A crane hoist follow-up hydraulic system and control method

Abstract

The application discloses a crane hoist follow-up hydraulic system and a control method. The hydraulic system adopts a hoist motor, a telescopic oil cylinder, a hoist balance valve, a telescopic balance valve, a hoist proportional reversing valve, a telescopic proportional reversing valve, a pressure reducing valve and a brake opening valve. The P port of the telescopic proportional reversing valve is connected with the P port of the hoist proportional reversing valve and the P1 port of the pressure reducing valve. The T port of the telescopic proportional reversing valve is connected with the T port of the hoist proportional reversing valve. The A port of the telescopic proportional reversing valve is connected with the V1 port of the telescopic balance valve. The B port of the telescopic proportional reversing valve is connected with the V2 port of the telescopic balance valve. The C2 port of the telescopic balance valve is connected with the rod cavity of the telescopic oil cylinder. The C1 port of the telescopic balance valve is connected with the rodless cavity of the telescopic oil cylinder. The application can realize linkage control of the telescopic arm action and the hoist winding and unwinding action, has high automation degree, improves work efficiency, can effectively control hoisting accidents and has high safety performance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of engineering machinery, and discloses a crane hoist follow-up hydraulic system and a control method. BACKGROUND

[0002] When a crane operator is performing telescopic boom operation, generally only one operation is performed. With the extension of the crane boom, the hook gradually rises and approaches the boom head sheave under the condition that the hoist is not moving. At this time, the operator will stop the telescopic boom, and then continue the suspended telescopic operation after operating the hoist mechanism to the appropriate position until the telescopic operation is completed. This requires the operator to constantly suspend and continue the telescopic operation of the boom, which is low in work efficiency. If the operator manually controls the telescopic operation of the boom and the simultaneous operation of the hoist, the operation quality of the operator is required to be high. If the operation is not handled properly, the height limiting switch is triggered, the main boom extension is suspended, and in severe cases, the steel wire rope may be broken. Moreover, when the length of the boom is long and the operating environment is poor, the operator is difficult to master the accurate position of the hook, and manual operation is prone to cause hoisting accidents.

[0003] In the prior art, the operator needs to constantly suspend the operation of the telescopic boom and the luffing to perform the winding and unwinding of the hoist rope, which is low in operation efficiency. Moreover, when the length of the boom is long and the weather is bad, the operator is difficult to master the accurate position of the hook, and manual operation is prone to cause hoisting accidents. SUMMARY

[0004] The present application provides a crane hoist follow-up hydraulic system and a control method, which aims to solve at least one of the above-mentioned defects in the prior art.

[0005] One aspect of the present application relates to a crane hoist follow-up hydraulic system, which comprises a hoist motor, a telescopic cylinder, a hoist balance valve, a telescopic balance valve, a hoist proportional directional valve, a telescopic proportional directional valve, a pressure reducing valve and a brake opening valve. The P port of the telescopic proportional directional valve is connected to the P port of the hoist proportional directional valve and the P1 port of the pressure reducing valve. The T port of the telescopic proportional directional valve is connected to the T port of the hoist proportional directional valve. The A port of the telescopic proportional directional valve is connected to the V1 port of the telescopic balance valve. The B port of the telescopic proportional directional valve is connected to the V2 port of the telescopic balance valve. The C2 port of the telescopic balance valve is connected to the rod cavity of the telescopic cylinder. The C1 port of the telescopic balance valve is connected to the rodless cavity of the telescopic cylinder. The A port of the hoist proportional directional valve is connected to the A port of the hoist balance valve and the hoist motor. The B port of the hoist proportional directional valve is connected to the K port of the hoist balance valve and the B port of the hoist motor. The B port of the hoist balance valve is connected to the A port of the hoist motor. The P2 port of the pressure reducing valve is connected to the P port of the brake opening valve. The K port of the pressure reducing valve is connected to the T port of the brake opening valve. The A port of the brake opening valve is connected to the speed reducer of the hoist motor. The a port of the brake opening valve is connected to the Br port of the hoist balance valve.

[0006] Further, the hoist motor adopts a variable plunger motor.

[0007] Further, a pressure sensor is installed at the G port of the hoist motor, and the pressure sensor is connected to the controller to input the measured motor pressure value to the controller.

[0008] Another aspect of the present application relates to a control method applied to the crane hoist follow-up hydraulic system, which comprises the following steps:

[0009] During the boom extension and retraction operation, the boom length sensor captures the length AL1 of the boom, and the hoist mechanism synchronously retracts and extends the wire rope by the same length AL2 to keep the distance between the hook and the ground unchanged;

[0010] The controller calculates the extension and retraction cylinder flow of the hydraulic system to the extension and retraction cylinder in the same time T according to the length AL1 of the boom, and the extension and retraction cylinder flow includes the extension flow Q1 and the retraction flow Q2;

[0011] The controller calculates the rotation speed N1 of the hoist reduction gear, the rotation speed N2 of the hoist motor, and the flow Q3 required by the hoist motor according to the length AL2 of the wire rope, the circumference L3 of one turn of the wire rope on the drum, and the reduction ratio K between the hoist motor and the reduction gear;

[0012] The flow distribution of the combined operation of the extension and retraction boom operation and the hoist retracting and extending operation is calculated according to the rotation speed N1 of the hoist reduction gear, the rotation speed N2 of the hoist motor, the flow Q3 required by the hoist motor, and the condition AL1 = AL2;

[0013] According to the flow distribution of the combined operation of the extension and retraction boom operation and the hoist retracting and extending operation, the extension and retraction proportional directional valve is synchronously associated with the hoist proportional directional valve to complete the combined operation of the extension and retraction boom and the hoist.

[0014] Further, the step of calculating the extension and retraction cylinder flow of the hydraulic system to the extension and retraction cylinder in the same time T according to the length AL1 of the boom includes:

[0015] It is judged whether the hoist follow-up function is turned on;

[0016] If it is identified that the hoist follow-up function is turned on, the first preset current is equal to the extension and retraction preset current, and the second preset current is equal to the hoist preset current, then the hoist motor pressure P1 and the hoist motor displacement Vg are obtained;

[0017] The extension flow Q1 and the retraction flow Q2 are obtained according to the hoist motor displacement Vg, the first preset current, and the second preset current.

[0018] Further, the step of judging whether the winch follow-up function is started further comprises:

[0019] If the winch follow-up function is started and the first preset current is equal to the telescopic preset current and the second preset current is equal to zero, the control unit controls the single telescopic arm to move.

[0020] Further, the arm extending flow Q1 is calculated by the following formula:

[0021]

[0022] Wherein, Q1 is the arm extending flow, D1 is the cylinder diameter of the oil cylinder, ΔL1 is the length of the arm, and T is the same time.

[0023] The arm retracting flow Q2 is calculated by the following formula:

[0024]

[0025] Wherein, Q2 is the arm retracting flow, D1 is the cylinder diameter of the oil cylinder, D2 is the rod diameter of the oil cylinder, ΔL1 is the length of the arm, and T is the same time.

[0026] Further, the rotation speed N1 of the winch speed reducer is calculated by the following formula:

[0027]

[0028] Wherein, N1 is the rotation speed of the winch speed reducer, ΔL2 is the length of the steel wire rope, L3 is the circumference of one turn of the steel wire rope on the winch drum, and T is the same time.

[0029] The rotation speed N2 of the winch motor is calculated by the following formula:

[0030]

[0031] Wherein, N2 is the rotation speed of the winch motor, N1 is the rotation speed of the winch speed reducer, and K is the speed reduction ratio between the winch motor and the speed reducer.

[0032] The flow Q3 required by the winch motor is calculated by the following formula:

[0033]

[0034] Wherein, Q3 is the flow required by the winch motor, N2 is the rotation speed of the winch motor, Vg is the displacement of the winch motor, and η is the volumetric efficiency of the winch motor.

[0035] Further, the flow distribution of the combination of the telescopic arm movement and the winch winding and unwinding movement includes the flow distribution when the arm is extended, which is calculated by the following formula:

[0036]

[0037] Wherein, Q1 is the boom flow, Q2 is the stick flow, D1 is the cylinder diameter of the oil cylinder, K is the speed reduction ratio between the winch motor and the speed reducer; L3 is the circumference of a coil of the steel wire rope on the drum, and Vg is the displacement of the winch motor.

[0038] Further, the flow distribution of the combined action of the boom action and the winch winding and unwinding action includes the flow distribution when the stick is retracted, and the flow distribution when the stick is retracted is calculated by the following formula:

[0039]

[0040] Wherein, Q2 is the stick flow, Q3 is the flow required by the winch motor, D1 is the cylinder diameter of the oil cylinder, D2 is the rod diameter of the oil cylinder, K is the speed reduction ratio between the winch motor and the speed reducer; L3 is the circumference of a coil of the steel wire rope on the drum, and Vg is the displacement of the winch motor.

[0041] The beneficial effects obtained by the present application are:

[0042] The application provides a crane hoist follow-up hydraulic system and a control method, the hydraulic system adopts a hoist motor, a telescopic oil cylinder, a hoist balance valve, a telescopic balance valve, a hoist proportional reversing valve, a telescopic proportional reversing valve, a pressure reducing valve and a brake opening valve, the P port of the telescopic proportional reversing valve is connected with the P port of the hoist proportional reversing valve and the P1 port of the pressure reducing valve, the T port of the telescopic proportional reversing valve is connected with the T port of the hoist proportional reversing valve, the A port of the telescopic proportional reversing valve is connected with the V1 port of the telescopic balance valve, the B port of the telescopic proportional reversing valve is connected with the V2 port of the telescopic balance valve, the C2 port of the telescopic balance valve is connected with the rod cavity of the telescopic oil cylinder, the C1 port of the telescopic balance valve is connected with the rodless cavity of the telescopic oil cylinder, the A port of the hoist proportional reversing valve is connected with the A port of the hoist balance valve and the hoist motor, the B port of the hoist proportional reversing valve is connected with the K port of the hoist balance valve and the B port of the hoist motor, the B port of the hoist balance valve is connected with the A port of the hoist motor, the P2 port of the pressure reducing valve is connected with the P port of the brake opening valve, the K port of the pressure reducing valve is connected with the T port of the brake opening valve, the A port of the brake opening valve is connected with the speed reducer of the hoist motor, and the a port of the brake opening valve is connected with the Br port of the hoist balance valve. The crane hoist follow-up hydraulic system and the control method provided by the application give the relationship formula of the flow required by the telescopic and hoist combination action hydraulic drive under different working conditions, and the hydraulic system matches the speed according to different hoisting conditions after the hoist follow-up function is opened; the hoist follow-up function is to open the telescopic proportional reversing valve and the hoist proportional reversing valve at the same time, and not to connect the oil ports at both ends of the hoist motor to be in a floating state, and the latter is not applicable to the hoist follow-up under the hoisting condition; the application range is wider, the electric proportional multi-way valve for domestic large-tonnage cranes can be applied, and the pilot proportional valve for small-tonnage cranes can also be used, the principle of which is to control the size of the reversing current, the remote controller can be directly used for operation, or the operation panel with a direction recognition rocker can be used, and the application is not limited to the hydraulic control pilot handle; the linkage control of the telescopic arm action and the hoist winding and unwinding action can be realized, the automation degree is high, the work efficiency is improved, the hoisting accidents can be effectively controlled, and the safety performance is high. BRIEF DESCRIPTION OF DRAWINGS

[0043] Figure 1 It is a principle schematic view of an embodiment of the crane hoist follow-up hydraulic system of the application;

[0044] Figure 2 It is a flow schematic view of an embodiment of the method of the crane hoist follow-up hydraulic system of the application.

[0045] BRIEF DESCRIPTION OF DRAWINGS

[0046] 10, hoist motor; 20, telescopic oil cylinder; 30, hoist balance valve; 40, telescopic balance valve; 50, hoist proportional reversing valve; 60, telescopic proportional reversing valve; 70, pressure reducing valve; 80, brake opening valve. Detailed Implementation

[0047] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods.

[0048] like Figure 1 and Figure 2 As shown, the first embodiment of the present invention proposes a crane winch follow-up hydraulic system, including a winch motor 10, a telescopic cylinder 20, a winch balance valve 30, a telescopic balance valve 40, a winch proportional directional valve 50, a telescopic proportional directional valve 60, a pressure reducing valve 70, and a brake opening valve 80. The P port of the telescopic proportional directional valve 60 is connected to the P port of the winch proportional directional valve 50 and the P1 port of the pressure reducing valve 70, respectively. The T port of the telescopic proportional directional valve 60 is connected to the T port of the winch proportional directional valve 50. The A port of the telescopic proportional directional valve 60 is connected to the V1 port of the telescopic balance valve 40, the B port of the telescopic proportional directional valve 60 is connected to the V2 port of the telescopic balance valve 40, and the C2 port of the telescopic balance valve 40 is connected to the telescopic cylinder. The rod-side chamber of cylinder 20 is connected to the rodless chamber of cylinder 20; the C1 port of telescopic balance valve 40 is connected to the rodless chamber of telescopic cylinder 20; the A port of winch proportional directional valve 50 is connected to the A port of winch balance valve 30 and winch motor 10 respectively; the B port of winch proportional directional valve 50 is connected to the K port of winch balance valve 30 and winch motor 10 respectively; the B port of winch balance valve 30 is connected to the A port of winch motor 10; the P2 port of pressure reducing valve 70 is connected to the P port of brake opening valve 80; the K port of pressure reducing valve 70 is connected to the T port of brake opening valve 80; the A port of brake opening valve 80 is connected to the reducer of winch motor 10; the a port of brake opening valve 80 is connected to the Br port of winch balance valve 30. The crane winch follow-up hydraulic system provided in this embodiment controls the distance between the hook and the ground to remain constant. During the boom extension and retraction process, the winch motor drives the winch mechanism to control the length of the wire rope. The boom extension and retraction movements and the winch winding and unwinding movements share the main hydraulic circuit. Therefore, only the boom extension is operated, and the boom extension proportional directional valve 60 is synchronously energized with the winch proportional directional valve 50. Before this, the measured relationship between the proportional directional valve and the current has been imported into the controller. The preset current magnitudes I1 and I2 for the two movements are adjusted according to the relationship between the proportional directional valve and the current to complete the boom extension and winch follow-up combined movement.

[0049] In the above structure, please see Figure 1 , Figure 1The crane hoist follow-up hydraulic system proposed in the embodiment, the hoist motor 10 adopts a variable plunger motor, the displacement change is related to the lifting load. The G port of the hoist motor 10 is provided with a pressure sensor, the pressure sensor is connected with the controller, and the measured motor pressure value is introduced into the controller. The motor pressure value is converted into the displacement value in real time by the controller according to the preset motor pressure and displacement variable relationship. The crane hoist follow-up hydraulic system proposed in the embodiment can realize linkage control of the telescopic arm action and the hoist winding and unwinding action, has high automation degree, improves work efficiency, can effectively control the occurrence of hoisting accidents, and has high safety performance.

[0050] As shown in Figure 2 The embodiment also relates to a control method applied to the crane hoist follow-up hydraulic system.

[0051] In step S100, the arm telescopic length sensor captures the length AL1 of the arm during the arm telescoping action, and the hoist mechanism synchronously winds and unwinds the steel wire rope length AL2 of the same length to keep the distance between the hook and the ground unchanged.

[0052] In order to meet this condition, the hydraulic system needs to judge how much hydraulic oil is provided to the proportional valve to drive the hoist motor through the controller, and the winding and unwinding length of the steel wire rope is controlled by controlling the rotating speed of the hoist motor and the hoist speed reducer.

[0053] In step S200, the controller converts the telescopic cylinder flow of the hydraulic system to the telescopic cylinder under the same time T according to the length AL1 of the arm.

[0054] In step S300, the controller converts the rotating speed N1 of the hoist speed reducer, the rotating speed N2 of the hoist motor and the required flow Q3 of the hoist motor according to the steel wire rope length AL2, the circumference L3 of one circle of the steel wire rope on the winding drum and the speed reduction ratio K between the hoist motor and the speed reducer.

[0055] In step S400, the flow distribution of the two combined actions of the telescopic arm action and the hoist winding and unwinding action is calculated according to the rotating speed N1 of the hoist speed reducer, the rotating speed N2 of the hoist motor, the required flow Q3 of the hoist motor and the condition AL1=AL2.

[0056] The flow distribution of the two combined actions of the telescopic arm action and the hoist winding and unwinding action includes the flow distribution during the arm extension and the flow distribution during the arm retraction. In the embodiment, the flow distribution during the arm extension or the flow distribution during the arm retraction is calculated according to the rotating speed N1 of the hoist speed reducer, the rotating speed N2 of the hoist motor, the required flow Q3 of the hoist motor and the condition AL1=AL2.

[0057] Step S500, according to the flow distribution of the combination of the telescopic arm action and the winch winding and unwinding action, operating the telescopic arm, the telescopic proportional valve is synchronously associated with the winch proportional valve to be powered on, completing the telescopic arm winch follow-up combination action.

[0058] Further, please see Figure 2 The control method of the crane winch follow-up hydraulic system provided by the embodiment, step S200 includes:

[0059] Step S210, judging whether the winch follow-up function is opened.

[0060] Step S220, if it is identified that the winch follow-up function is opened and the first preset current is equal to the telescopic preset current and the second preset current is equal to the winch preset current, then the winch motor pressure P1 and the winch motor displacement Vg are obtained.

[0061] If the controller identifies that the winch follow-up function is opened and I1=Id, I2=Ic, then the winch motor pressure P1 and the winch motor displacement Vg are obtained.

[0062] Step S230, according to the winch motor displacement Vg, the first preset current and the second preset current, the telescopic arm flow Q1 and the telescopic arm retraction flow Q2 are obtained.

[0063] Preferably, please see Figure 2 The control method of the crane winch follow-up hydraulic system provided by the embodiment, step S210 further includes:

[0064] Step S240, if it is identified that the winch follow-up function is opened and the first preset current is equal to the telescopic preset current and the second preset current is equal to zero, then the single telescopic arm action is controlled.

[0065] If the controller identifies that the winch follow-up function is not opened and I1=Id, I1=0, then the single telescopic arm action is controlled.

[0066] Further, the control method of the crane winch follow-up hydraulic system provided by the embodiment, the telescopic arm flow Q1 is calculated by the following formula:

[0067]

[0068] In formula (1), Q1 is the telescopic arm flow, D1 is the cylinder diameter of the oil cylinder, ΔL1 is the length of the arm, and T is the same time.

[0069] The telescopic arm retraction flow Q2 is calculated by the following formula:

[0070]

[0071] In formula (2), Q2 is the arm retraction flow, D1 is the cylinder diameter, D2 is the cylinder rod diameter, ΔL1 is the arm length, and T is the same time.

[0072] Further, the hoist reducer speed N1 is calculated by the following formula:

[0073]

[0074] In formula (3), N1 is the hoist reducer speed, ΔL2 is the wire rope length, L3 is the wire rope one circle length on the drum, and T is the same time.

[0075] The hoist motor speed N2 is calculated by the following formula:

[0076]

[0077] In formula (4), N2 is the hoist motor speed, N1 is the hoist reducer speed, and K is the speed reduction ratio between the hoist motor and the reducer;

[0078] The hoist motor required flow Q3 is calculated by the following formula:

[0079]

[0080] In formula (5), Q3 is the hoist motor required flow, N2 is the hoist motor speed, Vg is the hoist motor displacement, and η is the hoist motor volumetric efficiency.

[0081] According to the above formula, it can be concluded that:

[0082]

[0083] In formula (6), ΔL2 is the wire rope length, η is the hoist motor volumetric efficiency, Q3 is the hoist motor required flow, K is the speed reduction ratio between the hoist motor and the reducer; L3 is the wire rope one circle length on the drum, and Vg is the hoist motor displacement.

[0084] Further, in order to save energy, the hydraulic system flow of the crane often only meets the single working condition or has a slight excess, and the excessive output flow flows out from the overflow valve, which is a waste and generates a lot of heat. In this case, the hoist follow-up involves the flow distribution under the combined action. The flow distribution of the two combined actions of the telescopic arm action and the hoist winding and unwinding action includes the flow distribution when the arm is extended. According to the above formula and the condition ΔL1 = ΔL2, the flow distribution when the arm is extended is calculated by the following formula:

[0085]

[0086] In formula (7), Q1 is the boom extension flow, Q3 is the flow required by the winch motor, D1 is the cylinder diameter of the oil cylinder, K is the speed reduction ratio between the winch motor and the speed reducer, L3 is the circumference of one turn of the steel wire rope on the drum, and Vg is the displacement of the winch motor.

[0087] Further, the flow distribution of the two combined actions of the boom extension and the winch winding and unwinding includes the flow distribution when the boom is retracted, which is calculated by the following formula:

[0088]

[0089] In formula (8), Q2 is the boom retraction flow, Q3 is the flow required by the winch motor, D1 is the cylinder diameter of the oil cylinder, D2 is the rod diameter of the oil cylinder, K is the speed reduction ratio between the winch motor and the speed reducer, L3 is the circumference of one turn of the steel wire rope on the drum, and Vg is the displacement of the winch motor.

[0090] It can be seen that the flow distribution of the two combined actions only changes with the change of the displacement of the winch motor. The winch motor for the crane is a variable plunger motor, and the displacement change is related to the lifting load. The winch motor G port is provided with a pressure sensor, which can introduce the measured motor pressure value into the controller. Moreover, the boom extension and the winch winding and unwinding share the main oil circuit, so only the boom needs to be operated, and the extension proportional directional valve is synchronously associated with the winch proportional directional valve to be powered on. Before this, the relationship between the measured proportional directional valve and the current has been introduced into the controller. The preset current sizes I1 and I2 of the two actions are adjusted according to the flow relationship of the above formula, and the boom and winch combined action can be completed. The logic flow is shown in Figure 2 .

[0091] The embodiment provides a crane hoist follow-up hydraulic system and a control method, wherein compared with the prior art, the hydraulic system adopts a hoist motor, a telescopic oil cylinder, a hoist balance valve, a telescopic balance valve, a hoist proportional reversing valve, a telescopic proportional reversing valve, a pressure reducing valve and a brake opening valve, the P port of the telescopic proportional reversing valve is connected with the P port of the hoist proportional reversing valve and the P1 port of the pressure reducing valve, the T port of the telescopic proportional reversing valve is connected with the T port of the hoist proportional reversing valve, the A port of the telescopic proportional reversing valve is connected with the V1 port of the telescopic balance valve, the B port of the telescopic proportional reversing valve is connected with the V2 port of the telescopic balance valve, the C2 port of the telescopic balance valve is connected with the rod cavity of the telescopic oil cylinder, the C1 port of the telescopic balance valve is connected with the rodless cavity of the telescopic oil cylinder; the A port of the hoist proportional reversing valve is connected with the A port of the hoist balance valve and the hoist motor, the B port of the hoist proportional reversing valve is connected with the K port of the hoist balance valve and the B port of the hoist motor, the B port of the hoist balance valve is connected with the A port of the hoist motor; the P2 port of the pressure reducing valve is connected with the P port of the brake opening valve, the K port of the pressure reducing valve is connected with the T port of the brake opening valve, the A port of the brake opening valve is connected with the speed reducer of the hoist motor, and the a port of the brake opening valve is connected with the Br port of the hoist balance valve. The crane hoist follow-up hydraulic system and the control method provided by the embodiment give the relationship formula of the flow required by the hydraulic drive of the telescopic and hoist combination action under different working conditions, and the hydraulic system matches the speed according to different hoisting conditions after the hoist follow-up function is opened; the hoist follow-up function is to open the telescopic proportional reversing valve and the hoist proportional reversing valve at the same time, and is not to connect the oil ports at both ends of the hoist motor to be in a floating state, and the latter is not applicable to the hoist follow-up under the hoisting condition; the application range is wider, the electric proportional multi-way valve for domestic large-tonnage cranes can be applied, and the small-tonnage pilot proportional valve can also be used, the principle of which is to control the size of the reversing current, the remote controller can be directly used for operation, or the operation panel with the direction recognition rocker can be used, and the application is not limited to the hydraulic control pilot handle.

[0092] Although preferred embodiments of the application have been described, those skilled in the art will be able to make additional changes and modifications, once they have the basic inventive concept. Therefore, the appended claims are intended to be interpreted as including all changes and modifications that fall within the scope of the application. Obviously, those skilled in the art can make various modifications and variations to the application without departing from the spirit and scope of the application. Thus, if these modifications and variations of the application fall within the scope of the claims of the application and equivalent technologies thereof, the application is also intended to include these modifications and variations.

Claims

1. A control method of a crane hoist follow-up hydraulic system applied to a crane hoist follow-up hydraulic system, characterized by, The crane hoist follow-up hydraulic system comprises a hoist motor (10), a telescopic oil cylinder (20), a hoist balance valve (30), a telescopic balance valve (40), a hoist proportional reversing valve (50), a telescopic proportional reversing valve (60), a pressure reducing valve (70) and a brake opening valve (80), the P port of the telescopic proportional reversing valve (60) is connected with the P port of the hoist proportional reversing valve (50) and the P1 port of the pressure reducing valve (70) respectively, the T port of the telescopic proportional reversing valve (60) is connected with the T port of the hoist proportional reversing valve (50), the A port of the telescopic proportional reversing valve (60) is connected with the V1 port of the telescopic balance valve (40), the B port of the telescopic proportional reversing valve (60) is connected with the V2 port of the telescopic balance valve (40), the C2 port of the telescopic balance valve (40) is connected with the rod cavity of the telescopic oil cylinder (20), and the C1 port of the telescopic balance valve (40) is connected with the rodless cavity of the telescopic oil cylinder (20); the A port of the hoist proportional reversing valve (50) is connected with the A port of the hoist balance valve (30) and the hoist motor (10) respectively, the B port of the hoist proportional reversing valve (50) is connected with the K port of the hoist balance valve (30) and the B port of the hoist motor (10) respectively, and the B port of the hoist balance valve (30) is connected with the A port of the hoist motor (10); the P2 port of the pressure reducing valve (70) is connected with the P port of the brake opening valve (80), the K port of the pressure reducing valve (70) is connected with the T port of the brake opening valve (80), the A port of the brake opening valve (80) is connected with the speed reducer of the hoist motor (10), the a port of the brake opening valve (80) is connected with the Br port of the hoist balance valve (30), and the control method comprises: When the boom is telescoping, the boom telescoping length sensor captures the length ΔL1 of the boom, and the hoisting mechanism synchronously retracts and releases the same length ΔL2 of the steel wire rope to keep the distance between the hook and the ground unchanged; The controller calculates the telescopic oil cylinder flow of the hydraulic system to the telescopic oil cylinder under the same time T according to the length ΔL1 of the boom, and the telescopic oil cylinder flow comprises the telescopic boom flow Q1 and the telescoping boom flow Q2; The controller calculates the rotation speed N1 of the hoist speed reducer, the rotation speed N2 of the hoist motor and the flow Q3 required by the hoist motor according to the length ΔL2 of the steel wire rope, the circumference L3 of one turn of the steel wire rope on the drum and the speed reduction ratio K between the hoist motor and the speed reducer; The flow distribution of the telescopic boom action and the hoist retracting and releasing action is calculated according to the rotation speed N1 of the hoist speed reducer, the rotation speed N2 of the hoist motor, the flow Q3 required by the hoist motor and the condition ΔL1=ΔL2; According to the flow distribution of the telescopic boom action and the hoist retracting and releasing action, the telescopic boom is operated, the telescopic proportional reversing valve is synchronously associated with the hoist proportional reversing valve to be powered on, and the telescopic boom and hoist follow-up combined action is completed.

2. The control method of a crane hoist follow-up hydraulic system according to claim 1, characterized by, The hoist motor (10) is a variable plunger motor.

3. The control method of a crane hoist follow-up hydraulic system according to claim 1, characterized by, The G port of the winch motor (10) is provided with a pressure sensor connected to a controller for inputting the measured motor pressure value to the controller.

4. The control method of a crane hoist follow-up hydraulic system according to claim 1, characterized by, The step of converting the length ΔL1 of the arm into the flow of the telescopic cylinder of the hydraulic system to the telescopic cylinder at the same time T, which includes the flow Q1 of the arm extension and the flow Q2 of the arm retraction, comprises: determining whether the winch follow-up function is enabled; if it is identified that the winch follow-up function is enabled and the first preset current is equal to the telescopic preset current and the second preset current is equal to the winch preset current, then obtaining the winch motor pressure P1 and the winch motor displacement Vg; according to the winch motor displacement Vg, the first preset current and the second preset current, obtaining the flow Q1 of the arm extension and the flow Q2 of the arm retraction.

5. The control method of a crane hoist follow-up hydraulic system according to claim 4, characterized by, The step of determining whether the winch follow-up function is enabled further comprises: if it is identified that the winch follow-up function is enabled and the first preset current is equal to the telescopic preset current and the second preset current is equal to zero, then controlling the single telescopic arm action.

6. The control method of a crane hoist follow-up hydraulic system according to claim 1, characterized by, The flow Q1 of the arm extension is calculated by the following formula: wherein Q1 is the flow of the arm extension, D1 is the cylinder diameter of the oil cylinder, ΔL1 is the length of the arm, and T is the same time; The flow Q2 of the arm retraction is calculated by the following formula: wherein Q2 is the flow of the arm retraction, D1 is the cylinder diameter of the oil cylinder, D2 is the rod diameter of the oil cylinder, ΔL1 is the length of the arm, and T is the same time.

7. The control method of a crane hoist follow-up hydraulic system according to claim 1, characterized by, The speed N1 of the winch speed reducer is calculated by the following formula: wherein N1 is the speed of the winch speed reducer, ΔL2 is the length of the steel wire rope, L3 is the circumference of one turn of the steel wire rope on the drum, and T is the same time; The speed N2 of the winch motor is calculated by the following formula: wherein N2 is the speed of the winch motor, N1 is the speed of the winch speed reducer, and K is the speed reduction ratio between the winch motor and the speed reducer; The required flow Q3 of the winch motor is calculated by the following formula: wherein Q3 is the required flow of the winch motor, N2 is the speed of the winch motor, Vg is the displacement of the winch motor, and η is the volumetric efficiency of the winch motor.

8. The control method of a crane hoist follow-up hydraulic system according to claim 7, characterized by, The flow distribution of the two combined actions of the telescopic arm action and the winch winding and unwinding action includes the flow distribution when the arm is extended, which is calculated by the following formula: wherein Q1 is the flow of the arm extension, Q3 is the required flow of the winch motor, D1 is the cylinder diameter of the oil cylinder, K is the speed reduction ratio between the winch motor and the speed reducer, L3 is the circumference of one turn of the steel wire rope on the drum, and Vg is the displacement of the winch motor.

9. The control method of a hoist follow-up hydraulic system of a crane according to claim 7, characterized by, The flow distribution of the two combined actions of the telescopic arm action and the winch winding and unwinding action includes the flow distribution when the arm is retracted, which is calculated by the following formula: wherein Q2 is the flow of the arm retraction, Q3 is the required flow of the winch motor, D1 is the cylinder diameter of the oil cylinder, D2 is the rod diameter of the oil cylinder, K is the speed reduction ratio between the winch motor and the speed reducer, L3 is the circumference of one turn of the steel wire rope on the drum, and Vg is the displacement of the winch motor.

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