Double-speed control loop hydraulic system and control method thereof

Abstract

The invention discloses a double-speed control loop hydraulic system and a control method thereof, and relates to the field of customs quarantine, and the system comprises a hydraulic cylinder assembly which comprises a hydraulic cylinder and a displacement sensor; a first hydraulic lock; the quick loop assembly, the first hydraulic lock and the hydraulic cylinder assembly are connected through a pipeline to form a quick adjusting subsystem; the low-speed loop assembly, the first hydraulic lock and the hydraulic cylinder assembly are connected to form a low-speed adjusting subsystem. By adopting the combination of the hydraulic lock and the double loops, the position of the hydraulic cylinder is more reliable, and meanwhile, the stable operation state can be maintained under the extreme working condition. The invention provides a hydraulic cylinder control scheme which is efficient, accurate, stable and low in cost, and is widely applicable to hydraulic systems needing rapid adjustment and accurate positioning.

Description

Technical Field

[0001] The present invention relates to the field of hydraulic systems, and more particularly to a dual-speed control circuit hydraulic system and a control method thereof. Background Art

[0002] In many hydraulic cylinder usage scenarios, especially in industrial equipment and construction machinery, it is often necessary to accurately adjust the speed and displacement of the hydraulic cylinder. Existing solutions mainly rely on servo valves or proportional valves.

[0003] The servo valve can achieve precise flow control and adjust the speed and displacement of the hydraulic cylinder. However, when moving at high speed, the servo valve needs to provide sufficient oil supply, which causes serious heating of the system and large pressure loss. At the same time, the servo valve has high requirements for oil cleanliness (generally it needs to reach NAS6 level or above), and it is easy to be contaminated by welding slag, iron filings, etc. during on-site installation, which affects the service life.

[0004] The cost of proportional valves is lower than that of servo valves, but their control accuracy is poor and cannot meet high-precision requirements, especially under low-speed fine-tuning conditions, where it is difficult to ensure positioning accuracy.

[0005] It is necessary to provide a hydraulic system and a control method thereof in order to solve at least part of the above problems. Summary of the invention

[0006] A series of simplified concepts are introduced in the Summary of the Invention section, which will be further described in detail in the Detailed Description of the Invention section. The Summary of the Invention section of this application does not mean to attempt to define the key features and essential technical features of the claimed technical solution, nor does it mean to attempt to determine the scope of protection of the claimed technical solution.

[0007] In a first aspect, the present application proposes a dual-speed control circuit hydraulic system, comprising: A hydraulic cylinder assembly, wherein the hydraulic cylinder assembly comprises a hydraulic cylinder and a displacement sensor; First hydraulic lock; A fast loop assembly, wherein the fast loop assembly, the first hydraulic lock and the hydraulic cylinder assembly are connected through pipelines to form a fast adjustment subsystem; A slow circuit component, the slow circuit component, the first hydraulic lock and the hydraulic cylinder component are connected to form a slow adjustment subsystem.

[0008] In a feasible implementation, the above-mentioned fast circuit assembly includes a solenoid reversing valve, a first balancing valve and a second hydraulic lock; The first opening of the electromagnetic reversing valve is connected to the pressure oil inlet P, the second opening of the electromagnetic reversing valve is connected to the pressure oil outlet T, the third outlet of the electromagnetic reversing valve is connected to the first opening of the first balancing valve, the second opening of the first balancing valve is connected to the A port of the hydraulic cylinder assembly, the second hydraulic lock is connected to the B port of the hydraulic cylinder assembly and the fourth opening of the electromagnetic reversing valve, the hydraulic cylinder assembly includes the A port and the B port, the A port is used for the input of hydraulic oil, and the B port is used for the return of hydraulic oil, the electromagnetic reversing valve is a four-way valve, and the electromagnetic reversing valve includes four openings, the first opening of the electromagnetic reversing valve is the pressure oil inlet of the electromagnetic reversing valve, the second opening of the electromagnetic reversing valve is the oil return port of the electromagnetic reversing valve, the third opening of the electromagnetic reversing valve is used to control the extension of the hydraulic cylinder assembly, and the fourth opening of the electromagnetic reversing valve is used to control the retraction of the hydraulic cylinder assembly.

[0009] In a feasible implementation manner, the above-mentioned slow circuit assembly includes a third hydraulic lock, a fourth hydraulic lock, a fifth hydraulic lock, a second balancing valve, a first overflow valve, a second overflow valve, a solenoid valve and a bidirectional servo pump group; The first opening of the third hydraulic lock is connected to the B port of the hydraulic cylinder assembly, and the second opening of the third hydraulic lock is connected to the B1 port of the bidirectional servo pump assembly through the first pipeline; The first opening of the second balancing valve is connected to the A port of the hydraulic cylinder assembly, and the second opening of the second balancing valve is connected to the A1 port of the bidirectional servo pump assembly through a second pipeline; The first port of the solenoid valve is connected to the second pipeline, and the second port of the solenoid valve is connected to the pressure oil outlet T through a third pipeline; The fourth hydraulic lock and the fifth hydraulic lock are connected to the first pipeline and the second pipeline, and the fourth hydraulic lock and the fifth hydraulic lock are also connected to an oil replenishment pipeline; The first overflow valve and the second overflow valve are connected to the first pipeline and the second pipeline, and the third pipeline is also connected between the first overflow valve and the second overflow valve. The bidirectional servo pump group includes a servo motor and a variable piston pump. The servo motor drives the variable piston pump to rotate forward or reverse to realize bidirectional flow of hydraulic oil.

[0010] In a second aspect, the present application proposes a control method for the dual-speed control circuit hydraulic system described in the first aspect, comprising: Obtaining current load information, current stroke information, hydraulic cylinder rated load information, environmental information, control mode information and target stroke information of the dual-speed control loop hydraulic system; The working states of the fast loop component and the slow loop component are controlled according to the current load information, the current stroke information, the hydraulic cylinder rated load information, the environmental information, the control mode information and the target stroke information.

[0011] In a feasible implementation manner, the working state of the fast loop assembly includes a target stroke of the fast loop assembly and a loading speed of the fast loop assembly, and the working state of the slow loop assembly includes a target stroke of the slow loop assembly and a loading speed of the fast loop assembly; The controlling of the working states of the fast loop component and the slow loop component according to the current load information, the current stroke information, the rated load information of the hydraulic cylinder, the environmental information, the control mode information and the target stroke information includes: Determine the target stroke of the fast circuit component and the target stroke of the slow circuit component according to the current load information, the current stroke information, the rated load information of the hydraulic cylinder, the environmental information, the control mode information and the target stroke information; When the current working condition is that the fast loop assembly is working, controlling the loading speed of the fast loop assembly according to the current load information, the current stroke information, the control mode information and the target stroke information; When the current working condition is that the above-mentioned slow loop component is working, the loading speed of the above-mentioned slow loop component is controlled according to the above-mentioned current load information, the above-mentioned current stroke information, the above-mentioned control mode information and the target stroke information.

[0012] In a feasible implementation manner, determining the target stroke of the fast loop component and the target stroke of the slow loop component according to the current load information, the current stroke information, the rated load information of the hydraulic cylinder, the environmental information, the control mode information and the target stroke information includes: Constructing a feature vector according to the current load information, the current stroke information, the rated load information of the hydraulic cylinder, the environmental information and the target stroke information; Define the state space based on the above eigenvectors; Establish reinforcement learning actions based on fast adjustment ratio and slow adjustment ratio; Determining a reward function according to the control mode, wherein the reward function includes a positioning accuracy term, a time efficiency term, and an energy consumption term; Establish a reinforcement learning model according to the state space, the reinforcement learning action and the reward function to obtain the initial ratio of fast adjustment and slow adjustment; Determine the adjustment ratio of fast regulation and slow regulation according to the current load information, the current travel information, the target travel information and the fuzzy rule base; The target stroke of the fast loop component and the target stroke of the slow loop component are determined according to the initial ratio of the fast regulation and the slow regulation and the adjustment ratio of the fast regulation and the slow regulation.

[0013] In a feasible implementation manner, controlling the loading speed of the fast loop assembly according to the current load information, the current travel information, the control mode information and the target travel information includes: Determine a dynamic coefficient according to the current load information, the current stroke information, the control mode information and the target stroke information; Construct an adaptive PID control model based on the above dynamic coefficients; The loading speed of the fast loop component is controlled based on the adaptive PID control model.

[0014] In a feasible implementation manner, controlling the loading speed of the slow loop component according to the current load information, the current travel information, the control mode information and the target travel information includes: Determining an objective function according to the current load information, the current stroke information, the control mode information and the target stroke information, wherein the objective function includes a position error term, a speed stability term, an acceleration smoothness term and a load adaptability term; Determining a weight coefficient of the objective function according to the control mode information; The loading speed of the slow loop component is controlled according to the objective function and the quadratic programming method.

[0015] In a feasible implementation, it also includes: When the current working condition is that the fast loop component is working and the environmental information exceeds the preset environmental threshold for a first time period, reducing the loading speed of the fast loop component and generating a first warning information; After reducing the loading speed of the fast loop component for a second period of time, if the environmental information still exceeds the preset environmental threshold, the mode is switched to the slow loop component loading mode and a second warning information is generated.

[0016] In a feasible implementation, it also includes: After running for a third period of time in the slow loop component loading mode, if the environmental information still exceeds the preset environmental threshold, loading is suspended and a third warning information is generated, wherein the first period, the second period and the third period are determined according to the abnormality of the environmental information, the first period is used to determine the temporary loading speed adjustment time of the fast loop component, the second period is used for the switching time when the abnormality has not been restored, and the third period is used for the suspension of loading when the slow loop component still cannot return to normal.

[0017] In summary, this embodiment uses the fast circuit component and the slow circuit component in combination, and the fast circuit component provides a large flow of oil to the hydraulic cylinder in the fast forward and backward stage, and the slow circuit component provides a small flow of oil in the precise forward and backward stage, thereby reducing energy consumption. The design of the slow circuit component ensures that the hydraulic cylinder can still maintain a high control accuracy when working at a low speed, and achieves fine adjustment and position retention. Compared with the heating problem caused by the continuous high-load operation of the servo valve, the fast and slow circuits in this embodiment work in stages, avoiding excessive heat generated by the system due to continuous high-flow oil supply. Since it is no longer completely dependent on the servo valve, the strict requirements for oil cleanliness are reduced. The pipelines and oil tanks of the hydraulic system do not need to be made of expensive stainless steel, which reduces equipment costs and maintenance difficulties. By adopting a hydraulic lock and a dual-circuit combination, the position of the hydraulic cylinder is more reliably maintained, and a stable operating state can be maintained under extreme working conditions. In summary, this embodiment provides an efficient, accurate, stable and low-cost hydraulic cylinder control solution, which is widely applicable to hydraulic systems that require rapid adjustment and precise positioning.

[0018] Other advantages, objectives and features of the present application will be reflected in part through the following description, and in part will be understood by those skilled in the art through study and practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present specification. Also, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings: Figure 1 A structural schematic diagram of a hydraulic system for a dual-speed control circuit provided in an embodiment of the present application; Figure 2 A schematic diagram of a dual-speed control circuit hydraulic system provided in an embodiment of the present application; Figure 3 A schematic flow chart of a control method for a dual-speed control circuit hydraulic system provided in an embodiment of the present application; Figure 1 and Figure 2The corresponding relationship between the reference numerals and the names of the drawings is as follows: 10 hydraulic cylinder assembly, 20 first hydraulic lock, 30 fast circuit assembly, 40 slow circuit assembly; 301 electromagnetic reversing valve, 302 first balancing valve, 303 second hydraulic lock; 401 the third hydraulic lock, 402 the fourth hydraulic lock, 403 the fifth hydraulic lock, 404 the second balancing valve, 405 the first overflow valve, 406 the second overflow valve, 407 the solenoid valve, 408 the two-way servo pump group, 409 the first pipeline, 410 the second pipeline, 411 the third pipeline, 412 the oil replenishing pipeline. DETAILED DESCRIPTION

[0020] The terms "first", "second", "third", "fourth", etc. (if any) in the specification and claims of this application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments described herein can be implemented in an order other than that illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices. 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. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments.

[0021] See also Figure 1 and Figure 2 , Figure 1 A structural schematic diagram of a hydraulic system for a dual-speed control circuit provided in an embodiment of the present application; Figure 2 A schematic diagram of a dual-speed control circuit hydraulic system provided in an embodiment of the present application, the system may specifically include: A hydraulic cylinder assembly 10, wherein the hydraulic cylinder assembly 10 comprises a hydraulic cylinder 101 and a displacement sensor 102; A first hydraulic lock 20; A fast loop assembly 30, wherein the fast loop assembly 30, the first hydraulic lock 20 and the hydraulic cylinder assembly 10 are connected through pipelines to form a fast adjustment subsystem; The slow circuit assembly 40, the slow circuit assembly 40, the first hydraulic lock 20 and the hydraulic cylinder assembly 10 are connected to form a slow adjustment subsystem.

[0022] Exemplarily, the present embodiment provides a hydraulic cylinder assembly, including a hydraulic cylinder assembly 10 , a first hydraulic lock 20 , a fast circuit assembly 30 , and a slow circuit assembly 40 .

[0023] The hydraulic cylinder assembly 10 includes a hydraulic cylinder 101 and a displacement sensor 102. The hydraulic cylinder 101 is used to perform reciprocating linear motion to achieve push-pull functions. The displacement sensor 102 is used to detect the actual position and displacement of the hydraulic cylinder to provide a feedback signal for the control system to adjust.

[0024] The first hydraulic lock 20 is used to lock the position of the hydraulic cylinder when necessary to prevent the load from sliding down or shifting. The hydraulic lock has a self-locking function and can maintain the position of the hydraulic cylinder when the machine is shut down or the power is off.

[0025] The fast circuit assembly 30 is connected to the hydraulic cylinder assembly 10 and the first hydraulic lock 20 through pipelines to form a fast adjustment subsystem. This circuit is mainly used for the rapid advance and retreat of the hydraulic cylinder. When the hydraulic cylinder needs to approach or withdraw quickly, the fast circuit assembly drives the hydraulic cylinder with a larger oil supply to shorten the non-working stroke time and improve the working efficiency.

[0026] The slow circuit assembly 40 is also connected to the hydraulic cylinder assembly 10 and the first hydraulic lock 20 through pipelines to form a slow adjustment subsystem. It is used for precise fine adjustment of the hydraulic cylinder. When the hydraulic cylinder needs to be accurately positioned or load controlled at a lower speed, the slow circuit assembly adjusts through precise oil supply with a small flow rate to achieve smooth and precise movement.

[0027] In summary, this embodiment uses the fast circuit component and the slow circuit component in combination, and the fast circuit component provides a large flow of oil to the hydraulic cylinder in the fast forward and backward stage, and the slow circuit component provides a small flow of oil in the precise forward and backward stage, thereby reducing energy consumption. The design of the slow circuit component ensures that the hydraulic cylinder can still maintain a high control accuracy when working at a low speed, and achieves fine adjustment and position retention. Compared with the heating problem caused by the continuous high-load operation of the servo valve, the fast and slow circuits in this embodiment work in stages, avoiding excessive heat generated by the system due to continuous high-flow oil supply. Since it is no longer completely dependent on the servo valve, the strict requirements for oil cleanliness are reduced. The pipelines and oil tanks of the hydraulic system do not need to be made of expensive stainless steel, which reduces equipment costs and maintenance difficulties. By adopting a hydraulic lock and a dual-circuit combination, the position of the hydraulic cylinder is more reliably maintained, and a stable operating state can be maintained under extreme working conditions. In summary, this embodiment provides an efficient, accurate, stable and low-cost hydraulic cylinder control solution, which is widely applicable to hydraulic systems that require rapid adjustment and precise positioning.

[0028] In a feasible implementation, the above-mentioned fast circuit assembly includes a solenoid reversing valve, a first balancing valve and a second hydraulic lock; The first opening of the electromagnetic reversing valve is connected to the pressure oil inlet P, the second opening of the electromagnetic reversing valve is connected to the pressure oil outlet T, the third outlet of the electromagnetic reversing valve is connected to the first opening of the first balancing valve, the second opening of the first balancing valve is connected to the A port of the hydraulic cylinder assembly, the second hydraulic lock is connected to the B port of the hydraulic cylinder assembly and the fourth opening of the electromagnetic reversing valve, the hydraulic cylinder assembly includes the A port and the B port, the A port is used for the input of hydraulic oil, and the B port is used for the return of hydraulic oil, the electromagnetic reversing valve is a four-way valve, and the electromagnetic reversing valve includes four openings, the first opening of the electromagnetic reversing valve is the pressure oil inlet of the electromagnetic reversing valve, the second opening of the electromagnetic reversing valve is the oil return port of the electromagnetic reversing valve, the third opening of the electromagnetic reversing valve is used to control the extension of the hydraulic cylinder assembly, and the fourth opening of the electromagnetic reversing valve is used to control the retraction of the hydraulic cylinder assembly.

[0029] Exemplarily, the fast loop assembly 30 is connected to the hydraulic cylinder assembly 10 and the first hydraulic lock 20 through a pipeline to form a fast adjustment subsystem. This loop is mainly used for the rapid advance and retreat of the hydraulic cylinder. When the hydraulic cylinder needs to approach or withdraw quickly, the fast loop assembly drives the hydraulic cylinder through a larger oil supply to shorten the non-working stroke time and improve the working efficiency.

[0030] The fast circuit assembly 30 includes a solenoid reversing valve 301 , a first balancing valve 302 and a second hydraulic lock 303 .

[0031] The first opening of the electromagnetic reversing valve 301 is connected to the pressure oil inlet P, the second opening is connected to the pressure oil outlet T, the third opening is connected to the first opening of the first balance valve 302 , and the fourth opening is connected to the second hydraulic lock 303 .

[0032] The second opening of the first balancing valve 302 is connected to the port A of the hydraulic cylinder assembly 10, and is used to control the movement direction and speed of the hydraulic cylinder piston rod, while ensuring the smooth operation of the hydraulic cylinder.

[0033] The second hydraulic lock 303 is connected to the B port of the hydraulic cylinder assembly 10 and is used to lock the position of the hydraulic cylinder when necessary to prevent accidental movement.

[0034] Through the cooperation of the electromagnetic reversing valve 301, the first balancing valve 302 and the second hydraulic lock 303, the fast loop assembly 30 realizes the rapid movement of the hydraulic cylinder, while ensuring the safety and reliability of the operation process.

[0035] In a feasible implementation manner, the above-mentioned slow circuit assembly includes a third hydraulic lock, a fourth hydraulic lock, a fifth hydraulic lock, a second balancing valve, a first overflow valve, a second overflow valve, a solenoid valve and a bidirectional servo pump group; The first opening of the third hydraulic lock is connected to the B port of the hydraulic cylinder assembly, and the second opening of the third hydraulic lock is connected to the B1 port of the bidirectional servo pump assembly through the first pipeline; The first opening of the second balancing valve is connected to the A port of the hydraulic cylinder assembly, and the second opening of the second balancing valve is connected to the A1 port of the bidirectional servo pump assembly through a second pipeline; The first port of the solenoid valve is connected to the second pipeline, and the second port of the solenoid valve is connected to the pressure oil outlet T through a third pipeline; The fourth hydraulic lock and the fifth hydraulic lock are connected to the first pipeline and the second pipeline, and the fourth hydraulic lock and the fifth hydraulic lock are also connected to an oil replenishment pipeline; The first overflow valve and the second overflow valve are connected to the first pipeline and the second pipeline, and the third pipeline is also connected between the first overflow valve and the second overflow valve. The bidirectional servo pump group includes a servo motor and a variable piston pump. The servo motor drives the variable piston pump to rotate forward or reverse to realize bidirectional flow of hydraulic oil.

[0036] Exemplarily, the slow circuit assembly 40 is also connected to the hydraulic cylinder assembly 10 and the first hydraulic lock 20 through pipelines to form a slow adjustment subsystem. It is used for precise fine-tuning of the hydraulic cylinder. When the hydraulic cylinder needs to be precisely positioned or load controlled at a lower speed, the slow circuit assembly is adjusted through precise oil supply with a small flow rate to achieve smooth and precise movement.

[0037] The slow circuit assembly 40 includes a third hydraulic lock 401 , a fourth hydraulic lock 402 , a fifth hydraulic lock 403 , a second balancing valve 404 , a first overflow valve 405 , a second overflow valve 406 , a solenoid valve 407 and a bidirectional servo pump group 408 .

[0038] The first opening of the third hydraulic lock 401 is connected to the B port of the hydraulic cylinder assembly 10 , and the second opening is connected to the B1 port of the bidirectional servo pump assembly 408 through the first pipeline 409 .

[0039] The first opening of the second balancing valve 404 is connected to the A port of the hydraulic cylinder assembly 10 , and the second opening is connected to the A1 port of the bidirectional servo pump assembly 408 through the second pipeline 410 .

[0040] The first port of the solenoid valve 407 is connected to the second pipeline 410 , and the second port is connected to the pressure oil outlet T through the third pipeline 411 , so as to release the pressure oil when necessary.

[0041] The fourth hydraulic lock 402 and the fifth hydraulic lock 403 are connected to the first pipeline 409 and the second pipeline 410 to achieve hydraulic locking when the hydraulic cylinder stops and prevent the load from sliding down.

[0042] The oil replenishment pipeline 412 is connected between the fourth hydraulic lock 402 and the fifth hydraulic lock 403 to ensure that the system maintains a sufficient amount of oil when operating in a closed loop to prevent oil shortage.

[0043] The first overflow valve 405 and the second overflow valve 406 are connected to the first pipeline 409 and the second pipeline 410 to control the system pressure and avoid damage to the equipment due to excessive pressure. At the same time, they are also connected to the pressure oil outlet T through the third pipeline 411 to ensure smooth reflux of overflow oil.

[0044] Through the synergistic effect of these elements, the slow circuit assembly 40 can achieve precise fine adjustment of the hydraulic cylinder, which is particularly suitable for scenes requiring high-precision positioning. Through the combined effect of the fast circuit assembly and the slow circuit assembly, the hydraulic cylinder assembly can achieve a combination of fast approach and precise approach.

[0045] Specifically, Figure 2 As shown, the present application adopts a control method of combining a fast circuit and a slow fine-tuning circuit. The fast circuit is on the left side of the hydraulic principle diagram, and the slow fine-tuning circuit is on the right side. The fast circuit is directly controlled by an electromagnetic reversing valve 301, and the slow fine-tuning circuit is controlled by a micro bidirectional servo pump group 408. A built-in displacement sensor 102 is installed on the hydraulic cylinder 101 to detect the position and running speed of the hydraulic cylinder piston. The fast circuit subsystem and the slow circuit subsystem are not used at the same time. When working quickly, the third hydraulic lock 401 and the second balancing valve 404 isolate the slow circuit oil circuit. When working slowly, the second hydraulic lock 303 and the first balancing valve 302 isolate the fast circuit oil circuit, so as to ensure that the fast circuit and the slow circuit do not interfere with each other when working.

[0046] Under fast working conditions: when the hydraulic cylinder 101 is extended quickly, the pressure oil enters the first opening of the electromagnetic reversing valve 301 from the P port, the electromagnet YV2 is energized, the valve core of the electromagnetic reversing valve 301 moves to the right, the first opening is connected to the third opening, the fourth opening is connected to the second opening, the oil enters the first balance valve 302 through the third opening of the electromagnetic reversing valve 301, and then enters the first hydraulic lock 20 installed on the hydraulic cylinder, and then enters the piston chamber of the hydraulic cylinder. The oil in the piston rod chamber returns to the oil return port T through the second hydraulic lock 201 and the fourth opening of the electromagnetic reversing valve 301. When the hydraulic cylinder retracts quickly, the pressure oil enters the first opening of the electromagnetic reversing valve 301 from the P port, the electromagnet YV1 is energized, the valve core of the electromagnetic reversing valve moves to the left, the first opening is connected to the fourth opening, the third opening is connected to the second opening, and the oil enters the second hydraulic lock 201 through the oil port of the electromagnetic reversing valve 4 and then enters the piston rod chamber of the hydraulic cylinder. The oil in the piston chamber returns to the return oil port T through the first hydraulic lock 20, the first balancing valve 302, and the third opening of the electromagnetic reversing valve.

[0047] Under slow fine-tuning conditions: when the hydraulic cylinder is slowly extended, the servo motor of the two-way servo pump group 408 rotates forward, and the pressure oil enters the second balance valve 404 from the A1 port, passes through the first hydraulic lock 20 on the hydraulic cylinder and enters the piston chamber of the hydraulic cylinder 101, and the hydraulic oil in the piston rod chamber passes through the third hydraulic lock 401 and flows back to the B1 port of the two-way servo pump group 408. Due to the volume difference between the two chambers of the hydraulic cylinder, the oil flowing back from the piston rod chamber is not enough to compensate for the needs of the piston chamber, and the oil in the oil replenishment circuit P1 passes through the fourth hydraulic lock 402 and enters the B1 port of the two-way servo pump group. When the hydraulic cylinder retracts slowly, the servo motor of the two-way servo pump group 408 reverses, and the pressure oil enters the third hydraulic lock 401 from the B1 port and enters the piston rod chamber of the hydraulic cylinder 101. The hydraulic oil in the piston rod chamber passes through the second balance valve 404 and flows back to the A1 port of the two-way servo pump group 408. Due to the volume difference between the two chambers of the hydraulic cylinder, part of the oil in the piston chamber enters the A1 port of the two-way servo pump, and part of the oil passes through the solenoid valve 407 and is discharged back to the oil return port T.

[0048] In a second aspect of the present application, a control method is also provided for the dual-speed control circuit hydraulic system of the first aspect, such as Figure 3 As shown, including: S110, obtaining current load information, current stroke information, hydraulic cylinder rated load information, environmental information, control mode information and target stroke information of the dual-speed control loop hydraulic system; Exemplarily, the system acquires the following information: current load information, current stroke information, hydraulic cylinder rated load information, environmental information, control mode information and target stroke information for subsequent control decisions.

[0049] The current load information includes but is not limited to the actual load of the hydraulic cylinder at the current moment, which is used to determine whether it is necessary to adjust the loading speed or switch to the slow circuit. The current stroke information, that is, the current position of the hydraulic cylinder, is used to determine the deviation between the current operating state and the target position. The rated load information of the hydraulic cylinder provides the maximum load capacity of the hydraulic cylinder. Environmental information includes but is not limited to oil temperature, ambient temperature and system pressure, etc., which are used to determine whether there are abnormal working conditions. The control mode information is the manually selected control mode, which usually includes accuracy priority, efficiency priority and energy saving priority. The system makes different control decisions based on the mode. The target stroke information is the final position that the hydraulic cylinder needs to reach, to ensure that the control target is clear.

[0050] S120. Control the working states of the fast loop component and the slow loop component according to the current load information, the current stroke information, the hydraulic cylinder rated load information, the environmental information, the control mode information and the target stroke information.

[0051] Exemplarily, based on the collected information, the system controls the working status of the fast loop component and the slow loop component through an intelligent algorithm.

[0052] The system calculates the target travel of the fast loop based on the current load, travel information and target travel. When the fast loop is working, the system prioritizes maintaining a higher loading speed based on the control mode (such as efficiency priority). If an increase in load or abnormal ambient temperature is detected, the system will reduce the loading speed to ensure equipment safety.

[0053] When approaching the target position, the system switches to the slow loop and sets the target stroke of the slow loop according to the accuracy requirements. In the slow loop, the system reduces the loading speed to ensure that the hydraulic cylinder is accurately positioned near the target position. If the position error is detected to exceed the threshold, the system fine-tunes by further adjusting the speed of the slow loop.

[0054] In summary, the high-speed operation of the fast-loop components shortens the long-stroke execution time of the hydraulic cylinder. The system dynamically adjusts the switching points and loading speeds of the fast and slow loops according to different control modes and working conditions, and uses intelligent algorithms to achieve automatic optimization, reduce manual intervention, and improve the level of intelligent control.

[0055] In a feasible implementation manner, the working state of the fast loop assembly includes a target stroke of the fast loop assembly and a loading speed of the fast loop assembly, and the working state of the slow loop assembly includes a target stroke of the slow loop assembly and a loading speed of the fast loop assembly; The controlling of the working states of the fast loop component and the slow loop component according to the current load information, the current stroke information, the rated load information of the hydraulic cylinder, the environmental information, the control mode information and the target stroke information includes: Determine the target stroke of the fast circuit component and the target stroke of the slow circuit component according to the current load information, the current stroke information, the rated load information of the hydraulic cylinder, the environmental information, the control mode information and the target stroke information; When the current working condition is that the fast loop assembly is working, controlling the loading speed of the fast loop assembly according to the current load information, the current stroke information, the control mode information and the target stroke information; When the current working condition is that the above-mentioned slow loop component is working, the loading speed of the above-mentioned slow loop component is controlled according to the above-mentioned current load information, the above-mentioned current stroke information, the above-mentioned control mode information and the target stroke information.

[0056] Exemplarily, the working state of the fast loop assembly includes "target travel of the fast loop assembly" and "loading speed of the fast loop assembly". The target travel refers to the travel distance that needs to be covered in the fast stage, which is used to quickly approach the target position over a large range or long distance. The loading speed of the fast loop assembly refers to the operating speed adopted by the fast loop assembly in the target travel.

[0057] The working status of the slow loop component includes the "target stroke of the slow loop component" and the "loading speed of the slow loop component". The target stroke refers to the precise working or fine-tuning stroke that needs to be covered in the slow stage, which is used for precise positioning or small-range adjustment. The loading speed of the slow loop component refers to the operating speed of the slow loop component when performing fine control.

[0058] The system makes a comprehensive judgment based on the above current load information, the above current stroke information, the above rated load information of the hydraulic cylinder, the above environmental information, the above control mode information and the above target stroke information, and divides which section of the stroke is executed by the fast circuit component and which section of the stroke is executed by the slow circuit component. For example: if the load is small and the remaining stroke is long, more is allocated to the fast circuit; if the load is large or high-precision adjustment is required, the slow circuit stroke is appropriately extended. According to the difference between the current position and the target stroke, it is judged whether to switch to slow speed. Ensure that the stroke is distributed within the rated load range to avoid overload. If the temperature, oil condition, etc. are not conducive to high-speed operation, the fast stroke is appropriately shortened and the slow stroke is extended.

[0059] The control mode information can be selected as accuracy priority, efficiency priority or energy saving priority mode. Different allocation strategies will be used in different modes (for example, a longer fast stroke is preferred when efficiency is prioritized). Finally, according to the overall mission requirements, the total stroke is divided into two parts: "fast stroke + slow stroke". By combining the above information, the target stroke of the fast loop component and the target stroke of the slow loop component are determined.

[0060] When the system is in a condition where the fast loop component is working, the loading speed needs to be adjusted according to the following factors. For example: if the load increases suddenly, the loading speed can be reduced to avoid impact; if the load is small, a higher operating speed can be maintained. When approaching the starting point or target position of the slow loop, the system can slow down in advance to make a smooth transition. In efficiency priority mode, higher loading speeds are encouraged to shorten the overall execution time; in accuracy priority mode, deceleration is carried out in advance when approaching the switching point to avoid position overshoot; in energy saving priority mode, the speed is actively reduced under high load or high temperature conditions to reduce energy consumption. Through real-time monitoring and feedback, the fast loop component completes most of the long-distance movement with high efficiency and switches to the slow loop in time before the end of the stroke.

[0061] When the system is in the working condition of the slow loop component, the main focus is on high precision and system stability, so the loading speed needs to be adjusted according to the following requirements, such as: if the load is close to the rated level, reduce the speed to ensure positioning accuracy and system safety. If it is close to the end of the target stroke, further reduce the speed to achieve micron-level or higher accuracy. In the accuracy priority mode, the loading speed is maintained at a low level to minimize the position error; in the efficiency priority mode, the speed is slightly increased while ensuring accuracy to improve the beat; in the energy saving priority mode, the speed is actively reduced under continuous high load or high ambient temperature. The slow loop is usually the last part of the stroke, and the system performs fine-tuning according to the pre-divided slow target stroke segments. With the help of the slow loop component, the hydraulic cylinder can achieve precise positioning or flexible adjustment in a small range in the final stroke stage.

[0062] In a feasible implementation manner, determining the target stroke of the fast loop component and the target stroke of the slow loop component according to the current load information, the current stroke information, the rated load information of the hydraulic cylinder, the environmental information, the control mode information and the target stroke information includes: Constructing a feature vector according to the current load information, the current stroke information, the rated load information of the hydraulic cylinder, the environmental information and the target stroke information; Define the state space based on the above eigenvectors; Establish reinforcement learning actions based on fast adjustment ratio and slow adjustment ratio; Determining a reward function according to the control mode, wherein the reward function includes a positioning accuracy term, a time efficiency term, and an energy consumption term; Establish a reinforcement learning model according to the state space, the reinforcement learning action and the reward function to obtain the initial ratio of fast adjustment and slow adjustment; Determine the adjustment ratio of fast regulation and slow regulation according to the current load information, the current travel information, the target travel information and the fuzzy rule base; The target stroke of the fast loop component and the target stroke of the slow loop component are determined according to the initial ratio of the fast regulation and the slow regulation and the adjustment ratio of the fast regulation and the slow regulation.

[0063] Exemplarily, this embodiment provides a method for determining the target stroke of a fast circuit component and a slow circuit component of a hydraulic system based on reinforcement learning and fuzzy control. By integrating current load information, current stroke information, hydraulic cylinder rated load information, environmental information, control mode information and target stroke information, the target stroke of the fast circuit and the slow circuit is intelligently determined to achieve precise control of the hydraulic system.

[0064] Construct a feature vector based on the current load information, current stroke information, hydraulic cylinder rated load information, environmental information and target stroke information , using the feature vector Indicates the current status of the hydraulic system:

[0065] is the current load information, is the current travel location, is the target trip location information, For the rated load information of the hydraulic cylinder, Includes ambient temperature information.

[0066] According to the feature vector , divide the state space of the hydraulic system :

[0067] The state space is used to characterize the specific state of the hydraulic system under different operating conditions.

[0068] Establishing the action space of reinforcement learning based on the adjustment ratio of fast loop and slow loop :

[0069] To quickly adjust the ratio, To adjust the ratio slowly, The sum of the ratios of fast and slow adjustments is 1, ensuring reasonable task distribution.

[0070] Define different reward functions according to the control mode (accuracy priority, efficiency priority or energy saving priority) The reward function consists of the following three parts: 1. Positioning accuracy item

[0071] is the accuracy penalty coefficient.

[0072] 2. Time efficiency item

[0073] is the time penalty coefficient, The time to reach the target journey.

[0074] 3. Energy consumption items

[0075] is the energy consumption penalty coefficient, is the current load information, It is the current speed information.

[0076] Depending on the control mode, different weighted combinations are used to form the final reward function:

[0077] For example: Accuracy priority mode:

[0078] Efficiency priority mode:

[0079] Energy saving priority mode:

[0080] Based on state space , action space And the reward function , use reinforcement learning algorithms (such as deep reinforcement learning DDPG or Q-Learning) to build a reinforcement learning model.

[0081] The goal of reinforcement learning is to maximize the cumulative reward function :

[0082] is the policy function, is the discount factor, is the total time step By training the reinforcement learning model, the initial ratio of fast adjustment and slow adjustment is obtained :

[0083] in, is the cumulative reward function, measuring the The expected total reward obtained by the agent during the entire time period. Indicated in strategy The mathematical expectation of the reward. is the strategy function, which represents the agent in the state space The rules for selecting actions. is the discount factor, ranging from , used to balance the importance of current rewards and future rewards. The value focuses more on short-term rewards, while higher It is worth focusing more on long-term returns. For the The instant reward obtained at any moment represents the benefit obtained after performing a specific action in a certain state. is the total time step, which indicates the maximum number of time steps in the reinforcement learning process.

[0084] In order to further optimize the initial ratio, the fuzzy rule base is used for adjustment based on the actual working condition changes. The fuzzy input is the current load change rate and the current stroke error. ,in, is the current load, is the load at the previous moment, is the rated load. Current stroke error , fuzzy output is a fast adjustment adjustment and slow speed adjustment .

[0085] Fuzzy rules can include but are not limited to: 1. If Increase and If it decreases, the fast adjustment ratio will be reduced and the slow adjustment ratio will be increased.

[0086] 2. If Reduce and If it increases, the fast adjustment ratio will increase and the slow adjustment ratio will decrease.

[0087] According to the simulation rule base, calculate the final adjustment ratio:

[0088] Finally, the target stroke of the fast loop component and the slow loop component is determined according to the ratio of fast and slow speed adjustment:

[0089] in, is the target travel of the fast loop assembly, is the target stroke of the slow-speed loop component.

[0090] This embodiment provides a hydraulic system target stroke control method based on reinforcement learning and fuzzy control. The hydraulic system can adaptively adjust the loading speed under different working conditions and control modes to achieve comprehensive optimization of accuracy, efficiency and energy saving.

[0091] In a feasible implementation manner, controlling the loading speed of the fast loop assembly according to the current load information, the current travel information, the control mode information and the target travel information includes: Determine a dynamic coefficient according to the current load information, the current stroke information, the control mode information and the target stroke information; Construct an adaptive PID control model based on the above dynamic coefficients; The loading speed of the fast loop component is controlled based on the adaptive PID control model.

[0092] Exemplarily, in the loading speed control of the fast loop assembly, the dynamic coefficient is used to adjust the proportional, integral and derivative parameters of the PID controller to adapt to different operating conditions and control modes.

[0093] The dynamic coefficient is determined based on the current load information, current travel information, control mode information and target travel information. Current load information Reflects the real-time load of the hydraulic cylinder and affects the control strength of the loading speed. Current stroke information Indicates the current position of the hydraulic cylinder, used to determine the distance to the target stroke. Control mode information Including accuracy priority, efficiency priority or energy saving priority, which affects the weight distribution of dynamic coefficients. Target travel information It is the target position of the hydraulic cylinder and provides an adjustment basis for the acceleration.

[0094] The dynamic coefficient calculation formula includes: 1. Proportional coefficient : Adjust the proportionality factor based on the comprehensive judgment of load and position error:

[0095] in, is the initial proportionality factor, is the position error adjustment coefficient, is the load regulation factor, is the rated load of the hydraulic cylinder.

[0096] 2. Integral coefficient : When the position error is small, speed up the response of the integral term to reduce the steady-state error:

[0097] in, is the initial integration coefficient, is the position error adjustment coefficient, is the load regulation factor.

[0098] 3. Differential coefficient : When the load changes dramatically, increase the weight of the derivative term to suppress oscillation:

[0099] in, is the initial differential coefficient, is the load change adjustment factor To ensure system stability and security, the loading speed must also meet the following restrictions: 1. Maximum speed limit

[0100] 2. Minimum speed limit

[0101] 3. Acceleration stability

[0102] is the maximum acceleration allowed by the system.

[0103] Depending on the control mode, the parameters of the adaptive PID control model will be adjusted. See Table 1 for details: Table 1

[0104] In the precision priority mode, the position error is minimized first, and the role of proportional and integral terms is emphasized. In the efficiency priority mode, the response speed is improved, and the differential term is appropriately increased to reduce overshoot. In the energy saving priority mode, unnecessary acceleration changes are reduced, and the adjustment is mainly based on the differential term. Through this method, the hydraulic system can control the fast loop components under different working conditions to achieve precise loading speed control, meeting the different needs of accuracy, efficiency and energy saving.

[0105] In a feasible implementation manner, controlling the loading speed of the slow loop component according to the current load information, the current travel information, the control mode information and the target travel information includes: Determining an objective function according to the current load information, the current stroke information, the control mode information and the target stroke information, wherein the objective function includes a position error term, a speed stability term, an acceleration smoothness term and a load adaptability term; Determining a weight coefficient of the objective function according to the control mode information; The loading speed of the slow loop component is controlled according to the objective function and the quadratic programming method.

[0106] Exemplarily, the objective function It contains four types of sub-target items: position error item, velocity smoothness item, acceleration smoothness item and load adaptability item. Its mathematical form is as follows:

[0107] in, is the weight coefficient of the objective function, which is set dynamically according to the control mode; is the position error term; is the velocity stability term; is the acceleration smoothness term; is the load adaptability item.

[0108] Position error term for:

[0109] in, is the target location information, It is the current location information.

[0110] The position error term is used to penalize the error between the current stroke and the target stroke. The fourth power form intensifies the penalty for large errors and smoothes the response to small errors, which is helpful for precision control.

[0111] Speed ​​stability for:

[0112] in, is the current speed information, It is the speed information of the next moment.

[0113] The speed smoothness term controls the smoothness of speed changes and suppresses mutations. The exponential form is used to quickly amplify the impact of speed mutations, which helps to achieve smooth acceleration during efficiency control.

[0114] Acceleration smoothness term for:

[0115] in, is the current acceleration information, is the acceleration information at the next moment, is the linear adjustment coefficient, is the secondary adjustment coefficient.

[0116] The acceleration smoothness term is used to limit the fluctuation of loading acceleration, and the linear term Ensure sensitive response to small changes, quadratic term Suppress drastic jumps and enhance system stability.

[0117] Load adaptability item for:

[0118] in, is the current load information, is the load information at the next moment, For rated load information, is the load change regulation coefficient, It is the current speed information.

[0119] The load adaptability item is used to suppress high-speed operation under high load or load mutation conditions, dynamically adapt to load changes, reduce energy consumption, and improve energy saving and equipment protection capabilities.

[0120] To optimize loading speed , taking the constructed objective function as the cost function, construct the following quadratic programming problem:

[0121] in, is the loading speed at the next moment, is the objective function.

[0122] The constraints are: Speed ​​Constraints:

[0123] in, is the minimum loading speed allowed by the system, The maximum loading speed allowed by the system.

[0124] Acceleration constraints:

[0125] is the maximum allowable loading acceleration, To control the cycle.

[0126] Travel limit (to prevent overrun):

[0127] The standard quadratic programming (QP) solver can be used to obtain the optimal loading speed under the constraints. . Solved The loading speed command for the next control cycle is applied to the slow loop component. At the same time, the system can collect feedback (such as position, speed, load, etc.) in real time and reconstruct the objective function to form a closed-loop control strategy.

[0128] In a feasible implementation, it also includes: When the current working condition is that the fast loop component is working and the environmental information exceeds the preset environmental threshold for a first time period, reducing the loading speed of the fast loop component and generating a first warning information; After reducing the loading speed of the fast loop component for a second period of time, if the environmental information still exceeds the preset environmental threshold, the mode is switched to the slow loop component loading mode and a second warning information is generated.

[0129] In a feasible implementation, it also includes: After running for a third period of time in the slow loop component loading mode, if the environmental information still exceeds the preset environmental threshold, loading is suspended and a third warning information is generated, wherein the first period, the second period and the third period are determined according to the abnormality of the environmental information, the first period is used to determine the temporary loading speed adjustment time of the fast loop component, the second period is used for the switching time when the abnormality has not been restored, and the third period is used for the suspension of loading when the slow loop component still cannot return to normal.

[0130] Exemplarily, in the first stage: when the current working condition is the fast loop component working mode and the environmental information is detected to exceed the preset environmental threshold and lasts for more than a first time period, the system performs an operation to reduce the loading speed of the fast loop component. Specifically: Adjust the loading speed factor according to the preset , reducing the loading speed of the fast loop components.

[0131]

[0132] in, is the original loading speed of the fast loop assembly; Adjusted loading speed for fast loop components; is the speed reduction factor.

[0133] When the loading speed is reduced, the system generates a first warning message to inform the operator that the current environmental information is abnormal and prompts the operator to check the equipment operation status. The first warning message may be: the environmental information exceeds the preset threshold, the loading speed of the fast loop component has been reduced, please check the equipment status.

[0134] Phase 2: After the fast loop component reduces the loading speed, if the environmental information still exceeds the preset threshold and has lasted for more than the second time period, the system performs the following operations: 1. Switch to the slow loop component loading mode. The system stops the operation of the fast loop component and switches to the slow loop component loading mode to reduce the overall load and operating temperature of the hydraulic system. 2. Generate a second warning message. The system generates a second warning message to remind the operator that it has switched to the slow loading mode. The second warning message can be: The environmental information continues to be abnormal, and the system has switched to the slow loop component loading mode to protect the equipment.

[0135] Phase 3: After running in the slow loop component loading mode, if the environmental information still exceeds the preset threshold and has lasted for more than the third period of time, the system performs the following operations: 1. The system suspends the loading action of the hydraulic cylinder to prevent further damage to the equipment due to environmental deterioration.

[0136]

[0137] 2. While loading is suspended, the system generates a third warning message, prompting the operator that the environment is seriously abnormal and that inspection and maintenance measures must be taken immediately. The third warning message can be: The environment information continues to be abnormal, the system has suspended loading, please check the equipment immediately and perform maintenance.

[0138] This implementation method uses a phased adjustment strategy through real-time monitoring of environmental information. While ensuring the stable operation of the hydraulic system, it timely reduces the loading speed or switches to slow loading mode when the environment is abnormal to avoid equipment overload or overheating. The operator is notified of abnormal equipment conditions in a timely manner through phased early warning information, facilitating rapid response. After the environmental information returns to normal, the loading speed can be quickly restored to reduce production losses caused by downtime. By reducing the loading speed and switching to slow mode, energy consumption is effectively reduced and the service life of the equipment is extended.

[0139] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A dual-speed control circuit hydraulic system, characterized in that: include: A hydraulic cylinder assembly, the hydraulic cylinder assembly comprising a hydraulic cylinder and a displacement sensor; First hydraulic lock; A fast loop assembly, wherein the fast loop assembly, the first hydraulic lock and the hydraulic cylinder assembly are connected through pipelines to form a fast adjustment subsystem; A slow speed circuit component, wherein the slow speed circuit component, the first hydraulic lock and the hydraulic cylinder component are connected to form a slow speed adjustment subsystem.

2. The dual-speed control circuit hydraulic system according to claim 1, characterized in that: The fast circuit assembly includes a solenoid reversing valve, a first balancing valve and a second hydraulic lock; The first opening of the electromagnetic reversing valve is connected to the pressure oil inlet P, the second opening of the electromagnetic reversing valve is connected to the pressure oil outlet T, the third outlet of the electromagnetic reversing valve is connected to the first opening of the first balancing valve, the second opening of the first balancing valve is connected to the A port of the hydraulic cylinder assembly, the second hydraulic lock is connected to the B port of the hydraulic cylinder assembly and the fourth opening of the electromagnetic reversing valve, the hydraulic cylinder assembly includes the A port and the B port, the A port is used for the input of hydraulic oil, and the B port is used for the return of hydraulic oil, the electromagnetic reversing valve is a four-way valve, and the electromagnetic reversing valve includes four openings, the first opening of the electromagnetic reversing valve is the pressure oil inlet of the electromagnetic reversing valve, the second opening of the electromagnetic reversing valve is the oil return port of the electromagnetic reversing valve, the third opening of the electromagnetic reversing valve is used to control the extension of the hydraulic cylinder assembly, and the fourth opening of the electromagnetic reversing valve is used to control the retraction of the hydraulic cylinder assembly.

3. The dual-speed control circuit hydraulic system according to claim 2, characterized in that: The slow circuit assembly includes a third hydraulic lock, a fourth hydraulic lock, a fifth hydraulic lock, a second balancing valve, a first overflow valve, a second overflow valve, a solenoid valve and a bidirectional servo pump group; The first opening of the third hydraulic lock is connected to the B port of the hydraulic cylinder assembly, and the second opening of the third hydraulic lock is connected to the B1 port of the bidirectional servo pump assembly through the first pipeline; The first opening of the second balancing valve is connected to the A port of the hydraulic cylinder assembly, and the second opening of the second balancing valve is connected to the A1 port of the bidirectional servo pump assembly through a second pipeline; The first port of the solenoid valve is connected to the second pipeline, and the second port of the solenoid valve is connected to the pressure oil outlet T through a third pipeline; The fourth hydraulic lock and the fifth hydraulic lock are connected to the first pipeline and the second pipeline, and the fourth hydraulic lock and the fifth hydraulic lock are also connected to an oil replenishment pipeline; The first overflow valve and the second overflow valve are connected to the first pipeline and the second pipeline, and the third pipeline is also connected between the first overflow valve and the second overflow valve. The bidirectional servo pump group includes a servo motor and a variable piston pump. The servo motor drives the variable piston pump to rotate forward or reverse to realize bidirectional flow of hydraulic oil.

4. A control method for a dual-speed control circuit hydraulic system according to any one of claims 1 to 3, characterized in that: include: Acquiring current load information, current stroke information, hydraulic cylinder rated load information, environmental information, control mode information and target stroke information of the dual-speed control loop hydraulic system; The working states of the fast loop component and the slow loop component are controlled according to the current load information, the current stroke information, the hydraulic cylinder rated load information, the environmental information, the control mode information and the target stroke information.

5. The control method according to claim 4, characterized in that: The working state of the fast loop assembly includes a target stroke of the fast loop assembly and a loading speed of the fast loop assembly, and the working state of the slow loop assembly includes a target stroke of the slow loop assembly and a loading speed of the fast loop assembly; The controlling the working states of the fast loop component and the slow loop component according to the current load information, the current stroke information, the rated load information of the hydraulic cylinder, the environmental information, the control mode information and the target stroke information includes: Determine the target stroke of the fast circuit component and the target stroke of the slow circuit component according to the current load information, the current stroke information, the hydraulic cylinder rated load information, the environmental information, the control mode information and the target stroke information; When the current working condition is that the fast loop assembly is working, controlling the loading speed of the fast loop assembly according to the current load information, the current stroke information, the control mode information and the target stroke information; When the current working condition is that the slow loop component is working, the loading speed of the slow loop component is controlled according to the current load information, the current stroke information, the control mode information and the target stroke information.

6. The control method according to claim 5, characterized in that: The determining the target stroke of the fast circuit component and the target stroke of the slow circuit component according to the current load information, the current stroke information, the rated load information of the hydraulic cylinder, the environmental information, the control mode information and the target stroke information comprises: constructing a feature vector according to the current load information, the current stroke information, the hydraulic cylinder rated load information, the environmental information and the target stroke information; defining a state space according to the feature vector; Establish reinforcement learning actions based on fast adjustment ratio and slow adjustment ratio; Determining a reward function according to the control mode, wherein the reward function includes a positioning accuracy term, a time efficiency term, and an energy consumption term; Establishing a reinforcement learning model according to the state space, the reinforcement learning action and the reward function to obtain initial proportions of fast adjustment and slow adjustment; Determine the adjustment ratio of fast regulation and slow regulation according to the current load information, the current travel information, the target travel information and a fuzzy rule base; The target stroke of the fast loop component and the target stroke of the slow loop component are determined according to the initial ratio of the fast adjustment and the slow adjustment and the adjustment ratio of the fast adjustment and the slow adjustment.

7. The control method according to claim 5, characterized in that: The controlling the loading speed of the fast loop assembly according to the current load information, the current stroke information, the control mode information and the target stroke information comprises: determining a dynamic coefficient according to the current load information, the current stroke information, the control mode information and the target stroke information; Constructing an adaptive PID control model according to the dynamic coefficients; The loading speed of the fast loop component is controlled based on the adaptive PID control model.

8. The control method according to claim 5, characterized in that: The controlling the loading speed of the slow loop component according to the current load information, the current stroke information, the control mode information and the target stroke information comprises: Determining an objective function according to the current load information, the current stroke information, the control mode information and the target stroke information, wherein the objective function includes a position error term, a speed smoothness term, an acceleration smoothness term and a load adaptability term; Determining a weight coefficient of the objective function according to the control mode information; The loading speed of the slow loop component is controlled according to the objective function and the quadratic programming method.

9. The control method according to claim 5, characterized in that: Also includes: When the current working condition is that the fast loop component is working and the environmental information exceeds the preset environmental threshold for a first time period, reducing the loading speed of the fast loop component and generating a first warning information; After reducing the loading speed of the fast loop component for a second period of time, if the environmental information still exceeds the preset environmental threshold, switch to the slow loop component loading mode and generate a second warning information, wherein the first period of time and the second period of time are determined according to the abnormality degree of the environmental information, the first period of time is used to determine the temporary loading speed adjustment time of the fast loop component, and the second period of time is used for the switching time when the abnormality has not been restored.

10. The control method according to claim 9, characterized in that: Also includes: After the slow loop component runs for a third period of time in the loading mode, if the environmental information still exceeds the preset environmental threshold, loading is suspended and a third warning information is generated, wherein the third period of time is determined based on the degree of abnormality of the environmental information, and the third period of time is used to suspend loading when the slow loop component still cannot return to normal.

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