A control method based on crane boom luffing

Abstract

The present invention provides a control method based on the luffing of a crane boom. The method comprises the following steps: firstly, the boom is debugged for no-load raising and no-load lowering, and then the boom is controlled for loaded raising and loaded lowering, so that the boom and the load can be raised and lowered smoothly. During the luffing process, the method can prevent the oil pressure from increasing instantaneously during the raising process, thereby preventing the boom from being stuck after being raised instantaneously, thereby avoiding damage to the luffing cylinder. At the same time, the method ensures that the opening of the balance valve is adjusted by controlling the pressure change in the oil circuit during the luffing and lowering process, thereby avoiding the occurrence of a descent jitter phenomenon, and can accurately control the raising and lowering process of the boom.

Description

Technical Field

[0001] The present invention relates to the technical field of cranes, and in particular to a control method based on the luffing of a crane boom. Background Art

[0002] In the actual operation process of engineering cranes, the actuator is usually a luffing cylinder. In the process of boom luffing, hydraulic closed-loop control is generally adopted. However, in actual application, due to different loads, the boom often shakes violently and has poor micro-mobility during the process of collapse and lowering. In order to solve this technical problem, a patent document with Chinese patent application number 201510391773.1 and announcement date 2017.06.30 discloses a boom luffing hydraulic system, including a main pump, a main valve, a luffing cylinder, a first An oil circuit and a second oil circuit, the first oil circuit is connected to the first chamber oil port of the boom cylinder, the second oil circuit is connected to the second chamber oil port of the boom cylinder, the first oil circuit is connected to the first working oil port of the main valve, the second oil circuit is connected to the second working oil port of the main valve, the main pump is connected to the oil inlet of the main valve, and a pressure control valve is arranged in the first oil circuit; it also includes a servo pump and a servo oil circuit, the servo pump supplies oil to the servo oil circuit, the servo oil circuit is connected to the pilot oil port of the pressure control valve, and a hydraulic valve is arranged in the servo oil circuit, which controls the opening of the pressure control valve.

[0003] In the above-mentioned document, the pressure of the small chamber oil port of the boom cylinder is detected by a pressure sensor, and the controller obtains the pressure sensor signal. When the boom is lowered too fast, the controller controls the displacement of the main pump and the opening of the pressure control valve to achieve the control of the boom lowering amplitude. Since the main pump is connected to the boom cylinder through the main valve, and the pressure control valve is connected to the other end of the boom cylinder, it cannot ensure a balancing valve between the two oil circuits connected to the boom cylinder. In addition, it does not clearly define the control method during the rising process, and there are rising jams and falling jitters during the rising and falling of the boom during the boom luffing process. Summary of the Invention

[0004] The purpose of the present invention is to provide a control method based on the boom luffing of a crane. During the luffing process, it can prevent the oil pressure from increasing instantaneously during the ascent, which may cause the boom to get stuck after it is instantly raised, thereby avoiding damage to the luffing cylinder. At the same time, it ensures that the opening of the balancing valve is adjusted by controlling the change in pressure in the oil circuit during the luffing descent process, thereby avoiding the descent jitter phenomenon and accurately controlling the ascent and descent process of the boom.

[0005] To achieve the above-mentioned object, a control method based on the boom luffing of a crane is provided, which is implemented by a boom luffing system. The boom luffing system includes a main pump oil circuit, a reversing valve, a pressure relief oil circuit, a first oil circuit, a second oil circuit, and a luffing cylinder. A balancing valve is provided between the first oil circuit and the second oil circuit. The method comprises the following steps:

[0006] S1 performs no-load luffing commissioning on the boom, including no-load raising and no-load lowering.

[0007] During no-load lifting, S1.1 opens the first pressure valve connected to the main pump oil circuit. The hydraulic oil in the main pump oil circuit then flows into the first oil circuit through the reversing valve. The second oil circuit then flows into the pressure relief oil circuit for pressure relief after passing through the reversing valve. At the same time, the pressure value of the first pressure valve is adjusted to allow the boom to rise at a uniform speed driven by the luffing cylinder.

[0008] S1.2 After the boom reaches the preset height, stop rising;

[0009] S1.3 During the no-load lowering process, the reversing valve is adjusted to allow the hydraulic oil in the main pump oil circuit to flow into the second oil circuit. The oil pressure in the first oil circuit passes through the reversing valve and enters the pressure relief oil circuit for pressure relief, thereby opening the balancing valve through the branch oil circuit, thereby driving the boom to descend at a uniform speed.

[0010] In the above method, during the no-load debugging process, the hydraulic oil pressure of the main pump oil circuit is adjusted by the first pressure valve, and the reversing valve is used to switch the main pump oil circuit to supply oil to the first oil circuit, and then the second oil circuit is relieved of pressure, thereby preventing the boom from swaying and shaking due to excessive pressure at the beginning of the ascent. By adjusting the pressure of the first pressure valve to control the opening of the balancing valve, the boom can be lowered stably to avoid momentary pauses during the descent; and by adjusting the pressure of the first pressure valve to control the opening of the balancing valve, the pressure difference between the first oil circuit and the second oil circuit is kept constant, thereby achieving stability of the boom and the load, effectively avoiding pauses or shaking problems, and the control method is simple and reliable.

[0011] Furthermore, after step S1, step S2 is included to perform boom load amplitude control, including load increase and load decrease.

[0012] S2.1 During the load raising process, the pressure value of the first pressure valve is adjusted to keep the pressure difference between the first oil circuit and the second oil circuit constant, thereby causing the luffing cylinder to drive the boom to rise at a constant speed;

[0013] S2.2 After the boom and the load have risen to a preset height, the main pump in the main pump oil circuit stops working, and then the boom and the load are driven to rotate to a preset angle through the slewing mechanism, and the process proceeds to step S2.3;

[0014] S2.3 During the load lowering process, the opening of the balancing valve is controlled by adjusting the pressure of the first pressure valve to ensure that the pressure difference between the first oil circuit and the second oil circuit is a fixed value, thereby driving the boom and the load to descend at a uniform speed;

[0015] After unloading the load, the boom is in an unloaded state in S3, and step S1 is repeated to reset the boom.

[0016] With the above arrangement, during the boom load raising and luffing process, by adjusting the pressure value of the first pressure valve, it is possible to prevent the luffing cylinder from extending momentarily when excessive pressure is initially supplied to the luffing cylinder, causing the boom and the load to be momentarily stuck or jittered. The boom and the load can only rise normally and at a uniform speed after the normal pressure supply is restored. However, controlling the opening of the balancing valve by controlling the flow of hydraulic oil can easily make the opening of the balancing valve too small, and the hydraulic oil of the luffing cylinder cannot flow back to the oil tank through the balancing valve, causing the boom and the load to accelerate downward under the action of their own gravity. Only when the opening of the balancing valve is able to allow the part of the hydraulic oil of the luffing cylinder in the retraction process to flow back to the oil tank through the balancing valve and the first oil circuit can the descent speed of the boom and the load be actively controlled, and pauses or jitters will occur in this process.

[0017] Furthermore, the step S1.1 also includes S1.1 to S1.3,

[0018] S1.1.1 Open the first pressure valve connected to the main pump oil circuit, then adjust the reversing valve and simultaneously open the pressure valve group connected to the reversing valve;

[0019] S1.1.2 Start the motor to drive the oil pump, so that the hydraulic oil in the main pump oil circuit flows into the first oil circuit after passing through the reversing valve, and then flows through the balancing valve into the luffing cylinder;

[0020] S1.1.3 adjusts the pressure value of the first pressure valve so that the pressure difference between the first oil circuit and the second oil circuit is a fixed value T1, thereby driving the luffing cylinder to extend and driving the boom to rise at a uniform speed.

[0021] The above setting, by adjusting the pressure value of the first pressure valve, prevents the boom from rising sharply and instantly due to excessive pressure when it first starts to rise.

[0022] Furthermore, the step S1.3 also includes S1.3.1 to S1.3.3,

[0023] S1.3.1 Adjust the reversing valve so that the hydraulic oil in the main pump oil circuit flows into the secondary oil circuit after passing through the reversing valve. The secondary oil circuit then opens the balancing valve through the branch oil circuit, and at the same time drives the luffing cylinder to retract.

[0024] S1.3.2 controls the pressure of the main pump oil circuit distributed to the second oil circuit after passing through the reversing valve by adjusting the pressure value of the first pressure valve, thereby controlling the opening of the balancing valve. This ensures that after the first oil circuit is connected to the luffing cylinder through the balancing valve, the pressure difference between the first oil circuit and the second oil circuit is a fixed value T2, thereby driving the boom to descend at a uniform speed.

[0025] S1.3.3 After the boom is lowered and reset, stop lowering.

[0026] The above arrangement controls the opening of the balancing valve by adjusting the pressure of the first pressure valve, thereby achieving stable descent of the boom and avoiding momentary pauses during the descent process.

[0027] Furthermore, the step S2.1 also includes S2.1.1 to S2.1.3,

[0028] S2.1.1 Open the first pressure valve connected to the main pump oil circuit, then adjust the reversing valve and simultaneously open the pressure valve group connected to the reversing valve;

[0029] S2.1.2 Start the motor to drive the oil pump, so that the hydraulic oil in the main pump oil circuit flows into the first oil circuit after passing through the reversing valve, and then flows through the balancing valve into the luffing cylinder;

[0030] S2.1.3 adjusts the pressure value of the first pressure valve so that the pressure difference between the first oil circuit and the second oil circuit is a fixed value T3, thereby driving the variable-length oil cylinder to extend, driving the boom and the load to rise at a uniform speed.

[0031] The above setting, by adjusting the pressure value of the first pressure valve, can prevent the boom and load from being stuck or jittered momentarily only after the pressure supply to the boom cylinder is restored to normal, causing the boom and load to extend momentarily when the pressure is too high at the beginning.

[0032] Furthermore, the step S2.3 also includes S2.3.1 to S2.3.3,

[0033] S2.3.1 Adjust the reversing valve so that the hydraulic oil in the main pump oil circuit flows into the secondary oil circuit after passing through the reversing valve. The secondary oil circuit then opens the balancing valve through the branch oil circuit, and at the same time drives the luffing cylinder to retract.

[0034] S2.3.2 controls the pressure of the main pump oil circuit distributed to the second oil circuit after passing through the reversing valve by adjusting the pressure value of the first pressure valve, thereby controlling the opening of the balancing valve. This ensures that after the first oil circuit is connected to the luffing cylinder through the balancing valve, the pressure difference between the first oil circuit and the second oil circuit is a fixed value T4, thereby driving the boom and the load to descend at a uniform speed.

[0035] S2.3.3 After the boom and the load are lowered to the preset position, stop the main pump in the main pump oil circuit and unload the load.

[0036] The above setting controls the opening of the balancing valve by adjusting the pressure of the first pressure valve, so that the pressure difference between the first oil circuit and the second oil circuit remains unchanged, thereby achieving stable descent of the boom and the load, and effectively avoiding the inaccurate control of the hydraulic oil flow rate, which leads to the opening of the balancing valve being unable to achieve a fixed pressure difference between the first oil circuit and the second oil circuit, thereby causing pauses or jitters during the descent of the boom and the load. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is the workflow diagram of the present invention.

[0038] Figure 2 It is a connection diagram of the hydraulic system in the present invention.

[0039] Figure 3 for Figure 2 Enlarged view of point E in the middle.

[0040] Figure 4 for Figure 2 Enlarged view of point F in the middle. DETAILED DESCRIPTION

[0041] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0042] like Figure 1-4 As shown, a control method based on the boom luffing of a crane includes a boom luffing hydraulic system, which includes a main pump oil circuit 1, a reversing valve 2, a pressure relief oil circuit 3, a first oil circuit 4, a second oil circuit 5 and a luffing cylinder 60. The main pump oil circuit 1 is connected to the pressure relief oil circuit 3 and the reversing valve 2, respectively. The main pump oil circuit 1 and the pressure relief oil circuit 4 are both connected to the oil tank 6. The main pump oil circuit 1 includes an oil pump 11 and a third oil circuit 13 connected to the oil pump 11. One end of the third oil circuit 13 is connected to the oil outlet C of the oil pump 11, and the oil inlet D of the oil pump 11 is connected to the oil tank 6. The oil pump 11 is connected to the output end of a motor 12 arranged on the outside of the oil pump 11, so that the oil pump 11 can be controlled to work by the motor 12, and the hydraulic oil in the oil tank 6 is drawn into the third oil circuit 13.

[0043] The pressure relief oil circuit 3 includes a first pressure valve 31 and a return oil filter. One end of the first pressure valve 31 is connected to the other end of the third oil circuit 13. The other end of the first pressure valve 31 is respectively connected to the valve port A of the reversing valve 2, the valve port B of the reversing valve 2 and the return oil filter. The return oil filter is connected to the oil tank 6. A pressure valve group is provided at the valve port A of the reversing valve 2 and the valve port B of the reversing valve 2. In this embodiment, the stroke of the valve core of the reversing valve 2 can be adjusted by moving the handle provided on the outside of the reversing valve 2 to adjust the pressure flowing through the reversing valve 2. When the pressure of the hydraulic oil passing through the reversing valve 2 reaches a fixed value, the pressure is relieved through the pressure relief oil circuit 3, so that the first pressure valve 31 can be opened and the return oil filter can be connected. The oil filter is connected, so that the local hydraulic oil in the main pump oil circuit 1 flows back to the oil tank 6 through the first pressure valve 31 and the return oil filter; the pressure valve group includes a second pressure valve 42 and a third pressure valve 43, one end of the second pressure valve 42 is connected to the valve port A of the reversing valve 2, and one end of the third pressure valve 43 is connected to the valve port B of the reversing valve 2, and the other end of the second pressure valve 42 and the other end of the third pressure valve 43 are both connected to the return oil filter. In this way, when the hydraulic oil in the first oil circuit 4 flows back to the reversing valve 2, the local pressure of the reversing valve 2 can be unloaded through the pressure valve group, so that the local hydraulic oil flows through the pressure valve group to the return oil filter, and finally flows back to the oil tank 6, to prevent the reversing valve 2 from being damaged by excessive pressure.

[0044] The return oil filter includes a pressure gauge 7, a filter 8 and a one-way valve 9. The one-way valve 9 is connected in parallel at both ends of the filter 8. The rear end of the filter 8 is connected to the oil tank 6, and the pressure gauge 7 is connected to the front end of the filter 8, so that it is convenient to monitor the oil pressure entering the filter 8 through the pressure gauge 7. At the same time, the local hydraulic oil can be diverted through the one-way valve 9 to avoid damage to the filter 8 due to excessive oil pressure.

[0045] The P1 valve port of the reversing valve 2 is connected to one end of the first oil circuit 4, and the P2 valve port of the reversing valve 2 is connected to one end of the second oil circuit 5. A balancing valve 10 is provided between the first oil circuit 4 and the luffing cylinder 60, and a branch oil circuit 20 is provided between the second oil circuit 4 and the balancing valve 10. The balancing valve 10 is connected through the branch oil circuit 20. The balancing valve 10 is respectively connected to the other end of the first oil circuit 4 and one end of the luffing cylinder 60, and the other end of the second oil circuit 5 is connected to the other end of the luffing cylinder 60. In this embodiment, the luffing cylinder 60 is a single-piston rod luffing cylinder. A single piston rod 603 is provided, which divides the interior of the luffing cylinder 60 into a first chamber 601 and a second chamber 602. The first chamber 601 is connected to the balancing valve 10, and the second chamber 602 is connected to the other end of the second oil circuit 5, so that the first oil circuit 4 can be connected to the first chamber 601 through the balancing valve 10, and the second oil circuit 5 is connected to the second chamber 602, thereby pushing the single piston rod 603 to move in the luffing cylinder 60, thereby realizing luffing lifting. In this embodiment, the first chamber 601 and the second chamber 602 are filled with hydraulic oil.

[0046] In this embodiment, the boom luffing hydraulic system is used to control the luffing cylinder 60, and the two ends of the luffing cylinder 60 are respectively connected to the slewing mechanism and the boom. In this way, the boom can be raised or lowered under the drive of the luffing cylinder 60.

[0047] In this embodiment, a first pressure sensor 604 and a second pressure sensor 605 are respectively provided on the first chamber 601 and the second chamber 602. The hydraulic oil pressures in the first chamber 601 and the second chamber 602 are respectively tested by the first pressure sensor 604 and the second pressure sensor 605, so that the pressure value of the first pressure valve 31 can be adjusted according to the pressure difference between the first pressure sensor 604 and the second pressure sensor 605.

[0048] The following specific steps are also included:

[0049] S1 is to conduct no-load luffing commissioning on the boom, including S1.1~S1.3.

[0050] S1.1 During the no-load rising process, including S1.1.1 to S1.1.3,

[0051] S1.1.1 Open the first pressure valve connected to the main pump oil circuit, then adjust the reversing valve and simultaneously open the pressure valve group connected to the reversing valve, so that the reversing valve moves to the first chamber A1 position. The first oil circuit 4 is connected to the main pump oil circuit, and the second oil circuit 5 is connected to the third pressure valve through the reversing valve port B.

[0052] S1.1.2 Start the motor to drive the oil pump, so that the hydraulic oil in the main pump oil circuit flows through the reversing valve into the first oil circuit, and then flows through the balancing valve into the first chamber 601 of the luffing cylinder;

[0053] S1.1.3 In this embodiment, the hydraulic oil pressure values ​​of the first and second oil circuits are obtained respectively by the first pressure sensor 604 and the second pressure sensor 605. The pressure of the first pressure valve 31 is then adjusted so that the pressure difference between the first oil circuit 4 and the second oil circuit 5 is a fixed value T1. At this time, the pressure of the first oil circuit 4 is greater than the pressure of the second oil circuit 5, and the pressure of the second oil circuit 5 is less than the pressure required to open the balancing valve 10. Therefore, the hydraulic oil in the second oil circuit 5 cannot pass through the balancing valve 10 and directly flows back to the reversing valve 2, thereby driving the luffing cylinder to extend and causing the boom to rise at a uniform speed.

[0054] S1.2 After the boom has risen to the preset height, the motor is turned off to stop the boom from rising;

[0055] S1.3 During the no-load descent process, including S1.3.1 to S1.3.3,

[0056] S1.3.1 Adjust reversing valve 2 to reversing direction, moving it to the third chamber B1. The second oil circuit 5 connects to the main pump oil circuit 1, and the first oil circuit 4 connects to the second pressure valve 42 via port A to relieve pressure. This allows the hydraulic oil in the main pump oil circuit to flow through reversing valve 2 and into the second oil circuit 5. Simultaneously, the second pressure valve 42 connects to the first oil circuit 4 at port A of the reversing valve. The second oil circuit 5 then opens the balancing valve 10 via the branch oil circuit. Simultaneously, the second oil circuit 5 connects to the second chamber 602 of the luffing cylinder, driving the luffing cylinder to retract.

[0057] S1.3.2 controls the pressure of the main pump oil circuit distributed to the second oil circuit 5 after passing through the reversing valve 2 by adjusting the pressure value of the first pressure valve 31, thereby controlling the opening of the balancing valve 10. This ensures that after the first oil circuit 4 is connected to the first chamber 601 of the luffing cylinder through the balancing valve 10, the pressure values ​​of the first pressure sensor 604 and the second pressure sensor 605 are adjusted to ensure that the pressure difference between the first oil circuit and the second oil circuit is a fixed value T2, thereby driving the boom to descend at a uniform speed. In this embodiment, the fixed value T2 is equal to the fixed value T1.

[0058] S1.3.3 After the boom has lowered and reset to rest on the boom support frame, stop descending.

[0059] S2 is used to control the boom load amplitude, including S2.1~S2.3.

[0060] S2.1 During the load increase process, including S2.1.1 to S2.1.3,

[0061] S2.1.1 Open first pressure valve 31 connected to the main pump oil circuit, then adjust reversing valve 2. Simultaneously, open the pressure valve group connected to reversing valve 2, connecting third pressure valve 43 to second oil circuit 5 at port B of the reversing valve. This allows the hydraulic oil pressure in second oil circuit 5 to exceed the preset pressure of third pressure valve 43, causing third pressure valve 43 to conduct, allowing the local hydraulic oil in the second oil circuit to flow through third pressure valve 43 to the return oil for pressure relief, thus preventing damage to reversing valve 2.

[0062] S2.1.2 Start the motor to drive the oil pump. The hydraulic oil in the main pump oil circuit flows through reversing valve 2 to the first chamber A1. After that, the reversing valve P1 port connects with the main pump oil circuit 1 and flows into the first oil circuit 4. The first oil circuit 4 is connected to the third pressure valve 43 through the reversing valve P1 port and the A port for pressure relief. The oil then flows through the balancing valve 10 and enters the first chamber 601 of the luffing cylinder.

[0063] S2.1.3 adjusts the pressure in the first pressure valve using the pressure values ​​of the first pressure sensor 604 and the second pressure sensor 605, so that the pressure difference between the first oil circuit 4 and the second oil circuit 5 is a fixed value T3. At this point, the pressure in the first oil circuit 4 is greater than the pressure in the second oil circuit 5, and the pressure in the second oil circuit 5 is less than the pressure required to open the balancing valve 10. Therefore, the hydraulic oil in the second oil circuit 5 cannot pass through the balancing valve 10 and flows directly back to the reversing valve 5, thereby driving the luffing cylinder to extend, causing the boom and the load to rise at a uniform speed.

[0064] S2.2 After the boom and the load have risen to a preset height, the motor is turned off, the main pump in the main pump oil circuit stops working, and the boom and the load are then rotated to a preset angle through the slewing mechanism, and the process proceeds to step S2.3;

[0065] S2.3, during the load reduction process, includes S2.3.1 to S2.3.3.

[0066] S2.3.1 Adjust the reversing valve 2 to reverse so that the reversing valve 2 is switched to the third chamber B1, so that the second oil circuit 5 is connected to the main pump oil circuit 1 through the reversing valve, and the first oil circuit 4 is connected to the second pressure valve 42 through the P1 port and the A port of the reversing valve to achieve pressure relief, so that the hydraulic oil in the main pump oil circuit flows into the second oil circuit 5 after passing through the reversing valve 2, and at the same time, the second pressure valve 42 is connected to the first oil circuit 4 at the valve port A of the reversing valve, and then the second oil circuit 5 opens the balancing valve through the branch oil circuit, and at the same time, the second oil circuit 5 is connected to the second chamber 602 of the boom cylinder, driving the boom cylinder to retract. In this way, after the first oil circuit 4 is connected to the boom cylinder through the balancing valve 10, when the hydraulic oil pressure in the first oil circuit 4 is greater than the preset pressure of the second pressure valve 42, the second pressure valve 42 is turned on, so that the local hydraulic oil in the first oil circuit 4 flows to the return oil filter through the second pressure valve 42 to prevent damage to the reversing valve 2;

[0067] S2.3.2 controls the pressure of the main pump oil circuit distributed to the second oil circuit 5 after it passes through the reversing valve 2 by adjusting the pressure value of the first pressure valve 31. This in turn controls the opening of the balancing valve 10. This ensures that after the first oil circuit 4 is connected to the first chamber 601 of the luffing cylinder through the balancing valve 10, the pressure values ​​of the first pressure sensor 604 and the second pressure sensor 605 are adjusted to ensure that the pressure difference between the first and second oil circuits is a fixed value T4, thereby driving the boom and the load to descend at a uniform speed.

[0068] S2.3.3 After the boom and the load have been lowered to the preset position, the main pump in the main pump oil circuit shall be stopped and the load shall be unloaded;

[0069] After unloading the load, the boom is in an unloaded state in step S3, and steps S1.1 to S1.2 are repeated. Then, the slewing mechanism is rotated in the reverse direction by the preset angle in step S2.2, and step S1.3 is repeated.

[0070] The working principle of the present invention is as follows: during the no-load debugging process, the hydraulic oil pressure of the main pump oil circuit 1 is adjusted by the first pressure valve 31, and the reversing valve 2 is used to reverse the direction so that the main pump oil circuit 1 supplies oil to the first oil circuit 4, and then the second oil circuit 5 is relieved of pressure, thereby preventing the boom from swinging and rising sharply due to excessive pressure at the beginning of the ascent. By adjusting the pressure of the first pressure valve 31 to control the opening of the balance valve, the boom can be lowered stably to avoid momentary pauses during the descent; and by adjusting the pressure of the first pressure valve 31 to control the opening of the balance valve, the pressure difference between the first oil circuit 4 and the second oil circuit 5 is fixed, thereby achieving stability of the boom and the load, effectively avoiding pauses or jitters, and the control method is simple and reliable.

Claims

1. A control method for crane boom luffing, implemented through a boom luffing system, comprising a main pump oil circuit, a reversing valve, a pressure relief oil circuit, a first oil circuit, a second oil circuit, and a luffing cylinder, characterized in that: A balancing valve is provided between the first oil circuit and the second oil circuit; the process includes the following steps: S1 performs no-load luffing commissioning on the boom, including no-load raising and no-load lowering; During no-load lifting, S1.1 opens the first pressure valve connected to the main pump oil circuit. The hydraulic oil in the main pump oil circuit then flows into the first oil circuit through the reversing valve. The second oil circuit then flows into the pressure relief oil circuit for pressure relief after passing through the reversing valve. At the same time, the pressure value of the first pressure valve is adjusted to allow the boom to rise at a uniform speed driven by the luffing cylinder. S1.2 After the boom reaches the preset height, stop rising; S1.3 During the no-load lowering process, the reversing valve is adjusted to allow the hydraulic oil in the main pump oil circuit to flow into the second oil circuit. The oil pressure in the first oil circuit flows through the reversing valve and enters the pressure relief oil circuit for pressure relief, thereby opening the balancing valve through the branch oil circuit, thereby driving the boom to descend at a uniform speed. S2 performs boom load amplitude control, including load raising and load lowering. S2.1 During the load raising process, by adjusting the pressure value of the first pressure valve, the pressure difference between the first oil circuit and the second oil circuit remains unchanged, thereby causing the boom to rise at a constant speed driven by the luffing cylinder; including S2.1.1~S2.1.3, S2.1.1 Open the first pressure valve connected to the main pump oil circuit, then adjust the reversing valve and simultaneously open the pressure valve group connected to the reversing valve; S2.1.2 Start the motor to drive the oil pump, so that the hydraulic oil in the main pump oil circuit flows into the first oil circuit after passing through the reversing valve, and then flows through the balancing valve into the luffing cylinder; S2.1.3 adjusts the pressure value of the first pressure valve so that the pressure difference between the first oil circuit and the second oil circuit is a fixed value T3, thereby driving the luffing cylinder to extend, causing the boom and the load to rise at a uniform speed; S2.2 After the boom and the load have risen to a preset height, the main pump in the main pump oil circuit stops working, and then the boom and the load are driven to rotate to a preset angle through the slewing mechanism, and the process proceeds to step S2.3; S2.3 During the load lowering process, the opening of the balancing valve is controlled by adjusting the pressure of the first pressure valve to ensure that the pressure difference between the first oil circuit and the second oil circuit is a fixed value, thereby driving the boom and the load to descend at a uniform speed; including S2.3.1~S2.3.3, S2.3.1 Adjust the reversing valve so that the hydraulic oil in the main pump oil circuit flows into the secondary oil circuit after passing through the reversing valve. The secondary oil circuit then opens the balancing valve through the branch oil circuit, and at the same time drives the luffing cylinder to retract. S2.3.2 controls the pressure of the main pump oil circuit distributed to the second oil circuit after passing through the reversing valve by adjusting the pressure value of the first pressure valve, thereby controlling the opening of the balancing valve. This ensures that after the first oil circuit is connected to the luffing cylinder through the balancing valve, the pressure difference between the first oil circuit and the second oil circuit is a fixed value T4, thereby driving the boom and the load to descend at a uniform speed. S2.3.3 After the boom and the load have been lowered to the preset position, the main pump in the main pump oil circuit shall be stopped and the load shall be unloaded; After unloading the load, the boom is in an unloaded state in S3, and step S1 is repeated to reset the boom.

2. The control method based on crane boom luffing according to claim 1, characterized in that: The step S1.1 also includes S1.1.1 to S1.1.3, S1.1.1 Open the first pressure valve connected to the main pump oil circuit, then adjust the reversing valve and simultaneously open the pressure valve group connected to the reversing valve; S1.1.2 Start the motor to drive the oil pump, so that the hydraulic oil in the main pump oil circuit flows into the first oil circuit after passing through the reversing valve, and then flows through the balancing valve into the luffing cylinder; S1.1.3 adjusts the pressure value of the first pressure valve so that the pressure difference between the first oil circuit and the second oil circuit is a fixed value T1, thereby driving the luffing cylinder to extend and driving the boom to rise at a uniform speed.

3. The control method based on crane boom luffing according to claim 1, characterized in that: The step S1.3 also includes S1.3.1 to S1.3.3, S1.3.1 Adjust the reversing valve so that the hydraulic oil in the main pump oil circuit flows into the secondary oil circuit after passing through the reversing valve. The secondary oil circuit then opens the balancing valve through the branch oil circuit, and at the same time drives the luffing cylinder to retract. S1.3.2 controls the pressure of the main pump oil circuit distributed to the second oil circuit after passing through the reversing valve by adjusting the pressure value of the first pressure valve, thereby controlling the opening of the balancing valve. This ensures that after the first oil circuit is connected to the luffing cylinder through the balancing valve, the pressure difference between the first oil circuit and the second oil circuit is a fixed value T2, thereby driving the boom to descend at a uniform speed. S1.3.3 After the boom is lowered and reset, stop lowering.

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