Energy-saving control method and device for independent control system of load port, and readable storage medium

Abstract

This invention discloses an energy-saving control method and device for an independent load port control system, as well as a readable storage medium. The method includes the following steps: acquiring a command signal and the load condition of the first actuator; when the load condition is a negative load and the command signal indicates that the second working link is to operate, acquiring a first pressure difference, which is the pressure difference between the oil outlet chamber of the first actuator and the oil inlet of the first working link; when the first pressure difference is greater than a first pressure difference threshold, controlling the first main valve and the fourth main valve to open, so that the first working link inputs the gravity potential energy recovery flow into the oil inlet circuit and provides it to the second working link for use. This establishes an energy recovery loop, maximizing the recovery and utilization of gravity potential energy.

Description

Technical Field

[0001] This invention relates to hydraulic control systems, and more specifically, to an energy-saving control method for a load port independent control system. Furthermore, it also relates to an energy-saving control device and a readable storage medium for a load port independent control system. Background Technology

[0002] In traditional hydraulic control systems for construction machinery, the inlet and outlet of each actuator are typically controlled by a single-core proportional valve in a mechanical-hydraulic manner. As a flow distribution unit for multiple actuators, this control valve suffers from inlet pressure loss, outlet pressure loss, and potential energy loss, resulting in low energy efficiency. For example, during boom lowering and retraction, the gravitational potential energy generated is lost as heat at the oil circuit throttling orifice, not only wasting energy but also increasing the oil temperature and reducing the lifespan of hydraulic components.

[0003] Currently, there are two main energy-saving control methods. One is the traditional single-valve-core system, which incorporates a flow regeneration valve within the multi-way valve. This valve opens during boom descent, allowing gravitational potential energy to be recovered. While this method achieves some degree of boom return oil reuse, the flow regeneration valve has a certain opening pressure, meaning energy can only be recovered under high pressure, resulting in a low energy recovery rate. Furthermore, the recovered energy can only supply the current working cycle; during combined operations, the gravitational potential energy cannot be used by other working cycles. Moreover, the valve core needs to be designed according to specific requirements, leading to complex valve core and flow channel designs. Changes in requirements necessitate modifications to the valve core design, resulting in poor versatility.

[0004] Another approach involves adding an accumulator to the hydraulic system. When the boom lowers, gravitational potential energy is converted into hydraulic energy and stored in the accumulator. When the boom raises, the accumulator releases the hydraulic energy, converting it into mechanical energy to propel the boom upwards, thus achieving energy savings. However, because the pressure and volume of the accumulator significantly impact the system's energy efficiency, the energy recovery rate is relatively low.

[0005] As can be seen from the above-mentioned existing technologies, how to achieve a high energy recovery and utilization rate to achieve a better energy-saving effect remains a technical problem that urgently needs to be solved in the hydraulic field. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide an energy-saving control method for an independent load port control system, which can improve the energy recovery effect and reduce system energy.

[0007] To address the aforementioned technical problems, this invention provides an energy-saving control method for a load port independent control system. The load port independent control system includes multiple working links, a controller, a first actuator, an oil inlet circuit connected to the oil inlet of each working link, and a return oil circuit connected to the return oil inlet of each working link. At least one of the working links is an energy recovery working link. The energy recovery working link includes a first main valve, a second main valve, a third main valve, a fourth main valve, and a branch return oil passage. The first main valve is installed between the first working port of the first actuator and the branch return oil passage. The second main valve is installed between the first working port of the first actuator and the oil inlet circuit. The third main valve is installed between the second working port of the first actuator and the branch return oil passage. The fourth main valve is installed between the second working port of the first actuator and the oil inlet circuit. Pressure detection devices are installed at the oil inlet and return ports of the energy recovery working link, as well as at the first and second working ports of the first actuator. The energy-saving control method includes the following steps:

[0008] Acquire the command signal and the load condition of the first actuator;

[0009] When the load condition is a negative load and the command signal indicates that the second working link is to work, the first pressure difference is obtained. The first pressure difference is the pressure difference between the oil outlet chamber of the first actuator and the oil inlet of the first working link.

[0010] When the first differential pressure is greater than the first differential pressure threshold, the first main valve and the fourth main valve are controlled to open, so that the first working link inputs the gravity potential energy recovery flow into the oil inlet circuit and provides it to the second working link for use.

[0011] Optionally, after acquiring the command signal and the load condition of the first actuator, the method further includes: when the load condition is a negative load and the command signal indicates that the second working link is not working, controlling the first main valve and the third main valve to open, so that the first actuator and the return oil circuit form a hydraulic circuit.

[0012] Furthermore, after obtaining the first differential pressure, the method further includes: when the first differential pressure is not greater than the first differential pressure threshold, controlling the first main valve and the third main valve to open, so that the first actuator and the return oil circuit form a hydraulic circuit.

[0013] Furthermore, obtaining the load conditions of the first actuator includes:

[0014] Obtain the pressure at the first working port and the pressure at the second working port;

[0015] The direction of the load force is determined based on the pressure at the first working port and the pressure at the second working port;

[0016] When the direction of the load force is the same as the direction of movement indicated by the command signal, the load condition of the first actuator is determined to be a negative load.

[0017] When the direction of the load force is opposite to the direction of motion indicated by the command signal, the load condition of the first actuator is determined to be a positive load.

[0018] Furthermore, after acquiring the command signal and the load condition of the first actuator, the method further includes:

[0019] When the first actuator is under positive load, the pressure at the oil inlet of the first working link is detected;

[0020] If the pressure at the oil inlet of the first working link is less than the high and low pressure identification threshold, control the second main valve and the fourth main valve to open;

[0021] When the pressure at the oil inlet of the first working link is greater than or equal to the high and low pressure identification threshold, the second main valve and the third main valve are controlled to open.

[0022] Optionally, the load port independent control system further includes a second actuator, wherein controlling the opening of the first main valve and the fourth main valve when the first differential pressure is greater than the first differential pressure threshold includes:

[0023] When the first differential pressure is greater than the first differential pressure threshold, the oil outlet flow rate of the first actuator and the oil inlet flow rate of the second actuator are obtained;

[0024] When the oil outlet flow rate of the first actuator is not greater than the oil inlet flow rate of the second actuator, the first main valve and the fourth main valve are controlled to open.

[0025] When the oil outlet flow rate of the first actuator is greater than the oil inlet flow rate of the second actuator, the first main valve, the third main valve, and the fourth main valve are controlled to open.

[0026] Furthermore, the second actuator includes a third working port and a fourth working port, and the second working link includes a fifth main valve. The fifth main valve includes a working oil port connected to the third working port, a working oil port connected to the fourth working port, an oil inlet connected to the oil inlet circuit, and a return oil port connected to the oil return circuit.

[0027] Optionally, controlling the opening of the first main valve, the third main valve, and the fourth main valve includes:

[0028] Based on the pressure difference between the oil outlet of the first actuator and the oil return port of the first working link, the valve opening of the third main valve is controlled to distribute the flow rate returning to the oil tank.

[0029] Optionally, the first main valve, the second main valve, the third main valve, and the fourth main valve are each connected to a proportional pilot valve, and the method further includes:

[0030] The opening and closing of the first main valve, the second main valve, the third main valve, and the fourth main valve are controlled by the proportional pilot valve.

[0031] Another aspect of the present invention provides an energy-saving control device for a load port independent control system. The load port independent control system includes a first working link, a first actuator, a second working link, an oil inlet circuit, and a oil return circuit. The first working link includes a first main valve, a second main valve, a third main valve, a fourth main valve, and a branch oil return passage. The first main valve is installed between the first working port of the first actuator and the branch oil return passage. The second main valve is installed between the first working port of the first actuator and the oil inlet circuit. The third main valve is installed between the second working port of the first actuator and the branch oil return passage. The fourth main valve is installed between the second working port of the first actuator and the oil inlet circuit. The energy-saving control device includes:

[0032] The first acquisition module is used to acquire the instruction signal and the load condition of the first actuator;

[0033] The second acquisition module is used to acquire a first pressure difference when the load condition is a negative load and the acquired command signal indicates that the second working link is working. The first pressure difference is the pressure difference between the oil outlet chamber of the first actuator and the oil inlet of the first working link.

[0034] The control module is used to control the opening of the first main valve and the fourth main valve when the first differential pressure is greater than the first differential pressure threshold, so that the first working link inputs the gravity potential energy recovery flow into the oil inlet circuit and provides it to the second working link for use.

[0035] In another aspect, the present invention provides a readable storage medium storing executable instructions, which, when executed by the controller, implement the energy-saving control method of the load port independent control system described in any of the above technical solutions.

[0036] Through the above technical solution, this invention connects two main valves to the two working chambers of the first actuator, one for oil inlet and the other for oil return, forming a four-valve-core independent load port control system. The load condition is identified, and the controller controls the opening and closing of the four main valves according to different conditions, forming different hydraulic circuits. When the load condition is a negative load and a compound action is performed, the first working link inputs the recovered gravitational potential energy into the oil inlet circuit during the compound action, providing it to the second working link. This achieves flow sharing of the recovered flow during the compound action, maximizing energy recovery.

[0037] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0038] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the following detailed description to explain the invention, but do not constitute a limitation thereof. In the drawings:

[0039] Figure 1 This is a hydraulic schematic diagram of the independent load port control system in the first specific embodiment of the present invention;

[0040] Figure 2 This is a schematic diagram of the independent load port control system in the first specific embodiment of the present invention;

[0041] Figure 3 This is a simplified hydraulic schematic diagram of the control circuit P-A1-B1-P in the first specific embodiment of the present invention;

[0042] Figure 4 This is a simplified hydraulic schematic diagram of the control circuit P-A1-B1-T in the first specific embodiment of the present invention;

[0043] Figure 5 This is a simplified hydraulic schematic diagram of the control circuit T-A1-B1-T in the first specific embodiment of the present invention;

[0044] Figure 6 This is a simplified hydraulic schematic diagram of the control circuit T-A1-B1-P in the first specific embodiment of the present invention;

[0045] Figure 7 This is a simplified hydraulic schematic diagram of the control circuit T-A1-B1-P / T in the first specific embodiment of the present invention;

[0046] Figure 8 This is a hydraulic schematic diagram of the independent load port control system in the second specific embodiment of the present invention;

[0047] Figure 9This is a logic diagram of the energy-saving control method of the independent load port control system in a specific embodiment of the present invention;

[0048] Figure 10 This is a flowchart of the energy-saving control method of the independent load port control system in a specific embodiment of the present invention.

[0049] Explanation of reference numerals in the attached figures

[0050] 1. Hydraulic pump 21. Filter

[0051] 22 Pressure reducing valve 31 First pilot valve

[0052] 32 Second pilot valve 33 Third pilot valve

[0053] 34 Fourth pilot valve 35 Fifth pilot valve

[0054] 36 Sixth pilot valve 41 First main valve

[0055] 42 Second main valve 43 Third main valve

[0056] 44 Fourth main valve 45 Fifth main valve

[0057] 46 Branch return oil passage 51 First safety valve

[0058] 52 Second safety valve 53 Third safety valve

[0059] 54 Fourth safety valve 61 First pressure detection device

[0060] 62 Second pressure detection device 63 Third pressure detection device

[0061] 64 Fourth pressure detection device 65 Fifth pressure detection device

[0062] 66 Sixth pressure detection device 71 First actuator

[0063] 72 Second Actuator 8 Controller

[0064] A1 First working point of the first execution agency B1 Second working point of the first execution agency

[0065] A2 The third working port of the second execution agency B2 The fourth working port of the second execution agency

[0066] P Inlet T Outlet

[0067] 47. Sixth Main Valve Detailed Implementation

[0068] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0069] Furthermore, the terms “first,” “second,” “third,” “fourth,” “fifth,” and “sixth” are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with “first,” “second,” “third,” “fourth,” “fifth,” or “sixth” may explicitly or implicitly include one or more of the stated features.

[0070] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "set," "connect," and "install" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0071] First, it should be noted that those skilled in the art, after understanding the technical concept of the hydraulic connection relationship of this invention, can also make simple substitutions to the oil circuit or valves to achieve the function of the load port independent control system of this invention, which also falls within the protection scope of this invention. Related hydraulic components, such as directional valves, hydraulic cylinders, motors, and hydraulic pumps, are well known to those skilled in the art and are commonly used components in existing hydraulic systems. Therefore, these hydraulic components will only be briefly described below, while the focus will be on the original hydraulic connection relationship of the load port independent control system of this invention.

[0072] Reference Figure 9 and Figure 10 This invention provides an energy-saving control method for a load port independent control system. The load port independent control system includes a first working link, a first actuator 71, a second working link, an oil inlet circuit, and an oil return circuit. The first working link includes a first main valve 41, a second main valve 42, a third main valve 43, a fourth main valve 44, and a branch oil return circuit 46. The first main valve 41 is installed between the first working port A1 of the first actuator 71 and the branch oil return circuit 46. The second main valve 42 is installed between the first working port A1 of the first actuator 71 and the oil inlet circuit. The third main valve 43 is installed between the second working port B1 of the first actuator 71 and the branch oil return circuit 46. The fourth main valve 44 is installed between the second working port B1 of the first actuator 71 and the oil inlet circuit. The energy-saving control method includes the following steps:

[0073] Acquire command signals and load conditions of the first actuator 71;

[0074] When the load condition is negative and the command signal indicates that the second working link is working, the first pressure difference is obtained. The first pressure difference is the pressure difference between the oil outlet chamber of the first actuator 71 and the oil inlet of the first working link.

[0075] When the first differential pressure exceeds the first differential pressure threshold, the first main valve 41 and the fourth main valve 44 are opened, so that the first working link inputs the gravity potential energy recovery flow into the inlet oil circuit and provides it to the second working link. The first differential pressure threshold refers to the differential pressure setting threshold across the corresponding main valve, used to control whether the main valve is opened.

[0076] This invention connects two main valves to the two working chambers of the first actuator, one for oil inlet and the other for oil return, forming a four-valve-core independent load port control system. The system identifies the load condition and, based on different conditions, controls the opening and closing of the four main valves to create different hydraulic circuits. When the load is negative and undergoes a compound action, the first working link inputs the recovered gravitational potential energy into the oil inlet circuit, providing it to the second working link. This achieves flow sharing of the recovered flow during the compound action, maximizing energy recovery.

[0077] In one feasible implementation, such as Figure 1 As shown, the first working link of the present invention belongs to a four-valve core control system, and the second working link belongs to a single-valve core system. The second working link includes a fifth main valve 45. One working port of the fifth main valve 45 is connected to the third working port A2 of the second actuator 72, and the other working port of the fifth main valve 45 is connected to the fourth working port B2 of the second actuator 72. The fifth main valve 45 can be a three-position four-way valve. By controlling the reversing of the fifth main valve 45, one of the third working port A2 and the fourth working port B2 of the second actuator 72 can be used for oil inlet and the other for oil return. Alternatively, when the fifth main valve 45 is in the neutral position, the connection between the third working port A2 and the fourth working port B2 of the second actuator 72 and the oil inlet and oil return lines is blocked. The third working port A2 of the second actuator 72 can be equipped with a third safety valve 53. One port of the third safety valve 53 is connected to the third working port A2 of the second actuator 72, and the other port is connected to the return oil circuit. Similarly, the fourth working port B2 of the second actuator 72 can be equipped with a fourth safety valve 54. One port of the fourth safety valve 54 is connected to the fourth working port B2 of the second actuator 72, and the other port is connected to the return oil circuit. The second actuator 72 can be a hydraulic cylinder or a hydraulic motor, etc.

[0078] In other feasible implementations, such as Figure 8As shown, the second working link described above can also be a four-valve core structure similar to the first working link. Specifically, the second actuator 72 includes a third working port A2 and a fourth working port B2, and the second working link includes at least one sixth main valve 47. A sixth main valve 47 is installed on each of the following oil lines: between the third working port A2 and the inlet oil line, between the third working port A2 and the return oil line, between the fourth working port B2 and the inlet oil line, and between the fourth working port B2 and the return oil line. Thus, the second working link also forms a four-valve core control system, which identifies the load condition and, according to different conditions, controls the opening and closing of the four sixth main valves 47 to form different hydraulic circuits. When the second working link is under negative load and performs a compound operation, the second working link inputs the recovered gravitational potential energy into the oil inlet circuit during the compound operation, providing it to the first working link for use. This achieves flow sharing of the recovered flow during the compound operation, maximizing energy recovery. Alternatively, when the first working link is under negative load and performs a compound operation, the first working link inputs the recovered gravitational potential energy into the oil inlet circuit during the compound operation, providing it to the second working link for use. This achieves flow sharing of the recovered flow during the compound operation, maximizing energy recovery. This allows the first and second working links to share the recovered flow during the compound operation, maximizing energy recovery, depending on the different operating conditions. Furthermore, the sixth main valve 47 can be controlled electronically. For example, the control chamber of the sixth main valve 47 is connected to a pilot valve, which controls the sixth main valve 47. The pilot valve can be a proportional solenoid valve.

[0079] Specifically, this can be determined by the presence or absence of the flow command signal Q1 from the first working link and the flow command signal Q2 from the second working link. If Q2 > 0 is detected, it indicates that the first actuator 71 and the second actuator 72 are operating simultaneously, i.e., performing a compound action. At this time, it is necessary to further detect the first difference and the pressure P of the oil outlet chamber connected to the second working port B1 of the first actuator 71. B1 Pressure P at the oil inlet P connected to the energy recovery unit P A comparison is made to determine whether the gravitational potential energy recovered by the first actuator 71 can be used to drive the second actuator 72. If the first difference is not greater than the first differential pressure threshold, it indicates that the gravitational potential energy recovered by the first actuator 71 is insufficient to drive the second actuator 72. At this time, the first main valve 41 and the third main valve 43 are opened to allow the first actuator 71 to establish a pressure difference threshold. Figure 5In the T-A1-B1-T circuit shown, the first actuator 71 operates using the gravitational potential energy of the boom, while the second actuator 72 is supplied with oil by the hydraulic pump 1, thus reducing energy consumption during combined operation. If the first differential pressure is greater than the first differential pressure threshold, it indicates that the pressure in the oil outlet chamber of the first actuator 71 is greater than the driving force of the second actuator 72, which can drive the second actuator 72 to move. Further determination is needed as to whether all or part of the gravitational potential energy recovered by the first actuator 71 is used to drive the second actuator 72. When all the gravitational potential energy recovered by the first actuator 71 is used to drive the second actuator 72, the controller 8 controls the first main valve 41 and the fourth main valve 44. The first main valve 41 draws oil using gravitational potential energy, while the fourth main valve 44 delivers the hydraulic oil output from the oil outlet chamber of the first actuator 71 to the oil inlet circuit, supplying it to the second actuator 72. If this is still insufficient to meet the flow requirements of the second actuator 72, the remaining flow needs to be increased by the hydraulic pump 1. When the gravitational potential energy recovered by the first actuator 71 is used to drive the second actuator 72, it indicates that the flow rate of the oil outlet chamber of the first actuator 71 is greater than the flow rate required by the second actuator 72. The controller 8 controls the opening degree of the valve ports of the first main valve 41, the third main valve 43 and the fourth main valve 44. The first main valve 41 draws oil by relying on gravitational potential energy. The fourth main valve 44 delivers the hydraulic oil output from the oil outlet chamber of the first actuator 71 to the oil inlet circuit and supplies it to the second actuator 72. According to the pressure difference between the oil outlet chamber of the first actuator 71 and the return oil port of the energy recovery working connection, the opening degree of the valve port of the third main valve 43 is controlled to distribute the flow rate returning to the oil tank, so that the remaining flow rate returns to the oil tank through the third main valve 43. The entire compound action does not require the hydraulic pump 1 to supply oil, thus reducing energy consumption.

[0080] Reference Figure 9 The steps for identifying the load condition of the first actuator 71 are as follows:

[0081] Obtain the pressure at the first working port A1 and the pressure at the second working port B1 of the first actuator 71;

[0082] The direction of the load force is determined based on the pressure at the first working port A1 and the pressure at the second working port B1 of the first actuator 71, such as through the pressure difference between the first working port A1 and the second working port B1 of the first actuator 71.

[0083] Specifically, the pressure difference between the first working port A1 and the second working port B1 of the first actuator 71 is compared with the load condition identification threshold. The load force direction is determined based on the comparison result between the pressure difference between the first working port A1 and the second working port B1 of the first actuator 71 and the load condition identification threshold. When the determined load force direction is the same as the motion direction indicated by the command signal, the load condition of the first actuator 71 is determined to be a negative load.

[0084] When the determined load force direction is opposite to the motion direction indicated by the command signal, the load condition of the first actuator 71 is determined to be a positive load.

[0085] Specifically, taking the first working port A1 of the first actuator 71 as an example where oil is inlet and the second working port B1 of the first actuator 71 is outlet, the load condition is identified according to formulas (1) and (2);

[0086] P B1 *A B1 / A A1 -P A1 Formula (1)

[0087] P B1 *A B1 / A A1 -P A1 ≤t Formula (2)

[0088] Where t is the load condition identification threshold, which can be set according to requirements, with a setting range of 0-15 bar. A1 A is the cavity area of ​​the oil inlet chamber connected to the first working port A1 of the first actuator 71. B1 Let the area of ​​the oil outlet chamber connected to the second working port B1 of the first actuator 71 be the cavity area. If formula (1) is satisfied, it means that the pressure difference between the first working port A1 and the second working port B1 of the first actuator 71 is greater than the load condition identification threshold, and the load force direction is the same as the movement direction indicated by the command signal. The load condition of the first actuator 71 is identified as a negative load. If formula (2) is satisfied, it means that the pressure difference between the first working port A1 and the second working port B1 of the first actuator 71 is less than or equal to the load condition identification threshold, and the load force direction is opposite to the movement direction indicated by the command signal. The load condition of the first actuator 71 is identified as a positive load condition. In other words, by comparing the pressure difference between the oil inlet and outlet of the first actuator 71 with the magnitude of t, the direction of the load force is determined. This is then combined with the movement direction indicated by the command signal, and the load condition of the first actuator 71 is determined by these two conditions.

[0089] In a specific embodiment of the present invention, when the first actuator 71 is under negative load and the command signal indicates that the second working link is not working, specifically, if Q2 = 0 is detected, it indicates that only the first actuator 71 is operating, the second working link is not operating, and it is in a single-action condition. The controller 8 needs to control the first main valve 41 and the third main valve 43 to open. The valve core displacement of the third main valve 43 is controlled by the flow rate control to make the flow rate through the third main valve 43 equal to Q1. The first main valve 41 can then fully open its valve port, establishing... Figure 5 The T-A1-B1-T circuit shown relies on the gravitational potential energy of the boom to achieve its movement. The first main valve 41 connects to the return oil circuit for oil suction. At this time, the oil supply of hydraulic pump 1 is Q=0, and the movement is achieved entirely by gravitational potential energy, with no energy consumption.

[0090] When the first actuator 71 is under positive load, the pressure at the oil inlet of the first working link needs to be detected. If the pressure at the oil inlet of the first working link is less than the high and low pressure identification threshold, the second main valve 42 and the fourth main valve 44 are controlled to open. If the pressure at the oil inlet of the first working link is greater than or equal to the high and low pressure identification threshold, the second main valve 42 and the third main valve 43 are controlled to open.

[0091] Specifically, when the first actuator 71 is under positive load, if the pressure at the inlet of the first working link is less than the high / low pressure identification threshold, the first actuator 71 is under low pressure positive load. The controller 8 then controls the second main valve 42 and the fourth main valve 44 to open. The valve core displacement of the second main valve 42 is controlled by flow control to ensure the flow rate through the second main valve 42 equals Q1. The fourth main valve 44 can then fully open. At this time, the hydraulic pump 1 supplies oil Q = Q1 + Q2 - Q1*A. B1 / A A1 ,Establish Figure 3 The P-A1-B1-P circuit shown recovers the flow rate of the oil outlet chamber, reduces the oil supply of the electronically controlled pump 1, and lowers system energy consumption. If the pressure at the inlet of the first working link is greater than or equal to the high / low pressure identification threshold, the first actuator 71 is in a high-pressure positive load condition. Then, the controller 8 controls the second main valve 42 and the third main valve 43 to open. At this time, the oil supply of the hydraulic pump 1 is Q = Q1 + Q2, establishing... Figure 4 The P-A1-B1-T circuit is shown.

[0092] This invention forms a four-valve-core system by connecting the first main valve 41 and the second main valve 42 through the first working port A1 of the first actuator, and connecting the third main valve 43 and the fourth main valve 44 through the second working port B1 of the first actuator. Depending on different operating conditions, the controller 8 controls the opening and closing of the first main valve 41, the second main valve 42, the third main valve 43, and the fourth main valve 44, primarily for energy recovery under heavy load conditions. Specifically, in single-action conditions, the system can achieve action using gravitational potential energy without energy consumption; in compound-action conditions, the recovered gravitational potential energy can be input into the oil inlet circuit for use by other working components, achieving flow sharing of the recovered flow during compound actions. Furthermore, it enables real-time switching of the connection between the cylinder's inlet and outlet oil chambers and the oil inlet and outlet circuits during operating condition changes, avoiding the mid-position jamming problem of traditional single-valve-core or dual-valve-core switching.

[0093] The above mainly uses a system composed of a first working link and a second working link as an example for explanation. It can be understood that the specific number of the first working link and the second working link can be selected according to the design needs to form various technical solutions. The principles of various technical solutions and the technical effects they can achieve are basically the same.

[0094] To detect the pressure at the inlet and outlet of the first working link, the pressure at the first working port A1 and the second working port B1 of the first actuator 71, and the pressure at the third working port A2 and the fourth working port B2 of the second actuator 72. Specifically, refer to Figure 1 The inlet P of the first working link is connected to the hydraulic pump 1, meaning the oil inlet circuit is connected to the hydraulic pump 1, and the hydraulic pump 1 supplies oil to each working link. The return port T of the first working link is connected to the oil tank, meaning the return oil circuit is connected to the oil tank, and is used for oil return from each working link. Further, a first pressure detection device 61 is installed at the outlet of the hydraulic pump 1 to detect the pressure at the inlet P of the energy recovery working link, and a second pressure detection device 62 is installed at the oil outlet of the oil tank to detect the pressure at the return port T of the energy recovery working link. A third pressure detection device 63 can be installed at the first working port A1 of the first actuator 71, and a fourth pressure detection device 64 can be installed at the second working port B1 of the first actuator 71. A fifth pressure detection device 65 can be installed at the third working port A2 of the second actuator 72, and a sixth pressure detection device 66 can be installed at the fourth working port B2 of the second actuator 72. The first pressure detection device 61, the second pressure detection device 62, the third pressure detection device 63, the fourth pressure detection device 64, the fifth pressure detection device 65, and the sixth pressure detection device 66 are all connected to the controller 8. The first pressure detection device 61, the second pressure detection device 62, the third pressure detection device 63, the fourth pressure detection device 64, the fifth pressure detection device 65, and the sixth pressure detection device 66 can be pressure sensors or other pressure detection instruments.

[0095] Generally, the first main valve 41, the second main valve 42, the third main valve 43, the fourth main valve 44, and the fifth main valve 45 can be controlled electrically. Specifically, the first main valve 41, the second main valve 42, the third main valve 43, and the fourth main valve 44 can be two-position two-way solenoid valves; alternatively, solenoid valves can be added to control the first main valve 41, the second main valve 42, the third main valve 43, and the fourth main valve 44, as described above. Figure 1The control chamber of the first main valve 41 is connected to the first pilot valve 31, the control chamber of the second main valve 42 is connected to the second pilot valve 32, the control chamber of the third main valve 43 is connected to the third pilot valve 33, and the control chamber of the fourth main valve 44 is connected to the fourth pilot valve 34. The first pilot valve 31, the second pilot valve 32, the third pilot valve 33, and the fourth pilot valve 34 can be solenoid valves, preferably proportional solenoid valves. The first pilot valve 31, the second pilot valve 32, the third pilot valve 33, and the fourth pilot valve 34 are all communicatively connected to the controller 8, forming a fully electronic control mode. This avoids the influence of pressure and accumulator volume on the energy recovery rate in traditional methods. Energy recovery is performed according to the identified working conditions, and the energy recovery rate is greatly improved.

[0096] Specifically, the control chamber of the first main valve 41 is connected to the working port of the first pilot valve 31, the control chamber of the second main valve 42 is connected to the working port of the second pilot valve 32, the control chamber of the third main valve 43 is connected to the working port of the third pilot valve 33, and the control chamber of the fourth main valve 44 is connected to the working port of the fourth pilot valve 34; the return ports of the first pilot valve 31, the second pilot valve 32, the third pilot valve 33, and the fourth pilot valve 34 are all connected to the return oil circuit; the first pilot valve... The oil inlet of 31, the oil inlet of the second pilot valve 32, the oil inlet of the third pilot valve 33, and the oil inlet of the fourth pilot valve 34 are all connected to the pilot oil circuit. The pilot oil circuit is equipped with a filter 21 and a pressure reducing valve 22. The pilot oil circuit can be directly connected to the hydraulic pump 1, or it can be connected to the oil inlet circuit. The pressure reducing valve 22 reduces the pressure of the high-pressure oil to form pilot oil, which is used to perform pilot control on the first main valve 41, the second main valve 42, the third main valve 43, and the fourth main valve 44.

[0097] In a specific embodiment, the first working port A1 of the first actuator 71 is connected to the first safety valve 51. One oil port of the first safety valve 51 is connected to the first working port A1 of the first actuator 71, and the other oil port is connected to the branch return oil passage 46. Similarly, the second working port B1 of the first actuator 71 is connected to the second safety valve 52. One oil port of the second safety valve 52 is connected to the second working port B1 of the first actuator 71, and the other oil port is connected to the branch return oil passage 46.

[0098] In a specific embodiment, the fifth main valve 45 can be a three-position four-way solenoid valve, and the controller 8 controls the switching of the fifth main valve 45. Alternatively, one end of the control chamber of the fifth main valve 45 can be connected to the working port of the fifth pilot valve 35, and the other end of the control chamber can be connected to the working port of the sixth pilot valve 36. The oil inlet ports of the fifth pilot valve 35 and the sixth pilot valve 36 are both connected to the pilot oil circuit, and the oil return ports of the fifth pilot valve 35 and the sixth pilot valve 36 are both connected to the return oil circuit. The fifth pilot valve 35 and the sixth pilot valve 36 can be proportional solenoid valves. The fifth pilot valve 35 and the sixth pilot valve 36 can be communicatively connected to the controller 8, and the controller 8 indirectly controls the switching of the fifth main valve 45 through the fifth pilot valve 35 and the sixth pilot valve 36.

[0099] Reference Figures 1 to 8The load port independent control system in a preferred embodiment of the present invention includes a first working link, a first actuator 71, a second working link, a second actuator 72, a controller 8, an oil inlet circuit, and an oil return circuit. The oil inlet circuit is connected to the oil inlets of the first and second working links for supplying oil to the first and second working links. The oil return circuit is connected to the oil return ports of the first and second working links for returning oil to the first and second working links. The first working link is connected to the first actuator 71 for controlling the first actuator 71. The first actuator 71 is preferably a hydraulic cylinder. The first working link includes a first main valve 41 and a second main valve 42. 2. The third main valve 43, the fourth main valve 44, and the branch return oil passage 46 are provided. The first main valve 41 is installed on the oil line between the first working port A1 of the first actuator 71 and the branch return oil passage 46. The second main valve 42 is installed on the oil line between the first working port A1 of the first actuator 71 and the oil inlet line. The third main valve 43 is installed on the oil line between the second working port B1 of the first actuator 71 and the branch return oil passage 46. The fourth main valve 44 is installed on the oil line between the second working port B1 of the first actuator 71 and the oil inlet line. The first main valve 41, the second main valve 42, the third main valve 43, and the fourth main valve 44 can be two-position two-way valves. The control chamber of the first main valve 41 is connected to the working port of the first pilot valve 31; the control chamber of the second main valve 42 is connected to the working port of the second pilot valve 32; the control chamber of the third main valve 43 is connected to the working port of the third pilot valve 33; and the control chamber of the fourth main valve 44 is connected to the working port of the fourth pilot valve 34. The return ports of the first pilot valve 31, the second pilot valve 32, the third pilot valve 33, and the fourth pilot valve 34 are all connected to the return ports. The oil circuits are connected; the oil inlet of the first pilot valve 31, the oil inlet of the second pilot valve 32, the oil inlet of the third pilot valve 33, and the oil inlet of the fourth pilot valve 34 are all connected to the pilot oil circuit. The pilot oil circuit is equipped with a filter 21 and a pressure reducing valve 22. The pilot oil circuit is connected to the oil inlet circuit. The pressure reducing valve 22 reduces the pressure of the high-pressure oil to form pilot oil, which is used to perform pilot control on the first main valve 41, the second main valve 42, the third main valve 43, and the fourth main valve 44.The second working link includes a fifth main valve 45. The third working port A2 and the fourth working port B2 of the second actuator 72 are both connected to the fifth main valve 45. The fifth main valve 45 can be a three-position four-way valve. The second actuator 72 is preferably a hydraulic cylinder. By controlling the reversing of the fifth main valve 45, one of the third working ports A2 and B2 of the second actuator 72 can be used for oil inlet, while the other can be used for oil return. Alternatively, when the fifth main valve 45 is in the neutral position, the connection between the third working ports A2 and B2 of the second actuator 72 and the oil inlet and return lines is blocked. One end of the control chamber of the fifth main valve 45 is connected to the fifth pilot valve. The working port of the fifth pilot valve 35 is connected, and its other end control chamber is connected to the working port of the sixth pilot valve 36. The oil inlet ports of the fifth pilot valve 35 and the sixth pilot valve 36 are both connected to the pilot oil circuit. The oil return ports of the fifth pilot valve 35 and the sixth pilot valve 36 are both connected to the return oil circuit. The first pilot valve 31, the second pilot valve 32, the third pilot valve 33, the fourth pilot valve 34, the fifth pilot valve 35 and the sixth pilot valve 36 can be proportional solenoid valves. The first pilot valve 31, the second pilot valve 32, the third pilot valve 33, the fourth pilot valve 34, the fifth pilot valve 35 and the sixth pilot valve 36 can be connected to the controller 8 for communication. A first pressure detection device 61 is installed at the outlet of the hydraulic pump 1 to detect the pressure at the inlet P of the first working link. A second pressure detection device 62 is installed at the oil port of the oil tank to detect the pressure at the return port T of the first working link. A third pressure detection device 63 is installed at the first working port A1 of the first actuator 71, a fourth pressure detection device 64 is installed at the second working port B1 of the first actuator 71, a fifth pressure detection device 65 is installed at the third working port A2 of the second actuator 72, and a sixth pressure detection device 66 is installed at the fourth working port B2 of the second actuator 72. All pressure detection devices 61, 62, 63, 64, 65, and 66 are pressure sensors and are communicatively connected to the controller 8. The hydraulic pump 1 can be an electrically controlled pump.

[0100] Reference Figure 2 This invention uses a controller 8 to collect in real time the flow command signals Q1 and Q2 from the handle, the pressure signal from the working oil port of the actuator, the engine speed signal η, and the hydraulic pump displacement signal. The controller 8 then identifies the working conditions and sets the control loop through a control algorithm. The controller 8 then outputs a corresponding current to the proportional pilot solenoid valve, controls the output of the corresponding valve core displacement of each main valve according to the flow control mode, and automatically switches the hydraulic loop to maximize energy recovery and utilization.

[0101] The specific control process is as follows: Figure 9 As shown, taking the boom lowering and retraction process as an example, the first actuator 71 and the second actuator 72 can be hydraulic cylinders to drive the boom. Based on the above-mentioned independent load port control system, energy-saving control is achieved. The specific control method steps are as follows:

[0102] Step 1: The controller 8 acquires the flow command signal Q1 from the first actuator 71 and the flow command signal Q2 from the second actuator 72 via the bus, and acquires the pressure P at the first working port A1 of the first actuator 71 via the third pressure detection device 63. A1 The pressure P at the second working port B1 of the first actuator 71 is collected by the fourth pressure detection device 64. B1 The pressure P at the third working port A2 of the second actuator 72 is collected by the fifth pressure detection device 65. A2 The pressure P at the fourth working port B2 of the second actuator 72 is collected by the sixth pressure detection device 66. B2 .

[0103] Step 2: Identify the load condition of the first actuator 71 and determine whether the load corresponding to the first actuator 71 is a positive load or a negative load;

[0104] Taking the first working port A1 of the first actuator 71 as an example where oil is inlet and the second working port B1 of the first actuator 71 is outlet, the load condition is identified according to formulas (1) and (2);

[0105] P B1 *A B1 / A A1 -P A1 >t Formula (1)

[0106] P B1 *A B1 / A A1 -P A1 ≤t Formula (2)

[0107] Where t is the load condition identification threshold, which can be set according to requirements, with a setting range of 0-15 bar. A1Let AB1 be the area of ​​the inlet chamber connected to the first working port A1 of the first actuator 71, and AB1 be the area of ​​the outlet chamber connected to the second working port B1 of the first actuator 71. If formula (1) is satisfied, it means that the pressure difference between the first working port A1 and the second working port B1 of the first actuator 71 is greater than the load force direction determined by the load condition identification threshold and is the same as the movement direction indicated by the command signal. The load condition of the first actuator 71 is identified as a negative load condition. If formula (2) is satisfied, it means that the pressure difference between the first working port A1 and the second working port B1 of the first actuator 71 is less than or equal to the load force direction determined by the load condition identification threshold and is opposite to the movement direction indicated by the command signal. The load condition of the first actuator 71 is identified as a positive load condition. A negative load is a load that is the same as the movement direction of the hydraulic cylinder. Conversely, it is a positive load. In other words, the load condition is identified by comparing the pressure difference between the inlet and outlet of the first actuator 71 with the magnitude of t.

[0108] Step 3: If the load condition is identified as a positive load condition, the pressure P at the oil inlet P is detected by the first pressure detection device 61. P When P P When the voltage is below the high / low voltage identification threshold, the system is determined to be in a low-voltage positive load condition. The high / low voltage identification threshold can be set according to requirements, such as 20 bar, 30 bar, 40 bar, 50 bar, etc. Figure 9 In this embodiment, the high / low voltage identification threshold is set to 50 bar as an example for description. (Refer to...) Figure 3 The controller 8 controls the opening of the second pilot valve 32 and the fourth pilot valve 34. Pilot oil acts on the second main valve 42 and the fourth main valve 44 respectively through the second pilot valve 32 and the fourth pilot valve 34. The valve core displacement of the second main valve 42 is controlled by the flow rate control, so that the flow rate through the second main valve 42 is equal to Q1. The fourth main valve 44 can be fully opened. At this time, the oil supply of the hydraulic pump 1 is Q = Q1 + Q2 - Q1*A. B1 / A A1 ,Establish Figure 3 The P-A1-B1-P circuit shown recovers the flow rate of the oil outlet chamber, reduces the oil supply of the electronically controlled pump 1, and lowers the system energy consumption.

[0109] When P P When the pressure exceeds the high / low pressure identification threshold, the system is determined to be under high-pressure positive load conditions. To reduce the oil supply pressure, refer to... Figure 4The controller 8 controls the opening of the second pilot valve 32 and the third pilot valve 33. Pilot oil acts on the second main valve 42 and the third main valve 43 respectively through the second pilot valve 32 and the third pilot valve 33. The valve core displacement of the second main valve 42 is controlled by flow rate control to ensure that the flow rate through the second main valve 42 is equal to Q1. The valve core displacement of the third main valve 43 is controlled by pressure to achieve a small back pressure control. At this time, the oil supply of the hydraulic pump 1 is Q = Q1 + Q2, establishing... Figure 4 The P-A1-B1-T circuit is shown.

[0110] Step 4: If the load condition is identified as a negative load condition, the controller 8 determines whether to perform a combined action based on the flow command signals Q1 and Q2. If Q2 = 0 is detected, only the first actuator 71 operates. At this time, the controller 8 controls the first pilot valve 31 and the second pilot valve 32 to open. Pilot oil acts on the first main valve 41 and the third main valve 43 respectively through the first pilot valve 31 and the second pilot valve 32. The valve core displacement of the third main valve 43 is speed-controlled by the flow control, so that the flow rate through the third main valve 43 is equal to Q1. The first main valve 41 can then fully open its valve port, establishing... Figure 5 The T-A1-B1-T circuit shown relies on the gravitational potential energy of the boom to achieve its movement. The first main valve 41 connects to the return oil circuit for oil suction. At this time, the oil supply of hydraulic pump 1 is Q=0, and the movement is achieved entirely by gravitational potential energy, with no energy consumption.

[0111] If Q2>0 is detected, it indicates that the first actuator 71 and the second actuator 72 operate simultaneously, i.e., perform a compound action, increasing the pressure P in the oil outlet chamber connected to the second working port B1 of the first actuator 71, which is collected by the fourth pressure detection device 64. B1 The pressure P at the oil inlet is collected by the first pressure detection device 61. P Comparison,

[0112] P B1 -P P ≤u formula (3)

[0113] P B1 -P P > Formula (4)

[0114] Where u is the threshold value set for the pressure difference between the two sides of the main valve. If it satisfies formula (3), it means that the gravitational potential energy recovered by the first actuator 71 is insufficient to drive the second actuator 72 to move. At this time, the controller 8 controls the first pilot valve 31 and the third pilot valve 33 to open. The pilot oil acts on the first main valve 41 and the third main valve 43 respectively through the first pilot valve 31 and the third pilot valve 33. The valve core displacement of the third main valve 43 is controlled by the flow control to make the flow through the third main valve 43 equal to Q1. The first main valve 41 can fully open the valve port and establish Figure 5In the T-A1-B1-T circuit shown, the first actuator 71 operates using the gravitational potential energy of the boom, and the first main valve 41 connects to the return oil circuit for oil suction. At this time, the hydraulic pump 1 supplies oil at a rate of Q = Q2, which reduces energy consumption during combined operations.

[0115] If formula (4) is satisfied, then proceed to step 5 below.

[0116] Step 5: If formula (4) is satisfied, it means that the pressure in the oil outlet chamber of the first actuator 71 is greater than the driving force of the second actuator 72, and the gravitational potential energy can be recovered and enter the oil inlet circuit for use by the second actuator 72. The oil inlet flow command of the first actuator 71 is Q1, and the oil inlet flow command of the second actuator 72 is Q2. At this time, it is necessary to compare the oil outlet flow of the first actuator 71 with the oil inlet flow of the second actuator 72:

[0117] Q1*A B1 / A A1 ≤Q2 formula (5)

[0118] Q1*A B1 / A A1 >Q2 formula (6)

[0119] If formula (5) is satisfied, then proceed to step 6; if formula (6) is satisfied, then proceed to step 7.

[0120] Step 6: Through calculation, if the flow rate of the oil outlet chamber of the first actuator 71 is found to be less than the flow rate of the oil inlet chamber of the second actuator 72, the controller 8 controls the first pilot valve 31 and the fourth pilot valve 34 to open. The pilot oil acts on the first main valve 41 and the fourth main valve 44 respectively through the first pilot valve 31 and the fourth pilot valve 34. The valve core displacement of the fourth main valve 44 is controlled by the flow rate control. The pressure difference ΔP = P on both sides of the fourth main valve 44 is collected in real time. B1 -P P Based on the pressure difference across the valve core, determine the valve core displacement so that the flow rate through the fourth main valve 44 is equal to Q1*A. B1 / A A1 The first main valve 41 can fully open its valve port. For the first actuator 71, a system is established. Figure 6 The T-A1-B1-P circuit shown relies on gravitational potential energy for oil suction. Since the required flow rate of the inlet chamber of the second actuator 72 is Q2, and the flow rate of the outlet chamber of the first actuator 71 is less than the required flow rate of the second actuator 72, the remaining flow rate needs to be provided by the hydraulic pump 1. At this time, the oil supply quantity of the hydraulic pump 1 is Q = Q2 - Q1 * A B1 / A A1 This can reduce energy consumption during complex actions.

[0121] Step 7: Through calculation, if the oil outlet flow rate of the first actuator 71 is found to be greater than the oil inlet flow rate of the second actuator 72, the controller 8 controls the first pilot valve 31, the third pilot valve 33, and the fourth pilot valve 34 to open. Pilot oil acts on the first main valve 41, the third main valve 43, and the fourth main valve 44 respectively through the first pilot valve 31, the third pilot valve 33, and the fourth pilot valve 34. The valve core displacement of the fourth main valve 44 is controlled by the flow rate control. The pressure difference ΔP = P on both sides of the fourth main valve 44 is collected in real time. B1 -P P Based on the pressure difference across the valve core, the valve core displacement is determined, ensuring that the flow rate through the fourth main valve 44 equals Q2. All the flow is directed through the oil inlet to the fifth main valve 45 of the second actuator 72, at which point the fifth main valve 45 of the second actuator 72 remains fully open. The valve core displacement of the third main valve 43 is controlled by flow rate control to eliminate excess flow. The pressure difference across the third main valve 43, ΔP = P, is collected in real time. B1 -P T , where P T This refers to the pressure at the return port T, which causes the flow rate through the third main valve 43 to be Q1*A. B1 / A A1 -Q2; The first main valve 41 can fully open its valve port, relying on gravitational potential energy to draw in oil and establish... Figure 7 The P-A1-B1-P / T circuit is shown. The first actuator 71 is connected to the oil inlet circuit. Besides supplying the second actuator 72, a portion of the flow from the outlet chamber of the first actuator 71 is returned to the oil tank via the third main valve 43. The flow recovery from the first actuator 71 is sufficient to meet the flow command requirements of the second actuator 72; therefore, the oil supply Q of hydraulic pump 1 is 0. When a compound action is achieved, the second actuator 72 is driven by the gravitational potential energy flow recovery from the first actuator 71. The entire compound action does not require oil supply from hydraulic pump 1, achieving zero energy consumption.

[0122] In the above embodiments, the control process of the energy-saving control method is described using the example of oil entering through the first working port A1 of the first actuator 71 and oil exiting through the second working port B1 of the first actuator 71. Similarly, when oil exits through the first working port A1 of the first actuator 71 and oil enters through the second working port B1 of the first actuator 71, the same energy-saving control method can be performed and the same energy-saving control effect can be achieved. For those skilled in the art, based on the above specific energy-saving control process, it is possible to obtain the energy-saving control method when oil exits through the first working port A1 of the first actuator 71 and oil enters through the second working port B1 of the first actuator 71, which also falls within the protection scope of this invention.

[0123] This invention establishes multiple circuits by controlling a four-valve-core system consisting of a first main valve 41, a second main valve 42, a third main valve 43, and a fourth main valve 44. Based on the operating conditions, four energy-saving circuits are established: P-A1-B1-P, T-A1-B1-T, T-A1-B1-P, and T-A1-B1-P / T, maximizing energy recovery. Specifically, the four-valve-core system can effectively recover gravitational potential energy under negative load conditions. The recovered gravitational potential energy can enter the oil inlet circuit, achieving flow sharing during compound operations. Compared to existing energy recovery systems that require valve core design for single-unit applications, resulting in complex valve core structures and limited versatility, the four-valve-core system of this invention features identical valve core designs and simple valve core throttling groove designs. The circuits are established through a control algorithm, and only the relevant control algorithm parameters need to be changed to adapt to various energy recovery structures, demonstrating good versatility. It avoids the influence of pressure and accumulator volume on the energy recovery rate in traditional methods, employing fully electronic control to recover energy based on identified operating conditions, significantly improving the energy recovery rate.

[0124] Currently, some systems employ independent valve control at the load port for energy saving. This method breaks the constraints of coupled regulation between the valve inlet and outlet, allowing the system to switch to a more energy-efficient hydraulic circuit. Specifically, the actuator's two working ports are connected to three-position three-way valves. However, in actual operation, multiple working conditions often exist within the same continuous motion, requiring switching to a more energy-efficient hydraulic circuit based on these conditions. During circuit switching, the valve core may be in a neutral position, causing jamming and vibration, affecting operational stability. For example, during the excavator's boom retraction, the load changes from negative to positive. The corresponding control circuit switches from an inlet-inlet-outlet-inlet circuit to an inlet-inlet-outlet-return circuit. The main valve core at the outlet may over-neutralize during this switching, causing severe fluctuations in flow and pressure, significantly impacting vehicle handling and system lifespan. To address this, the present invention employs a four-valve-core independent control system for the load port. By individually controlling the four valve cores at the oil inlet and outlet, the real-time switching of the oil cylinder's inlet and outlet oil chamber connection pipeline can be achieved during operating condition switching. The switching process is stable, avoiding the mid-position jamming problem of traditional single-valve-core or dual-valve-core switching.

[0125] Furthermore, it should be noted that the independent load port control system of the present invention is not limited to the above. Figure 1 The combination of the first and second working links to form a four-valve-core system, as shown, can be combined with a single-valve-core system, or it can be a combination of four-valve-core systems with another four-valve-core system. The four-valve-core system refers to... Figure 1The control system formed by the first working link shown can also be a combination of a four-valve-core system and a two-valve-core system. Here, the two-valve-core system refers to a system where each of the two working ports of the actuator is connected to a three-position three-way valve. By controlling the two three-position three-way valves, the two working ports of the actuator can be controlled separately. However, this two-valve-core system suffers from a problem of mid-position jamming during real-time switching of the oil cylinder's inlet and outlet oil chamber connecting pipelines. Because the technical solution of this invention uses a four-valve-core control system, it can establish different energy-saving loops according to the working conditions, maximizing energy recovery and achieving flow sharing of recovered flow during compound actions. Through coordinated control of the four valves, the mid-position jamming problem of traditional single-valve-core or dual-valve-core switching is avoided.

[0126] This invention also provides an energy-saving control device based on a load port independent control system. The load port independent control system includes a first working link, a first actuator 71, a second working link, an oil inlet circuit, and a oil return circuit. The first working link includes a first main valve 41, a second main valve 42, a third main valve 43, a fourth main valve 44, and a branch oil return passage 46. The first main valve 41 is installed between the first working port A1 of the first actuator 71 and the branch oil return passage 46. The second main valve 42 is installed between the first working port A1 of the first actuator 71 and the oil inlet circuit. The third main valve 43 is installed between the second working port B1 of the first actuator 71 and the branch oil return passage 46. The fourth main valve 44 is installed between the second working port B1 of the first actuator 71 and the oil inlet circuit. The energy-saving control device includes:

[0127] The first acquisition module is used to acquire the instruction signal and the load condition of the first actuator 71;

[0128] The second acquisition module is used to acquire the first pressure difference when the load condition is negative and the acquired command signal indicates that the second working link is working. The first pressure difference is the pressure difference between the oil outlet chamber of the first actuator 71 and the oil inlet of the first working link.

[0129] The control module is used to control the first main valve 41 and the fourth main valve 44 to open when the first differential pressure is greater than the first differential pressure threshold, so that the first working link inputs the gravity potential energy recovery flow into the oil inlet circuit and provides it to the second working link. The first acquisition module, the second acquisition module, and the control module are conventional functional modules in the control system. Those skilled in the art, based on the above technical solution of this invention, can select the appropriate functional modules; therefore, specific examples will not be provided.

[0130] The present invention also provides a readable storage medium storing executable instructions, which, when executed by the controller, implement the energy-saving control method of the load port independent control system described above.

[0131] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0132] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0133] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. An energy-saving control method for an independent load port control system, characterized in that, The independent load port control system includes a first working link, a first actuator (71), a second actuator (72), a second working link, an oil inlet circuit, and an oil return circuit. The first working link includes a first main valve (41), a second main valve (42), a third main valve (43), a fourth main valve (44), and a branch oil return passage (46). The first main valve (41) is installed between the first working port (A1) of the first actuator (71) and the branch oil return passage (46). The second main valve (42) is installed between the first working port (A1) of the first actuator (71) and the oil inlet circuit. The third main valve (43) is installed between the second working port (B1) of the first actuator (71) and the branch oil return passage (46). The fourth main valve (44) is installed between the second working port (B1) of the first actuator (71) and the oil inlet circuit. The energy-saving control method includes: Obtain the instruction signal and the load condition of the first actuator (71); When the load condition is a negative load and the command signal indicates that the second working link is to work, the first pressure difference is obtained. The first pressure difference is the pressure difference between the oil outlet chamber of the first actuator (71) and the oil inlet of the first working link. When the first differential pressure is greater than the first differential pressure threshold, the oil outlet flow rate of the first actuator (71) and the oil inlet flow rate of the second actuator (72) are obtained; When the oil outlet flow rate of the first actuator (71) is not greater than the oil inlet flow rate of the second actuator (72), the first main valve (41) and the fourth main valve (44) are controlled to open so that the first working link inputs the gravity potential energy recovery flow rate into the oil inlet circuit and provides it to the second working link for use; When the oil outlet flow rate of the first actuator (71) is greater than the oil inlet flow rate of the second actuator (72), the first main valve (41), the third main valve (43) and the fourth main valve (44) are controlled to open.

2. The energy-saving control method for the independent load port control system according to claim 1, characterized in that, After acquiring the command signal and the load condition of the first actuator (71), the method further includes: When the load condition is negative and the command signal indicates that the second working link is not working, the first main valve (41) and the third main valve (43) are controlled to open, so that the first actuator (71) and the return oil circuit form a hydraulic circuit.

3. The energy-saving control method for the independent load port control system according to claim 1, characterized in that, After obtaining the first differential pressure, the method further includes: When the first differential pressure is not greater than the first differential pressure threshold, the first main valve (41) and the third main valve (43) are controlled to open, so that the first actuator (71) and the return oil circuit form a hydraulic circuit.

4. The energy-saving control method for the independent load port control system according to claim 1, characterized in that, Obtaining the load status of the first actuator (71) includes: Obtain the pressure at the first working port (A1) and the pressure at the second working port (B1); The direction of the load force is determined based on the pressure at the first working port (A1) and the pressure at the second working port (B1); When the direction of the load force is the same as the direction of motion indicated by the command signal, the load condition of the first actuator (71) is determined to be a negative load; When the direction of the load force is opposite to the direction of motion indicated by the command signal, the load condition of the first actuator (71) is determined to be a positive load.

5. The energy-saving control method for the independent load port control system according to claim 1, characterized in that, After acquiring the command signal and the load condition of the first actuator (71), the method further includes: When the first actuator (71) is under positive load, the pressure at the oil inlet of the first working link is detected; If the pressure at the oil inlet of the first working link is less than the high and low pressure identification threshold, control the second main valve (42) and the fourth main valve (44) to open; When the pressure at the oil inlet of the first working link is greater than or equal to the high and low pressure identification threshold, the second main valve (42) and the third main valve (43) are controlled to open.

6. The energy-saving control method for the independent load port control system according to claim 1, characterized in that, The second actuator (72) includes a third working port (A2) and a fourth working port (B2). The second working link includes a fifth main valve (45). The fifth main valve (45) includes a working oil port connected to the third working port (A2), a working oil port connected to the fourth working port (B2), an oil inlet connected to the oil inlet circuit, and a return oil port connected to the oil return circuit.

7. The energy-saving control method for the independent load port control system according to claim 1, characterized in that, The control of opening the first main valve (41), the third main valve (43), and the fourth main valve (44) includes: Based on the pressure difference between the oil outlet of the first actuator (71) and the oil return port of the first working link, the valve opening of the third main valve (43) is controlled to distribute the flow rate back to the oil tank.

8. The energy-saving control method for an independent load port control system according to any one of claims 1 to 7, characterized in that, The first main valve (41), the second main valve (42), the third main valve (43), and the fourth main valve (44) are each connected to a proportional pilot valve. The method further includes: The opening and closing of the first main valve (41), the second main valve (42), the third main valve (43) and the fourth main valve (44) are controlled by the proportional pilot valve.

9. An energy-saving control device for an independent load port control system, characterized in that, The independent control system for the load port includes a first working link, a first actuator (71), a second actuator (72), a second working link, an oil inlet circuit, and an oil return circuit. The first working link includes a first main valve (41), a second main valve (42), a third main valve (43), a fourth main valve (44), and a branch oil return passage (46). The first main valve (41) is installed between the first working port (A1) of the first actuator (71) and the branch oil return passage (46). The second main valve (42) is installed between the first working port (A1) of the first actuator (71) and the oil inlet circuit. The third main valve (43) is installed between the second working port (B1) of the first actuator (71) and the branch oil return passage (46). The fourth main valve (44) is installed between the second working port (B1) of the first actuator (71) and the oil inlet circuit. The energy-saving control device includes: The first acquisition module is used to acquire the instruction signal and the load condition of the first actuator (71); The second acquisition module is used to acquire a first pressure difference when the load condition is a negative load and the command signal indicates that the second working link is working. The first pressure difference is the pressure difference between the oil outlet chamber of the first actuator (71) and the oil inlet of the first working link. The control module is used to acquire the oil outlet flow rate of the first actuator (71) and the oil inlet flow rate of the second actuator (72) when the first differential pressure is greater than the first differential pressure threshold; when the oil outlet flow rate of the first actuator (71) is not greater than the oil inlet flow rate of the second actuator (72), control the first main valve (41) and the fourth main valve (44) to open so that the first working link inputs the gravity potential energy recovery flow rate into the oil inlet circuit and provides it to the second working link for use; when the oil outlet flow rate of the first actuator (71) is greater than the oil inlet flow rate of the second actuator (72), control the first main valve (41), the third main valve (43) and the fourth main valve (44) to open.

10. A readable storage medium storing executable instructions, characterized in that, When the executable instruction is executed by the controller (8), it implements the energy-saving control method of the load port independent control system as described in any one of claims 1 to 8.

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