Multi-cylinder variable amplitude control system and method and engineering machinery

Abstract

The invention discloses a multi-cylinder variable amplitude control system and method and engineering machinery. The system comprises a plurality of variable-amplitude oil cylinders; the variable-amplitude balance valves are connected with the variable-amplitude oil cylinders in a one-to-one correspondence mode, each variable-amplitude balance valve comprises a main valve element and an oil liquid communication valve element, each oil liquid communication valve element is connected with a rodless cavity of the corresponding variable-amplitude oil cylinder, the oil liquid communication valve elements are connected through a series connection pipeline, and the main valve elements and the oil liquid communication valve elements are in linkage. When the variable-amplitude balance valve is opened, the communicating valve element is also opened, a multi-cylinder rodless cavity can communicate with a series pipeline through the oil liquid communicating valve element, and therefore the double-cylinder synchronism is improved; when the variable-amplitude balance valve is closed, the communicating valve element is also closed synchronously, and the variable-amplitude balance valve plays a role in safety protection, so that the system safety is higher.

Description

Technical Field

[0001] The present application relates to the technical field of engineering machinery, and in particular to a system and method for multi-cylinder amplitude control and engineering machinery. Background Art

[0002] In the field of construction machinery, the synchronous control of multi-cylinder luffing systems (such as crane booms and concrete pump truck booms) directly impacts operational accuracy and safety. Traditional multi-cylinder luffing systems typically achieve synchronization through mechanical rigid connections or simple hydraulic parallel circuits. However, these systems present significant technical bottlenecks. While mechanical rigid connections (such as connecting rod mechanisms) can enforce synchronization, they cannot accommodate load variations among multiple cylinders (such as unilateral overload). Furthermore, mechanical wear can easily degrade synchronization accuracy. This is particularly true for luffing large-span booms (e.g., over 50 meters), where cumulative errors can reach 10-20mm. In severe cases, this can cause the boom to tilt or even lead to safety accidents.

[0003] Therefore, the multi-cylinder luffing control system used in the prior art has the problem of low safety. Summary of the Invention

[0004] The purpose of the embodiments of the present application is to provide a system, method and engineering machinery for multi-cylinder luffing control, so as to solve the problem of low safety of the multi-cylinder luffing control system used in the prior art.

[0005] In order to achieve the above objectives, the present application provides, in a first aspect, a multi-cylinder luffing control system, the system comprising: Multiple luffing cylinders; Multiple variable amplitude balancing valves, each variable amplitude balancing valve is connected to each variable amplitude cylinder one by one, the variable amplitude balancing valve includes a main valve core and an oil-connecting valve core, each oil-connecting valve core is connected to the rodless cavity of each variable amplitude cylinder, and each oil-connecting valve core is connected through a series pipeline, and the main valve core and the oil-connecting valve core are linked.

[0006] In the embodiment of the present application, the variable amplitude balancing valve further includes: Filter, used to filter impurities in the oil; The pilot pressure reducing valve is used to receive the pressure signal of the pilot control oil and reduce the pressure to output a stable pilot control pressure. Safety relief valve is used to protect the system from overload.

[0007] A second aspect of the present application provides a method for multi-cylinder luffing control, which is applied to the above-mentioned multi-cylinder luffing control system, and the method includes: When multiple luffing cylinders perform a luffing and dropping action, the current pressure value of the rodless cavity of each luffing cylinder is obtained; determining a target pressure difference based on a plurality of current pressure values; determining a target control current for each variable amplitude balancing valve according to a plurality of current pressure values ​​when the target pressure difference is greater than a first preset pressure threshold and less than a second preset pressure threshold, wherein the first preset pressure threshold is less than the second preset pressure threshold; The current of each luffing balancing valve is adjusted according to the target control current to adjust the flow of the rodless cavity of each luffing cylinder.

[0008] In an embodiment of the present application, a target control current for each variable amplitude balancing valve is determined based on multiple current pressure values, including: obtaining the movement duration of each variable amplitude cylinder and the initial oil volume of the rod chamber of each variable amplitude cylinder; determining the target cylinder and the cylinder to be adjusted from the multiple variable amplitude cylinders, wherein the cylinder to be adjusted is the variable amplitude cylinder other than the target cylinder in the multiple variable amplitude cylinders; determining the rodless chamber flow difference between each to-be-adjusted cylinder and the target cylinder based on the current pressure value, the movement duration and the initial oil volume; and determining the target control current of the variable amplitude balancing valve corresponding to each to-be-adjusted cylinder based on the rodless chamber flow difference.

[0009] In an embodiment of the present application, the rodless cavity flow difference between each cylinder to be adjusted and the target cylinder is determined based on the current pressure value, movement duration and initial oil volume, including: determining the current pressure difference between the cylinder to be adjusted and the target cylinder based on the current pressure value; determining the rodless cavity volume difference between the cylinder to be adjusted and the target cylinder based on the current pressure difference, initial oil volume and preset hydraulic oil bulk modulus; determining the rodless cavity flow difference based on the rodless cavity volume difference and movement duration.

[0010] In an embodiment of the present application, determining the target control current of the variable amplitude balancing valve corresponding to the cylinder to be adjusted based on the rodless cavity flow difference includes: obtaining the current current of the variable amplitude balancing valve corresponding to the cylinder to be adjusted and the current flow of the rodless cavity of the cylinder to be adjusted; determining the target control current based on the current current, the current flow and the rodless cavity flow difference.

[0011] In an embodiment of the present application, the target control current is determined based on the current current, the current flow and the rodless chamber flow difference, including: when the current pressure value of the cylinder to be adjusted is greater than the current pressure value of the target cylinder, the sum of the current flow and the rodless chamber flow difference is determined as a first calculated value; the product of the first calculated value and the current current is determined as a second calculated value; and the ratio of the second calculated value to the current flow is determined as the target control current of the variable amplitude balancing valve corresponding to the cylinder to be adjusted.

[0012] In an embodiment of the present application, the target control current is determined based on the current current, the current flow and the rodless chamber flow difference, including: when the current pressure value of the cylinder to be adjusted is less than the current pressure value of the target cylinder, the difference between the current flow and the rodless chamber flow difference is determined as a third calculated value; the product of the third calculated value and the current current is determined as a fourth calculated value; and the ratio of the fourth calculated value to the current flow is determined as the target control current of the variable amplitude balancing valve corresponding to the cylinder to be adjusted.

[0013] In an embodiment of the present application, the method further includes: controlling the plurality of luffing cylinders to stop performing the luffing lowering action when the target pressure difference is greater than or equal to a second preset pressure threshold.

[0014] In an embodiment of the present application, the method includes: when the target pressure difference is less than or equal to a first preset pressure threshold, maintaining the current control current of each variable amplitude balancing valve unchanged and continuing to perform the variable amplitude falling action.

[0015] A third aspect of the present application provides an engineering machine, comprising: the above-mentioned multi-cylinder amplitude control system.

[0016] The multi-cylinder variable amplitude control system includes multiple variable amplitude oil cylinders and multiple variable amplitude balancing valves. Each variable amplitude balancing valve is connected to each variable amplitude oil cylinder in a one-to-one correspondence. The variable amplitude balancing valve includes a main valve core and an oil-liquid connecting valve core. Each oil-liquid connecting valve core is connected to the rodless cavity of each variable amplitude oil cylinder, and each oil-liquid connecting valve core is connected via a series pipeline. The main valve core and the oil-liquid connecting valve core are linked together. When the variable amplitude balancing valve in this application is opened, the connecting valve core is also opened. The rodless cavity of the multi-cylinder can be connected via the oil-liquid connecting valve core and the series pipeline, thereby improving the synchronization of the two cylinders. When the variable amplitude balancing valve is closed, the connecting valve core is also closed synchronously. The variable amplitude balancing valve serves as a safety protection, making the system safer.

[0017] Other features and advantages of the embodiments of the present application will be described in detail in the subsequent detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings are used to provide a further understanding of the embodiments of the present application and constitute a part of the specification. Together with the following detailed description, they are used to explain the embodiments of the present application but do not constitute a limitation on the embodiments of the present application. In the accompanying drawings: Figure 1 A schematic diagram of a multi-cylinder variable-luffing hydraulic system provided in a specific embodiment of the present application; Figure 2 A flow chart of a method for multi-cylinder amplitude control provided in an embodiment of the present application; Figure 3 A flowchart of a crane dual-cylinder luffing synchronization control method provided in a specific embodiment of the present application.

[0019] Description of Reference Numerals DETAILED DESCRIPTION

[0020] To make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. It should be understood that the specific implementation methods described herein are only used to illustrate and explain the embodiments of the present application and are not used to limit the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0021] It should be noted that if the embodiments of the present application involve directional indications (such as up, down, left, right, front, back, etc.), such directional indications are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0022] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present application, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of such features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the fact that they can be implemented by ordinary technicians in this field. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0023] Traditional synchronization technologies for crane twin-bar luffing systems primarily include counterbalance valve control, dual-cylinder serial piping, and rodless chamber pressure monitoring. The rodless chamber of a dual-cylinder luffing system typically utilizes dual or triple-luffing counterbalance valves within the counterbalance valve control technology. By sharing the pilot oil source for the counterbalance valves, the opening consistency of the counterbalance valves is improved, thereby enhancing synchronization between the two cylinders. However, in practice, pilot oil pipelines vary in length and shape, leading to varying pressure losses and making it impossible to guarantee completely consistent pilot pressure across all counterbalance valves. This variation in pressure losses is particularly pronounced in cold temperatures. Furthermore, individual counterbalance valves exhibit varying consistency, leading to flow variations even with the same pilot pressure across different counterbalance valves. In abnormal situations, such as when a counterbalance valve is damaged and unable to open, serious installation errors can occur. Dual-cylinder serial piping can only balance a limited flow rate. When the flow rates of the two cylinders differ significantly, significant desynchronization between the two cylinders can still occur. Pressure monitoring technology primarily monitors extreme pressures, providing alarms or tripping to protect crane operations, without enhancing synchronization. In response to the above problems, embodiments of the present application provide a system and method for multi-cylinder amplitude control to improve dual-cylinder synchronization while enhancing system safety and reliability.

[0024] The present invention provides a multi-cylinder amplitude control system, which includes: Multiple luffing cylinders; Multiple variable amplitude balancing valves, each variable amplitude balancing valve is connected to each variable amplitude cylinder one by one, the variable amplitude balancing valve includes a main valve core and an oil-connecting valve core, each oil-connecting valve core is connected to the rodless cavity of each variable amplitude cylinder, and each oil-connecting valve core is connected through a series pipeline, and the main valve core and the oil-connecting valve core are linked.

[0025] In an embodiment of the present application, the multi-cylinder boom control system in the embodiment of the present application can be applied to various engineering machinery that require multi-cylinder boom control, such as large crane equipment. The system includes multiple boom cylinders and multiple boom balancing valves, and each boom balancing valve is connected to each boom cylinder in a one-to-one correspondence. Among them, the boom cylinder is used to cooperate with multiple actuators to drive the boom mechanism of the engineering machinery. The boom balancing valve integrates a main valve core and an oil-liquid connecting valve core. The main valve core is used to control the main oil circuit, and the oil-liquid connecting valve core is used to adjust the pressure of the rodless chamber. Specifically, the main valve core is responsible for controlling the oil inlet and return of the boom cylinder, directly determining the extension and retraction movement of the cylinder. When the hydraulic system supplies oil to the main valve core, the main valve core moves, opens or closes the oil circuit leading to the boom cylinder, and realizes the extension or retraction of the cylinder. The oil-liquid connecting valve core is connected to the rodless chamber of the boom cylinder, and indirectly controls the movement state of the cylinder by adjusting the oil pressure in the rodless chamber. When the oil connecting valve core is opened, the oil in the rodless chamber can flow between the cylinders through the series pipeline to achieve pressure balance.

[0026] In the embodiment of the present application, the oil-liquid connecting valve core is linked to the main valve core, and is opened and closed synchronously with the main valve core, thereby realizing the connection of the rodless chambers of each boom cylinder during normal operation, and improving the synchronization of the system. When the main valve core is closed, the oil-liquid connecting valve core is closed, and the balance valve plays a safety protection role. In the traditional dual-cylinder boom hydraulic system, the rodless chamber oil is connected through the series pipeline and the explosion-proof valve. If the series pipeline bursts, the explosion-proof valve plays a safety protection role. However, if the explosion-proof valve leaks a large amount or an abnormality occurs, a safety accident of the boom falling may still occur. In the embodiment of the present application, the oil-liquid connecting valve core is linked to the main valve core. If the series pipeline bursts, the oil-liquid connecting valve core and the main valve core are both closed, thereby shutting down the system action, and the boom balance valve plays a safety protection role, which is safer.

[0027] The above technical solution provides a multi-cylinder variable amplitude control system, including multiple variable amplitude oil cylinders; multiple variable amplitude balancing valves, each variable amplitude balancing valve is connected to each variable amplitude oil cylinder in a one-to-one correspondence, and the balancing valve includes a main valve core and an oil-liquid connecting valve core, each oil-liquid connecting valve core is connected to the rodless cavity of each variable amplitude oil cylinder, and each oil-liquid connecting valve core is connected through a series pipeline, and the main valve core and the oil-liquid connecting valve core are linked. In this application, when the balancing valve is opened, the connecting valve core is also opened, and the rodless cavity of the multi-cylinder can be connected through the oil-liquid connecting valve core and the series pipeline, thereby improving the synchronization of the two cylinders; when the balancing valve is closed, the connecting valve core is also closed synchronously, and the balancing valve plays a safety protection role, making the system safer.

[0028] Figure 1 This is a schematic diagram of a multi-cylinder luffing hydraulic system according to a specific embodiment of the present application. As shown in Figure 1, using a dual-cylinder system as an example, the dual-cylinder luffing hydraulic system comprises: a left luffing cylinder 1, a left lower chamber luffing balancing valve 2, a relief valve 3, a fuel tank 4, an engine 5, a hydraulic pump 6, a main valve 7, a right lower chamber luffing balancing valve 8, and a right luffing cylinder 10. The hydraulic pump 6, driven by the engine 5, draws oil from the fuel tank 4. The output pressure oil is distributed through the main valve 7 (a reversing valve) to the left lower chamber luffing balancing valve 2 and the right lower chamber luffing balancing valve 8, thereby controlling the operation of the left and right luffing cylinders 1 and 10. The relief valve 3 is connected in parallel with the system to limit the outlet pressure of the hydraulic pump 6, returning excess oil to the fuel tank 4. Both the left lower chamber luffing balancing valve 2 and the right lower chamber luffing balancing valve 8 include a main valve core 11 and an oil communication valve core 12.

[0029] Specifically, engine 5 serves as the power source, rotating hydraulic pump 6, converting mechanical energy into hydraulic energy and providing pressurized oil to the entire system. The pressurized oil output by hydraulic pump 6 is connected to port P (the oil inlet) of main valve 7. Main valve 7, through energization of solenoids Y1 and Y2, switches the direction of the pressurized oil to either port A or port B, thereby controlling the direction (extension / retraction) of the left and right boom cylinders. Ports A and B of main valve 7 are connected to the control ports of the left lower chamber boom balancing valve 2 and the right lower chamber boom balancing valve 8, respectively. By switching the main valve, a control signal is transmitted, triggering the main valve core 11 of the balancing valve to actuate, opening the oil supply and return channels of the cylinders. The left lower chamber boom balancing valve 2 communicates with the rodless chamber of the left boom cylinder 1, controlling the oil supply and return to the rodless chamber. The right lower chamber boom balancing valve 8 communicates with the rodless chamber of the right boom cylinder 10, similarly controlling the flow of oil there. The main valve core 11 and the oil-connecting valve core 12 within the balancing valve work in concert. These valves automatically adjust oil pressure and flow when the cylinder is subject to load disturbances (such as a tendency for the load to tip over when amplitude adjustment stops). This maintains cylinder stability and prevents overspeed retraction and load drop, thus providing both "cylinder locking" and "cushioning" functions. Relief valve 3 is connected in parallel to the outlet of hydraulic pump 6 (or the inlet side of main valve 7). When system pressure exceeds the set value of relief valve 3 (e.g., due to hydraulic pump overload or pipeline blockage), the relief valve opens, directing high-pressure oil back to tank 4, protecting system piping and components from damage due to excessive pressure. Tank 4 stores hydraulic oil, providing a source for hydraulic pump 6 and recovering system oil, dissipating heat and settling impurities, thereby maintaining hydraulic oil cleanliness and maintaining a stable system oil temperature. The left luffing cylinder 1 and the right luffing cylinder 10 serve as actuators. Through the rodless chamber and rod chamber (not marked in the figure, generally below the cylinder) oil intake and oil return, the piston rods are extended (luffing up) and retracted (luffing down) to drive the main arm luffing mechanism to change the boom angle and complete the luffing function of the lifting operation.

[0030] like Figure 1 As shown, in the embodiment of the present application, the variable amplitude balancing valve further includes: Filter 13, used to filter impurities in the oil; The pilot pressure reducing valve 14 is used to receive the pressure signal of the pilot control oil and reduce the pressure of the pressure signal to output a stable pilot control pressure; The safety relief valve 15 is used to protect the system from overload.

[0031] Specifically, the oil first passes through filter 13 to remove impurities before entering the main valve core 11 of the variable amplitude balancing valve. It then flows to the oil connecting valve core 12, preventing particulate matter and other contaminants from entering the valve block, avoiding valve core sticking and wear, protecting the normal operation of the valve block and the entire hydraulic system, and improving the reliability and service life of the system. Simultaneously, the pilot control oil first enters the pilot pressure reducing valve 14 for pressure regulation. The output stable pilot pressure acts on the main valve core 11, controlling the opening and other states of the main valve core 11. This precisely controls the movement of the main valve core 11 and other components, making the adjustment of the main valve core 11 more precise and the response more timely, thus achieving precise regulation of system pressure and flow. In addition, when the system pressure rises abnormally and reaches the set value of the safety relief valve 15, the safety relief valve 15 opens, and the oil flows back to the low-pressure side (such as the oil tank) through it. At this time, a pressure unloading passage is formed with the main oil circuit where the main valve core 11, the oil connecting valve core 12, etc. are located to ensure system safety; under normal working conditions, the various components work together, and the main valve core 11, under the control of the pilot pressure reducing valve 14 and the cooperation of the oil connecting valve core 12, realizes precise control of the oil in the main oil circuit, drives the actuator to work stably, and the filter 13 continuously filters the oil entering the valve group, providing a clean medium environment for the reliable operation of the entire valve group.

[0032] In the embodiment of the present application, both the left lower chamber variable amplitude balancing valve 2 and the right lower chamber variable amplitude balancing valve 8 are equipped with an electrified proportional pilot oil pressure reducing valve scheme. According to the opening requirements of the left and right rodless chamber balancing valves, the currents of the electromagnets Y3 and Y4 of the left lower chamber variable amplitude balancing valve 2 and the right lower chamber variable amplitude balancing valve 8 can be controlled separately, thereby controlling the opening sizes of the left lower chamber variable amplitude balancing valve 2 and the right lower chamber variable amplitude balancing valve 8 respectively.

[0033] At the same time, both the left lower chamber boom balancing valve 2 and the right lower chamber boom balancing valve 8 have integrated oil-fluid communication valve cores 12. When the pilot oil source opens the main valve cores 11 of the left lower chamber boom balancing valve 2 and the right lower chamber boom balancing valve 8, the oil-fluid communication valve cores 12 are simultaneously opened, connecting the rodless chambers of the two cylinders through the oil-fluid communication valve cores 12 and the series pipeline of the boom balancing valve E port. This improves the synchronization of the two cylinders during the boom lowering process. When the boom balancing valves close, the oil-fluid communication valve cores 12 close, and the balancing valves act as a safety protection. In traditional two-cylinder boom hydraulic systems, the rodless chambers are connected via series pipelines and explosion-proof valves. If the series pipelines burst, the explosion-proof valves act as a safety protection. However, if the explosion-proof valves leak significantly or malfunction, the boom may still fall. In the embodiment of the present application, if the series pipelines burst, the system is shut down, and the balancing valves act as a safety protection, providing greater safety. Improving the synchronization of the two cylinders improves safety and reliability.

[0034] Traditional hydraulic parallel circuits independently control the flow of each cylinder through a balancing valve, lacking a dynamic coordination mechanism. When the load of a cylinder suddenly changes, the pressure in the rodless chamber becomes unbalanced, resulting in uneven flow distribution and a synchronization error of up to 5-10mm / m of arm length. Furthermore, when the series pipeline bursts, it relies solely on the passive protection of the explosion-proof valve. If the explosion-proof valve is abnormal, it can easily cause the boom to fall, resulting in insufficient safety. In response to this, the embodiment of the present application also provides a method for multi-cylinder boom control, which is used to dynamically match and control the opening requirements of the boom balancing valve corresponding to each boom during the boom drop process based on the target pressure difference in the rodless chamber of each boom cylinder, ensuring that each boom cylinder moves in unison and improving the accuracy of multi-cylinder boom synchronization.

[0035] Figure 2 This is a flow chart of a method for multi-cylinder amplitude control provided in an embodiment of the present application. Figure 2 As shown, an embodiment of the present application provides a method for multi-cylinder luffing control, which is applied to the multi-cylinder luffing control system in the above embodiment. The method may include the following steps.

[0036] Step 101 : When multiple luffing cylinders are performing a luffing and dropping action, obtain the current pressure value of the rodless chamber of each luffing cylinder.

[0037] Step 102: determining a target pressure difference according to a plurality of current pressure values.

[0038] Step 103 , when the target pressure difference is greater than a first preset pressure threshold and less than a second preset pressure threshold, determining a target control current for each variable amplitude balancing valve according to a plurality of current pressure values, wherein the first preset pressure threshold is less than the second preset pressure threshold.

[0039] Step 104 : adjusting the current of each luffing balancing valve according to the target control current to adjust the flow of the rodless chamber of each luffing cylinder.

[0040] Specifically, during the luffing and lowering process, pressure sensors located in the rodless chambers of each luffing cylinder collect the current pressure value of the rodless chamber of each luffing cylinder. A target pressure differential is then determined based on the current pressure value. In one example, when there are two luffing cylinders, the target pressure differential is the difference between the pressure values ​​of the rodless chambers of the two luffing cylinders. In another example, when there are three or more luffing cylinders, the target pressure differential is the maximum difference between the pressure values ​​of the rodless chambers of the luffing cylinders.

[0041] Furthermore, the target pressure difference is compared with the first and second preset pressure values. The first preset pressure value is smaller than the second preset pressure value. The first preset pressure value is the lower limit of the adjustable range at which the system determines the cylinder synchronization deviation. Adjustments below this lower limit are unnecessary to avoid frequent adjustments that may cause system oscillation. The second preset pressure value is the upper limit of the adjustable range at which the system determines the cylinder synchronization deviation. Values ​​above this upper limit may trigger an alarm or emergency braking. Both the first and second preset pressure thresholds can be calibrated experimentally.

[0042] Specifically, when the target pressure difference is greater than a first preset pressure threshold and less than a second preset pressure threshold, a target control current for each luffing balancing valve is determined based on multiple current pressure values. In one example, the target control current for each luffing balancing valve can be determined using a PID algorithm or a preset mapping table based on the target pressure difference and the current pressure value of each luffing cylinder. Finally, the current of each luffing balancing valve is adjusted according to the target control current, thereby regulating the flow rate of the rodless chamber of each luffing cylinder to ensure consistent movement of each luffing cylinder.

[0043] In this way, during the luffing and lowering process, the opening requirements of the corresponding luffing balance valves are dynamically matched and controlled based on the target pressure difference in the rodless chamber of each luffing cylinder, ensuring the consistent movement of each cylinder and improving the synchronization accuracy of multi-cylinder luffing. This also reduces costs. Crane dual-cylinder luffing systems generally include pressure monitoring, eliminating the need for additional costs.

[0044] In an embodiment of the present application, the method further includes: controlling the plurality of luffing cylinders to stop performing the luffing lowering action when the target pressure difference is greater than or equal to a second preset pressure threshold.

[0045] It is understood that if the target pressure difference is greater than or equal to the second preset pressure threshold, it indicates that the luffing cylinders are seriously out of sync, requiring emergency braking to control the luffing cylinders to stop the luffing and lowering action, thereby interrupting the luffing and lowering action to avoid a safety accident. Preferably, the system can output an alarm signal simultaneously through audio, visual, and text messages to remind operators to take timely countermeasures.

[0046] In an embodiment of the present application, the method includes: when the target pressure difference is less than or equal to a first preset pressure threshold, maintaining the current control current of each variable amplitude balancing valve unchanged and continuing to perform the variable amplitude falling action.

[0047] It can be understood that when the target pressure difference is less than or equal to the second preset pressure threshold, it means that the current synchronization of each amplitude adjustment cylinder is high and no adjustment is required. The current control current of each amplitude adjustment balancing valve is maintained unchanged, and the amplitude adjustment falling action is continued to avoid frequent adjustments that cause system oscillations.

[0048] In an embodiment of the present application, a target control current for each variable amplitude balancing valve is determined based on multiple current pressure values, including: obtaining the movement duration of each variable amplitude cylinder and the initial oil volume of the rod chamber of each variable amplitude cylinder; determining the target cylinder and the cylinder to be adjusted from the multiple variable amplitude cylinders, wherein the cylinder to be adjusted is the variable amplitude cylinder other than the target cylinder in the multiple variable amplitude cylinders; determining the rodless chamber flow difference between each to-be-adjusted cylinder and the target cylinder based on the current pressure value, the movement duration and the initial oil volume; and determining the target control current of the variable amplitude balancing valve corresponding to each to-be-adjusted cylinder based on the rodless chamber flow difference.

[0049] It's understandable that to determine the target control current for each luffing balancing valve, the movement duration of each luffing cylinder and the initial oil volume in the rod chamber of each luffing cylinder can be obtained. The movement duration is the time it takes for the cylinder to move from its starting position to its current position, reflecting the progress of the movement. This can be recorded using a timer or the PLC's internal clock module. The initial oil volume in the rod chamber refers to the oil volume in the rod chamber when the luffing cylinder is fully extended. This can be determined based on the cylinder's inner diameter, rod diameter, and stroke.

[0050] Furthermore, a target cylinder and a cylinder to be adjusted are determined from among the multiple luffing cylinders. The target cylinder is first determined, and then the other luffing cylinders from the multiple luffing cylinders, excluding the target cylinder, are determined as the cylinders to be adjusted. In one example, the target cylinder may be the cylinder with the highest current pressure value among the multiple luffing cylinders. Since the maximum load also results in the greatest resistance to movement, the cylinder with the highest pressure is used as a reference to ensure that all cylinders can overcome the maximum load, thus avoiding under-actuation and resulting boom jamming. In another example, the target cylinder may be the cylinder with the lowest current pressure value among the multiple luffing cylinders. Selecting the cylinder with the lowest pressure (lightest load) as a reference ensures that the output force of all cylinders can meet the current load requirements, thus preventing excessive system pressure due to overloading of a cylinder. In another example, the average pressure value can be determined based on the current pressure values ​​of the rodless chambers of multiple variable-length cylinders, and then the variable-length cylinder whose current pressure value is closest to the average pressure value among the multiple variable-length cylinders is determined as the target cylinder. By selecting the cylinder with a neutral pressure, the adjustment amount of the high-pressure side and low-pressure side cylinders can be made relatively balanced, avoiding excessive throttling of the cylinder on one side.

[0051] Furthermore, based on the current pressure value, movement duration and initial oil volume, the rodless cavity flow difference between each cylinder to be adjusted and the target cylinder is determined, and finally the target control current of the variable amplitude balancing valve corresponding to each cylinder to be adjusted is determined based on the rodless cavity flow difference.

[0052] In an embodiment of the present application, the rodless cavity flow difference between each cylinder to be adjusted and the target cylinder is determined based on the current pressure value, movement duration and initial oil volume, including: determining the current pressure difference between the cylinder to be adjusted and the target cylinder based on the current pressure value; determining the rodless cavity volume difference between the cylinder to be adjusted and the target cylinder based on the current pressure difference, initial oil volume and preset hydraulic oil bulk modulus; determining the rodless cavity flow difference based on the rodless cavity volume difference and movement duration.

[0053] Specifically, the rodless chamber flow rate difference between the oil cylinder to be adjusted and the target oil cylinder satisfies the following formula: ; ; ; in, is the current pressure value of the oil cylinder to be adjusted, is the current pressure value of the target cylinder, is the absolute value of the current pressure difference between the cylinder to be adjusted and the target cylinder, is the initial oil volume of the rod cavity, is the preset hydraulic oil bulk modulus, is the volume difference between the rodless chamber of the cylinder to be adjusted and the target cylinder; is the movement duration of the luffing cylinder, It is the rodless chamber flow difference between the cylinder to be adjusted and the target cylinder.

[0054] In an embodiment of the present application, determining the target control current of the variable amplitude balancing valve corresponding to the cylinder to be adjusted based on the rodless cavity flow difference includes: obtaining the current current of the variable amplitude balancing valve corresponding to the cylinder to be adjusted and the current flow of the rodless cavity of the cylinder to be adjusted; determining the target control current based on the current current, the current flow and the rodless cavity flow difference.

[0055] It can be understood that the current current refers to the actual current flowing through the luffing balancing valve corresponding to each luffing cylinder, and the current flow rate refers to the actual flow rate in the rodless chamber of each luffing cylinder. The target control current for the luffing balancing valve corresponding to the cylinder to be regulated is determined based on the current pressure relationship between the target cylinder and the target cylinder, the current current and flow rate of the target cylinder, and the difference in rodless chamber flow rate between the target and target cylinders.

[0056] In an embodiment of the present application, the target control current is determined based on the current current, the current flow and the rodless chamber flow difference, including: when the current pressure value of the cylinder to be adjusted is greater than the current pressure value of the target cylinder, the sum of the current flow and the rodless chamber flow difference is determined as a first calculated value; the product of the first calculated value and the current current is determined as a second calculated value; and the ratio of the second calculated value to the current flow is determined as the target control current of the variable amplitude balancing valve corresponding to the cylinder to be adjusted.

[0057] Specifically, when the current pressure value of the cylinder to be adjusted is greater than the current pressure value of the target cylinder, the target control current of the variable amplitude balancing valve corresponding to the cylinder to be adjusted satisfies the following formula: ; in, The target control current of the variable amplitude balancing valve corresponding to the oil cylinder to be adjusted The current of the variable amplitude balancing valve corresponding to the oil cylinder to be adjusted, is the current flow of the cylinder to be adjusted, It is the rodless chamber flow difference between the cylinder to be adjusted and the target cylinder.

[0058] In an embodiment of the present application, the target control current is determined based on the current current, the current flow and the rodless chamber flow difference, including: when the current pressure value of the cylinder to be adjusted is less than the current pressure value of the target cylinder, the difference between the current flow and the rodless chamber flow difference is determined as a third calculated value; the product of the third calculated value and the current current is determined as a fourth calculated value; and the ratio of the fourth calculated value to the current flow is determined as the target control current of the variable amplitude balancing valve corresponding to the cylinder to be adjusted.

[0059] Specifically, when the current pressure value of the cylinder to be adjusted is greater than the current pressure value of the target cylinder, the target control current of the variable amplitude balancing valve corresponding to the cylinder to be adjusted satisfies the following formula: ; in, The target control current of the variable amplitude balancing valve corresponding to the oil cylinder to be adjusted The current of the variable amplitude balancing valve corresponding to the oil cylinder to be adjusted, is the current flow of the cylinder to be adjusted, It is the rodless chamber flow difference between the cylinder to be adjusted and the target cylinder.

[0060] In a specific embodiment of the present application, the dual-cylinder luffing hydraulic system described in the above embodiment is used as an example for a crane. During the crane's dual-cylinder luffing process, differences in the force applied to the left and right luffing cylinders, differences in the balancing valves, and differences in the pilot oil lines lead to differences in the pilot oil pressures of the left and right rodless chamber balancing valves, which can easily cause the left and right luffing cylinders to become out of sync. By collecting the rodless chamber pressures of the left and right luffing cylinders, calculating the pressure differential between the left and right rodless chambers, and dynamically matching the opening requirements of the left and right rodless chamber balancing valves, the currents of the left and right rodless chamber balancing valves are adjusted respectively, and the flow rates of the left and right rodless chambers are controlled, thereby improving the synchronization of the dual-luffing cylinders. Figure 3 A flowchart of a crane dual-cylinder luffing synchronization control method provided in a specific embodiment of the present application is shown in Figure 3. The control flow of the crane dual-cylinder luffing synchronization control method includes: S11, the variable amplitude drop begins.

[0061] S12. Collect the pressure values ​​of the left and right amplitude rodless chambers.

[0062] S13. Calculate the pressure difference between the left and right amplitude-adjusting rodless chambers.

[0063] S14: Determine whether the pressure difference is greater than a first preset pressure threshold. If yes, proceed to step S15; otherwise, proceed to step S19.

[0064] S15: Determine whether the pressure difference is greater than a second preset pressure threshold. If yes, proceed to step S111; otherwise, proceed to step S16.

[0065] S16. Dynamically match the current of the dual-cylinder rodless cavity balancing valve according to the pressure difference.

[0066] S17, adjust the current of the double-cylinder variable amplitude rodless cavity balancing valve.

[0067] S18: Determine whether the pressure difference between the left and right rodless chambers is greater than a first preset pressure value. If yes, proceed to step S15; otherwise, proceed to step S19.

[0068] S19, normal luffing and lowering of the arm.

[0069] S110, the boom is lowered after the luffing is completed, and the process goes to step S112.

[0070] S111, limit the amplitude change and falling action.

[0071] S112, end.

[0072] Specifically, when the luffing begins, the left and right rodless chamber pressures are collected, and the pressure difference between the two rodless chambers is calculated. A determination is made as to whether the pressure difference is greater than a first preset pressure threshold. If so, the luffing continues normally. If so, a determination is made as to whether it is greater than a second preset pressure threshold. If so, the luffing operation is restricted. If not, the opening requirements of the left and right balancing valves are dynamically matched based on the pressure difference. Based on this dynamically matched opening requirement, the current values ​​of the left and right rodless chamber balancing valves are matched, and the balancing valve currents are adjusted accordingly to control the flow rates in the left and right rodless chambers and improve the synchronization of the dual luffing cylinders.

[0073] In the specific embodiment of the present application, when the amplitude drop begins, the pressures P1 and P2 of the left and right amplitude rodless cavities are collected, and the pressure difference ΔP of the left and right rodless cavities is calculated, that is: ; Among them, P1 is the pressure of the left rodless chamber, and P2 is the pressure of the right rodless chamber.

[0074] Determine whether the pressure difference is greater than the first preset pressure threshold. If less than, the amplitude is lowered normally. If greater than, continue to determine whether it is greater than the second preset pressure threshold. If greater than, the amplitude is limited to fall. If less than, calculate the flow difference ΔQ of the rodless cavity of the left and right amplitude cylinders based on the pressure difference. First, calculate the volume difference of the left and right rodless cavities based on the pressure value. ,Right now: ; Where K is the bulk modulus of hydraulic oil, The cavity is the initial oil volume of the rod cavity.

[0075] Then the flow difference ΔQ is: ; Where t is time.

[0076] According to the dynamically matched left and right variable-luff rodless cavity flow difference ΔQ, the left and right rodless cavity balancing valve current values ​​are matched, and the balancing valve current is adjusted accordingly to control the left and right rodless cavity flows and improve the synchronization of the dual variable-luff cylinders.

[0077] In one example, the current of the high-pressure side rodless cavity balancing valve can be increased, and the target control current of the high-pressure side rodless cavity balancing valve can be increased. for: ; in, is the actual current of the high-pressure side rodless cavity balancing valve, that is, the current current. Adjust the front flow, i.e. the current flow, for the high pressure side.

[0078] In another example, the current of the low-pressure side rodless cavity balancing valve can be reduced, and the target control current of the low-pressure side rodless cavity balancing valve can be reduced. for: ; in, is the actual current of the low-pressure side rodless cavity balancing valve, that is, the current current. Adjust the front flow, i.e. the current flow, for the low-pressure side.

[0079] In summary, the flow difference between the left and right variable-length rodless cavities can be calculated based on the pressure difference between the left and right rodless cavities, and the current values ​​of the left and right rodless cavity balance valves can be dynamically matched. The balance valve current can be adjusted accordingly to control the flow rates of the left and right rodless cavities and improve the synchronization of the dual variable-length cylinders.

[0080] In this way, during the luffing process, the opening requirements of the dual-luffing cylinder balance valves are dynamically matched and controlled based on the pressure difference in the rodless chambers of the dual-luffing cylinders, ensuring the coordinated movement of the two cylinders and improving the synchronization accuracy of the two-cylinder luffing. This also reduces costs, as crane dual-cylinder luffing systems generally include pressure monitoring, eliminating the need for additional costs.

[0081] The present application also provides an engineering machine, comprising: a multi-cylinder amplitude control system in the above embodiment.

[0082] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware. Furthermore, the present application may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0083] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems) and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0084] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1The function specified in one or more boxes.

[0085] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0086] In a typical configuration, a computing device includes one or more processors (CPUs), input / output interfaces, network interfaces, and memory.

[0087] The memory may include non-permanent memory in a computer-readable medium, random access memory (RAM) and / or non-volatile memory in the form of read-only memory (ROM) or flash RAM. The memory is an example of a computer-readable medium.

[0088] Computer-readable media includes both permanent and non-permanent, removable and non-removable media that can be implemented using any method or technology for information storage. Information can be computer-readable instructions, data structures, program modules, or other data. Examples of computer storage media include, but are not limited to, phase-change RAM (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, compact disc read-only memory (CD-ROM), digital versatile disc (DVD) or other optical storage, magnetic cassettes, magnetic disk storage or other magnetic storage devices, or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined herein, computer-readable media does not include transitory computer-readable media, such as modulated data signals and carrier waves.

[0089] It should also be noted that the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, commodity, or apparatus that includes a series of elements includes not only those elements but also other elements not explicitly listed, or includes elements inherent to such process, method, commodity, or apparatus. In the absence of further limitations, an element defined by the phrase "comprises a ..." does not exclude the presence of other identical elements in the process, method, commodity, or apparatus that includes the element.

[0090] The above are merely embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application should all be included within the scope of the claims of the present application.

Claims

1. A multi-cylinder amplitude control system, characterized in that: The system comprises: Multiple luffing cylinders; Multiple variable amplitude balancing valves, each variable amplitude balancing valve is connected to each variable amplitude cylinder in a one-to-one correspondence, the variable amplitude balancing valve includes a main valve core and an oil-liquid connecting valve core, each oil-liquid connecting valve core is connected to the rodless chamber of each variable amplitude cylinder, and each oil-liquid connecting valve core is connected through a series pipeline, and the main valve core and the oil-liquid connecting valve core are linked.

2. The system according to claim 1, wherein: The variable amplitude balancing valve also includes: Filter, used to filter impurities in the oil; A pilot pressure reducing valve is used to receive a pressure signal of the pilot control oil and reduce the pressure of the pressure signal to output a stable pilot control pressure; The safety relief valve is used to protect the system from overload.

3. A method for multi-cylinder amplitude control, characterized in that: The method applied to the multi-cylinder amplitude control system according to any one of claims 1 to 2 includes: During the process of the multiple luffing cylinders performing the luffing and falling action, obtaining the current pressure value of the rodless cavity of each luffing cylinder; determining a target pressure difference based on the plurality of current pressure values; When the target pressure difference is greater than a first preset pressure threshold and less than a second preset pressure threshold, determining a target control current for each of the variable amplitude balancing valves according to the multiple current pressure values, wherein the first preset pressure threshold is less than the second preset pressure threshold; The current of each of the luffing balancing valves is adjusted according to the target control current to adjust the flow of the rodless chamber of each of the luffing cylinders.

4. The method according to claim 3, characterized in that Determining the target control current of each of the variable amplitude balancing valves according to the multiple current pressure values ​​includes: Obtaining the movement duration of each of the luffing cylinders and the initial oil volume of the rod chamber of each of the luffing cylinders; Determining a target cylinder and a cylinder to be adjusted from the plurality of luffing cylinders, wherein the cylinder to be adjusted is a luffing cylinder other than the target cylinder among the plurality of luffing cylinders; Determining the rodless chamber flow difference between each of the oil cylinders to be adjusted and the target oil cylinder according to the current pressure value, the movement duration, and the initial oil volume; The target control current of the variable amplitude balancing valve corresponding to each of the oil cylinders to be adjusted is determined according to the rodless chamber flow difference.

5. The method according to claim 4, characterized in that The determining, based on the current pressure value, the movement duration, and the initial oil volume, of the rodless chamber flow difference between each of the oil cylinders to be adjusted and the target oil cylinder includes: determining a current pressure difference between the oil cylinder to be adjusted and the target oil cylinder according to the current pressure value; determining a rodless chamber volume difference between the oil cylinder to be adjusted and the target oil cylinder according to the current pressure difference, the initial oil volume, and a preset hydraulic oil bulk modulus; The rodless cavity flow difference is determined according to the rodless cavity volume difference and the movement duration.

6. The method according to claim 4, characterized in that The step of determining the target control current of the variable amplitude balancing valve corresponding to the oil cylinder to be adjusted according to the rodless chamber flow difference comprises: Obtaining the current current of the variable amplitude balancing valve corresponding to the oil cylinder to be adjusted and the current flow of the rodless chamber of the oil cylinder to be adjusted; The target control current is determined according to the current current, the current flow rate, and the rodless cavity flow rate difference.

7. The method according to claim 6, characterized in that The determining the target control current according to the current current, the current flow rate, and the rodless cavity flow rate difference includes: In a case where the current pressure value of the oil cylinder to be adjusted is greater than the current pressure value of the target oil cylinder, determining the sum of the current flow rate and the rodless chamber flow rate difference as a first calculated value; determining a product of the first calculated value and the current current as a second calculated value; The ratio of the second calculated value to the current flow rate is determined as the target control current of the variable amplitude balancing valve corresponding to the oil cylinder to be adjusted.

8. The method according to claim 6, characterized in that The determining the target control current according to the current current, the current flow rate, and the rodless cavity flow rate difference includes: When the current pressure value of the oil cylinder to be adjusted is less than the current pressure value of the target oil cylinder, determining the difference between the current flow rate and the rodless chamber flow rate difference as a third calculated value; determining a product of the third calculated value and the current current as a fourth calculated value; The ratio of the fourth calculated value to the current flow rate is determined as the target control current of the variable amplitude balancing valve corresponding to the oil cylinder to be adjusted.

9. The method according to claim 3, characterized in that The method further comprises: When the target pressure difference is greater than or equal to the second preset pressure threshold, the plurality of luffing cylinders are controlled to stop performing the luffing lowering action.

10. The method according to claim 3, characterized in that The method comprises: When the target pressure difference is less than or equal to the first preset pressure threshold, the current control current of each of the variable amplitude balancing valves is maintained unchanged, and the variable amplitude falling action is continued.

11. An engineering machine, characterized in that: include: A multi-cylinder luffing control system according to any one of claims 1 to 2.

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