Automatic flow distribution control method, system, device and excavator

Abstract

The present invention provides a method, system, device and excavator for automatic flow distribution control, including: obtaining the current pressure value in each cylinder collected by the cylinder pressure sensor of each action part, inputting the current pressure value in the cylinder of each action part into a pre-established working mode classification model to determine the current working mode of the excavator; establishing a distribution control model between the speed of each cylinder and the valve core opening of the pilot proportional control valve according to the current working mode of the excavator; and distributing the flow of each cylinder valve core in real time according to the distribution control model. The present invention can realize automatic flow distribution under different working conditions. The operator does not need to actively select the working condition. The algorithm in the main controller of flow distribution can calculate the current load of each cylinder according to the pressure in the hydraulic main pump and each cylinder cavity, thereby judging the current working mode and performing real-time flow distribution calculation on the valve body of each action part.

Description

Technical Field

[0001] The present invention relates to the field of excavators, and in particular to a method, system, device and excavator for automatically distributing and controlling flow under different load operations of an excavator. Background Art

[0002] The operation of an excavator places relatively high demands on the operator, and different working conditions require different requirements for the movement amplitude and speed of each action handle.

[0003] However, not all excavator operators have the ability to adapt to different working conditions. For example, some operators are used to working in loading and unloading conditions, but suddenly they cannot find the feel when it comes to leveling operations, and they are very uncomfortable, resulting in low work efficiency.

[0004] Some existing adaptive technologies under different working conditions are relatively simple and rough control strategies. For example, when the load is detected to be increased, the overall engine speed is increased, or the overall pump flow is increased. This control method can only have a relatively limited improvement effect, because although the overall flow output has improved, there is not much improvement in the distribution of each valve core. For example, when the excavator is working under high load, according to its constant power control principle, the excavator hydraulic pump will provide a larger flow, but at this time, due to the unreasonable flow distribution of each action, the opening of each action valve core is different. If the opening is too large, the corresponding action is too fast, and if the opening is too small, the cylinder will be sucked empty and the action will be slow.

[0005] Therefore, the operator still feels uncoordinated when operating the excavator, and there is not much improvement in overall work efficiency. In addition, the fuel consumption is high, resulting in a waste of cost. Summary of the invention

[0006] In order to achieve automatic flow distribution under different working conditions, one aspect of the present invention provides an automatic flow distribution control method for an excavator under different load operations, the method comprising: obtaining the current pressure value in each cylinder collected by the cylinder pressure sensor of each action part, wherein each action part is composed of at least a boom, a dipper arm and a bucket; inputting the current pressure value in the cylinder of each action part into a pre-established working mode classification model to determine the current working mode of the excavator; establishing a distribution control model between the speed of each cylinder and the valve core opening of the pilot proportional control valve according to the current working mode of the excavator; and distributing the flow of each cylinder valve core in real time according to the distribution control model.

[0007] In order to realize automatic flow distribution under different working conditions, one aspect of the present invention provides an automatic flow distribution control system under different load operations of an excavator, the system comprising: a boom cylinder pressure sensor, used to obtain the pressure value in the boom cylinder; a dipper arm cylinder pressure sensor, used to obtain the pressure value in the dipper arm cylinder; a bucket cylinder pressure sensor, used to obtain the pressure value in the bucket cylinder; a flow distribution main controller, used to respectively obtain the current pressure values ​​in each cylinder collected by the boom, dipper arm, and bucket cylinder pressure sensors, and input them into a pre-established working mode classification model to determine the current working mode of the excavator, and establish a distribution control model between the speed of each cylinder and the valve core opening of the pilot electric proportional control valve according to the current working mode of the excavator; and a pilot electric proportional control valve, used to distribute the flow to the valve core of each cylinder in real time according to the distribution control model.

[0008] Preferably, the construction process of the working mode classification model includes: assuming that the average pressure of the boom cylinder is P boom , the average pressure of the boom cylinder is P arm , the average pressure of the bucket cylinder is P buck , where the working mode classification model includes at least the following four working modes: (1) Lifting and loading mode: At this time, the main load of the excavator is on the boom, so it is necessary to perform double pump confluence when the boom is lifted, and control the valve core opening to increase the boom lifting speed. When lifting and loading, the bucket arm action must be coordinated, so P boom >P arm >P buck (2) Arm unloading mode: At this time, the load is mainly on the arm, so the double pumps need to be combined to supply oil when the arm moves alone to speed up the arm movement. At this time, the arm valve core needs to be opened better than the other two valve cores. The bucket needs to move in coordination with the unloading action, so P arm >P buck >P boom (3) Excavation and filling mode: At this time, the load is mainly on the bucket, so the double pumps need to merge and supply oil when the bucket moves alone to speed up the bucket movement. At this time, the bucket valve core needs to be opened better than the other two valve cores. The digging needs to be coordinated with the arm movement, so P buck >P arm >P boom (4) No-load mode: At this time, the load is mainly on the boom, so the two pumps need to combine to supply oil when the boom moves alone to speed up the boom movement. At this time, the flow required for the arm and bucket is basically the same, so P boom >P arm ≈P buck .

[0009] Preferably, the construction process of the distribution control model includes: assuming that the cross-sectional area of ​​the cylinder (piston) is A, the cylinder diameter is D (mm), the rod diameter is d (mm), the cylinder input flow is Q, and the cylinder speed is v; the valve core opening of the pilot proportional control valve is C; and the relationship between the cylinder input flow Q and the cylinder speed v is obtained as follows:

[0010] (1.1);

[0011] The coefficients k1 and k2 are obtained by curve fitting using the least squares method:

[0012] (1.2);

[0013] The relationship between the oil cylinder speed v and the pilot proportional control valve spool opening C is obtained as follows:

[0014] (1.3).

[0015] Preferably, the construction process of the distribution control model further includes: after calculating formula (1.3), according to the current working mode of the excavator, multiplying the speed of each cylinder by a different coefficient θ, where the value range of the coefficient θ is 0-1; setting the speed coefficient of the boom cylinder to θ boom , the speed coefficient of the boom cylinder is θ arm , the speed coefficient of the bucket cylinder is θ buck , then the distribution control models of the boom, dipper arm and bucket can be derived as follows:

[0016] The relationship between the boom cylinder speed and the corresponding pilot proportional control valve spool opening is:

[0017] (1.31);

[0018] The relationship between the boom cylinder speed and the corresponding pilot proportional control valve spool opening is:

[0019] (1.32);

[0020] The relationship between the bucket cylinder speed and the corresponding pilot proportional control valve spool opening is:

[0021] (1.33).

[0022] One aspect of the present invention provides an automatic flow distribution control device for an excavator under different load operations, including a memory and a processor, wherein the memory is used to store a computer program, and the processor is used to call the computer program to execute the automatic flow distribution control method.

[0023] One aspect of the present invention provides an excavator, which includes a structure for installing the automatic flow distribution control system on the excavator.

[0024] The present invention can realize automatic flow distribution under different working conditions. The operator does not need to actively select the working condition. The algorithm in the flow distribution main controller can calculate the current load of each cylinder according to the pressure in the hydraulic main pump and each cylinder cavity, thereby judging the current working mode and performing real-time flow distribution calculation for the valve body of each action part. Even if the operator is not skilled in operation, he can fully adapt to the operation in different environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are merely embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0026] Figure 1 The figure shows a flow chart of an automatic flow distribution control method provided by one embodiment of the present invention;

[0027] Figure 2 Shown is a schematic structural diagram of an excavator provided by one embodiment of the present invention;

[0028] Figure 3 The figure shows the architecture of the automatic flow distribution system provided by one embodiment of the present invention;

[0029] Figure 4 The figure shows a schematic diagram of a control valve modification provided by one embodiment of the present invention;

[0030] Figure 5 The figure shows a schematic diagram of the power principle of an oil cylinder provided by one embodiment of the present invention;

[0031] Figure 6 It shows a schematic diagram of the structure of a flow automatic distribution control device provided by one embodiment of the present invention; and

[0032] Figure 7 Shown is a schematic diagram of the structure of a computer-readable storage medium provided by one embodiment of the present invention. DETAILED DESCRIPTION

[0033] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0034] One aspect of the present invention provides a method for automatically distributing and controlling flow under different load conditions of an excavator. The excavator described can be any common type of excavator. For example, an excavator using a hydraulic transmission system is usually composed of an excavator body, a power system, a transmission system, a working device, a slewing device, a control device, a traveling device, and auxiliary equipment.

[0035] refer to Figure 2 The working device of the excavator is a device that directly completes the excavation task, and is composed of at least an articulated boom 201, a dipper arm 202, a bucket 203, and a boom cylinder 204, a dipper arm cylinder 205, a bucket cylinder 206, etc., which are used to drive the boom 201, the dipper arm 202, and the bucket 203 to move.

[0036] refer to Figure 3 The transmission system of the excavator is used to transmit the power output by the power system to the working device, the slewing device and the traveling device, etc. It is composed of at least a hydraulic main pump 212 and a hydraulic main valve 213. The hydraulic main pump 212 is driven by the power system to deliver the hydraulic oil to the hydraulic main valve 213. The hydraulic main valve 213 distributes the hydraulic oil to the traveling motor to drive the traveling device to travel, and distributes the hydraulic oil to the boom cylinder 204, the arm cylinder 205, and the bucket cylinder 206 to drive the boom 201, the arm 202, and the bucket 203 to move.

[0037] In some embodiments, the excavator 100 also has a boom cylinder pressure sensor 207 capable of obtaining the pressure value in the boom cylinder 204, a boom cylinder pressure sensor 208 capable of obtaining the pressure value in the dipper cylinder 205, and a bucket cylinder pressure sensor 209 capable of obtaining the pressure value in the bucket cylinder 206; the boom cylinder pressure sensor 207 is arranged in the pipeline of the boom cylinder 204, the dipper cylinder pressure sensor 208 is arranged in the pipeline of the dipper cylinder 205, and the bucket cylinder pressure sensor 209 is arranged in the pipeline of the bucket cylinder 206.

[0038] In some embodiments, the pilot oil circuit is electronically controlled: the flow control of traditional hydraulic excavators is controlled by the change of the valve core opening of the pressure reducing valve when the handle is operated, which brings about the change of the pilot flow, thereby linearly controlling the opening of the valve core of each action part, thereby controlling the speed of each action part. However, in order to intelligently realize the adaptive opening change of each valve core in the present invention, the valve core should first be changed from hydraulic control to electronic control, such as Figure 4 As shown, add a pilot electric proportional control valve (solenoid valve). In this way, intelligent intervention can be achieved in the control of the valve core opening of each cylinder. When the pilot electric proportional control valve does not intervene, the oil distribution of each excavator still controls the valve core opening in the original way and automatically distributes the flow.

[0039] It should be understood that the operating parts described here refer to the boom 201 , the arm 202 , and the bucket 203 .

[0040] In some embodiments, the excavator further has a flow distribution main controller 210, which is used to obtain the current pressure values ​​in each cylinder 204, 205, 206 collected by the boom, dipper rod, and bucket cylinder pressure sensors 207, 208, 209, respectively, and input them into a pre-established working mode classification model to determine the current working mode of the excavator, and to establish a distribution control model between the speed of each cylinder and the valve core opening of the pilot electric proportional control valve 211 according to the current working mode of the excavator. The pilot electric proportional control valve 211 distributes the flow of each cylinder 204, 205, 206 valve core in real time according to the distribution control model.

[0041] One aspect of the present invention provides a flow automatic distribution control system, referring to Figure 3 As shown, in some embodiments, the system is composed of at least a hydraulic main pump 212, a hydraulic main valve 213, a boom cylinder pressure sensor 207, an arm cylinder pressure sensor 208, a bucket cylinder pressure sensor 209, a flow distribution main controller 210, and a pilot electric proportional control valve 211. The functional relationship between the components has been described above and will not be repeated here.

[0042] refer to Figure 1 As shown, in some embodiments, the automatic flow distribution control method is composed of at least S101~S104.

[0043] Among them, S101~S104 are preferably executed by the flow distribution main controller 210.

[0044] S101, obtaining the current pressure value in each cylinder collected by the cylinder pressure sensor of each action part;

[0045] S102, inputting the current pressure value in the oil cylinder of each action part into a pre-established working mode classification model to determine the current working mode of the excavator;

[0046] S103, establishing a distribution control model between the speed of each cylinder and the valve core opening of the pilot electric proportional control valve according to the current working mode of the excavator;

[0047] S104, distributing the flow rate of each cylinder valve core in real time according to the distribution control model.

[0048] It should be understood that the distinction of "working modes" in S1's working mode classification model is not based on large scenarios, but mainly on different working states of the excavator.

[0049] Construction of work mode classification model

[0050] When the excavator adjusts the gear and enters the working mode, the flow distribution main controller 210 does not control the cylinder valve core opening at first, and the hydraulic main valve 213 automatically distributes the valve core opening, and collects data through the cylinder pressure sensors 207, 208, and 209 of the three action parts. After working for a period of time, the working mode is distinguished according to the collected pressure data of each cylinder 204, 205, and 206. Set the lower limit pressure P of the cylinder min , when the effective pressure collected during the working cycle is greater than the lower limit pressure P min , the collected value is set to a valid value.

[0051] According to the above conditions, the average pressure of the boom cylinder 204 during the effective collection period is P boom The average pressure of the arm cylinder 205 during the effective collection period is P arm The average pressure of bucket cylinder 206 during the effective collection period is P buck .

[0052] The working mode classification model includes at least the following four working modes:

[0053] (1) Lifting and loading mode: At this time, the main load of the excavator is on the boom 201. Therefore, it is necessary to combine the two pumps when the boom 201 is lifted, and control the valve core opening to increase the lifting speed of the boom 201. When lifting and loading, it is necessary to cooperate with the action of the bucket arm, so P boom >P arm >P buck .

[0054] (2) Arm unloading mode: At this time, the load is mainly on the arm 202, so the double pumps need to merge and supply oil when the arm 202 moves alone to speed up the movement of the arm 202. At this time, the valve core of the arm 202 needs to be opened better than the other two valve cores. When unloading, it is necessary to cooperate with the bucket 203 to move, so P arm >P buck >P boom .

[0055] (3) Excavation and filling mode: At this time, the load is mainly on the bucket 203, so the two pumps need to merge and supply oil when the bucket 203 moves alone to speed up the movement of the bucket 203. At this time, the valve core of the bucket 203 needs to be opened better than the other two valve cores. When excavating, it is necessary to cooperate with the action of the arm 202, so P buck >P arm >P boom .

[0056] (4) No-load mode: At this time, the load is mainly on the boom 201, so the two pumps need to merge to supply oil when the boom 201 moves alone to speed up the movement of the boom 201. At this time, the flow rates required by the arm 202 and the bucket 203 are basically the same, so P boom >P arm ≈P buck .

[0057] On this basis, when the flow distribution main controller 210 obtains the current pressure values ​​in the cylinders 204, 205, 206 collected by the boom, arm, and bucket cylinder pressure sensors 207, 208, 209, by comparing the pressure values ​​of the cylinders 204, 205, 206, it is possible to calculate which of the above four working modes it complies with, that is, the comparison relationship between the pressure values ​​of the cylinders 204, 205, 206 and P boom >P arm >P buck ;P arm >P buck >P boom ;P buck >P arm >P boom ;P boom >P arm ≈P buck Matching is performed to obtain the corresponding working mode.

[0058] Construction of the distribution control model

[0059] In some embodiments, the control of the pilot electric proportional control valve 211 is that the digital signal processed by the flow distribution main controller 210 is converted into an analog voltage signal through D / A and then input into the proportional amplifier, which amplifies it and converts it into a current signal and inputs it into the proportional electromagnet. According to the speed requirement and the characteristic curve of the pilot electric proportional control valve 211, a valve opening is calculated, and a current signal is sent to drive the proportional electromagnet to generate a pilot driving force; the driving force makes the valve reach the desired opening, and after stabilization, a flow output is generated to enter the oil cylinder, and the oil cylinder will have a rising speed.

[0060] refer to Figure 5 As shown, the cylinder input flow Q = cylinder speed V * cylinder (piston) cross-sectional area A.

[0061] Therefore, given the cylinder input flow rate Q (mm / min), cylinder diameter D (mm), and rod diameter d (mm), the relationship between the cylinder input flow rate Q and the cylinder speed v (mm / min) can be calculated as follows:

[0062] (1.1).

[0063] The flow characteristics of the valve, different flow characteristics will have different valve openings. Generally speaking, solenoid valves are selected with equal percentage flow characteristics, so this type of solenoid valve is used for calculation here. Its characteristic is that the change is small at first and then larger. There is no clear calculation formula for the relationship between valve opening and flow pressure. Their relationship can only be expressed in a general functional form, and the specific relationship requires checking specific test curves. But in fact, flow is not the variable we directly control, and the opening C (the valve core opening of the pilot proportional control valve is C) is the variable we need. Therefore, the least squares method is used here to fit the curve to obtain the coefficients k1 and k2:

[0064] (1.2).

[0065] Therefore, the relationship between the cylinder speed v and the pilot proportional control valve spool opening C is obtained as follows:

[0066] (1.3).

[0067] After calculating formula (1.3), the speed of each cylinder is multiplied by a different coefficient θ according to the current working mode of the excavator, where the value range of the coefficient θ is 0-1.

[0068] According to the above, the value of θ should be different in different modes. Here, let the speed coefficient of the boom cylinder be θ boom , the speed coefficient of the boom cylinder is θ arm , the speed coefficient of the bucket cylinder is θbuck , then the distribution control models of the boom, dipper arm and bucket can be derived as follows:

[0069] The relationship between the boom cylinder speed and the corresponding pilot proportional control valve spool opening is:

[0070] (1.31).

[0071] The relationship between the boom cylinder speed and the corresponding pilot proportional control valve spool opening is:

[0072] (1.32).

[0073] The relationship between the bucket cylinder speed and the corresponding pilot proportional control valve spool opening is:

[0074] (1.33).

[0075] Different valve core opening relationships can be calculated according to different speed requirements, thereby realizing adaptive distribution of valve core flow in different working modes. This allows operators to easily switch between modes without changing their working habits.

[0076] Based on this algorithm, the present invention can realize automatic flow distribution under different working conditions. The operator does not need to actively select the working condition. The algorithm in the flow distribution main controller can calculate the current load of each cylinder according to the pressure in the hydraulic main pump and each cylinder cavity, thereby judging the current working mode and performing real-time flow distribution calculation for the valve body of each action part. Even if the operator is not skilled in operation, he can fully adapt to the operation in different environments.

[0077] refer to Figure 6 As shown, one aspect of the present invention provides an automatic flow distribution control device, including a memory 301 and a processor 302, wherein the memory 301 is used to store a computer program, and the processor 302 is used to call the computer program to execute the corresponding steps of the automatic flow distribution control method provided in an embodiment of the present invention.

[0078] One aspect of the present invention provides an excavator, the excavator comprising: Figure 3 The described automatic flow distribution control system is installed on the structure of the excavator. In addition, the excavator also has Figure 2 The whole or part of the structure described.

[0079] refer to Figure 7As shown, one aspect of the present invention provides a computer-readable storage medium, in which a computer program is stored. When the computer program runs on a computer, the corresponding steps of the automatic flow distribution control method provided in an embodiment of the present invention are executed.

[0080] The computer readable storage medium includes a computer program for executing a computer process on a computing device. In some embodiments, the computer readable storage medium is provided using a signal bearing medium 401. The signal bearing medium 401 may include one or more program instructions, which when executed by one or more processors may provide the above Figure 1 Thus, for example, one or more features of the method for automatically distributing flow rate can be performed by one or more instructions associated with the signal bearing medium 401. In addition, Figure 7 The program instructions in also describe example instructions. In some examples, the signal bearing medium may include a computer readable medium 402, such as, but not limited to, a hard drive, a compact disk (CD), a digital video disk (DVD), a digital tape, a memory, a read-only memory (ROM) or a random access memory (RAM), and the like.

[0081] In some implementations, signal bearing medium 401 may include computer recordable medium 403 such as, but not limited to, memory, read / write (R / W) CD, R / W DVD, and the like.

[0082] In some implementations, signal bearing medium 401 may include communication medium 404 such as, but not limited to, digital and / or analog communication media (eg, fiber optic cables, waveguides, wired communication links, wireless communication links, etc.).

[0083] The signal bearing medium 401 may be communicated by a wireless form of communication medium 404 (eg, a wireless communication medium complying with the IEEE 802.11 standard or other transmission protocols). The one or more program instructions may be, for example, computer executable instructions or logic implemented instructions.

[0084] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0085] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0086] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A method for automatically distributing and controlling flow under different loads of an excavator, characterized in that: The method comprises: Obtaining the current pressure value in each cylinder collected by the cylinder pressure sensor of each action part, wherein each action part is composed of at least a boom, a dipper arm and a bucket; Input the current pressure value in the oil cylinder of each action part into a pre-established working mode classification model to determine the current working mode of the excavator; Establishing a distribution control model between the speed of each cylinder and the spool opening of the pilot electric proportional control valve according to the current working mode of the excavator; and Distribute the flow of each cylinder valve core in real time according to the distribution control model; The construction process of the distribution control model includes: Let the cross-sectional area of ​​the cylinder piston be A, the cylinder diameter be D (mm), the rod diameter be d (mm), the cylinder input flow be Q, the cylinder speed be v; the valve core opening of the pilot proportional control valve be C; The relationship between the cylinder input flow Q and the cylinder speed v is obtained as follows: (1.1)； The coefficients k1 and k2 are obtained by curve fitting using the least squares method: (1.2)； The relationship between the oil cylinder speed v and the pilot proportional control valve spool opening C is obtained as follows: (1.3)。 2. The automatic flow distribution control method according to claim 1, characterized in that: The construction process of the working mode classification model includes: Assume the average pressure of the boom cylinder is P boom , the average pressure of the boom cylinder is P arm , the average pressure of the bucket cylinder is P buck , wherein the working mode classification model includes at least the following four working modes: (1) Lifting and loading mode: At this time, the main load of the excavator is on the boom, so it is necessary to combine the two pumps when the boom is lifted, and increase the valve core opening to increase the boom lifting speed. When lifting and loading, the bucket arm action must be coordinated, so P boom >P arm >P buck ; (2) Arm unloading mode: At this time, the load is mainly on the arm, so the double pumps need to be combined to supply oil when the arm moves alone to speed up the arm movement. At this time, the arm valve core needs to be opened better than the other two valve cores. When unloading, it is necessary to cooperate with the bucket movement, so P arm >P buck >P boom ; (3) Excavation and filling mode: At this time, the load is mainly on the bucket, so the two pumps need to merge to supply oil when the bucket moves alone to speed up the bucket movement. At this time, the bucket valve core needs to be opened better than the other two valve cores. The digging needs to be coordinated with the arm movement, so P buck >P arm >P boom ; (4) No-load mode: At this time, the load is mainly on the boom, so the two pumps need to merge to supply oil when the boom moves alone to speed up the boom movement. At this time, the flow required for the arm and bucket is basically the same, so P boom >P arm ≈P buck .

3. The automatic flow distribution control method according to claim 2, characterized in that: The construction process of the distribution control model also includes: After calculating formula (1.3), the speed of each cylinder is multiplied by a different coefficient θ according to the current working mode of the excavator, where the value range of the coefficient θ is 0-1; Let the speed coefficient of the boom cylinder be θ boom , the speed coefficient of the boom cylinder is θ arm , the speed coefficient of the bucket cylinder is θ buck , then the distribution control models of the boom, dipper arm and bucket can be derived as follows: The relationship between the boom cylinder speed and the corresponding pilot proportional control valve spool opening is: (1.31)； The relationship between the boom cylinder speed and the corresponding pilot proportional control valve spool opening is: (1.32)； The relationship between the bucket cylinder speed and the corresponding pilot proportional control valve spool opening is: (1.33)。 4. An automatic flow distribution control system for excavators under different load operations, characterized in that: The system comprises: A boom cylinder pressure sensor is used to obtain the pressure value in the boom cylinder; The arm cylinder pressure sensor is used to obtain the pressure value in the arm cylinder; Bucket cylinder pressure sensor, used to obtain the pressure value in the bucket cylinder; A flow distribution main controller, used to obtain the current pressure values ​​in each cylinder collected by the boom, arm and bucket cylinder pressure sensors, respectively, and input them into a pre-established working mode classification model to determine the current working mode of the excavator, and to establish a distribution control model between the speed of each cylinder and the valve core opening of the pilot proportional control valve according to the current working mode of the excavator; and A pilot electric proportional control valve is used to distribute the flow to the valve cores of each oil cylinder in real time according to the distribution control model; The construction process of the distribution control model includes: Let the cross-sectional area of ​​the cylinder piston be A, the cylinder diameter be D (mm), the rod diameter be d (mm), the cylinder input flow be Q, the cylinder speed be v; the valve core opening of the pilot proportional control valve be C; The relationship between the cylinder input flow Q and the cylinder speed v is obtained as follows: (1.1)； The coefficients k1 and k2 are obtained by curve fitting using the least squares method: (1.2)； The relationship between the oil cylinder speed v and the pilot proportional control valve spool opening C is obtained as follows: (1.3)。 5. The automatic flow distribution control system according to claim 4, characterized in that: The construction process of the working mode classification model includes: Assume the average pressure of the boom cylinder is P boom , the average pressure of the boom cylinder is P arm , the average pressure of the bucket cylinder is P buck , wherein the working mode classification model includes at least the following four working modes: (1) Lifting and loading mode: At this time, the main load of the excavator is on the boom, so it is necessary to combine the two pumps when the boom is lifted, and increase the valve core opening to increase the boom lifting speed. When lifting and loading, the bucket arm action must be coordinated, so P boom >P arm >P buck ; (2) Arm unloading mode: At this time, the load is mainly on the arm, so the double pumps need to be combined to supply oil when the arm moves alone to speed up the arm movement. At this time, the arm valve core needs to be opened better than the other two valve cores. When unloading, it is necessary to cooperate with the bucket movement, so P arm >P buck >P boom ; (3) Excavation and filling mode: At this time, the load is mainly on the bucket, so the two pumps need to merge to supply oil when the bucket moves alone to speed up the bucket movement. At this time, the bucket valve core needs to be opened better than the other two valve cores. The digging needs to be coordinated with the arm movement, so P buck >P arm >P boom ; (4) No-load mode: At this time, the load is mainly on the boom, so the two pumps need to merge to supply oil when the boom moves alone to speed up the boom movement. At this time, the flow required for the arm and bucket is basically the same, so P boom >P arm ≈P buck .

6. The automatic flow distribution control system according to claim 5, characterized in that: The construction process of the distribution control model also includes: After calculating formula (1.3), the speed of each cylinder is multiplied by a different coefficient θ according to the current working mode of the excavator, where the value range of the coefficient θ is 0-1; Let the speed coefficient of the boom cylinder be θ boom , the speed coefficient of the boom cylinder is θ arm , the speed coefficient of the bucket cylinder is θ buck , then the distribution control models of the boom, dipper arm and bucket can be derived as follows: The relationship between the boom cylinder speed and the corresponding pilot proportional control valve spool opening is: (1.31)； The relationship between the boom cylinder speed and the corresponding pilot proportional control valve spool opening is: (1.32)； The relationship between the bucket cylinder speed and the corresponding pilot proportional control valve spool opening is: (1.33)。 7. An automatic flow distribution control device for excavators under different load operations, characterized in that: It comprises a memory and a processor, wherein the memory is used to store a computer program, and the processor is used to call the computer program to execute the automatic flow distribution control method according to any one of claims 1 to 3.

8. An excavator, characterized in that: The excavator includes a structure in which the automatic flow distribution control system according to any one of claims 4 to 6 is installed on the excavator.

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