Oil replenishment control method, device, excavator and storage medium for excavator hydraulic system

Abstract

The present invention relates to the technical field of excavators, and specifically discloses a supplementary oil control method, device, excavator and storage medium for an excavator hydraulic system. The supplementary oil control method for the excavator hydraulic system determines the required rotational speed of the supplementary oil pump by obtaining the required flow rates of the boom cylinder, the stick cylinder, and the bucket cylinder, and based on the required flow rates of the boom cylinder, the stick cylinder, and the bucket cylinder; the supplementary oil pump operates at the required rotational speed; obtains the current pressure of the supplementary oil circuit; calculates the difference between the set pressure and the current pressure; determines the magnitude of the difference and the set value; when the difference is greater than the set value: increases the rotational speed of the supplementary oil pump by the set rotational speed on the current basis and returns to the step of obtaining the current pressure of the supplementary oil circuit, which can make the rotational speed of the supplementary oil pump match the total flow rate required by the three cylinders, and can ensure that the supplementary oil circuit can stably supply oil to the oil circuits where the three cylinders are located.

Description

Technical Field

[0001] The present invention relates to the technical field of excavators, and particularly to an oil replenishment control method, device, excavator and storage medium for an excavator hydraulic system. Background Art

[0002] The main actions of a hydraulic excavator include the whole machine walking (left walking, right walking), platform rotation, and the actions of the boom, stick and bucket of the working device. The main action performance of a hydraulic excavator includes excavation performance, loading performance, soil leveling performance, etc. This requires a good mutual coordination relationship among the actions, that is, controllability.

[0003] In the prior art, each actuator of the excavator hydraulic system is usually decoupled and supplied with oil separately to eliminate the energy waste caused by load coupling during the combined actions of multiple actuators of the excavator and improve the operability of each actuator. After the actuators are decoupled, an open hydraulic system or a closed hydraulic system can be used for oil supply. When a closed hydraulic system is used for oil supply, an oil replenishment pump is used to replenish the oil in the oil replenishment circuit, and the oil replenishment circuit replenishes the oil in the low-pressure oil circuit of the closed hydraulic system. The excess oil in the oil replenishment circuit overflows through an oil replenishment overflow valve, and the excess oil in the high-pressure oil circuit of the closed hydraulic system overflows through a high-pressure overflow valve. Among them, when the oil replenishment pump works, the start and stop of the oil replenishment pump are usually controlled based on the oil pressure of the oil replenishment circuit. After the oil replenishment pump is started, it usually runs at a rated speed, and the rated speed is usually set relatively high to ensure that the oil pressure of the oil replenishment circuit remains stable. This also results in too much oil overflowing through the oil replenishment overflow valve, causing energy waste; at the same time, the high-pressure overflow in the high-pressure oil circuit will cause the oil temperature to rise and affect the system thermal balance. Summary of the Invention

[0004] The purpose of the present invention is to provide an oil replenishment control method, device, excavator and storage medium for an excavator hydraulic system to solve the problem of easy energy waste when the oil replenishment pump of the excavator hydraulic system starts in the prior art.

[0005] In a first aspect, the present invention provides an oil replenishment control method for an excavator hydraulic system. The excavator hydraulic system includes a first closed hydraulic system, a second closed hydraulic system, a third closed hydraulic system and an oil replenishment pump. The first closed hydraulic system is used to drive the boom cylinder to act, the second closed hydraulic system is used to drive the stick cylinder to act, the third closed hydraulic system is used to drive the bucket cylinder to act. Both ends of the oil replenishment pump are respectively connected to a fuel tank and an oil replenishment circuit, and the oil replenishment circuit is used to supply oil to the first closed hydraulic system, the second closed hydraulic system and the third closed hydraulic system. The oil replenishment control method for the excavator hydraulic system includes:

[0006] Obtain the required flow rate of the boom cylinder, the required flow rate of the stick cylinder and the required flow rate of the bucket cylinder;

[0007] Determine the required speed of the make-up oil pump based on the required flow rate of the boom cylinder, the required flow rate of the stick cylinder, and the required flow rate of the bucket cylinder;

[0008] The make-up oil pump operates at the required speed;

[0009] Obtain the current pressure of the make-up oil circuit;

[0010] Calculate the difference between the set pressure and the current pressure;

[0011] Judge the magnitude of the difference and the set value;

[0012] If the difference is greater than the set value, increase the speed of the make-up oil pump by the set speed on the current basis and return to the step of obtaining the current pressure of the make-up oil circuit.

[0013] As a preferred technical solution of the make-up oil control method for the excavator hydraulic system, the first closed hydraulic system includes a first boom oil pump, a second boom oil pump, and a boom balance valve. One end of the first boom oil pump is connected to the first boom oil circuit, and the other end is connected to the second boom oil circuit. The first boom oil circuit is connected to the rodless chamber of the boom cylinder, and the second boom oil circuit is connected to the rod chamber of the boom cylinder. The boom balance valve is configured to connect the one with the smaller oil pressure in the first boom oil circuit and the second boom oil circuit to the make-up oil circuit. One end of the second boom oil pump is connected to the make-up oil circuit, and the other end is connected to the third boom oil circuit. The third boom oil circuit and the first boom oil circuit are connected;

[0014] Obtaining the required flow rate of the boom cylinder includes:

[0015] Obtain the flow rate of the oil flowing through the second boom oil pump and the flow rate of the oil flowing through the boom balance valve;

[0016] Determine the required flow rate of the boom cylinder based on the flow rate of the oil flowing through the second boom oil pump and the flow rate of the oil flowing through the boom balance valve.

[0017] As a preferred technical solution of the make-up oil control method for the excavator hydraulic system, the excavator includes a control handle for controlling the extension and retraction of the boom piston rod of the boom cylinder;

[0018] Obtaining the required flow rate of the boom cylinder includes:

[0019] Obtain the position of the control handle;

[0020] Determine the movement direction of the boom piston rod of the boom cylinder and the movement speed of the boom piston rod of the boom cylinder based on the position of the control handle;

[0021] Obtain the area of the rod chamber of the boom cylinder and the area of the non-rod chamber of the boom cylinder;

[0022] Determine the required flow rate of the boom cylinder based on the movement direction of the boom piston rod, the movement speed of the boom piston rod of the boom cylinder, the area of the rod chamber of the boom cylinder, and the area of the non-rod chamber of the boom cylinder.

[0023] As a preferred technical solution of the oil replenishment control method for the excavator hydraulic system, the second closed hydraulic system includes a first dipper stick oil pump, a second dipper stick oil pump, and a dipper stick balance valve. One end of the first dipper stick oil pump is connected to the first dipper stick oil circuit, and the other end is connected to the second dipper stick oil circuit. The first dipper stick oil circuit is connected to the non-rod chamber of the dipper stick cylinder, and the second dipper stick oil circuit is connected to the rod chamber of the dipper stick cylinder. The dipper stick balance valve is configured to connect the one with the smaller oil pressure in the first dipper stick oil circuit and the second dipper stick oil circuit to the oil replenishment oil circuit. One end of the second dipper stick oil pump is connected to the oil replenishment oil circuit, and the other end of the second dipper stick oil pump is connected to the third dipper stick oil circuit, and the third dipper stick oil circuit is connected to the first dipper stick oil circuit;

[0024] Obtaining the required flow rate of the dipper stick cylinder includes:

[0025] Obtain the flow rate of the oil flowing through the second dipper stick oil pump and the flow rate of the oil flowing through the dipper stick balance valve;

[0026] Determine the required flow rate of the dipper stick cylinder based on the flow rate of the oil flowing through the second dipper stick oil pump and the flow rate of the oil flowing through the dipper stick balance valve.

[0027] As a preferred technical solution of the oil replenishment control method for the excavator hydraulic system, the excavator includes a control handle for controlling the extension and retraction of the dipper stick piston rod of the dipper stick cylinder;

[0028] Obtaining the required flow rate of the dipper stick cylinder includes:

[0029] Obtain the position of the control handle;

[0030] Determine the movement direction and movement speed of the dipper stick piston rod based on the position of the control handle;

[0031] Obtain the area of the rod chamber of the dipper stick cylinder and the area of the non-rod chamber of the dipper stick cylinder;

[0032] Determine the required flow rate of the dipper stick cylinder based on the movement direction of the dipper stick piston rod, the movement speed of the dipper stick piston rod, the area of the rod chamber of the dipper stick cylinder, and the area of the non-rod chamber of the dipper stick cylinder.

[0033] As a preferred technical solution of the oil replenishment control method for the excavator hydraulic system, the third closed hydraulic system includes a first bucket oil pump, a second bucket oil pump, and a bucket balance valve. One end of the first bucket oil pump is connected to the first bucket oil circuit, and the other end is connected to the second bucket oil circuit. The first bucket oil circuit is connected to the rodless cavity of the bucket cylinder, and the second bucket oil circuit is connected to the rod cavity of the bucket cylinder. The bucket balance valve is configured to connect the oil circuit with the lower oil pressure in the first bucket oil circuit and the second bucket oil circuit to the oil replenishment oil circuit. One end of the second bucket oil pump is connected to the oil replenishment oil circuit, and the other end of the second bucket oil pump is connected to the third bucket oil circuit. The third bucket oil circuit is connected to the first bucket oil circuit;

[0034] Obtaining the required flow rate of the bucket cylinder includes:

[0035] Obtaining the flow rate of the oil flowing through the second bucket oil pump and the flow rate of the oil flowing through the bucket balance valve;

[0036] Determining the required flow rate of the bucket cylinder based on the flow rate of the oil flowing through the second bucket oil pump and the flow rate of the oil flowing through the bucket balance valve.

[0037] As a preferred technical solution of the oil replenishment control method for the excavator hydraulic system, the excavator includes a control handle for controlling the extension and retraction of the bucket piston rod of the bucket cylinder;

[0038] Obtaining the required flow rate of the bucket cylinder includes:

[0039] Obtaining the position of the control handle;

[0040] Determining the movement direction of the bucket piston rod of the bucket cylinder and the movement speed of the bucket piston rod of the bucket cylinder based on the position of the control handle;

[0041] Obtaining the area of the rod cavity of the bucket cylinder and the area of the rodless cavity of the bucket cylinder;

[0042] Determining the required flow rate of the bucket cylinder based on the movement direction of the bucket piston rod, the movement speed of the bucket piston rod of the bucket cylinder, the area of the rod cavity of the bucket cylinder, and the area of the rodless cavity of the bucket cylinder.

[0043] In a second aspect, the present invention provides an oil replenishment control device for an excavator hydraulic system. The excavator hydraulic system includes a first closed hydraulic system, a second closed hydraulic system, a third closed hydraulic system, and an oil replenishment pump. The first closed hydraulic system is used to drive the boom cylinder to actuate, the second closed hydraulic system is used to drive the arm cylinder to actuate, and the third closed hydraulic system is used to drive the bucket cylinder to actuate. Both ends of the oil replenishment pump are respectively connected to an oil tank and an oil replenishment oil circuit, and the oil replenishment oil circuit is used to supply oil to the first closed hydraulic system, the second closed hydraulic system, and the third closed hydraulic system. The oil replenishment control device of the excavator hydraulic system includes:

[0044] A flow rate acquisition module, configured to acquire the required flow rate of the boom cylinder, the required flow rate of the arm cylinder, and the required flow rate of the bucket cylinder;

[0045] A required rotation speed determination module, configured to determine the required rotation speed of the oil replenishment pump based on the required flow rate of the boom cylinder, the required flow rate of the arm cylinder, and the required flow rate of the bucket cylinder;

[0046] An execution module, configured to operate the oil replenishment pump at the required rotation speed;

[0047] A current pressure acquisition module, configured to acquire the current pressure of the oil replenishment oil circuit;

[0048] A difference calculation module, configured to calculate the difference between the set pressure and the current pressure;

[0049] A judgment module, configured to judge the magnitude of the difference and the set value;

[0050] A rotation speed increase module, configured to increase the rotation speed of the oil replenishment pump by a set rotation speed on the current basis when the difference is greater than the set value.

[0051] In a third aspect, the present invention provides an excavator, including:

[0052] One or more processors;

[0053] A storage device, configured to store one or more programs;

[0054] When the one or more programs are executed by the one or more processors, the one or more processors are enabled to control the excavator to implement the oil replenishment control method for the excavator hydraulic system as described in any of the above solutions.

[0055] In a fourth aspect, the present invention provides a storage medium, on which a computer program is stored. When the program is executed by a processor, the excavator is enabled to implement the oil replenishment control method for the excavator hydraulic system as described in any of the above solutions.

[0056] The beneficial effects of the present invention are as follows:

[0057] The invention provides an oil replenishment control method, device, excavator and storage medium for an excavator hydraulic system. The oil replenishment control method for the excavator hydraulic system determines the required speed of the oil replenishment pump by obtaining the required flow rates of the boom cylinder, the stick cylinder, and the bucket cylinder, and runs the oil replenishment pump at the required speed; obtains the current pressure of the oil replenishment oil circuit; calculates the difference between the set pressure and the current pressure; determines the magnitude of the difference from the set value; when the difference is greater than the set value: increases the speed of the oil replenishment pump by a set speed on the current basis and returns to the step of obtaining the current pressure of the oil replenishment oil circuit, which can make the speed of the oil replenishment pump match the total flow rate required by the boom cylinder, the bucket cylinder, and the stick cylinder, avoid excessive speed of the oil replenishment pump and cause energy waste, and the speed of the oil replenishment pump can also ensure that the oil pressure of the oil replenishment oil circuit stably supplies oil to the first closed hydraulic system, the second closed hydraulic system, and the third closed hydraulic system. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 FIG. 1 is a first structural schematic diagram of an excavator hydraulic system in an embodiment of the present invention;

[0059] Figure 2 FIG. 2 is a second structural schematic diagram of an excavator hydraulic system in an embodiment of the present invention;

[0060] Figure 3 FIG. 3 is a third structural schematic diagram of an excavator hydraulic system in an embodiment of the present invention;

[0061] Figure 4 FIG. 4 is a flowchart of an oil replenishment control method for an excavator hydraulic system in an embodiment of the present invention;

[0062] Figure 5 FIG. 5 is a structural schematic diagram of an oil replenishment control device for an excavator hydraulic system in an embodiment of the present invention;

[0063] Figure 6 FIG. 6 is a structural schematic diagram of a control system of an excavator hydraulic system provided in an embodiment of the present invention.

[0064] In the figure:

[0065] 1. Boom cylinder; 2. Arm cylinder; 3. Bucket cylinder; 4. Make-up oil pump; 5. Fuel tank; 6. Make-up oil circuit; 7. Make-up oil overflow valve; 8. First boom oil pump; 9. Boom balance valve; 10. First boom oil circuit; 11. Second boom oil circuit; 12. Second boom oil pump; 13. Third boom oil circuit; 14. Hydraulic control valve group; 15. First hydraulic control check valve; 16. Boom control valve; 17. First make-up oil check valve; 18. Second make-up oil check valve; 19. First overflow valve; 20. Second overflow valve; 21. First arm oil pump; 22. Arm balance valve; 23. First arm oil circuit; 24. Second arm oil circuit; 25. Second arm oil pump; 26. Third arm oil circuit; 27. Second hydraulic control check valve; 28. Third hydraulic control check valve; 29. Arm control valve; 30. Third make-up oil check valve; 31. Fourth make-up oil check valve; 32. Third overflow valve; 33. Fourth overflow valve; 34. Arm regeneration valve; 35. First bucket oil pump; 36. Bucket balance valve; 37. First bucket oil circuit; 38. Second bucket oil circuit; 39. Second bucket oil pump; 40. Third bucket oil circuit; 41. Fourth hydraulic control check valve; 42. Fifth hydraulic control check valve; 43. Bucket control valve; 44. Fifth make-up oil check valve; 45. Sixth make-up oil check valve; 46. Fifth overflow valve; 47. Sixth overflow valve; 48. Bucket regeneration valve;

[0066] 50. Flow acquisition module; 51. Demand speed determination module; 52. Execution module; 53. Current pressure acquisition module; 54. Difference calculation module; 55. Judgment module; 56. Speed increase module;

[0067] 100. Terminal device; 110. Processor; 120. ROM; 130. RAM; 140. Bus; 150. I / O interface; 160. Input unit; 170. Output unit; 180. Storage unit; 190. Communication unit. Detailed implementation manners

[0068] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0069] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. Among them, the terms "first position" and "second position" are two different positions. Moreover, the first feature being "above", "over" and "on" the second feature includes the first feature being directly above and obliquely above the second feature, or merely indicating that the first feature has a higher horizontal height than the second feature. The first feature being "under", "beneath" and "under" the second feature includes the first feature being directly below and obliquely below the second feature, or merely indicating that the first feature has a lower horizontal height than the second feature.

[0070] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "mounted", "connected" and "coupled" shall be construed in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0071] The embodiments of the present invention will be described in detail below. The examples of the embodiments are shown in the drawings, in which the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the drawings are exemplary and are only used to explain the present invention and should not be construed as a limitation to the present invention.

[0072] This embodiment provides a method for controlling the oil replenishment of an excavator hydraulic system. The method for controlling the oil replenishment of the excavator hydraulic system is applicable to the situation of automatically controlling an oil replenishment pump. The method for controlling the oil replenishment of the excavator hydraulic system can be executed by a control device for the oil replenishment of the excavator hydraulic system. The control device for the oil replenishment of the excavator hydraulic system can be implemented in a software and / or hardware manner and integrated in the excavator.

[0073] Please refer to Figures 1 to 3, the excavator hydraulic system includes a first closed hydraulic system, a second closed hydraulic system, a third closed hydraulic system, and a makeup oil pump 4. The first closed hydraulic system is used to drive the boom cylinder 1 to act, the second closed hydraulic system is used to drive the arm cylinder 2 to act, the third closed hydraulic system is used to drive the bucket cylinder 3 to act. Both ends of the makeup oil pump 4 are respectively connected to the fuel tank 5 and the makeup oil circuit 6, and the makeup oil circuit 6 is used to supply oil to the first closed hydraulic system, the second closed hydraulic system, and the third closed hydraulic system. With such a setting, the boom cylinder 1, the arm cylinder 2, and the bucket cylinder 3 are decoupled respectively, which is convenient for controlling the boom, the arm, and the bucket.

[0074] Among them, the makeup oil pump 4 specifically adopts an open pump. The excavator hydraulic system further includes a makeup oil overflow valve 7 connected to the makeup oil circuit 6, and the makeup oil overflow valve 7 is used to overflow the oil in the makeup oil circuit 6 that exceeds the set pressure to the fuel tank 5.

[0075] Please refer to Figure 1 , in this embodiment, the boom cylinder 1 includes a boom rod chamber and a boom rodless chamber with variable volume. The boom cylinder 1 further includes a boom piston rod and a boom cylinder block. The boom piston rod divides the inner cavity of the boom cylinder block into a boom rod chamber and a boom rodless chamber. The boom piston rod passes through the boom rod chamber so that the cross-sectional area of the boom rod chamber is smaller than that of the boom rodless chamber. The boom piston rod can move in the boom cylinder block, and when the boom piston rod moves, the volumes of the boom rod chamber and the boom rodless chamber increase and decrease reciprocally. Among them, in this embodiment, the boom cylinder block is hinged to the body of the excavator, and the boom piston rod is hinged to the boom.

[0076] Optionally, the first closed hydraulic system includes a first boom oil pump 8, a second boom oil pump 12, and a boom balance valve 9. One end of the first boom oil pump 8 is connected to a first boom oil circuit 10, and the other end is connected to a second boom oil circuit 11. The first boom oil circuit 10 is connected to the rodless chamber of the boom cylinder 1, and the second boom oil circuit 11 is connected to the rod chamber of the boom cylinder 1. The boom balance valve 9 is configured to connect the one with a lower oil pressure in the first boom oil circuit 10 and the second boom oil circuit 11 to the oil replenishing circuit 6. One end of the second boom oil pump 12 is connected to the oil replenishing circuit 6, and the other end of the second boom oil pump 12 is connected to a third boom oil circuit 13. The third boom oil circuit 13 and the first boom oil circuit 10 are connected. Since the cross-sectional areas of the rod chamber and the rodless chamber of the boom are different, there is a flow rate difference. When the first boom oil pump 8 drives the oil to flow between the rod chamber and the rodless chamber of the boom, the second boom oil pump 12 can be used to drive the oil to flow between the oil replenishing circuit 6 and the rodless chamber of the boom, and the boom balance valve 9 is used to connect the one with a lower oil pressure in the first boom oil circuit 10 and the second boom oil circuit 11 to the oil replenishing circuit 6 to balance the flow rate difference between the rod chamber and the rodless chamber of the boom. Moreover, the oil temperature in the oil replenishing circuit 6 is relatively low, and the hot oil in the boom hydraulic circuit can be replaced with the low-temperature oil in the oil replenishing circuit, which can ensure the normal oil temperature in the boom hydraulic circuit and thus ensure the normal operation of the boom cylinder 1. Among them, both the first boom oil pump 8 and the second boom oil pump 12 adopt closed pumps. The first boom oil pump 8 can rotate forward and backward, and the second boom oil pump 12 can also rotate forward and backward. Specifically, both the first boom oil pump 8 and the second boom oil pump 12 can adopt fixed-displacement pumps.

[0077] Among them, the movement direction of the piston rod and the direction of the load force on the piston rod jointly determine the oil pressure in the rodless chamber and the rod chamber. When it is defined that the direction of the load force is the same as the movement direction of the piston rod, the load force is a negative load, and when the direction of the load force is opposite to the movement direction of the piston rod, the load force is a positive load.

[0078] When the boom piston rod moves towards the extended position, the boom piston rod gradually extends outwards. The first boom oil pump 8 rotates forward and pumps the oil in the rod chamber of the boom into the rodless chamber of the boom. If the boom piston rod bears a positive load at this time, the oil pressure in the rod chamber of the boom is less than the oil pressure in the rodless chamber of the boom, then the boom balance valve 9 connects the second boom oil circuit 11 and the oil replenishing circuit 6. If the boom piston rod bears a negative load at this time, the oil pressure in the rod chamber of the boom is greater than the oil pressure in the rodless chamber of the boom, then the boom balance valve 9 connects the first boom oil circuit 10 and the oil replenishing circuit 6. When the boom piston rod moves towards the retracted position, the boom piston rod gradually retracts inwards. If the boom piston rod bears a positive load at this time, the oil pressure in the rod chamber of the boom is greater than the oil pressure in the rodless chamber of the boom, then the boom balance valve 9 connects the first boom oil circuit 10 and the oil replenishing circuit 6. If the boom piston rod bears a negative load at this time, the oil pressure in the rod chamber of the boom is less than the oil pressure in the rodless chamber of the boom, then the boom balance valve 9 connects the second boom oil circuit 11 and the oil replenishing circuit 6.

[0079] In this embodiment, the boom balance valve 9 is a hydraulic control valve. The boom balance valve 9 has a hydraulic control end A1 and a hydraulic control end A2. The hydraulic control end A1 is connected to the first boom oil circuit 10, and the hydraulic control end A2 is connected to the second boom oil circuit 11. The hydraulic control end A1 and the hydraulic control end A2 are respectively located on both sides of the spool of the boom balance valve 9, and the oil in the hydraulic control end A1 and the hydraulic control end A2 directly acts on the spool of the boom balance valve 9. By comparing the force exerted on the spool of the boom balance valve 9 by the oil in the hydraulic control end A1 and the force exerted on the spool of the boom balance valve 9 by the oil in the hydraulic control end A2, the stop position of the spool of the boom balance valve 9 is determined. Among them, the boom balance valve 9 has a left position, a right position and a middle position. When the boom balance valve 9 is in the left position, the boom balance valve 9 connects the oil replenishing circuit 6 and the second boom oil circuit 11; when the boom balance valve 9 is in the right position, the boom balance valve 9 connects the oil replenishing circuit 6 and the first boom oil circuit 10. When the boom balance valve 9 is in the middle position, both the first boom oil circuit 10 and the second boom oil circuit 11 are disconnected from the oil replenishing circuit 6.

[0080] In this embodiment, the first closed hydraulic system further includes a first hydraulic control check valve 15. Among them, the first hydraulic control check valve 15 is arranged on the first boom oil circuit 10. When the oil pressure of the oil delivered to the first hydraulic control check valve 15 exceeds the set value, it can make the first hydraulic control check valve 15 open and make the oil continue to be delivered to the rodless chamber of the boom; when the oil pressure of the oil delivered to the first hydraulic control check valve 15 does not exceed the set value, the first hydraulic control check valve 15 disconnects the first boom oil circuit 10. At this time, the first hydraulic control check valve 15 can be controlled to open or close through the hydraulic control valve group 14 of the first hydraulic control check valve 15. Among them, the specific structure of the first hydraulic control check valve 15 is the prior art and will not be elaborated here.

[0081] The first closed hydraulic system further includes a boom control valve 16. The boom control valve 16 is disposed in the first boom oil circuit 10 and is located between the connection of the third boom oil circuit 13 and the first boom oil circuit 10 and the first boom oil pump 8. The boom control valve 16 is used to open or close the first boom oil circuit 10.

[0082] The first closed hydraulic system further includes a first oil replenishing check valve 17 and a second oil replenishing check valve 18. The first oil replenishing check valve 17 is connected between the oil replenishing oil circuit 6 and the first boom oil circuit 10, and the first oil replenishing check valve 17 only allows the oil fluid to flow from the oil replenishing oil circuit 6 to the first boom oil circuit 10. The second oil replenishing check valve 18 only allows the oil fluid to flow from the oil replenishing oil circuit 6 to the second boom oil circuit 11.

[0083] The first closed hydraulic system further includes a first relief valve 19 and a second relief valve 20. The first relief valve 19 is connected between the oil replenishing oil circuit 6 and the first boom oil circuit 10, and the first relief valve 19 only allows the oil fluid to overflow from the rodless cavity of the boom through the first boom oil circuit 10 to the oil replenishing oil circuit 6. The second relief valve 20 is connected between the oil replenishing oil circuit 6 and the second boom oil circuit 11, and the second relief valve 20 only allows the oil fluid to overflow from the rod cavity of the boom through the second boom oil circuit 11 to the oil replenishing oil circuit 6.

[0084] Please refer to Figure 2 , the stick cylinder 2 includes a rod cavity of the stick with variable volume and a rodless cavity of the stick. The stick cylinder 2 further includes a stick piston rod and a stick cylinder block. The stick piston rod divides the inner cavity of the stick cylinder block into the rod cavity of the stick and the rodless cavity of the stick. The stick piston rod passes through the rod cavity of the stick so that the cross-sectional area of the rod cavity of the stick is smaller than that of the rodless cavity of the stick. The stick piston rod can move in the stick cylinder block, and when the stick piston rod moves, the volumes of the rod cavity of the stick and the rodless cavity of the stick increase and decrease reciprocally. Among them, in this embodiment, the stick cylinder block is hinged to the boom, and the stick piston rod is hinged to the stick.

[0085] Optionally, the second closed hydraulic system includes a first boom oil pump 21, a second boom oil pump 25, and a boom balance valve 22. One end of the first boom oil pump 21 is connected to a first boom oil circuit 23, and the other end is connected to a second boom oil circuit 24. The first boom oil circuit 23 is connected to the rodless chamber of the boom cylinder 2, and the second boom oil circuit 24 is connected to the rod chamber of the boom cylinder 2. The boom balance valve 22 is configured to connect the one with a lower oil pressure in the first boom oil circuit 23 and the second boom oil circuit 24 to the oil replenishing circuit 6. One end of the second boom oil pump 25 is connected to the oil replenishing circuit 6, and the other end of the second boom oil pump 25 is connected to a third boom oil circuit 26. The third boom oil circuit 26 and the first boom oil circuit 23 are connected. Since the cross-sectional areas of the rod chamber and the rodless chamber of the boom are different, there is a flow rate difference. When the first boom oil pump 21 drives the oil to flow between the rod chamber and the rodless chamber of the boom, the second boom oil pump 25 can be used to drive the oil to flow between the oil replenishing circuit 6 and the rodless chamber of the boom, and the boom balance valve 22 is used to connect the one with a lower oil pressure in the first boom oil circuit 23 and the second boom oil circuit 24 to the oil replenishing circuit 6 to balance the flow rate difference between the rod chamber and the rodless chamber of the boom. Moreover, the oil temperature in the oil replenishing circuit 6 is relatively low, and the hot oil in the boom hydraulic circuit can be replaced with the low-temperature oil in the oil replenishing circuit, which can ensure the normal oil temperature in the boom hydraulic circuit and thus ensure the normal operation of the boom cylinder 2. Among them, both the first boom oil pump 21 and the second boom oil pump 25 are closed pumps. The first boom oil pump 21 can rotate forward and backward, and the second boom oil pump 25 can also rotate forward and backward. Specifically, both the first boom oil pump 21 and the second boom oil pump 25 can be fixed-displacement pumps.

[0086] When the boom piston rod moves towards the extended position, the boom piston rod gradually extends outwards. The first boom oil pump 21 rotates forward and pumps the oil in the rod chamber of the boom into the rodless chamber of the boom. If the boom piston rod bears a positive load at this time, the oil pressure in the rod chamber of the boom is less than the oil pressure in the rodless chamber of the boom, then the boom balance valve 22 connects the second boom oil circuit 24 and the oil replenishing circuit 6. If the boom piston rod bears a negative load at this time, the oil pressure in the rod chamber of the boom is greater than the oil pressure in the rodless chamber of the boom, then the boom balance valve 22 connects the first boom oil circuit 23 and the oil replenishing circuit 6. When the boom piston rod moves towards the retracted position, the boom piston rod gradually retracts inwards. If the boom piston rod bears a positive load at this time, the oil pressure in the rod chamber of the boom is greater than the oil pressure in the rodless chamber of the boom, then the boom balance valve 22 connects the first boom oil circuit 23 and the oil replenishing circuit 6. If the boom piston rod bears a negative load at this time, the oil pressure in the rod chamber of the boom is less than the oil pressure in the rodless chamber of the boom, then the boom balance valve 22 connects the second boom oil circuit 24 and the oil replenishing circuit 6.

[0087] In this embodiment, the boom balance valve 22 is a hydraulically controlled valve. The boom balance valve 22 has a hydraulic control end A3 and a hydraulic control end A4. The hydraulic control end A3 is connected to the first boom oil circuit 23, and the hydraulic control end A4 is connected to the second boom oil circuit 24. The hydraulic control end A3 and the hydraulic control end A4 are respectively located on both sides of the spool of the boom balance valve 22, and the hydraulic oil at the hydraulic control end A3 and the hydraulic control end A4 directly acts on the spool of the boom balance valve 22. The force exerted by the hydraulic oil at the hydraulic control end A3 on the spool of the boom balance valve 22 is compared with the force exerted by the hydraulic oil at the hydraulic control end A4 on the spool of the boom balance valve 22 to determine the stop position of the spool of the boom balance valve 22. Among them, the boom balance valve 22 has a left position, a right position, and a middle position. When the boom balance valve 22 is in the left position, the boom balance valve 22 connects the oil replenishing circuit 6 and the second boom oil circuit 24; when the boom balance valve 22 is in the right position, the boom balance valve 22 connects the oil replenishing circuit 6 and the first boom oil circuit 23. When the boom balance valve 22 is in the middle position, both the first boom oil circuit 23 and the second boom oil circuit 24 are disconnected from the oil replenishing circuit 6.

[0088] In this embodiment, the second closed hydraulic system further includes a second hydraulic control check valve 27 and a third hydraulic control check valve 28. Among them, the second hydraulic control check valve 27 is disposed on the first boom oil circuit 23. When the oil pressure of the oil delivered to the second hydraulic control check valve 27 exceeds the set value, the second hydraulic control check valve 27 can be opened, and the oil continues to be delivered to the rodless cavity of the boom; when the oil pressure of the oil delivered to the second hydraulic control check valve 27 does not exceed the set value, the second hydraulic control check valve 27 disconnects the first boom oil circuit 23. At this time, the second hydraulic control check valve 27 can be controlled to open or close through the hydraulic control valve group of the second hydraulic control check valve 27. The third hydraulic control check valve 28 is disposed on the second boom oil circuit 24. When the oil pressure of the oil delivered to the third hydraulic control check valve 28 exceeds the set value, the third hydraulic control check valve 28 can be opened, and the oil continues to be delivered to the rod end cavity of the boom; when the oil pressure of the oil delivered to the third hydraulic control check valve 28 does not exceed the set value, the third hydraulic control check valve 28 disconnects the second boom oil circuit 24. At this time, the third hydraulic control check valve 28 can be controlled to open or close through the hydraulic control valve group of the third hydraulic control check valve 28. Among them, the specific structures of the second hydraulic control check valve 27 and the third hydraulic control check valve 28 are prior art and will not be elaborated here.

[0089] The second closed hydraulic system further includes a boom control valve 29. The boom control valve 29 is disposed on the first boom oil circuit 23 and is located between the connection of the third boom oil circuit 26 and the first boom oil circuit 23 and the first boom oil pump 21. The boom control valve 29 is used to open or close the first boom oil circuit 23.

[0090] The second closed hydraulic system further includes a third oil replenishing check valve 30 and a fourth oil replenishing check valve 31. The third oil replenishing check valve 30 is connected between the oil replenishing oil circuit 6 and the first dipper stick oil circuit 23, and the third oil replenishing check valve 30 only allows the oil fluid to flow from the oil replenishing oil circuit 6 to the first dipper stick oil circuit 23. The fourth oil replenishing check valve 31 only allows the oil fluid to flow from the oil replenishing oil circuit 6 to the second dipper stick oil circuit 24.

[0091] The second closed hydraulic system further includes a third overflow valve 32 and a fourth overflow valve 33. The third overflow valve 32 is connected between the oil replenishing oil circuit 6 and the first dipper stick oil circuit 23, and the third overflow valve 32 only allows the oil fluid to overflow from the rodless cavity of the dipper stick to the oil replenishing oil circuit 6 through the first dipper stick oil circuit 23. The fourth overflow valve 33 is connected between the oil replenishing oil circuit 6 and the second dipper stick oil circuit 24, and the fourth overflow valve 33 only allows the oil fluid to overflow from the rod cavity of the dipper stick to the oil replenishing oil circuit 6 through the second dipper stick oil circuit 24.

[0092] The second closed hydraulic system further includes a dipper stick regeneration valve 34. The dipper stick regeneration valve 34 is configured to connect or disconnect the first dipper stick oil circuit 23 and the second dipper stick oil circuit 24. Specifically, the connection point of the dipper stick regeneration valve 34 and the first dipper stick oil circuit 23 is located between the dipper stick control valve 29 and the second hydraulic control check valve 27. When the dipper stick regeneration valve 34 is opened, the oil fluid can directly flow between the rodless cavity and the rod cavity of the dipper stick, and flows from the side with higher pressure to the side with lower pressure, enabling the rapid movement of the dipper stick piston rod.

[0093] Please refer to Figure 3 , the bucket cylinder 3 includes a bucket rod cavity and a bucket rodless cavity with variable volume. The bucket cylinder 3 further includes a bucket piston rod and a bucket cylinder block. The bucket piston rod divides the inner cavity of the bucket cylinder block into the bucket rod cavity and the bucket rodless cavity. The bucket piston rod passes through the bucket rod cavity, making the cross-sectional area of the bucket rod cavity smaller than that of the bucket rodless cavity. The bucket piston rod can move within the bucket cylinder block, and when the bucket piston rod moves, the volumes of the bucket rod cavity and the bucket rodless cavity increase and decrease reciprocally. Among them, in this embodiment, the bucket cylinder block is hinged to the dipper stick, and the bucket piston rod is hinged to the bucket.

[0094] Optionally, the third closed hydraulic system includes a first bucket oil pump 35, a second bucket oil pump 39, and a bucket balance valve 36. One end of the first bucket oil pump 35 is connected to a first bucket oil circuit 37, and the other end is connected to a second bucket oil circuit 38. The first bucket oil circuit 37 is connected to the rodless chamber of the bucket cylinder 3, and the second bucket oil circuit 38 is connected to the rod chamber of the bucket cylinder 3. The bucket balance valve 36 is configured to connect the one with a lower oil pressure in the first bucket oil circuit 37 and the second bucket oil circuit 38 to the oil replenishing circuit 6. One end of the second bucket oil pump 39 is connected to the oil replenishing circuit 6, and the other end of the second bucket oil pump 39 is connected to a third bucket oil circuit 40. The third bucket oil circuit 40 and the first bucket oil circuit 37 are connected. Due to the different cross-sectional areas of the rod chamber and the rodless chamber of the bucket, there is a flow rate difference. When the first bucket oil pump 35 drives the oil to flow between the rod chamber and the rodless chamber of the bucket, the second bucket oil pump 39 can be used to drive the oil to flow between the oil replenishing circuit 6 and the rodless chamber of the bucket, and the bucket balance valve 36 can connect the one with a lower oil pressure in the first bucket oil circuit 37 and the second bucket oil circuit 38 to the oil replenishing circuit 6 to balance the flow rate difference between the rod chamber and the rodless chamber of the bucket. Moreover, the oil temperature in the oil replenishing circuit 6 is relatively low, and the hot oil in the bucket hydraulic circuit can be replaced with the low-temperature oil in the oil replenishing circuit, which can ensure the normal oil temperature in the bucket hydraulic circuit and thus ensure the normal operation of the bucket cylinder 3. Among them, both the first bucket oil pump 35 and the second bucket oil pump 39 adopt closed pumps. The first bucket oil pump 35 can rotate forward and backward, and the second bucket oil pump 39 can also rotate forward and backward. Specifically, both the first bucket oil pump 35 and the second bucket oil pump 39 can adopt fixed-displacement pumps.

[0095] When the bucket piston rod moves towards the extended position, the bucket piston rod gradually extends outwards. The first bucket oil pump 35 rotates forward and pumps the oil in the rod chamber of the bucket into the rodless chamber of the bucket. If the bucket piston rod bears a positive load at this time, the oil pressure in the rod chamber of the bucket is less than the oil pressure in the rodless chamber of the bucket, then the bucket balance valve 36 connects the second bucket oil circuit 38 and the oil replenishing circuit 6. If the bucket piston rod bears a negative load at this time, the oil pressure in the rod chamber of the bucket is greater than the oil pressure in the rodless chamber of the bucket, then the bucket balance valve 36 connects the first bucket oil circuit 37 and the oil replenishing circuit 6. When the bucket piston rod moves towards the retracted position, the bucket piston rod gradually retracts inwards. If the bucket piston rod bears a positive load at this time, the oil pressure in the rod chamber of the bucket is greater than the oil pressure in the rodless chamber of the bucket, then the bucket balance valve 36 connects the first bucket oil circuit 37 and the oil replenishing circuit 6. If the bucket piston rod bears a negative load at this time, the oil pressure in the rod chamber of the bucket is less than the oil pressure in the rodless chamber of the bucket, then the bucket balance valve 36 connects the second bucket oil circuit 38 and the oil replenishing circuit 6.

[0096] In this embodiment, the bucket balance valve 36 is a hydraulically controlled valve. The bucket balance valve 36 has a hydraulic control end A5 and a hydraulic control end A6. The hydraulic control end A5 is connected to the first bucket oil circuit 37, and the hydraulic control end A6 is connected to the second bucket oil circuit 38. The hydraulic control end A5 and the hydraulic control end A6 are respectively located on both sides of the spool of the bucket balance valve 36, and the hydraulic oil at the hydraulic control end A5 and the hydraulic control end A6 directly acts on the spool of the bucket balance valve 36. The force exerted on the spool of the bucket balance valve 36 by the hydraulic oil at the hydraulic control end A5 and the force exerted on the spool of the bucket balance valve 36 by the hydraulic oil at the hydraulic control end A6 are compared to determine the stop position of the spool of the bucket balance valve 36. Among them, the bucket balance valve 36 has a left position, a right position, and a middle position. When the bucket balance valve 36 is in the left position, the bucket balance valve 36 connects the oil replenishing circuit 6 and the second bucket oil circuit 38; when the bucket balance valve 36 is in the right position, the bucket balance valve 36 connects the oil replenishing circuit 6 and the first bucket oil circuit 37. When the bucket balance valve 36 is in the middle position, both the first bucket oil circuit 37 and the second bucket oil circuit 38 are disconnected from the oil replenishing circuit 6.

[0097] In this embodiment, the third closed hydraulic system further includes a fourth hydraulic control check valve 41 and a fifth hydraulic control check valve 42. Among them, the fourth hydraulic control check valve 41 is arranged on the first bucket oil circuit 37. When the oil pressure of the oil delivered to the fourth hydraulic control check valve 41 exceeds the set value, the fourth hydraulic control check valve 41 can be opened, and the oil continues to be delivered to the rodless cavity of the bucket; when the oil pressure of the oil delivered to the fourth hydraulic control check valve 41 does not exceed the set value, the fourth hydraulic control check valve 41 disconnects the first bucket oil circuit 37. At this time, the fourth hydraulic control check valve 41 can be controlled to open or close through the hydraulic control valve group of the fourth hydraulic control check valve 41. The fifth hydraulic control check valve 42 is arranged on the second bucket oil circuit 38. When the oil pressure of the oil delivered to the fifth hydraulic control check valve 42 exceeds the set value, the fifth hydraulic control check valve 42 can be opened, and the oil continues to be delivered to the rod cavity of the bucket; when the oil pressure of the oil delivered to the fifth hydraulic control check valve 42 does not exceed the set value, the fifth hydraulic control check valve 42 disconnects the second bucket oil circuit 38. At this time, the fifth hydraulic control check valve 42 can be controlled to open or close through the hydraulic control valve group of the fifth hydraulic control check valve 42. Among them, the specific structures of the fourth hydraulic control check valve 41 and the fifth hydraulic control check valve 42 are prior arts and will not be elaborated here.

[0098] The third closed hydraulic system further includes a bucket control valve 43. The bucket control valve 43 is arranged on the first bucket oil circuit 37 and is located between the connection of the third bucket oil circuit 40 and the first bucket oil circuit 37 and the first bucket oil pump 35. The bucket control valve 43 is used to open or close the first bucket oil circuit 37.

[0099] The third closed hydraulic system further includes a fifth oil replenishing check valve 44 and a sixth oil replenishing check valve 45. The fifth oil replenishing check valve 44 is connected between the oil replenishing oil circuit 6 and the first bucket oil circuit 37, and the fifth oil replenishing check valve 44 only allows the oil fluid to flow from the oil replenishing oil circuit 6 to the first bucket oil circuit 37. The sixth oil replenishing check valve 45 only allows the oil fluid to flow from the oil replenishing oil circuit 6 to the second bucket oil circuit 38.

[0100] The third closed hydraulic system further includes a fifth overflow valve 46 and a sixth overflow valve 47. The fifth overflow valve 46 is connected between the oil replenishing oil circuit 6 and the first bucket oil circuit 37, and the fifth overflow valve 46 only allows the oil fluid to overflow from the rodless cavity of the bucket to the oil replenishing oil circuit 6 through the first bucket oil circuit 37. The sixth overflow valve 47 is connected between the oil replenishing oil circuit 6 and the second bucket oil circuit 38, and the sixth overflow valve 47 only allows the oil fluid to overflow from the rod cavity of the bucket to the oil replenishing oil circuit 6 through the second bucket oil circuit 38.

[0101] The third closed hydraulic system further includes a bucket regeneration valve 48. The bucket regeneration valve 48 is configured to connect or disconnect the first bucket oil circuit 37 and the second bucket oil circuit 38. Specifically, the connection point of the bucket regeneration valve 48 and the first bucket oil circuit 37 is located between the bucket control valve 43 and the fourth hydraulic check valve 41. When the bucket regeneration valve 48 is opened, the direct flow of the oil fluid between the rodless cavity and the rod cavity of the bucket can be realized, and the oil fluid flows from the side with higher pressure to the side with lower pressure, enabling the rapid movement of the bucket piston rod.

[0102] Wherein, the first boom oil pump 8 and the second boom oil pump 12 can both be driven by an electric motor or an internal combustion engine; the first stick oil pump 21 and the second stick oil pump 25 can both be driven by an electric motor or an internal combustion engine; the first bucket oil pump 35 and the second bucket oil pump 39 can both be driven by an electric motor or an internal combustion engine.

[0103] Please refer to Figure 4 , the oil replenishing control method of the excavator hydraulic system includes the following steps:

[0104] S100: Obtain the required flow rates of the boom cylinder, the stick cylinder, and the bucket cylinder.

[0105] Specifically, obtaining the flow rate requirement of the boom cylinder may include:

[0106] S1011: Obtain the flow rate of the oil fluid flowing through the second boom oil pump and the flow rate of the oil fluid flowing through the boom balance valve.

[0107] S1012: Determine the required flow rate of the boom cylinder based on the flow rate of the oil fluid flowing through the second boom oil pump and the flow rate of the oil fluid flowing through the boom balance valve.

[0108] The flow rate of the oil flowing through the second boom oil pump and the flow rate of the oil flowing through the boom balance valve can be detected by a flow sensor.

[0109] Taking the extension of the boom piston rod as an example, when the boom piston rod extends, driven by the first boom oil pump, the oil in the rod chamber of the boom is pumped into the rodless chamber of the boom. If the boom piston rod bears a positive load at this time, the oil pressure in the rod chamber of the boom is less than the oil pressure in the rodless chamber of the boom, and the boom balance valve connects the second boom oil circuit and the oil replenishing circuit. Since the cross-sectional area of the rod chamber of the boom is smaller than the cross-sectional area of the rodless chamber of the boom, therefore, the flow rate of the oil required to enter the rodless chamber of the boom needs to be greater than the flow rate of the oil discharged from the rod chamber of the boom, and the oil in the oil replenishing circuit enters the second boom oil circuit through the boom balance valve; at the same time, the second boom oil pump drives the oil to enter the rodless chamber of the boom from the oil replenishing circuit through the third boom oil circuit. Therefore, the sum of the flow rate of the oil flowing through the second boom oil pump and the flow rate of the oil flowing through the boom balance valve is the required flow rate of the boom cylinder at this time, and the required flow rate of the boom cylinder is positive.

[0110] If the boom piston rod bears a negative load at this time, the oil pressure in the rod chamber of the boom is greater than the oil pressure in the rodless chamber of the boom, then the boom balance valve connects the first boom oil circuit and the oil replenishing circuit. At this time, under the action of the oil pressure difference between the rod chamber and the rodless chamber of the boom, the oil can flow from the rod chamber of the boom to the rodless chamber of the boom through the first boom oil pump, and the oil drives the first boom oil pump to rotate. If the first boom oil pump is driven by an electric motor, the first boom oil pump can also drive the electric motor to generate electricity. And the boom balance valve connects the first boom oil circuit and the oil replenishing circuit, and the oil in the oil replenishing circuit enters the rodless chamber of the boom through the boom balance valve to make up for the flow difference between the rod chamber and the rodless chamber of the boom; at the same time, the second boom oil pump does not work, that is, the oil flow rate through the second boom oil pump is zero. At this time, the sum of the flow rate of the oil flowing through the second boom oil pump and the flow rate of the oil flowing through the boom balance valve is also the required flow rate of the boom cylinder at this time, and the required flow rate of the boom cylinder is positive.

[0111] Similarly, when the boom piston rod retracts, the sum of the flow rate of the oil flowing through the second boom oil pump and the flow rate of the oil flowing through the boom balance valve is also the required flow rate of the boom cylinder at this time, but when the boom piston rod retracts, the required flow rate of the boom cylinder is negative.

[0112] As an alternative solution, obtaining the flow rate requirement of the boom cylinder may further include:

[0113] S1021: Obtain the position of the control handle.

[0114] The control handle is used to control the movement direction and movement speed of the boom piston rod, and it is a prior art and will not be elaborated here. The position of the control handle can be detected by a position sensor arranged on the control handle.

[0115] S1022: Determine the movement direction and movement speed of the boom piston rod of the boom cylinder based on the position of the control handle.

[0116] The first mapping relationship between the position of the control handle and the movement direction of the boom piston rod is pre-stored in the memory. The movement direction of the boom piston rod can be determined according to the position of the control handle and the first mapping relationship. The movement direction of the boom piston rod includes the extending direction and the retracting direction, and the first mapping relationship can be obtained through a large number of previous experiments.

[0117] The second mapping relationship between the position of the control handle and the movement speed of the boom piston rod is pre-stored in the memory. The movement speed of the boom piston rod can be determined according to the position of the control handle and the second mapping relationship. The second mapping relationship can be obtained through a large number of previous experiments.

[0118] S1023: Obtain the area of the rod chamber of the boom cylinder and the area of the rodless chamber of the boom cylinder.

[0119] The area of the rod chamber of the boom cylinder and the area of the rodless chamber of the boom cylinder are both related to the specific model of the boom cylinder and can be pre-stored in the memory.

[0120] S1024: Determine the required flow rate of the boom cylinder based on the movement direction of the boom piston rod, the movement speed of the boom piston rod, the area of the rod chamber of the boom cylinder, and the area of the rodless chamber of the boom cylinder.

[0121] The map1 of the movement direction of the boom piston rod, the movement speed of the boom piston rod, the area of the rod chamber of the boom cylinder, the area of the rodless chamber of the boom cylinder, and the required flow rate of the boom cylinder is pre-stored in the memory. The required flow rate of the boom cylinder is determined according to the movement direction of the boom piston rod, the movement speed of the boom piston rod, the area of the rod chamber of the boom cylinder, the area of the rodless chamber of the boom cylinder, and map1.

[0122] Wherein, the movement speed of the boom piston rod is V1, the movement direction of the boom piston rod is the extending direction, the area of the rod chamber of the boom cylinder is A 11 , the area of the rodless chamber of the boom cylinder is A 12 , and the required flow rate of the boom cylinder is Q1. The corresponding relationship model of map1 is: Q1 = V1 * A 11 -V1 * A 12 .

[0123] Obtaining the flow rate requirement of the stick cylinder may include:

[0124] S1031: Obtain the flow rate of the oil flowing through the second stick oil pump and the flow rate of the oil flowing through the stick balance valve;

[0125] S1032: Determine the required flow rate of the boom cylinder based on the flow rate of the oil flowing through the second boom oil pump and the flow rate of the oil flowing through the boom balance valve.

[0126] The flow rate of the oil flowing through the second boom oil pump and the flow rate of the oil flowing through the boom balance valve can be detected by a flow sensor.

[0127] Taking the extension of the boom piston rod as an example, when the boom piston rod extends, driven by the first boom oil pump, the oil in the rod chamber of the boom is pumped into the rodless chamber of the boom. If the boom piston rod bears a positive load at this time, the oil pressure in the rod chamber of the boom is less than the oil pressure in the rodless chamber of the boom, and the boom balance valve connects the second boom oil circuit and the supplementary oil circuit. Since the cross-sectional area of the rod chamber of the boom is smaller than the cross-sectional area of the rodless chamber of the boom, the flow rate of the oil required to enter the rodless chamber of the boom needs to be greater than the flow rate of the oil discharged from the rod chamber of the boom. The oil in the supplementary oil circuit enters the second boom oil circuit through the boom balance valve; at the same time, the second boom oil pump drives the oil to enter the rodless chamber of the boom from the supplementary oil circuit through the third boom oil circuit. Therefore, the sum of the flow rate of the oil flowing through the second boom oil pump and the flow rate of the oil flowing through the boom balance valve is the required flow rate of the boom cylinder at this time, and the required flow rate of the boom cylinder is positive.

[0128] If the boom piston rod bears a negative load at this time, the oil pressure in the rod chamber of the boom is greater than the oil pressure in the rodless chamber of the boom, then the boom balance valve connects the first boom oil circuit and the supplementary oil circuit. At this time, under the action of the oil pressure difference between the rod chamber and the rodless chamber of the boom, the oil can flow from the rod chamber of the boom to the rodless chamber of the boom through the first boom oil pump, and the oil drives the first boom oil pump to rotate. If the first boom oil pump is driven by an electric motor, the first boom oil pump can also drive the electric motor to generate electricity. Moreover, the boom balance valve connects the first boom oil circuit and the supplementary oil circuit, and the oil in the supplementary oil circuit enters the rodless chamber of the boom through the boom balance valve to make up for the flow rate difference between the rod chamber and the rodless chamber of the boom; at the same time, the second boom oil pump does not work, that is, the oil flow rate through the second boom oil pump is zero. At this time, the sum of the flow rate of the oil flowing through the second boom oil pump and the flow rate of the oil flowing through the boom balance valve is also the required flow rate of the boom cylinder at this time, and the required flow rate of the boom cylinder is positive.

[0129] Similarly, when the boom piston rod retracts, the sum of the flow rate of the oil flowing through the second boom oil pump and the flow rate of the oil flowing through the boom balance valve is also the required flow rate of the boom cylinder at this time, but when the boom piston rod retracts, the required flow rate of the boom cylinder is negative.

[0130] Obtaining the flow rate requirement of the boom cylinder may further include:

[0131] S1041: Obtain the position of the control handle.

[0132] Among them, the control handle is used to control the movement direction and movement speed of the stick piston rod, and it is a prior art, so it will not be elaborated here. The position sensor arranged on the control handle can detect the position of the control handle.

[0133] S1042: Determine the movement direction and movement speed of the stick piston rod of the stick cylinder based on the position of the control handle.

[0134] The third mapping relationship between the position of the control handle and the movement direction of the stick piston rod is pre-stored in the memory. According to the position of the control handle and the third mapping relationship, the movement direction of the stick piston rod can be determined. Among them, the movement direction of the stick piston rod includes the extending direction and the retracting direction, and the third mapping relationship can be obtained through a large number of previous experiments.

[0135] The fourth mapping relationship between the position of the control handle and the movement speed of the stick piston rod is pre-stored in the memory. According to the position of the control handle and the fourth mapping relationship, the movement speed of the stick piston rod can be determined. Among them, the fourth mapping relationship can be obtained through a large number of previous experiments.

[0136] S1043: Obtain the area of the rod chamber of the stick cylinder and the area of the rodless chamber of the stick cylinder.

[0137] The area of the rod chamber of the stick cylinder and the area of the rodless chamber of the stick cylinder are both related to the specific model of the stick cylinder, and can be pre-stored in the memory.

[0138] S1044: Determine the required flow rate of the stick cylinder based on the movement direction of the stick piston rod, the movement speed of the stick piston rod, the area of the rod chamber of the stick cylinder, and the area of the rodless chamber of the stick cylinder.

[0139] The map2 of the movement direction of the stick piston rod, the movement speed of the stick piston rod, the area of the rod chamber of the stick cylinder, the area of the rodless chamber of the stick cylinder, and the required flow rate of the stick cylinder is pre-stored in the memory. According to the movement direction of the stick piston rod, the movement speed of the stick piston rod, the area of the rod chamber of the stick cylinder, the area of the rodless chamber of the stick cylinder, and map2, the required flow rate of the stick cylinder is determined.

[0140] Among them, the movement speed of the stick piston rod is V2, the movement direction of the stick piston rod is the extending direction, the area of the rod chamber of the stick cylinder is A 21 , the area of the rodless chamber of the stick cylinder is A 22 , the required flow rate of the stick cylinder is Q2, then the relationship model corresponding to map2 is: Q2 = V2 * A 21 -V2 * A 22 .

[0141] Obtaining the flow rate requirement of the bucket cylinder can include:

[0142] S1051: Obtain the flow rate of the hydraulic fluid flowing through the second bucket oil pump and the flow rate of the hydraulic fluid flowing through the bucket balance valve.

[0143] S1052: Determine the required flow rate of the bucket cylinder based on the flow rate of the hydraulic fluid flowing through the second bucket oil pump and the flow rate of the hydraulic fluid flowing through the bucket balance valve.

[0144] The flow rate of the hydraulic fluid flowing through the second bucket oil pump and the flow rate of the hydraulic fluid flowing through the bucket balance valve can be detected by a flow sensor.

[0145] Taking the extension of the bucket piston rod as an example, when the bucket piston rod extends, driven by the first bucket oil pump, the hydraulic fluid in the rod chamber of the bucket is pumped into the rodless chamber of the bucket. If the bucket piston rod bears a positive load at this time, the oil pressure in the rod chamber of the bucket is less than the oil pressure in the rodless chamber of the bucket, and the bucket balance valve connects the second bucket oil circuit and the oil replenishing circuit. Since the cross-sectional area of the rod chamber of the bucket is smaller than the cross-sectional area of the rodless chamber of the bucket, therefore, the flow rate of the hydraulic fluid required to enter the rodless chamber of the bucket needs to be greater than the flow rate of the hydraulic fluid discharged from the rod chamber of the bucket, and the hydraulic fluid in the oil replenishing circuit enters the second bucket oil circuit through the bucket balance valve; at the same time, the second bucket oil pump drives the hydraulic fluid to enter the rodless chamber of the bucket from the oil replenishing circuit through the third bucket oil circuit. Therefore, the sum of the flow rate of the hydraulic fluid flowing through the second bucket oil pump and the flow rate of the hydraulic fluid flowing through the bucket balance valve is the required flow rate of the bucket cylinder at this time, and the required flow rate of the bucket cylinder is positive.

[0146] If the bucket piston rod bears a negative load at this time, the oil pressure in the rod chamber of the bucket is greater than the oil pressure in the rodless chamber of the bucket, then the bucket balance valve connects the first bucket oil circuit and the oil replenishing circuit. At this time, under the action of the oil pressure difference between the rod chamber and the rodless chamber of the bucket, the hydraulic fluid can flow from the rod chamber of the bucket through the first bucket oil pump to the rodless chamber of the bucket, and the hydraulic fluid drives the first bucket oil pump to rotate. If the first bucket oil pump is driven by an electric motor, the first bucket oil pump can also drive the electric motor to generate electricity. And, the bucket balance valve connects the first bucket oil circuit and the oil replenishing circuit, and the hydraulic fluid in the oil replenishing circuit enters the rodless chamber of the bucket through the bucket balance valve to make up for the flow rate difference between the rod chamber and the rodless chamber of the bucket; at the same time, the second bucket oil pump does not work, that is, the oil flow rate through the second bucket oil pump is zero. At this time, the sum of the flow rate of the hydraulic fluid flowing through the second bucket oil pump and the flow rate of the hydraulic fluid flowing through the bucket balance valve is also the required flow rate of the bucket cylinder at this time, and the required flow rate of the bucket cylinder is positive.

[0147] Similarly, when the bucket piston rod retracts, the sum of the flow rate of the hydraulic fluid flowing through the second bucket oil pump and the flow rate of the hydraulic fluid flowing through the bucket balance valve is also the required flow rate of the bucket cylinder at this time, but when the bucket piston rod retracts, the required flow rate of the bucket cylinder is negative.

[0148] Obtaining the flow rate requirement of the bucket cylinder may further include:

[0149] S1061: Obtain the position of the control handle.

[0150] The control handle is used to control the movement direction and movement speed of the bucket piston rod, and it is prior art, so it will not be elaborated here. The position of the control handle can be detected by a position sensor arranged on the control handle.

[0151] S1062: Determine the movement direction and movement speed of the bucket piston rod of the bucket cylinder based on the position of the control handle.

[0152] A fifth mapping relationship between the position of the control handle and the movement direction of the bucket piston rod is pre-stored in the memory. According to the position of the control handle and the fifth mapping relationship, the movement direction of the bucket piston rod can be determined. Among them, the movement direction of the bucket piston rod includes the extending direction and the retracting direction, and the fifth mapping relationship can be obtained through a large number of previous experiments.

[0153] A sixth mapping relationship between the position of the control handle and the movement speed of the bucket piston rod is pre-stored in the memory. According to the position of the control handle and the sixth mapping relationship, the movement speed of the bucket piston rod can be determined. Among them, the sixth mapping relationship can be obtained through a large number of previous experiments.

[0154] S1063: Obtain the area of the rod chamber of the bucket cylinder and the area of the rodless chamber of the bucket cylinder.

[0155] The area of the rod chamber of the bucket cylinder and the area of the rodless chamber of the bucket cylinder are both related to the specific model of the bucket cylinder and can be pre-stored in the memory.

[0156] S1064: Determine the required flow rate of the bucket cylinder based on the movement direction of the bucket piston rod, the movement speed of the bucket piston rod, the area of the rod chamber of the bucket cylinder, and the area of the rodless chamber of the bucket cylinder.

[0157] A map3 of the movement direction of the bucket piston rod, the movement speed of the bucket piston rod, the area of the rod chamber of the bucket cylinder, the area of the rodless chamber of the bucket cylinder, and the required flow rate of the bucket cylinder is pre-stored in the memory. According to the movement direction of the bucket piston rod, the movement speed of the bucket piston rod, the area of the rod chamber of the bucket cylinder, the area of the rodless chamber of the bucket cylinder, and map3, the required flow rate of the bucket cylinder is determined.

[0158] Among them, the movement speed of the bucket piston rod is V3, the movement direction of the bucket piston rod is the extending direction, the area of the rod chamber of the bucket cylinder is A 31 , the area of the rodless chamber of the bucket cylinder is A 32 , and the required flow rate of the bucket cylinder is Q3. Then the corresponding relationship model of map3 is: Q3 = V3 * A 31 - V3 * A 32 .

[0159] S200: Determine the required speed of the makeup oil pump based on the required flow rates of the boom cylinder, the stick cylinder, and the bucket cylinder.

[0160] The corresponding relationships among the required flow rates of the boom cylinder, the stick cylinder, the bucket cylinder, and the required speed of the makeup oil pump are pre-stored in the memory. According to the obtained required flow rates of the boom cylinder, the stick cylinder, and the bucket cylinder, and this corresponding relationship, the required speed of the makeup oil pump can be determined. This corresponding relationship can be obtained through a large number of previous experiments.

[0161] S300: The makeup oil pump operates at the required speed.

[0162] When the makeup oil pump operates at this required speed, it can make the flow rate of the oil supplemented by the makeup oil pump match the total flow rate required by the boom cylinder, the bucket cylinder, and the stick cylinder, avoiding excessive speed of the makeup oil pump, resulting in a large amount of oil overflow in the makeup oil circuit and causing energy waste.

[0163] S400: Obtain the current pressure of the makeup oil circuit.

[0164] The current pressure of the makeup oil circuit can be detected by a pressure sensor.

[0165] S500: Calculate the difference between the set pressure and the current pressure.

[0166] Among them, the set pressure can be set according to actual needs and is pre-stored in the memory.

[0167] S600: Judge the magnitude of the difference and the set value.

[0168] If the difference is greater than the set value, execute S700: If the difference is not greater than the set value, return to S100 and keep the speed of the makeup oil pump unchanged.

[0169] S700: Increase the speed of the makeup oil pump by the set speed on the current basis.

[0170] After executing S700, return to step S400.

[0171] Among them, the magnitude of the set speed can be set according to actual needs. When the difference is not greater than the set value, when the makeup oil circuit supplements oil to the first closed hydraulic system, the second closed hydraulic system, and the third closed hydraulic system, the makeup oil effect can be kept stable; when the difference is greater than the set value, it will affect the stability when the makeup oil circuit supplements oil to the first closed hydraulic system, the second closed hydraulic system, and the third closed hydraulic system. Therefore, the speed of the makeup oil pump is increased. In addition, the oil pressure for overflow of the makeup oil overflow valve is not less than the set oil pressure.

[0172] The oil replenishment control method for the excavator hydraulic system provided in this embodiment determines the required speed of the oil replenishment pump by obtaining the required flow rates of the boom cylinder, the stick cylinder, and the bucket cylinder, and runs the oil replenishment pump at the required speed; obtains the current pressure of the oil replenishment pipeline; calculates the difference between the set pressure and the current pressure; determines the magnitude of the difference compared to the set value; when the difference is greater than the set value: increases the speed of the oil replenishment pump by the set speed on the current basis and returns to the step of obtaining the current pressure of the oil replenishment pipeline, which can make the speed of the oil replenishment pump match the total flow rate required by the boom cylinder, the bucket cylinder, and the stick cylinder, avoid excessive speed of the oil replenishment pump and cause energy waste, and the speed of the oil replenishment pump can also ensure that the oil pressure of the oil replenishment pipeline stably supplies oil to the first closed hydraulic system, the second closed hydraulic system, and the third closed hydraulic system.

[0173] Embodiment 2

[0174] This embodiment provides an oil replenishment control device for an excavator hydraulic system. The oil replenishment control device for the excavator hydraulic system is used to implement the oil replenishment control method for the excavator hydraulic system in Embodiment 1 and has corresponding functional modules and beneficial effects for executing this method.

[0175] Please refer to Figure 5 , the oil replenishment control device for the excavator hydraulic system includes a flow rate acquisition module 50, a required speed determination module 51, an execution module 52, a current pressure acquisition module 53, a difference calculation module 54, a judgment module 55, and a speed increase module 56. Among them, the flow rate acquisition module 50 is used to obtain the required flow rates of the boom cylinder, the stick cylinder, and the bucket cylinder; the required speed determination module 51 is used to determine the required speed of the oil replenishment pump based on the required flow rates of the boom cylinder, the stick cylinder, and the bucket cylinder; the execution module 52 is used to run the oil replenishment pump at the required speed; the current pressure acquisition module 53 is used to obtain the current pressure of the oil replenishment pipeline; the difference calculation module 54 is used to calculate the difference between the set pressure and the current pressure; the judgment module 55 is used to judge the magnitude of the difference compared to the set value; when the difference is greater than the set value, the speed increase module 56 is used to increase the speed of the oil replenishment pump by the set speed on the current basis.

[0176] Embodiment 3

[0177] Figure 6It is a schematic structural diagram of a control system for an excavator hydraulic system provided by an embodiment of the present invention. The excavator (or referred to as a terminal device) is intended to represent various forms of digital computers, such as, laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The terminal device can also represent various forms of mobile devices, such as, personal digital processors, cellular phones, smart phones, wearable devices (such as helmets, glasses, watches, etc.) and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely illustrative and are not intended to limit the implementation of the present invention described herein and / or claimed.

[0178] As Figure 6 shown, the terminal device 100 includes one or more processors 110, and a storage device, the storage device is communicatively connected to the processor 110, and the storage device is such as ROM 120, random access RAM 130, etc. Among them, the storage device stores computer programs executable by one or more processors. The processor 110 can execute various appropriate actions and processes according to the computer program stored in the ROM 120 or the computer program loaded from the storage unit 180 into the random access RAM 130. In the RAM 130, various programs and data required for the operation of the terminal device 100 can also be stored. The processor 110, ROM 120, and RAM 130 are connected to each other through a bus 140. The I / O interface 150 is also connected to the bus 140.

[0179] A plurality of components in the terminal device 100 are connected to the I / O interface 150, including: an input unit 160, such as a keyboard, a mouse, etc.; an output unit 170, such as various types of displays, speakers, etc.; a storage unit 180, such as a disk, an optical disc, etc.; and a communication unit 190, such as a network card, a modem, a wireless communication transceiver, etc. The communication unit 190 allows the terminal device 100 to exchange information / data with other devices through a computer network such as the Internet and / or various telecommunication networks.

[0180] The processor 110 can be various general-purpose and / or special-purpose processing components with processing and computing capabilities. Some examples of the processor 110 include but are not limited to a central processing unit (CPU), a graphics processing unit (GPU), various dedicated artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, a digital signal processor (DSP), and any suitable processor, controller, microcontroller, etc. The processor 110 executes the various methods and processes described above, such as the oil replenishment control method for the excavator hydraulic system.

[0181] In some embodiments, the oil replenishment control method of the excavator hydraulic system can be implemented as a computer program, which is tangibly contained in a computer-readable storage medium, such as the storage unit 180. In some embodiments, part or all of the computer program can be loaded and / or installed onto the terminal device 100 via the ROM 120 and / or the communication unit 190. When the computer program is loaded into the RAM 130 and executed by the processor 110, one or more steps of the above-described oil replenishment control method of the excavator hydraulic system can be performed. Alternatively, in other embodiments, the processor 110 can be configured to execute the oil replenishment control method of the excavator hydraulic system by any other suitable means (e.g., by means of firmware).

[0182] The various embodiments of the systems and techniques described above in this document can be implemented in digital electronic circuit systems, integrated circuit systems, field programmable gate arrays (FPGA), application specific integrated circuits (ASIC), application specific standard products (ASSP), systems on a chip (SOC), complex programmable logic devices (CPLD), computer hardware, firmware, software, and / or combinations thereof. These various embodiments can include: being implemented in one or more computer programs, which can be executed and / or interpreted on a programmable system including at least one programmable processor, the programmable processor can be a dedicated or general-purpose programmable processor, and can receive data and instructions from a storage system, at least one input device, and at least one output device, and transmit the data and instructions to the storage system, the at least one input device, and the at least one output device.

[0183] The computer programs for implementing the methods of the present invention can be written in any combination of one or more programming languages. These computer programs can be provided to a processor of a general-purpose computer, a dedicated computer, or other programmable data processing devices, such that when the computer programs are executed by the processor, the functions / operations specified in the flowcharts and / or block diagrams are implemented. The computer programs can be executed entirely on the machine, partially on the machine, as a stand-alone software package partially on the machine and partially on a remote machine, or entirely on a remote machine or server.

[0184] In the context of the present invention, a computer-readable storage medium can be a tangible medium that can contain or store a computer program for use by or in connection with an instruction execution system, apparatus, or device. The computer-readable storage medium can include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatuses, or devices, or any suitable combination of the foregoing. Alternatively, the computer-readable storage medium can be a machine-readable signal medium. More specific examples of the machine-readable storage medium would include an electrical connection based on one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0185] To provide for interaction with a user, the systems and techniques described herein can be implemented on a terminal device that has: a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user; and a keyboard and a pointing device (e.g., a mouse or a trackball) by which the user can provide input to the terminal device. Other kinds of devices can also be used to provide for interaction with the user; for example, feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form (including acoustic input, speech input, or tactile input).

[0186] The systems and techniques described herein can be implemented in a computing system that includes a back-end component (e.g., as a data server), or a computing system that includes a middleware component (e.g., an application server), or a computing system that includes a front-end component (e.g., a user computer having a graphical user interface or a web browser through which the user can interact with an implementation of the systems and techniques described herein), or a computing system that includes any combination of such back-end, middleware, or front-end components. The components of the system can be interconnected by any form or medium of digital data communication (e.g., a communication network). Examples of communication networks include: a local area network (LAN), a wide area network (WAN), a blockchain network, and the Internet.

[0187] A computing system may include a client and a server. The client and the server are generally far from each other and usually interact via a communication network. The client-server relationship is created by computer programs running on respective computers and having a client-server relationship with each other. The server can be a cloud server, also known as a cloud computing server or a cloud host, which is a host product in the cloud computing service system, solving the defects of difficult management and weak business scalability existing in traditional physical hosts and VPS services.

[0188] It should be understood that various forms of processes shown above can be used, steps can be reordered, added or deleted. For example, the steps described in the present invention can be executed in parallel, sequentially or in a different order, as long as the desired results of the technical solution of the present invention can be achieved, and no limitation is made herein.

[0189] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, rather than limiting the implementation manners of the present invention. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to enumerate all the implementation manners here. Any modifications, equivalent replacements and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

1. A method for compensating oil control of an excavator hydraulic system, characterized in that, The excavator hydraulic system includes a first closed hydraulic system, a second closed hydraulic system, a third closed hydraulic system and a makeup oil pump. The first closed hydraulic system is used to drive the boom cylinder to act. The second closed hydraulic system is used to drive the arm cylinder to act. The third closed hydraulic system is used to drive the bucket cylinder to act. Both ends of the makeup oil pump are respectively connected to the fuel tank and the makeup oil circuit. The makeup oil circuit is used to supply oil to the first closed hydraulic system, the second closed hydraulic system and the third closed hydraulic system. The makeup oil control method of the excavator hydraulic system includes: Obtain the required flow rate of the boom cylinder, the required flow rate of the arm cylinder and the required flow rate of the bucket cylinder; Determine the required speed of the makeup oil pump based on the required flow rate of the boom cylinder, the required flow rate of the arm cylinder and the required flow rate of the bucket cylinder; The makeup oil pump operates at the required speed; Obtain the current pressure of the makeup oil circuit; Calculate the difference between the set pressure and the current pressure; Judge the magnitude of the difference and the set value; If the difference is greater than the set value, increase the speed of the makeup oil pump by the set speed on the current basis and return to the step of obtaining the current pressure of the makeup oil circuit; The first closed hydraulic system includes a first boom oil pump, a second boom oil pump and a boom balance valve. One end of the first boom oil pump is connected to the first boom oil circuit, and the other end is connected to the second boom oil circuit. The first boom oil circuit is connected to the rodless chamber of the boom cylinder. The second boom oil circuit is connected to the rod chamber of the boom cylinder. The boom balance valve is configured to connect the one with the smaller oil pressure in the first boom oil circuit and the second boom oil circuit to the makeup oil circuit. One end of the second boom oil pump is connected to the makeup oil circuit, and the other end of the second boom oil pump is connected to the third boom oil circuit. The third boom oil circuit is connected to the first boom oil circuit; Obtaining the required flow rate of the boom cylinder includes: Obtain the flow rate of the oil flowing through the second boom oil pump and the flow rate of the oil flowing through the boom balance valve; Determine the required flow rate of the boom cylinder based on the flow rate of the oil flowing through the second boom oil pump and the flow rate of the oil flowing through the boom balance valve.

2. The oil replenishment control method of the excavator hydraulic system according to claim 1, characterized in that The excavator includes a control handle, and the control handle is used to control the extension and retraction of the boom piston rod of the boom cylinder; Obtaining the required flow rate of the boom cylinder includes: Obtain the position of the control handle; Determine the movement direction and movement speed of the boom piston rod based on the position of the control handle; Obtain the area of the rod chamber of the boom cylinder and the area of the rodless chamber of the boom cylinder; Determine the required flow rate of the boom cylinder based on the movement direction of the boom piston rod, the movement speed of the boom piston rod, the area of the rod chamber of the boom cylinder and the area of the rodless chamber of the boom cylinder.

3. The oil replenishment control method for the hydraulic system of an excavator according to claim 1, wherein The second closed hydraulic system includes a first boom oil pump, a second boom oil pump, and a boom balance valve. One end of the first boom oil pump is connected to a first boom oil circuit, and the other end is connected to a second boom oil circuit. The first boom oil circuit is connected to the rodless chamber of the boom cylinder, and the second boom oil circuit is connected to the rod chamber of the boom cylinder. The boom balance valve is configured to connect the oil path with the lower oil pressure in the first boom oil circuit and the second boom oil circuit to the oil replenishing circuit. One end of the second boom oil pump is connected to the oil replenishing circuit, and the other end is connected to a third boom oil circuit, and the third boom oil circuit is connected to the first boom oil circuit; Obtaining the required flow rate of the boom cylinder includes: Obtaining the flow rate of the oil flowing through the second boom oil pump and the flow rate of the oil flowing through the boom balance valve; Determining the required flow rate of the boom cylinder based on the flow rate of the oil flowing through the second boom oil pump and the flow rate of the oil flowing through the boom balance valve.

4. The oil replenishment control method of the excavator hydraulic system according to claim 1, characterized in that The excavator includes a control handle for controlling the extension and retraction of the boom piston rod of the boom cylinder; Obtaining the required flow rate of the boom cylinder includes: Obtaining the position of the control handle; Determining the movement direction and movement speed of the boom piston rod based on the position of the control handle; Obtaining the area of the rod chamber of the boom cylinder and the area of the rodless chamber of the boom cylinder; Determining the required flow rate of the boom cylinder based on the movement direction of the boom piston rod, the movement speed of the boom piston rod, the area of the rod chamber of the boom cylinder, and the area of the rodless chamber of the boom cylinder.

5. The oil replenishment control method for the hydraulic system of an excavator according to claim 1, characterized in that, The third closed hydraulic system includes a first bucket oil pump, a second bucket oil pump, and a bucket balance valve. One end of the first bucket oil pump is connected to a first bucket oil circuit, and the other end is connected to a second bucket oil circuit. The first bucket oil circuit is connected to the rodless chamber of the bucket cylinder, and the second bucket oil circuit is connected to the rod chamber of the bucket cylinder. The bucket balance valve is configured to connect the oil path with the lower oil pressure in the first bucket oil circuit and the second bucket oil circuit to the oil replenishing circuit. One end of the second bucket oil pump is connected to the oil replenishing circuit, and the other end is connected to a third bucket oil circuit, and the third bucket oil circuit is connected to the first bucket oil circuit; Obtaining the required flow rate of the bucket cylinder includes: Obtaining the flow rate of the oil flowing through the second bucket oil pump and the flow rate of the oil flowing through the bucket balance valve; Determining the required flow rate of the bucket cylinder based on the flow rate of the oil flowing through the second bucket oil pump and the flow rate of the oil flowing through the bucket balance valve.

6. The oil replenishment control method for the hydraulic system of an excavator according to claim 1, characterized in that The excavator includes a control handle for controlling the extension and retraction of the bucket piston rod of the bucket cylinder; Obtaining the required flow rate of the bucket cylinder includes: Obtaining the position of the control handle; Determining the movement direction and movement speed of the bucket piston rod based on the position of the control handle; Obtaining the area of the rod chamber of the bucket cylinder and the area of the rodless chamber of the bucket cylinder; Determining the required flow rate of the bucket cylinder based on the movement direction of the bucket piston rod, the movement speed of the bucket piston rod, the area of the rod chamber of the bucket cylinder, and the area of the rodless chamber of the bucket cylinder.

7. An oil replenishment control device for an excavator hydraulic system, characterized in that, A method for controlling oil replenishment of an excavator hydraulic system according to any one of claims 1-6. The excavator hydraulic system includes a first closed hydraulic system, a second closed hydraulic system, a third closed hydraulic system, and an oil replenishment pump. The first closed hydraulic system is used to drive the boom cylinder to actuate. The second closed hydraulic system is used to drive the arm cylinder to actuate. The third closed hydraulic system is used to drive the bucket cylinder to actuate. Both ends of the oil replenishment pump are respectively connected to an oil tank and an oil replenishment oil circuit. The oil replenishment oil circuit is used to supply oil to the first closed hydraulic system, the second closed hydraulic system, and the third closed hydraulic system. The oil replenishment control device of the excavator hydraulic system includes: A flow rate acquisition module for acquiring the required flow rate of the boom cylinder, the required flow rate of the arm cylinder, and the required flow rate of the bucket cylinder; A required rotational speed determination module for determining the required rotational speed of the oil replenishment pump based on the required flow rate of the boom cylinder, the required flow rate of the arm cylinder, and the required flow rate of the bucket cylinder; An execution module for operating the oil replenishment pump at the required rotational speed; A current pressure acquisition module for acquiring the current pressure of the oil replenishment oil circuit; A difference calculation module for calculating the difference between the set pressure and the current pressure; A judgment module for judging the magnitude of the difference and the set value; A rotational speed increase module for increasing the rotational speed of the oil replenishment pump by a set rotational speed on the current basis when the difference is greater than the set value.

8. An excavator, characterized in that, Including: One or more processors; A storage device for storing one or more programs; When the one or more programs are executed by the one or more processors, the one or more processors control the excavator to implement the oil replenishment control method of the excavator hydraulic system according to any one of claims 1-6.

9. A storage medium having a computer program stored thereon, characterized in that, When the program is executed by the processor, the excavator implements the oil replenishment control method of the excavator hydraulic system according to any one of claims 1-6.

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