprising: Determine whether the oil flow rate required by the hydraulic lifting mechanism is greater than the oil flow rate range of the main hydraulic pump, if the oil flow rate required by the hydraulic lifting mechanism is not greater than the oil flow rate range of the main hydraulic pump, output the pressure oil through the main hydraulic pump; if the oil flow rate required by the hydraulic lifting mechanism is greater than the oil flow rate range of the main hydraulic pump, output the pressure oil through the auxiliary hydraulic pump and the main hydraulic pump together; Real-time detection of the oil pressure at the output end of the main hydraulic pump by a first pressure sensor and detection of the oil pressure in the hydraulic lifting mechanism by a second pressure sensor; When the oil pressure at the output end of the main hydraulic pump is equal to the oil pressure in the hydraulic lifting mechanism, the electro-hydraulic proportional reversing valve is controlled to open, and the output pressure oil drives the hydraulic lifting mechanism to move up and down; When the electro-hydraulic proportional reversing valve is controlled, the zero dead zone compensation is performed on the electro-hydraulic proportional reversing valve through a PID regulator, and the PID is expressed by the following formula 1: Formula 1 Among them, U(k) is the output value of the regulator at the kth sampling, T i is the integration time constant, T D is the differential time constant, T is the sampling control period, k is the sampling number, E(k) is the deviation value at the kth sampling, and E(k-1) is the deviation value at the k-1th sampling.

10. The hydraulic counterweight method according to claim 9, characterized in that: The method further comprises: When a failure occurs during the output of the pressure oil, the hydraulic lifting mechanism is driven by a manual pump to perform lifting motion.

Images