A system, method and working machine for multi-cylinder luffing control

Abstract

The application discloses a system, a method and a construction machine for multi-cylinder amplitude control. The system comprises: a plurality of amplitude cylinders; and a plurality of amplitude balance valves, each of which is connected to each of the amplitude cylinders in one-to-one correspondence. The amplitude balance valve comprises a main valve core and an oil communication valve core. Each oil communication valve core is connected to a rodless chamber of each amplitude cylinder, and each oil communication valve core is connected through a series pipeline. The main valve core and the oil communication valve core are linked. When the amplitude balance valve in the application is opened, the communication valve core is also opened. The multi-cylinder rodless chamber can be communicated through the oil communication valve core and the series pipeline, thereby improving the synchronization of the double cylinders. When the amplitude balance valve is closed, the communication valve core is also synchronously closed. The amplitude balance valve plays a safety protection role, and the system is safer.

Description

Technical Field

[0001] This application relates to the field of engineering machinery technology, specifically to a system, method, and engineering machinery for multi-cylinder variable amplitude control. Background Technology

[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 affects operational accuracy and safety. Traditional multi-cylinder luffing systems typically use rigid mechanical connections or simple hydraulic parallel circuits to achieve synchronization, but there are significant technical bottlenecks: rigid mechanical connections (such as linkage mechanisms) can force synchronization, but they cannot adapt to differences in load among multiple cylinders (such as unilateral uneven loading), and are prone to loss of synchronization accuracy due to mechanical wear. Especially when luffing large-span booms (such as those over 50 meters), the cumulative error can reach 10-20mm, which can lead to boom tilting or even safety accidents in severe cases.

[0003] Therefore, the multi-cylinder variable amplitude control system used in the existing technology has the problem of low safety. Summary of the Invention

[0004] The purpose of this application is to provide a system, method, and engineering machinery for multi-cylinder variable amplitude control, in order to solve the problem of low safety in the multi-cylinder variable amplitude control systems used in the prior art.

[0005] To achieve the above objectives, the first aspect of this application provides a multi-cylinder variable amplitude control system, the system comprising: Multiple variable amplitude hydraulic cylinders; Multiple luffing balance valves are provided, each connected to a luffing cylinder in a one-to-one correspondence. Each luffing balance valve includes a main valve core and an oil-hydraulic connecting valve core. Each oil-hydraulic connecting valve core is connected to the rodless chamber of each luffing cylinder, and the oil-hydraulic connecting valve cores are connected in series through pipelines. The main valve core and the oil-hydraulic connecting valve core are linked together.

[0006] In this embodiment of the application, the amplitude-changing balance valve further includes: Filter screens are used to filter impurities from oil. The pilot pressure reducing valve is used to receive the pressure signal of the pilot control oil and reduce the pressure signal to output a stable pilot control pressure. Safety relief valves are used to protect the system from overload.

[0007] A second aspect of this application provides a method for multi-cylinder variable amplitude control, applied to the aforementioned multi-cylinder variable amplitude control system, the method comprising: During the luffing and lowering action of multiple luffing cylinders, the current pressure value of the rodless chamber of each luffing cylinder is obtained; Determine the target pressure difference based on multiple current pressure values; When the target pressure difference is greater than the first preset pressure threshold and less than the second preset pressure threshold, the target control current for each amplitude balance valve is determined based on multiple current pressure values, wherein the first preset pressure threshold is less than the second preset pressure threshold. The current of each amplitude balance valve is adjusted according to the target control current in order to adjust the flow rate of the rodless chamber of each amplitude cylinder.

[0008] In this embodiment, determining the target control current for each luffing balance valve based on multiple current pressure values ​​includes: acquiring the movement duration of each luffing cylinder and the initial oil volume of the rod chamber of each luffing cylinder; identifying the target cylinder and the cylinder to be adjusted from the multiple luffing cylinders, wherein the cylinder to be adjusted is the luffing cylinder other than the target cylinder among the multiple luffing cylinders; determining the flow difference of the rodless chamber between each cylinder to be adjusted and the target cylinder based on the current pressure value, movement duration, and initial oil volume; and determining the target control current of the luffing balance valve corresponding to each cylinder to be adjusted based on the flow difference of the rodless chamber.

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

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

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

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

[0013] In this embodiment of the application, the method further includes: when the target pressure difference is greater than or equal to a second preset pressure threshold, controlling multiple luffing cylinders to stop performing luffing and falling actions.

[0014] In this embodiment of the 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 amplitude balance valve unchanged, and continuing to perform the amplitude drop action.

[0015] A third aspect of this application provides an engineering machinery, including: the aforementioned multi-cylinder variable amplitude control system.

[0016] The aforementioned multi-cylinder luffing control system includes multiple luffing cylinders and multiple luffing balance valves. Each luffing balance valve is connected to a corresponding luffing cylinder. Each luffing balance valve includes a main valve core and an oil-hydraulic connecting valve core. Each oil-hydraulic connecting valve core is connected to the rodless chamber of each luffing cylinder, and these valves are connected via a series pipeline. The main valve core and the oil-hydraulic connecting valve core are linked. In this application, when the luffing balance valve is open, the connecting valve core also opens, allowing the rodless chambers of the multiple cylinders to be connected via the oil-hydraulic connecting valve core and the series pipeline, thereby improving the synchronization of the two cylinders. When the luffing balance valve is closed, the connecting valve core also closes synchronously, providing safety protection and enhancing system safety.

[0017] Other features and advantages of the embodiments of this application will be described in detail in the following detailed description section. Attached Figure Description

[0018] The accompanying drawings are provided to further illustrate the embodiments of this application and form part of the specification. They are used together with the following detailed description to explain the embodiments of this application, but do not constitute a limitation on the embodiments of this application. In the drawings: Figure 1 A schematic diagram of a multi-cylinder variable amplitude hydraulic system provided in a specific embodiment of this application; Figure 2 A flowchart illustrating a multi-cylinder variable amplitude control method provided in an embodiment of this application; Figure 3 This is a flowchart illustrating a synchronous control method for a crane with dual cylinder luffing, provided as a specific embodiment of this application.

[0019] Explanation of reference numerals in the attached figures Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only for illustration and explanation of the embodiments of this application and are not intended to limit the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0021] It should be noted that if the embodiments of this application involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0022] Furthermore, if the embodiments of this application involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0023] Traditional synchronization technologies for double-cylinder luffing systems in cranes mainly include balance valve control technology, dual-cylinder series piping technology, and rodless chamber pressure detection technology. Among these, the balance valve control technology typically employs dual or triple luffing balance valves in the rodless chamber of a double-cylinder luffing system. By sharing a pilot oil source, the consistency of the balance valve openings is improved, thereby enhancing the synchronization of the two cylinders. However, in practical applications, differences in pilot oil line length and shape lead to varying pressure losses, making it impossible to guarantee completely consistent pilot pressures across all balance valves. This difference in pressure loss is particularly pronounced at lower temperatures. Furthermore, inconsistencies exist among the balance valves; even with the same pilot pressure, different balance valves exhibit varying flow rates. In abnormal situations, such as a damaged balance valve failing to open, serious installation accidents can occur. Dual-cylinder series piping technology can only balance limited flow rates; when the flow rates of the two cylinders differ significantly, severe asynchrony can still occur. Pressure monitoring technology primarily monitors extreme pressure levels to trigger alarms or cut-off actions, protecting crane operation safety, but it does not improve synchronization. To address the aforementioned issues, this application provides a system and method for multi-cylinder variable amplitude control, which improves the synchronization of the two cylinders while enhancing system safety and reliability.

[0024] This application provides a multi-cylinder variable amplitude control system, the system comprising: Multiple variable amplitude hydraulic cylinders; Multiple luffing balance valves are provided, each connected to a luffing cylinder in a one-to-one correspondence. Each luffing balance valve includes a main valve core and an oil-hydraulic connecting valve core. Each oil-hydraulic connecting valve core is connected to the rodless chamber of each luffing cylinder, and the oil-hydraulic connecting valve cores are connected in series through pipelines. The main valve core and the oil-hydraulic connecting valve core are linked together.

[0025] In this embodiment, the multi-cylinder luffing control system can be applied to various engineering machinery requiring multi-cylinder luffing control, such as large crane equipment. The system includes multiple luffing cylinders and multiple luffing balance valves, each connected to a corresponding luffing cylinder. The luffing cylinders are used to collaboratively drive the luffing mechanism of the engineering machinery with multiple actuators. The luffing balance valve integrates a main valve core and an oil-hydraulic connecting valve core. The main valve core controls the main oil circuit, while the oil-hydraulic connecting valve core regulates the pressure in the rodless chamber. Specifically, the main valve core controls the oil inlet and outlet of the luffing cylinder, directly determining its extension and retraction. When the hydraulic system supplies oil to the main valve core, the main valve core moves, opening or closing the oil circuit to the luffing cylinder, thus extending or retracting the cylinder. The oil-hydraulic connecting valve core is connected to the rodless chamber of the luffing cylinder, indirectly controlling the cylinder's movement state by adjusting the oil pressure in the rodless chamber. When the oil connection valve core is opened, the oil in the rodless chamber can flow between the cylinders through the series pipeline to achieve pressure equalization.

[0026] In this embodiment, the oil-hydraulic connecting valve core is linked to the main valve core, opening and closing synchronously. This ensures communication between the rodless chambers of each luffing cylinder during normal operation, improving system synchronization. When the main valve core is closed, the oil-hydraulic connecting valve core also closes, and the balance valve provides safety protection. In traditional dual-cylinder luffing hydraulic systems, the rodless chamber oil is connected via a series pipeline and an explosion-proof valve. If the series pipeline ruptures, the explosion-proof valve provides safety protection; however, if the explosion-proof valve leaks significantly or malfunctions, a boom fall may still occur. In this embodiment, the oil-hydraulic connecting valve core is linked to the main valve core. If the series pipeline ruptures, both the oil-hydraulic connecting valve core and the main valve core close, thus shutting down the system. The luffing balance valve provides safety protection, resulting in higher safety.

[0027] The above technical solution provides a multi-cylinder luffing control system, including multiple luffing cylinders and multiple luffing balance valves. Each luffing balance valve is connected to a corresponding luffing cylinder. Each balance valve includes a main valve core and an oil-hydraulic connecting valve core. Each oil-hydraulic connecting valve core is connected to the rodless chamber of each luffing cylinder, and the oil-hydraulic connecting valve cores are connected via a series pipeline. The main valve core and the oil-hydraulic connecting valve core are linked. In this application, when the balance valve is open, the connecting valve core also opens, allowing the rodless chambers of the multiple cylinders to be connected via the oil-hydraulic connecting valve core and the series pipeline, thereby improving the synchronization of the two cylinders. When the balance valve is closed, the connecting valve core also closes synchronously, providing safety protection and enhancing system safety.

[0028] Figure 1 This is a schematic diagram of a multi-cylinder luffing hydraulic system according to a specific embodiment of this application. As shown in Figure 1, taking a dual-cylinder system as an example, the dual-cylinder luffing hydraulic system includes: a left luffing cylinder 1, a left lower chamber luffing balance valve 2, a relief valve 3, an oil tank 4, an engine 5, a hydraulic pump 6, a main valve 7, a right lower chamber luffing balance valve 8, and a right luffing cylinder 10. The hydraulic pump 6 is driven by the engine 5, draws oil from the oil tank 4, and the output pressurized oil is distributed via the main valve 7 (directional valve) to the left lower chamber luffing balance valve 2 and the right lower chamber luffing balance valve 8, thereby controlling the operation of the left luffing cylinder 1 and the right luffing cylinder 10. The relief valve 3 is connected in parallel in the system to limit the outlet pressure of the hydraulic pump 6, and excess oil returns to the oil tank 4. Both the left lower chamber luffing balance valve 2 and the right lower chamber luffing balance valve 8 include a main valve core 11 and an oil-hydraulic connecting valve core 12.

[0029] Specifically, engine 5 serves as the power source, driving hydraulic pump 6 to rotate, converting mechanical energy into hydraulic energy to provide pressurized oil for the entire system. The pressurized oil output from hydraulic pump 6 is connected to port P (inlet) of main valve 7. Main valve 7 is energized by electromagnets Y1 and Y2 to switch the direction of pressurized oil flow to port A or port B, thereby controlling the direction of movement (extension / retraction) of the left and right luffing cylinders. Ports A and B of main valve 7 are connected to the control ports of the lower left luffing balance valve 2 and the lower right luffing balance valve 8, respectively. By switching the main valve, a control signal is transmitted, triggering the main valve core 11 of the balance valve to actuate and open the oil inlet / return channels of the cylinders. The lower left luffing balance valve 2 is connected to the rodless chamber of the left luffing cylinder 1, controlling the oil inlet and return of the rodless chamber; the lower right luffing balance valve 8 is connected to the rodless chamber of the right luffing cylinder 10, similarly controlling the oil flow. The main valve core 11 and the oil-connecting valve core 12 inside the balance valve are linked. When the cylinder is disturbed by the load (such as the load tending to tip over when the luffing stops), the hydraulic pressure and flow rate are automatically adjusted to maintain cylinder stability, prevent overspeed retraction and load drop, and achieve the functions of "cylinder locking" and "buffering". The relief valve 3 is connected in parallel to the outlet of the hydraulic pump 6 (or the oil inlet side of the main valve 7). When the system pressure exceeds the set value of the relief valve 3 (such as hydraulic pump overload or pipeline blockage), the relief valve opens, and the high-pressure oil returns directly to the oil tank 4, protecting the system pipelines and components and preventing damage due to excessive pressure. The oil tank 4 is used to store hydraulic oil, provide oil source for the hydraulic pump 6, and at the same time recover system return oil, which plays a role in heat dissipation, sedimentation of impurities, and maintaining the cleanliness of hydraulic oil and the stability of system oil temperature. The left luffing cylinder 1 and the right luffing cylinder 10 serve as actuators. Through the rodless chamber and the rod chamber (not shown in the figure, usually located below the cylinder), oil is introduced and returned to achieve the piston rod extension (luffing up) and retraction (luffing down) actions, thereby driving the main boom luffing mechanism to change the boom angle and complete the luffing function of lifting operations.

[0030] like Figure 1 As shown in the embodiments of this application, the amplitude-changing balance valve further includes: Filter screen 13 is 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 signal to output a stable pilot control pressure. Safety relief valve 15 is used for overload protection of the system.

[0031] Specifically, the hydraulic fluid first passes through filter screen 13 to filter impurities before entering the main valve core 11 of the variable amplitude balance valve. It then flows to the hydraulic connection valve core 12 to prevent particulate matter and other contaminants from entering the valve assembly, avoiding valve core jamming and wear, protecting the valve assembly and the normal operation of the entire hydraulic system, and improving system reliability and service life. Simultaneously, pilot control oil first enters the pilot pressure reducing valve 14 for pressure regulation. The stable pilot pressure output acts on the main valve core 11, controlling its opening and other states, thereby precisely controlling the actions of the main valve core 11 and other components. This allows for more precise adjustment and timely response of the main valve core 11, achieving accurate control 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, it forms a pressure relief passage with the main oil circuit containing the main valve core 11 and the oil connection valve core 12, ensuring system safety. Under normal operating conditions, the components work together. The main valve core 11, under the control of the pilot pressure reducing valve 14 and the cooperation of the oil connection valve core 12, achieves precise control of the oil in the main oil circuit, driving the actuator to work stably. The filter screen 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 this embodiment, both the lower left chamber amplitude-changing balance valve 2 and the lower right chamber amplitude-changing balance valve 8 are equipped with energized proportional pilot oil pressure reducing valves. According to the opening requirements of the left and right rodless chamber balance valves, the currents of the electromagnets Y3 and Y4 of the lower left chamber amplitude-changing balance valve 2 and the lower right chamber amplitude-changing balance valve 8 can be controlled separately, thereby controlling the opening size of the lower left chamber amplitude-changing balance valve 2 and the lower right chamber amplitude-changing balance valve 8 respectively.

[0033] Simultaneously, both the lower left chamber luffing balance valve 2 and the lower right chamber luffing balance valve 8 integrate an oil-hydraulic connecting valve core 12. When the pilot oil source opens the main valve core 11 of the lower left chamber luffing balance valve 2 and the lower right chamber luffing balance valve 8, the oil-hydraulic connecting valve core 12 is opened simultaneously, allowing the rodless chambers of the two cylinders to be connected via the oil-hydraulic connecting valve core 12 and the series pipeline of the luffing balance valve E port. This improves the synchronization of the two cylinders during the luffing descent process. When the luffing balance valve is closed, the oil-hydraulic connecting valve core 12 is closed, and the balance valve provides safety protection. In traditional dual-cylinder luffing hydraulic systems, the oil in the rodless chamber is connected via a series pipeline and an explosion-proof valve. If the series pipeline ruptures, the explosion-proof valve provides safety protection, but if the explosion-proof valve leaks significantly or malfunctions, a boom fall may still occur. In this embodiment, if the series pipeline ruptures, the system shuts down, and the balance valve provides safety protection, resulting in higher safety. Improving the synchronization of the two cylinders enhances safety and reliability.

[0034] Traditional hydraulic parallel circuits independently control the flow of each cylinder through balance valves, lacking a dynamic coordination mechanism. When the load on a cylinder changes abruptly, the pressure imbalance in the rodless chamber leads to uneven flow distribution, with synchronization errors reaching 5-10 mm / m of boom length. Furthermore, in the event of a series pipeline rupture, protection relies solely on the passive protection of the explosion-proof valve; if the explosion-proof valve malfunctions, it can easily cause the boom to fall, resulting in insufficient safety. To address this, this application also provides a multi-cylinder luffing control method. During the luffing descent process, based on the target pressure difference in the rodless chamber of each luffing cylinder, the opening requirements of the luffing balance valve corresponding to each luffing cylinder are dynamically matched and controlled to ensure consistent movement of each luffing cylinder and improve the synchronization accuracy of multi-cylinder luffing.

[0035] Figure 2 This is a flowchart illustrating a multi-cylinder variable amplitude control method provided in an embodiment of this application. Figure 2 As shown in the figure, this application provides a method for multi-cylinder variable amplitude control, which is applied to the multi-cylinder variable amplitude control system described above. The method may include the following steps.

[0036] Step 101: During the luffing and lowering action of multiple luffing cylinders, obtain the current pressure value of the rodless chamber of each luffing cylinder.

[0037] Step 102: Determine the target pressure difference based on multiple current pressure values.

[0038] Step 103: When the target pressure difference is greater than the first preset pressure threshold and less than the second preset pressure threshold, determine the target control current for each amplitude balance valve based on multiple current pressure values, wherein the first preset pressure threshold is less than the second preset pressure threshold.

[0039] Step 104: Adjust the current of each amplitude balance valve according to the target control current to adjust the flow rate of the rodless chamber of each amplitude cylinder.

[0040] Specifically, during the luffing descent process, pressure sensors distributed in the rodless chambers of each luffing cylinder collect the current pressure value of the rodless chamber. The target pressure difference is then determined based on this current pressure value. In one example, with two luffing cylinders, the target pressure difference is the difference between the pressure values ​​in the rodless chambers of the two cylinders. In another example, with three or more luffing cylinders, the target pressure difference is the maximum value of the pressure differences in the rodless chambers of each cylinder.

[0041] Furthermore, the relationship between the target pressure difference and the first and second preset pressure values ​​is compared. The first preset pressure value is less than the second preset pressure value. The first preset pressure value is the lower limit for the system to determine that the cylinder synchronization deviation is within the adjustable range; adjustments below this limit are unnecessary to avoid system oscillation caused by frequent adjustments. The second preset pressure value is the upper limit for the system to determine that the cylinder synchronization deviation is within the adjustable range; above this limit, the system 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, the target control current for each luffing balance valve is determined based on multiple current pressure values. In one example, the target control current for each luffing balance 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 balance valve is adjusted according to the target control current, thereby regulating the flow rate in the rodless chamber of each luffing cylinder to ensure consistent movement of each luffing cylinder.

[0043] Thus, during the luffing descent process, the opening requirements of the luffing balance valves corresponding to each luffing cylinder are dynamically matched and controlled according to the target pressure difference in the rodless chamber of each luffing cylinder, ensuring consistent movement of each luffing cylinder and improving the synchronization accuracy of multi-cylinder luffing. At the same time, the cost is low, as crane dual-cylinder luffing systems generally have pressure monitoring, eliminating the need for additional costs.

[0044] In this embodiment of the application, the method further includes: when the target pressure difference is greater than or equal to a second preset pressure threshold, controlling multiple luffing cylinders to stop performing luffing and falling actions.

[0045] It is understandable that if the target pressure difference is greater than or equal to the second preset pressure threshold, it indicates a serious asynchrony among the luffing cylinders, requiring emergency braking to stop each cylinder from performing the luffing descent action, thus interrupting the luffing descent and preventing a safety accident. Preferably, the system can simultaneously output alarm signals through sound, light, and text to remind operators to take timely countermeasures.

[0046] In this embodiment of the 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 amplitude balance valve unchanged, and continuing to perform the amplitude drop action.

[0047] It is understandable that when the target pressure difference is less than or equal to the second preset pressure threshold, it indicates that the synchronization of each variable-amplitude cylinder is high and no adjustment is needed. The current control current of each variable-amplitude balance valve remains unchanged, and the variable-amplitude descent action continues to be executed, thereby avoiding frequent adjustments that could cause system oscillation.

[0048] In this embodiment, determining the target control current for each luffing balance valve based on multiple current pressure values ​​includes: acquiring the movement duration of each luffing cylinder and the initial oil volume of the rod chamber of each luffing cylinder; identifying the target cylinder and the cylinder to be adjusted from the multiple luffing cylinders, wherein the cylinder to be adjusted is the luffing cylinder other than the target cylinder among the multiple luffing cylinders; determining the flow difference of the rodless chamber between each cylinder to be adjusted and the target cylinder based on the current pressure value, movement duration, and initial oil volume; and determining the target control current of the luffing balance valve corresponding to each cylinder to be adjusted based on the flow difference of the rodless chamber.

[0049] It is understandable that, to determine the target control current for each luffing balance valve, the motion duration of each luffing cylinder and the initial oil volume in the rod chamber of each cylinder can be obtained first. The motion duration is the time it takes for the cylinder to travel from its initial position to its current position, reflecting the progress of the action, and 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, and can be determined based on the cylinder's inner diameter, rod diameter, and stroke.

[0050] Furthermore, the target cylinder and the cylinder to be adjusted are determined from among the multiple luffing cylinders. First, the target cylinder is identified, and then the other luffing cylinders besides the target cylinder are identified as the cylinders to be adjusted. In one example, the target cylinder can be the cylinder with the highest current pressure value among the multiple luffing cylinders. Since the maximum load also results in the greatest motion resistance, using the cylinder with the highest pressure as the benchmark ensures that all cylinders can overcome the maximum load and avoids underdrive causing the boom to jam. In another example, the target cylinder can be the cylinder with the lowest current pressure value among the multiple luffing cylinders. Selecting the cylinder with the lowest pressure (lightest load) as the benchmark ensures that the output force of all cylinders can meet the current load requirements and prevents excessive system pressure due to overload of a single cylinder. In another example, the average pressure value can be determined based on the current pressure value of the rodless chamber of multiple luffing cylinders. Then, the luffing cylinder whose current pressure value is closest to the average pressure value is selected as the target cylinder. By selecting the cylinder with the middle pressure, the adjustment amount of the high-pressure side and the low-pressure side cylinders can be relatively balanced, avoiding excessive throttling of a single cylinder.

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

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

[0053] Specifically, the difference in flow rate in the rodless chamber between the cylinder to be adjusted and the target cylinder is determined by the following formula: ; ; ; in, The current pressure value of the cylinder to be adjusted. The current pressure value of the target hydraulic cylinder. This represents the absolute value of the current pressure difference between the cylinder to be adjusted and the target cylinder. This represents the initial oil volume in the rod chamber. To preset the bulk modulus of hydraulic oil, The difference in the volume of the rodless chamber between the cylinder to be adjusted and the target cylinder; The duration of motion of the variable amplitude cylinder. The difference in flow rate in the rodless chamber between the cylinder to be adjusted and the target cylinder.

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

[0055] It can be understood that the current current refers to the actual current of the luffing balance valve corresponding to each luffing cylinder, and the current flow rate refers to the actual current flow rate of the rodless chamber of each luffing cylinder. Based on the relationship between the current pressure values ​​of the cylinder to be adjusted and the target cylinder, the target control current of the luffing balance valve corresponding to the cylinder to be adjusted is determined according to the current current and current flow rate of the cylinder to be adjusted, as well as the difference in flow rate of the rodless chamber between the cylinder to be adjusted and the target cylinder.

[0056] In this embodiment of the application, determining the target control current based on the current current, the current flow rate, and the flow difference in the rodless chamber includes: when the current pressure value of the cylinder to be adjusted is greater than the current pressure value of the target cylinder, determining the sum of the current flow rate and the flow difference in the rodless chamber as a first calculated value; determining the product of the first calculated value and the current current as a second calculated value; and determining the ratio of the second calculated value to the current flow rate as the target control current of the variable amplitude balance 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 balance valve corresponding to the cylinder to be adjusted is determined according to the following formula: ; in, The target control current for the amplitude balance valve corresponding to the hydraulic cylinder to be adjusted. The current of the amplitude balance valve corresponding to the hydraulic cylinder to be adjusted. The current flow rate of the hydraulic cylinder to be adjusted. The difference in flow rate in the rodless chamber between the cylinder to be adjusted and the target cylinder.

[0058] In this embodiment of the application, the target control current is determined based on the current current, the current flow rate, and the difference in flow rate in the rodless chamber. This includes: when the current pressure value of the cylinder to be adjusted is less than the current pressure value of the target cylinder, determining the difference between the current flow rate and the difference in flow rate in the rodless chamber as a third calculated value; determining the product of the third calculated value and the current current as a fourth calculated value; and determining the ratio of the fourth calculated value to the current flow rate as the target control current of the variable amplitude balance 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 balance valve corresponding to the cylinder to be adjusted is determined according to the following formula: ; in, The target control current for the amplitude balance valve corresponding to the hydraulic cylinder to be adjusted. The current of the amplitude balance valve corresponding to the hydraulic cylinder to be adjusted. The current flow rate of the hydraulic cylinder to be adjusted. The difference in flow rate in the rodless chamber between the cylinder to be adjusted and the target cylinder.

[0060] In a specific embodiment of this application, the dual-cylinder luffing hydraulic system described above is used as an example in a crane. During the descent of the crane's dual-cylinder luffing system, differences in the forces on the left and right luffing cylinders, the differences in the balance valves, and the differences in the pilot oil lines lead to differences in the pilot oil pressure of the balance valves in the left and right rodless chambers, which can easily cause asynchrony between the left and right luffing cylinders. By collecting the pressure in the rodless chambers of the left and right luffing cylinders, calculating the pressure difference between the left and right rodless chambers, dynamically matching the opening requirements of the balance valves in the left and right rodless chambers, and adjusting the current of the balance valves in the left and right rodless chambers respectively, the flow rate in the left and right rodless chambers is controlled, thereby improving the synchronization of the dual luffing cylinders. Figure 3 This is a flowchart illustrating a crane dual-cylinder luffing synchronous control method according to a specific embodiment of this application. As shown in Figure 3, the control flow of the crane dual-cylinder luffing synchronous control method includes: S11, the variable amplitude drop begins.

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

[0062] S13. Calculate the pressure difference between the left and right variable rodless chambers.

[0063] S14. Determine whether the pressure difference is greater than the 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 the 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 chamber balance valve according to the pressure difference.

[0066] S17. Adjust the current of the balance valve in the rodless chamber of the double-cylinder variable amplitude transformer.

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

[0068] S19, Normal luffing boom drop.

[0069] S110, The luffing boom is lowered, proceed to step S112.

[0070] S111, Limiting the amplitude drop movement.

[0071] S112, End.

[0072] Specifically, at the start of the luffing descent, the pressure values ​​of the left and right rodless chambers are collected, the pressure difference between the left and right rodless chambers is calculated, and it is determined whether the pressure difference is greater than the first preset pressure threshold. If it is less than the first preset pressure threshold, the luffing descent proceeds normally. If it is greater than the first preset pressure threshold, it is further determined whether it is greater than the second preset pressure threshold. If it is greater than the second preset pressure threshold, the luffing descent action is restricted; if it is less than the second preset pressure threshold, the opening requirements of the left and right balance valves are dynamically matched according to the pressure difference. Based on the dynamically matched opening requirements of the left and right luffing balance valves, the current values ​​of the left and right rodless chamber balance valves are matched, and the balance valve currents are adjusted accordingly to control the flow rate of the left and right rodless chambers and improve the synchronization of the dual luffing cylinders.

[0073] In a specific embodiment of this application, at the start of the luffing descent, the pressures P1 and P2 in the left and right rodless chambers of the luffing system are collected, and the pressure difference ΔP between the left and right rodless chambers is calculated, i.e.: Where P1 is the pressure in the left rodless chamber and P2 is the pressure in the right rodless chamber.

[0074] The system checks if the pressure difference is greater than a first preset pressure threshold. If it is less, the amplitude reduction proceeds normally. If it is greater, the system checks if it is greater than a second preset pressure threshold. If it is greater, the amplitude reduction action is restricted. If it is less, the system calculates the flow difference ΔQ between the rodless chambers of the left and right amplitude cylinders based on the pressure difference. First, the volume difference between the left and right rodless chambers is calculated 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] The flow difference ΔQ is: ; Where t is time.

[0076] Based on the dynamically matched flow difference ΔQ between the left and right rodless chambers, the current values ​​of the balance valves for the left and right rodless chambers are matched, and the current of the balance valves is adjusted accordingly to control the flow of the left and right rodless chambers and improve the synchronization of the dual-amplitude cylinders.

[0077] In one example, the current of the high-voltage side rodless chamber balance valve can be increased, and the target control current of the high-voltage side rodless chamber balance valve can be increased. for: ; in, This represents the actual current of the rodless chamber balance valve on the high-pressure side, i.e., the current. The flow rate before adjusting the high-voltage side is the current flow rate.

[0078] In another example, the current of the low-pressure side rodless chamber balancing valve can be reduced, which is the target control current of the low-pressure side rodless chamber balancing valve. for: ; in, This represents the actual current of the rodless chamber balance valve on the low-pressure side, i.e., the current. The flow rate before adjustment on the low-pressure side is the current flow rate.

[0079] In summary, the flow rate difference between the left and right rodless chambers can be calculated based on the pressure difference between the left and right rodless chambers, and the current value of the balance valve of the left and right rodless chambers can be dynamically matched and the current of the balance valve can be adjusted accordingly, thereby controlling the flow rate of the left and right rodless chambers and improving the synchronization of the dual variable amplitude cylinders.

[0080] Thus, during the luffing descent process, the opening requirements of the balance valves of the two luffing cylinders are dynamically matched and controlled according to the pressure difference in the rodless chambers of the two cylinders, ensuring consistent movement of the two cylinders and improving the synchronization accuracy of the luffing. At the same time, the cost is low, as crane double-cylinder luffing systems generally have pressure monitoring, eliminating the need for additional costs.

[0081] This application also provides an engineering machinery, including: the multi-cylinder variable amplitude control system described in the above embodiments.

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

[0083] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0084] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1The function specified in one or more boxes.

[0085] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

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

[0087] Memory may include non-persistent memory in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM. Memory is an example of computer-readable media.

[0088] Computer-readable media includes both permanent and non-permanent, removable and non-removable media that can store information using any method or technology. Information can be computer-readable instructions, data structures, modules of programs, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (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, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transferable medium that can be used to store information accessible by a computing device. As defined herein, computer-readable media does not include transient computer-readable media, such as modulated data signals and carrier waves.

[0089] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0090] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A method for multi-cylinder variable amplitude control, characterized in that, A system for multi-cylinder luffing control includes multiple luffing cylinders and multiple luffing balance valves. Each luffing balance valve is connected to a corresponding luffing cylinder. Each luffing balance valve includes a main valve core, an oil-hydraulic connecting valve core, a filter screen, a pilot pressure reducing valve, and a safety relief valve. Each oil-hydraulic connecting valve core is connected to the rodless chamber of each luffing cylinder, and they are connected in series via pipelines. The main valve core and the oil-hydraulic connecting valve core are linked. The filter screen is used to filter impurities in the oil. The pilot pressure reducing valve receives the pressure signal from the pilot control oil and reduces the pressure to output a stable pilot control pressure. The safety relief valve provides overload protection for the system. The method includes: During the process of the multiple luffing cylinders performing the luffing and lowering action, the current pressure value of the rodless chamber of each of the luffing cylinders is obtained; The target pressure difference is determined based on multiple current pressure values; When the target pressure difference is greater than a first preset pressure threshold and less than a second preset pressure threshold, the target control current for each of the amplitude balance valves is determined based on 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 amplitude-changing balance valves is adjusted according to the target control current, so as to adjust the flow rate of the rodless chamber of each of the amplitude-changing cylinders; The step of determining the target control current for each of the variable amplitude balance valves based on multiple current pressure values ​​includes: The motion duration of each of the luffing cylinders and the initial oil volume of the rod chamber of each of the luffing cylinders are obtained; The target cylinder and the cylinder to be adjusted are determined from the plurality of luffing cylinders, wherein the cylinder to be adjusted is the luffing cylinder other than the target cylinder from the plurality of luffing cylinders; Based on the current pressure value, the duration of motion, and the initial oil volume, determine the difference in the rodless chamber flow rate between each of the cylinders to be adjusted and the target cylinder; The target control current of the amplitude balance valve corresponding to each of the cylinders to be adjusted is determined based on the flow difference in the rodless cavity.

2. The method according to claim 1, characterized in that, The step of determining the rodless chamber flow difference between each of the cylinders to be adjusted and the target cylinder based on the current pressure value, the duration of motion, and the initial oil volume includes: Based on the current pressure value, determine the current pressure difference between the cylinder to be adjusted and the target cylinder; The difference in rodless chamber volume between the cylinder to be adjusted and the target cylinder is determined based on the current pressure difference, the initial oil volume, and the preset hydraulic oil bulk modulus. The rodless cavity flow rate difference is determined based on the volume difference of the rodless cavity and the duration of motion.

3. The method according to claim 1, characterized in that, The step of determining the target control current of the variable amplitude balance valve corresponding to the cylinder to be adjusted based on the flow difference in the rodless cavity includes: Obtain the current current of the variable amplitude balance valve corresponding to the hydraulic cylinder to be adjusted and the current flow rate of the rodless chamber of the hydraulic cylinder to be adjusted; The target control current is determined based on the current current, the current flow rate, and the flow difference in the rodless cavity.

4. The method according to claim 3, characterized in that, Determining the target control current based on the current current, the current flow rate, and the flow difference in the rodless cavity includes: If 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 rate and the difference between the flow rates in the rodless chamber is determined as the first calculated value. The product of the first calculated value and the current current is determined as the 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 balance valve corresponding to the cylinder to be adjusted.

5. The method according to claim 3, characterized in that, Determining the target control current based on the current current, the current flow rate, and the flow difference in the rodless cavity includes: If 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 rate and the flow rate of the rodless chamber is determined as the third calculated value. The product of the third calculated value and the current current is determined as the 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 balance valve corresponding to the oil cylinder to be adjusted.

6. The method according to claim 1, characterized in that, The method further includes: 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 and lowering action.

7. The method according to claim 1, characterized in that, The method includes: If the target pressure difference is less than or equal to the first preset pressure threshold, the current control current of each of the amplitude balance valves remains unchanged, and the amplitude drop action continues to be performed.

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