An automatic calibration device and method for an electrically controlled main pump, and its efficiency compensation method.

Abstract

This invention discloses an automatic calibration device, method, and efficiency compensation method for an electronically controlled main pump in the field of excavator control technology. It aims to solve the problem of poor control accuracy caused by existing technologies failing to consider the consistency differences of the main pump and the internal leakage of the main pump under different pressures. It includes a control unit, a pump unit, a data acquisition unit, and a load unit. The pump unit includes a motor and a hydraulic pump. The output shaft of the motor is fixedly connected to the hydraulic pump. The hydraulic pump includes multiple main pumps connected in sequence. The main pumps are connected to an electro-proportional valve and a pilot pressure sensor to form a pilot oil circuit for the main pumps. This invention acquires the operating parameters of the main pump under different outlet pressures and displacements. Based on this, it performs efficiency compensation on the main pump by correcting the main pump current, considering the consistency problem of the main pump and the internal leakage problem of the main pump under different pressures, ensuring the effectiveness of efficiency compensation.

Description

Technical Field

[0001] This invention relates to an automatic calibration device and method for an electronically controlled main pump, and its efficiency compensation method, belonging to the field of excavator control technology. Background Technology

[0002] With the continuous iteration of hydraulic systems, medium and large tonnage excavators now generally adopt electronically controlled positive flow hydraulic systems and fully electronically controlled hydraulic systems. The electronically controlled main pump, as the power component of the entire hydraulic system, plays a crucial role. Due to differences in manufacturing precision, even main pumps from the same batch can vary. Furthermore, as load pressure increases, the internal leakage of the main pump increases, further reducing volumetric efficiency. All of these factors alter the current-displacement curve of the main pump, leading to deviations in output flow control and affecting overall machine efficiency and fuel consumption.

[0003] In existing hydraulic systems, the power control is typically achieved using the theoretical current-displacement curve provided by the manufacturer. This does not take into account the consistency of the main pump or its internal leakage under different pressures, resulting in poor control accuracy and affecting the performance of the hydraulic system. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide an automatic calibration device, method and efficiency compensation method for an electrically controlled main pump. This solves the problem that the existing hydraulic control system typically uses the theoretical current displacement curve provided by the manufacturer for power control when controlling the electrically controlled main pump, without considering the consistency of the main pump and the internal leakage of the main pump under different pressures, resulting in poor control accuracy.

[0005] To solve the above-mentioned technical problems, the present invention is implemented using the following technical solution:

[0006] In a first aspect, the present invention provides an automatic calibration device for an electrically controlled main pump, comprising a control unit, a pump unit, a data acquisition unit, and a load unit;

[0007] The pump unit includes a motor and a hydraulic pump. The output shaft of the motor is fixedly connected to the hydraulic pump. The hydraulic pump includes multiple main pumps connected in sequence. The main pump is connected to an electro-proportional valve and a pilot pressure sensor to form the pilot oil circuit of the main pump.

[0008] The main pump is connected to the load unit via a flow meter and a pressure sensor to form the load oil circuit of the main pump;

[0009] The multiple electro-proportional valves and multiple pressure sensors are all electrically connected to the control unit, and the multiple flow meters, multiple pressure sensors and multiple pilot pressure sensors are all electrically connected to the data acquisition unit.

[0010] Furthermore, the hydraulic pump is a dual hydraulic pump, which includes two main pumps.

[0011] Furthermore, the oil inlet of the hydraulic pump is connected to the oil tank, the oil outlet of the hydraulic pump is connected to the load unit through the flow meter and the pressure sensor, and the oil outlet of the load unit is connected to the oil tank.

[0012] In a second aspect, the present invention provides an automatic calibration method for an electrically controlled main pump and an efficiency compensation method thereof, based on the automatic calibration device for an electrically controlled main pump described in the first aspect, including an automatic calibration method for an electrically controlled main pump and an efficiency compensation method.

[0013] The automatic calibration method for the electrically controlled main pump includes the following steps:

[0014] Obtain the curves showing the changes in main pump current and displacement, as well as the main pump efficiency model;

[0015] The efficiency compensation method includes the following steps:

[0016] Based on the target flow rate of the main pump and the change curve of the main pump current and displacement, the target current of the main pump is obtained; based on the target displacement of the main pump, the actual outlet pressure and the efficiency model of the main pump, the output flow rate of the main pump is obtained, and the deviation between the target flow rate of the main pump and the output flow rate of the main pump is obtained. The deviation is judged against the preset range, and the target current of the main pump is corrected according to the judgment result to obtain the output current of the main pump and complete the efficiency compensation work.

[0017] Furthermore, the acquisition of the change curve of the main pump current and displacement specifically includes:

[0018] Adjust the hydraulic oil temperature of the main pump to reach the set temperature, adjust the outlet pressure of the main pump to reach the set pressure, and adjust the motor speed to reach the set speed.

[0019] Slowly apply current to the main pump, and within a preset time, the main pump current is loaded from the initial value to the maximum value. After the main pump current is maintained at the maximum value for a target time, slowly unload the main pump current, and unload the main pump current from the maximum value to the initial value according to the current loading rate. Repeat the slow current loading and slow current unloading operation multiple times to obtain the main pump current change curve.

[0020] The flow rate at the main pump outlet is acquired in real time, and the main pump displacement is calculated based on the flow rate at the main pump outlet to obtain the main pump displacement change curve.

[0021] Based on the main pump current variation curve and the main pump displacement variation curve, obtain the relationship graph between the main pump current and the displacement.

[0022] Based on the relationship diagram between the main pump current and displacement, multiple current points are selected from the relationship diagram based on preset requirements, and the displacement points corresponding to each current point are obtained. The change curve of the main pump current and displacement is then fitted.

[0023] Furthermore, obtaining the main pump efficiency model specifically includes:

[0024] The motor speed is adjusted to reach the set speed, and the actual output flow of the main pump under different displacements and different outlet pressures is obtained through the controller, load unit and data acquisition unit;

[0025] The theoretical output flow rate is calculated based on different displacements. Based on the ratio of theoretical output flow rate to actual output flow rate, the volumetric efficiency cloud map of the main pump under different displacements and different outlet pressures is obtained.

[0026] Based on the volumetric efficiency cloud map, the main pump efficiency model is obtained.

[0027] Furthermore, the expression for the efficiency model is as follows:

[0028] ;

[0029] In the formula: Main pump efficiency; For pressure calculation coefficients; For displacement calculation coefficients; V Main pump displacement; 、 Main pump displacement value; Main pump output flow; Main pump speed; This is due to export pressure.

[0030] Furthermore, the step of obtaining the main pump target current based on the main pump target flow rate and the change curve of the main pump current versus displacement; and obtaining the main pump output flow rate based on the main pump target displacement, actual outlet pressure, and the main pump efficiency model, specifically includes:

[0031] Calculate the target displacement of the main pump based on the target flow rate of the main pump;

[0032] The target current of the main pump is obtained based on the target displacement of the main pump and the curve of the change between the main pump current and the displacement.

[0033] The target displacement and actual outlet pressure of the main pump are input into the main pump efficiency model to obtain the output flow rate of the main pump.

[0034] Furthermore, the step of judging the deviation against a preset range and correcting the target current of the main pump based on the judgment result to obtain the output current of the main pump and complete the efficiency compensation work specifically includes:

[0035] Step a: If the deviation is within the preset range, the work ends and the efficiency compensation work is completed;

[0036] Step b: If the deviation is not within the preset range, use the fuzzy efficiency compensation algorithm to correct the main pump target current to obtain the main pump output current. Based on the main pump output current and the change curve of the main pump current and displacement, re-obtain the main pump target displacement. Based on the main pump target displacement and the actual outlet pressure, re-obtain the main pump output flow rate and re-obtain the deviation between the main pump target flow rate and the main pump output flow rate.

[0037] Step c: Repeat steps a and b until the deviation is within the preset range. The work is then completed, and the efficiency compensation work is finished.

[0038] Thirdly, the present invention provides an excavator including the electronically controlled main pump automatic calibration device described in the first aspect.

[0039] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0040] 1. This electronically controlled main pump automatic calibration device detects and controls the outlet pressure of the main pump through a pressure sensor and detects and controls the flow rate of the main pump through a flow meter, thereby obtaining the operating parameters of the main pump under different outlet pressures and different displacements. Based on this, the device performs efficiency compensation for the main pump by correcting the main pump current, taking into account the consistency of the main pump and the internal leakage of the main pump under different pressures, to ensure the effectiveness of efficiency compensation and improve the power control accuracy of the main pump.

[0041] 2. This automatic calibration method and efficiency compensation method for the electronically controlled main pump provide a practical solution for calibrating the main pump under different outlet pressures and displacements. By calibrating the main pump under different outlet pressures and displacements, its operating parameters are obtained, and efficiency data images are analyzed. Through the relationship between main pump efficiency, outlet pressure, displacement, and current, a main pump efficiency model is established. Considering the consistency problem of the main pump and the internal leakage problem of the main pump under different pressures, efficiency compensation is performed on the main pump output current. This ensures that the deviation between the main pump target flow and the main pump output flow is within a preset range, enabling precise control of the main pump output flow, improving the overall working efficiency, and reducing working oil consumption. Attached Figure Description

[0042] Figure 1 This is a schematic diagram of an automatic calibration device for an electrically controlled main pump according to an embodiment of the present invention;

[0043] Figure 2This is a schematic diagram of the main pump current variation curve provided according to an embodiment of the present invention;

[0044] Figure 3 This is a schematic diagram of the main pump displacement variation curve provided in an embodiment of the present invention;

[0045] Figure 4 This is a schematic diagram illustrating the relationship between the main pump current and displacement according to an embodiment of the present invention;

[0046] Figure 5 This is a volumetric efficiency cloud diagram of the main pump under different displacements and different outlet pressures according to an embodiment of the present invention.

[0047] Figure 6 This is a flowchart illustrating an automatic calibration method for an electrically controlled main pump and its efficiency compensation method according to an embodiment of the present invention.

[0048] Figure 7 This is a schematic flowchart of obtaining the change curve of main pump current and displacement according to an embodiment of the present invention;

[0049] Figure 8 This is a schematic diagram of the process for obtaining the main pump efficiency model according to an embodiment of the present invention;

[0050] Figure 9 This is a flowchart illustrating the process of obtaining a fuzzy efficiency compensation algorithm according to an embodiment of the present invention.

[0051] In the diagram: 1. Control unit; 2. Second electro-proportional valve; 3. First electro-proportional valve; 4. Second pilot pressure sensor; 5. First pilot pressure sensor; 6. Second flow meter; 7. Dual hydraulic pump; 8. Motor; 9. First flow meter; 10. First pressure sensor; 11. Data acquisition unit; 12. Load unit; 13. Second pressure sensor. Detailed Implementation

[0052] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0053] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are used only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0054] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances. Example 1:

[0055] like Figure 1 As shown, the present invention provides an automatic calibration device for an electrically controlled main pump, including a control unit 1, a pump unit, a data acquisition unit 11, and a load unit 12;

[0056] The pump unit includes a motor 8 and a hydraulic pump. The output shaft of the motor 8 is fixedly connected to the hydraulic pump. The hydraulic pump includes multiple main pumps connected in sequence. The main pump is connected to an electro-proportional valve and a pilot pressure sensor to form the pilot oil circuit of the main pump.

[0057] The main pump is connected to the load unit 12 via a flow meter and a pressure sensor to form the load oil circuit of the main pump;

[0058] The multiple electro-proportional valves and multiple pressure sensors are all electrically connected to the control unit 1, and the multiple flow meters, multiple pressure sensors and multiple pilot pressure sensors are all electrically connected to the data acquisition unit 11.

[0059] Specifically, the electro-proportional valve includes a first electro-proportional valve 3 and a second electro-proportional valve 2; the pilot pressure sensor includes a first pilot pressure sensor 5 and a second pilot pressure sensor 4; the pressure sensor includes a first pressure sensor 10 and a second pressure sensor 13; and the flow meter includes a first flow meter 9 and a second flow meter 6.

[0060] In one embodiment, the hydraulic pump is a dual hydraulic pump 7, which includes two main pumps, namely main pump one and main pump two. The oil inlet of the hydraulic pump is connected to the oil tank, and the oil outlet of the hydraulic pump is connected to the load unit 12 through the flow meter and the pressure sensor. The oil outlet of the load unit 12 is connected to the oil tank. Figure 1 Pump 1 is the main pump, and pump 2 is the main pump.

[0061] Specifically, the present invention includes a control unit 1, a pump unit, a data acquisition unit 11, and a load unit 12; the pump unit includes a motor 8, a dual hydraulic pump 7, a first electro-proportional valve 3, a second electro-proportional valve 2, a first pilot pressure sensor 5, and a second pilot pressure sensor 4; the first electro-proportional valve 3 and the first pilot pressure sensor 5 are connected to the first main pump to form the pilot oil circuit of the first main pump; the second electro-proportional valve 2 and the second pilot pressure sensor 4 are connected to the second main pump to form the pilot oil circuit of the second main pump; the first main pump, the first flow meter 9, the first pressure sensor 10, and the load unit 12 are connected to form the load oil circuit of the first main pump; the second main pump... The second flow meter 6, the second pressure sensor 13, and the load unit 12 are connected to form the load oil circuit of the main pump 2; the first electro-proportional valve 3, the second electro-proportional valve 2, the first pressure sensor 10, the second pressure sensor 13, and the control unit 1 are electrically connected; the first pilot pressure sensor 5, the second pilot pressure sensor 4, the first flow meter 9, the second flow meter 6, the first pressure sensor 10, the second pressure sensor 13, and the data acquisition unit 11 are electrically connected; the output shaft of the motor 8 is fixedly connected to the double hydraulic pump 7; the present invention detects and controls the outlet pressure of the main pump through the pressure sensor and detects and controls the flow rate of the main pump through the flow meter.

[0062] In practical operation, this invention first obtains the change curve of the main pump current and displacement, as well as the main pump efficiency model; based on the main pump target flow rate and the change curve of the main pump current and displacement, the main pump target current is obtained; based on the main pump target displacement, actual outlet pressure, and the main pump efficiency model, the main pump output flow rate is obtained, and the deviation between the main pump target flow rate and the main pump output flow rate is obtained. The deviation is judged against a preset range, and the main pump target current is corrected according to the judgment result to obtain the main pump output current, thus completing the efficiency compensation work; in this embodiment, the main pump can be main pump one or main pump two.

[0063] This invention uses a pressure sensor to detect and control the outlet pressure of the main pump and a flow meter to detect and control the flow rate of the main pump, thereby obtaining the operating parameters of the main pump under different outlet pressures and different displacements. Based on this, the efficiency of the main pump is compensated by correcting the main pump current, taking into account the consistency of the main pump and the internal leakage of the main pump under different pressures, to ensure the effectiveness of efficiency compensation and improve the power control accuracy of the main pump. Example 2:

[0064] like Figure 6 As shown, the present invention provides an automatic calibration method for an electrically controlled main pump and an efficiency compensation method thereof, based on the automatic calibration device for an electrically controlled main pump described in Embodiment 1, including an automatic calibration method for an electrically controlled main pump and an efficiency compensation method.

[0065] The automatic calibration method for the electrically controlled main pump includes the following steps:

[0066] Obtain the curves showing the changes in main pump current and displacement, as well as the main pump efficiency model;

[0067] The efficiency compensation method includes the following steps:

[0068] Based on the target flow rate of the main pump and the change curve of the main pump current and displacement, the target current of the main pump is obtained; based on the target displacement of the main pump, the actual outlet pressure and the efficiency model of the main pump, the output flow rate of the main pump is obtained, and the deviation between the target flow rate of the main pump and the output flow rate of the main pump is obtained. The deviation is judged against the preset range, and the target current of the main pump is corrected according to the judgment result to obtain the output current of the main pump and complete the efficiency compensation work.

[0069] like Figure 7 As shown in one embodiment, obtaining the change curve of the main pump current versus displacement specifically includes:

[0070] Adjust the hydraulic oil temperature of the main pump to reach the set temperature, adjust the outlet pressure of the main pump to reach the set pressure, and adjust the motor speed to reach the set speed.

[0071] Slowly apply current to the main pump, and within a preset time, the main pump current is loaded from the initial value to the maximum value. After the main pump current is maintained at the maximum value for a target time, slowly unload the main pump current, and unload the main pump current from the maximum value to the initial value according to the current loading rate. Repeat the slow current loading and slow current unloading operation multiple times to obtain the main pump current change curve.

[0072] The flow rate at the main pump outlet is acquired in real time, and the main pump displacement is calculated based on the flow rate at the main pump outlet to obtain the main pump displacement change curve.

[0073] Based on the main pump current variation curve and the main pump displacement variation curve, obtain the relationship graph between the main pump current and the displacement.

[0074] Based on the relationship diagram between the main pump current and displacement, multiple current points are selected from the relationship diagram based on preset requirements, and the displacement points corresponding to each current point are obtained. The change curve of the main pump current and displacement is then fitted.

[0075] Specifically, optionally, in this embodiment, the main pump can be either main pump one or main pump two; the hydraulic oil temperature in the automatic calibration device of the electrically controlled main pump reaches the set temperature, the main pump outlet pressure reaches the set value, the pilot pressure in the pump unit reaches the set value, and the motor speed reaches the set value; the main pump is slowly current-loaded through the control unit, and the current-load settings are as follows: Figure 2 As shown, the current is applied to its maximum value within a certain time period. After maintaining the maximum current stable for a target time, the current is unloaded back to its initial value according to the current loading rate. This loading setting is repeated multiple times, optionally three times. The flow rate at the main pump outlet is acquired in real time, and the flow rate change value during the current loading and unloading time period is converted into the main pump displacement change value, forming the main pump displacement change curve, as shown. Figure 3 As shown; the relationship between the main pump's current and displacement is obtained based on the displacement change curve and the current change curve, such as... Figure 4 As shown; based on preset requirements, multiple current points are taken between the minimum and maximum displacement and their corresponding displacements are obtained to fit the change curve of the main pump current and displacement. Optionally, the number of current points is eleven. Optionally, the current points taken between the minimum and maximum displacements in this application are average values.

[0076] like Figure 8 As shown in the figure, in one embodiment, obtaining the main pump efficiency model specifically includes:

[0077] The motor speed is adjusted to reach the set speed, and the actual output flow of the main pump under different displacements and different outlet pressures is obtained through the controller, load unit and data acquisition unit;

[0078] The theoretical output flow rate is calculated based on the displacement. Based on the ratio of the theoretical output flow rate to the actual output flow rate, the volumetric efficiency cloud map of the main pump under different displacements and different outlet pressures is obtained.

[0079] Based on the volumetric efficiency cloud map, the main pump efficiency model is obtained.

[0080] The efficiency model is expressed as follows:

[0081] ;

[0082] In the formula: Main pump efficiency; For pressure calculation coefficients; For displacement calculation coefficients; V Main pump displacement; 、 Main pump displacement value; Main pump output flow; Main pump speed; This is due to export pressure.

[0083] Specifically, the motor speed is brought to a set value, and the actual output flow rate of main pump one under different displacements and pressures is obtained through the control unit, load unit, and data acquisition unit; the motor speed is also brought to a set value, and the actual output flow rate of main pump two under different displacements and pressures is obtained through the control unit, load unit, and data acquisition unit; the theoretical output flow rate is calculated based on the displacement, and the volumetric efficiency cloud map of main pump one and main pump two under different displacements and pressures is generated based on the ratio of the actual output flow rate to the theoretical output flow rate, as shown in the figure. Figure 5 As shown, Figure 5 The different lines in the diagram represent different displacements, and the pressure is the outlet pressure.

[0084] In one embodiment, obtaining the main pump target current based on the main pump target flow rate and the change curve of the main pump current versus displacement; and obtaining the main pump output flow rate based on the main pump target displacement, actual outlet pressure, and the main pump efficiency model, specifically includes:

[0085] Calculate the target displacement of the main pump based on the target flow rate of the main pump;

[0086] The target current of the main pump is obtained based on the target displacement of the main pump and the curve of the change between the main pump current and the displacement.

[0087] The target displacement and actual outlet pressure of the main pump are input into the main pump efficiency model to obtain the output flow rate of the main pump.

[0088] like Figure 9 As shown, in one embodiment, the step of judging the deviation against a preset range and correcting the target current of the main pump based on the judgment result to obtain the output current of the main pump and complete the efficiency compensation work specifically includes:

[0089] Step a: If the deviation is within the preset range, the work ends and the efficiency compensation work is completed;

[0090] Step b: If the deviation is not within the preset range, use the fuzzy efficiency compensation algorithm to correct the main pump target current to obtain the main pump output current. Based on the main pump output current and the change curve of the main pump current and displacement, re-obtain the main pump target displacement. Based on the main pump target displacement and the actual outlet pressure, re-obtain the main pump output flow rate and re-obtain the deviation between the main pump target flow rate and the main pump output flow rate.

[0091] Step c: Repeat steps a and b until the deviation is within the preset range. The work is then completed, and the efficiency compensation work is finished.

[0092] This invention provides a practical solution for calibrating the main pump under different outlet pressures and displacements. By calibrating the main pump under different outlet pressures and displacements, its operating parameters are obtained, and efficiency data images are analyzed. By establishing the relationship between main pump efficiency, outlet pressure, displacement, and current, a main pump efficiency model is established. Considering the consistency problem of the main pump and the internal leakage problem of the main pump under different pressures, efficiency compensation is performed on the output current of the main pump. This ensures that the deviation between the target flow rate and the output flow rate of the main pump is within a preset range, and the output flow rate of the main pump is precisely controlled, thereby improving the overall working efficiency and reducing working oil consumption. Example 3:

[0093] The present invention provides an excavator, including the electronically controlled main pump automatic calibration device described in Embodiment 1.

[0094] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An automatic calibration method for an electrically controlled main pump and its efficiency compensation method, characterized in that, This includes automatic calibration methods and efficiency compensation methods for the electronically controlled main pump; The automatic calibration method for the electrically controlled main pump includes the following steps: Obtain the curves showing the changes in main pump current and displacement, as well as the main pump efficiency model; The efficiency compensation method includes the following steps: Based on the target flow rate of the main pump and the change curve of the main pump current and displacement, the target current of the main pump is obtained; based on the target displacement of the main pump, the actual outlet pressure and the efficiency model of the main pump, the output flow rate of the main pump is obtained, and the deviation between the target flow rate of the main pump and the output flow rate of the main pump is obtained. The deviation is judged against the preset range, and the target current of the main pump is corrected according to the judgment result to obtain the output current of the main pump and complete the efficiency compensation work. The acquisition of the main pump current and displacement variation curves specifically includes: Adjust the hydraulic oil temperature of the main pump to reach the set temperature, adjust the outlet pressure of the main pump to reach the set pressure, and adjust the motor speed to reach the set speed. Slowly apply current to the main pump, and within a preset time, the main pump current is loaded from the initial value to the maximum value. After the main pump current is maintained at the maximum value for a target time, slowly unload the main pump current, and unload the main pump current from the maximum value to the initial value according to the current loading rate. Repeat the slow current loading and slow current unloading operation multiple times to obtain the main pump current change curve. The flow rate at the main pump outlet is acquired in real time, and the main pump displacement is calculated based on the flow rate at the main pump outlet to obtain the main pump displacement change curve. Based on the main pump current variation curve and the main pump displacement variation curve, obtain the relationship graph between the main pump current and the displacement. Based on the relationship diagram between the main pump current and the displacement, multiple current points are selected in the relationship diagram between the main pump current and the displacement based on preset requirements, and the displacement points corresponding to each current point are obtained. The change curve of the main pump current and the displacement is then fitted. The method for obtaining the main pump efficiency model specifically includes: The motor speed is adjusted to reach the set speed, and the actual output flow of the main pump under different displacements and different outlet pressures is obtained through the controller, load unit and data acquisition unit; The theoretical output flow rate is calculated based on the displacement. Based on the ratio of the theoretical output flow rate to the actual output flow rate, the volumetric efficiency cloud map of the main pump under different displacements and different outlet pressures is obtained. Based on the volumetric efficiency cloud map, obtain the main pump efficiency model; The efficiency model is expressed as follows: ； In the formula: Main pump efficiency; For pressure calculation coefficients; For displacement calculation coefficients; V Main pump displacement; 、 Main pump displacement value; Main pump output flow; Main pump speed; This is due to export pressure.

2. The automatic calibration method for the electrically controlled main pump and its efficiency compensation method according to claim 1, characterized in that, The target current of the main pump is obtained based on the target flow rate of the main pump and the change curve of the main pump current versus displacement. Based on the target displacement of the main pump, the actual outlet pressure, and the main pump efficiency model, the output flow rate of the main pump is obtained, specifically including: Calculate the target displacement of the main pump based on the target flow rate of the main pump; The target current of the main pump is obtained based on the target displacement of the main pump and the curve of the change between the main pump current and the displacement. The target displacement and actual outlet pressure of the main pump are input into the main pump efficiency model to obtain the output flow rate of the main pump.

3. The automatic calibration method for the electrically controlled main pump and its efficiency compensation method according to claim 1, characterized in that, The process of judging the deviation from the preset range and correcting the target current of the main pump based on the judgment result to obtain the output current of the main pump and complete the efficiency compensation work specifically includes: Step a: If the deviation is within the preset range, the work ends and the efficiency compensation work is completed; Step b: If the deviation is not within the preset range, use the fuzzy efficiency compensation algorithm to correct the main pump target current to obtain the main pump output current. Based on the main pump output current and the change curve of the main pump current and displacement, re-obtain the main pump target displacement. Based on the main pump target displacement and the actual outlet pressure, re-obtain the main pump output flow rate and re-obtain the deviation between the main pump target flow rate and the main pump output flow rate. Step c: Repeat steps a and b until the deviation is within the preset range. The work is then completed, and the efficiency compensation work is finished.

4. An automatic calibration device for an electrically controlled main pump, used to implement the automatic calibration method for the electrically controlled main pump and its efficiency compensation method as described in any one of claims 1 to 3, characterized in that, Includes control unit, pump unit, data acquisition unit and load unit; The pump unit includes a motor and a hydraulic pump. The output shaft of the motor is fixedly connected to the hydraulic pump. The hydraulic pump includes multiple main pumps connected in sequence. The main pump is connected to an electro-proportional valve and a pilot pressure sensor to form the pilot oil circuit of the main pump. The main pump is connected to the load unit via a flow meter and a pressure sensor to form the load oil circuit of the main pump; The multiple electro-proportional valves and multiple pressure sensors are all electrically connected to the control unit, and the multiple flow meters, multiple pressure sensors and multiple pilot pressure sensors are all electrically connected to the data acquisition unit.

5. The automatic calibration device for the electrically controlled main pump according to claim 4, characterized in that, The hydraulic pump is a dual hydraulic pump, which includes two main pumps.

6. The automatic calibration device for the electrically controlled main pump according to claim 4, characterized in that, The inlet of the hydraulic pump is connected to the oil tank, the outlet of the hydraulic pump is connected to the load unit through the flow meter and the pressure sensor, and the outlet of the load unit is connected to the oil tank.

7. An excavator, characterized in that, Includes the automatic calibration device for the electrically controlled main pump as described in any one of claims 4 to 6.

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