A load-based main pump control method and excavator

Abstract

This invention discloses a load-based main pump control method and an excavator, belonging to the field of excavator control technology. The method includes acquiring the real-time pressure value of the excavator's main pump and the pressure value of the excavator's main pump in the previous statistical period; determining the step size of the current statistical period based on the pressure value of the excavator's main pump in the previous statistical period; calculating the real-time pressure gradient change rate in the current statistical period based on the real-time pressure value of the excavator's main pump and the step size of the current statistical period; determining the real-time pressure cutoff amplitude in the current statistical period based on the real-time pressure value of the excavator's main pump and the real-time pressure gradient change rate; and adjusting the real-time current of the excavator's main pump to control the main pump opening based on the real-time pressure cutoff amplitude in the current statistical period. This invention can adaptively adjust the excavator's main pump opening according to different working conditions, thereby reducing energy loss.

Description

Technical Field

[0001] This invention relates to a load-based main pump control method and an excavator, belonging to the field of excavator control technology. Background Technology

[0002] When an excavator is in operation, after the main pump pressure increases, a fixed-amplitude pressure cut-off mode is usually used to directly reduce the main pump current, and all excavators use the same control strategy.

[0003] Different excavators face different loads under different working conditions. Even when working in the same area, the load on the excavator will vary with the digging depth during the operation. The existing control strategy, which uses a fixed-amplitude pressure cut-off mode, does not adapt to changes in working conditions. When the excavator is under heavy load, the pressure cut-off is not sufficient, which will cause hydraulic overflow loss and thus result in higher fuel consumption of the whole machine. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a load-based main pump control method and excavator that can adaptively adjust the opening degree of the excavator's main pump according to different working conditions, thereby reducing energy loss. To achieve the above objective, this invention employs the following technical solution:

[0005] In a first aspect, the present invention provides a load-based main pump control method, comprising:

[0006] Obtain the real-time pressure value of the excavator's main pump and the pressure value of the excavator's main pump in the previous statistical period;

[0007] Based on the pressure value of the excavator's main pump in the previous statistical period, determine the step size of the current statistical period;

[0008] Calculate the real-time pressure gradient change rate within the current statistical period based on the real-time pressure value of the excavator's main pump and the step size of the current statistical period.

[0009] Based on the real-time pressure value and real-time pressure gradient change rate of the excavator's main pump, determine the real-time pressure cutoff amplitude within the current statistical period;

[0010] Based on the real-time pressure cutoff range within the current statistical period, the real-time current of the excavator's main pump is adjusted to control the main pump opening.

[0011] In conjunction with the first aspect, optionally, determining the step size of the current statistical period based on the pressure value of the excavator's main pump in the previous statistical period includes:

[0012] Select the time points when the pressure value is the highest and the pressure value is the lowest from the pressure values ​​of the excavator's main pump in the previous statistical period;

[0013] The time interval between the point when the pressure value is at its maximum and the point when the pressure value is at its minimum is used as the step size for the current statistical period.

[0014] Among them, when the pressure value at its maximum in the previous statistical period is less than the main pump overflow pressure, the pressure value of the excavator's main pump in the previous statistical period is invalid data. The step size of the current statistical period is determined based on the pressure value of the excavator's main pump in the previous statistical period with invalid data.

[0015] In conjunction with the first aspect, optionally, based on the real-time pressure value of the excavator's main pump and the step size of the current statistical period, the real-time pressure gradient change rate within the current statistical period is calculated, including:

[0016] Within the time interval from the start of the current statistical period to the real-time sampling time, select the maximum pressure value Pmax and the minimum pressure value Pmin;

[0017] The real-time pressure gradient change rate kt is calculated using the following formula:

[0018] kt = (Pmax - Pmin) / t,

[0019] Where t represents the duration of the time interval from the start sampling time to the real-time sampling time in the current statistical period, and t is less than or equal to the step size of the current statistical period.

[0020] In conjunction with the first aspect, optionally, determining the real-time pressure cutoff amplitude within the current statistical period based on the real-time pressure value and real-time pressure gradient change rate of the excavator's main pump includes:

[0021] Obtain the pressure cutoff amplitude corresponding to the pressure value of the excavator's main pump in the previous statistical period, and use it as the initial value of the pressure cutoff amplitude for the current statistical period;

[0022] Initialize the pressure threshold range;

[0023] In response to the real-time pressure value of the excavator's main pump being within the pressure threshold range, it is determined whether the real-time pressure gradient change rate exceeds the preset change threshold.

[0024] If it exceeds the threshold, calculate the magnitude of the real-time pressure gradient change rate exceeding the preset change threshold, and use the calculated magnitude to correct the initial value of the pressure cutoff amplitude to obtain the real-time pressure cutoff amplitude.

[0025] If the limit is not exceeded, the initial value of the pressure cutoff amplitude is corrected using a preset safety adjustment coefficient to obtain the real-time pressure cutoff amplitude.

[0026] In conjunction with the first aspect, optionally, the minimum value of the pressure threshold range is the constant power pump pressure setting value of the excavator, and the maximum value of the pressure threshold range is the average of the maximum values ​​of pressure values ​​for multiple statistical periods in the database.

[0027] In conjunction with the first aspect, optionally, in response to the excavator's main pump's real-time pressure value not reaching the excavator's constant power pump pressure setting value, the initial value of the pressure cutoff amplitude for the current statistical period is output as the real-time pressure cutoff amplitude.

[0028] In conjunction with the first aspect, optionally, in response to the real-time pressure value of the excavator's main pump exceeding the maximum value of the pressure threshold range, the maximum value of the output pressure cutoff amplitude is the real-time pressure cutoff amplitude; when the real-time pressure value of the excavator's main pump decreases and is within the pressure threshold range, a judgment is made on whether the real-time pressure gradient change rate exceeds a preset change threshold.

[0029] In conjunction with the first aspect, optionally, the database is updated through the following steps:

[0030] When the pressure value of the excavator's main pump reaches the excavator's constant power pump pressure set value, data recording is initiated. The recorded data includes the recording statistical period, sampling time point, and pressure value.

[0031] A sliding window mechanism is used to retain data from the most recent N statistical periods and remove old data that is outside the window range.

[0032] In conjunction with the first aspect, optionally, when the duration of the real-time pressure gradient change rate exceeding the preset change threshold reaches the preset time threshold, the maximum value of the output pressure cutoff amplitude is the real-time pressure cutoff amplitude, until the real-time pressure value of the excavator's main pump decreases and falls within the pressure threshold range.

[0033] Secondly, the present invention provides an excavator that uses a load-based main pump control method as described in the first aspect to adjust the real-time current of the excavator's main pump for main pump opening control.

[0034] Compared with the prior art, the beneficial effects achieved by the load-based main pump control method and excavator provided by the embodiments of the present invention include:

[0035] This invention obtains the real-time pressure value of the excavator's main pump and the pressure value of the excavator's main pump in the previous statistical period; based on the pressure value of the excavator's main pump in the previous statistical period, it determines the step size of the current statistical period; based on the real-time pressure value of the excavator's main pump and the step size of the current statistical period, it calculates the real-time pressure gradient change rate in the current statistical period; by calculating the real-time pressure gradient change rate, this invention can quickly identify load mutations in the current statistical period.

[0036] This invention determines the real-time pressure cutoff amplitude within the current statistical period based on the real-time pressure value and real-time pressure gradient change rate of the excavator's main pump. This invention can achieve precise adaptive control for different working conditions, avoid overflow losses caused by the traditional fixed amplitude pressure cutoff mode, and significantly reduce the energy consumption of the whole machine.

[0037] This invention adjusts the real-time current of the excavator's main pump to control the main pump opening based on the real-time pressure cutoff amplitude within the current statistical period. This invention can adaptively adjust the excavator's main pump opening according to different working conditions, effectively reducing hydraulic overflow loss and fuel consumption, reducing carbon emissions, conforming to the industry development trend of green manufacturing and energy conservation, reducing user operating costs, and achieving reduced energy loss. Attached Figure Description

[0038] Figure 1 This is a schematic flowchart of a load-based main pump control method according to Embodiment 1 of the present invention. Detailed Implementation

[0039] 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.

[0040] Example 1

[0041] like Figure 1 As shown, this embodiment provides a load-based main pump control method, including:

[0042] Obtain the real-time pressure value of the excavator's main pump and the pressure value of the excavator's main pump in the previous statistical period;

[0043] Based on the pressure value of the excavator's main pump in the previous statistical period, determine the step size of the current statistical period;

[0044] Calculate the real-time pressure gradient change rate within the current statistical period based on the real-time pressure value of the excavator's main pump and the step size of the current statistical period.

[0045] Based on the real-time pressure value and real-time pressure gradient change rate of the excavator's main pump, determine the real-time pressure cutoff amplitude within the current statistical period;

[0046] Based on the real-time pressure cutoff range within the current statistical period, the real-time current of the excavator's main pump is adjusted to control the main pump opening.

[0047] The specific steps include:

[0048] Step 1: Obtain the real-time pressure value of the excavator's main pump and the pressure value of the excavator's main pump in the previous statistical period.

[0049] If the maximum pressure value of the excavator's main pump in the previous statistical period is less than the main pump overflow pressure, then the pressure value of the excavator's main pump in the previous statistical period is invalid data. The pressure value of the excavator's main pump in the previous statistical period of the statistical period containing the invalid data is then retrieved again.

[0050] Before obtaining the real-time pressure value of the excavator's main pump for the first time, pressure tests on the excavator's main pump are conducted according to existing testing procedures to obtain an initial database.

[0051] This embodiment also includes updating the database: when the pressure value of the excavator's main pump reaches the excavator's constant power pump pressure setting value, data recording is started (the recorded data includes the recording statistical period, sampling time point, and pressure value); a sliding window mechanism is used to retain the data of the most recent N statistical periods and remove old data that exceeds the window range; invalid data deviations are filtered out using the eigenvalue method.

[0052] Step 2: Based on the pressure value of the excavator's main pump in the previous statistical period, determine the step size of the current statistical period.

[0053] Step 2.1: Select the time points when the pressure value of the excavator's main pump is the highest and the time points when the pressure value is the lowest from the pressure values ​​of the excavator's main pump in the previous statistical period.

[0054] Step 2.2: Use the time interval between the time point when the pressure value is at its maximum and the time point when the pressure value is at its minimum as the step size of the current statistical period.

[0055] If the pressure value of the excavator's main pump in the previous statistical period is invalid data, then the step size of the current statistical period is determined based on the pressure value of the excavator's main pump in the previous statistical period of the statistical period in which the invalid data is obtained again.

[0056] If the current statistical period is the first statistical period, the step size of the current statistical period is determined based on the time interval between the time point when the pressure value is at its maximum and the time point when the pressure value is at its minimum in the initial database.

[0057] In this embodiment, by dynamically adjusting the step size of the statistical period, it can be ensured that the data statistical period is synchronized with the actual load changes. For example, under heavy load conditions, the pressure changes drastically; shortening the step size of the data statistical period allows for rapid capture of transient pressure peaks, improving response speed. Conversely, under light load conditions, the pressure fluctuations are gradual; extending the step size of the data statistical period reduces redundant calculations.

[0058] In this embodiment, by dynamically adjusting the step size of the statistical period, noise that may be introduced by a fixed statistical period, such as short-term pressure fluctuations, can be avoided, ensuring that subsequent results truly reflect the load status.

[0059] Step 3: Calculate the real-time pressure gradient change rate within the current statistical period based on the real-time pressure value of the excavator's main pump and the step size of the current statistical period.

[0060] Step 3.1: Within the time interval from the start sampling time of the current statistical period to the real-time sampling time, select the maximum pressure value Pmax and the minimum pressure value Pmin.

[0061] Step 3.2: Calculate the real-time pressure gradient change rate kt, expressed by the following formula:

[0062] kt = (Pmax - Pmin) / t,

[0063] Where t represents the duration of the time interval from the start sampling time to the real-time sampling time in the current statistical period, and t is less than or equal to the step size of the current statistical period.

[0064] The real-time pressure gradient change rate is divided into positive pressure gradient change rate and negative pressure gradient change rate, which are determined by the pressure values ​​at the start and end times of the current statistical period.

[0065] Specifically, if the pressure value collected at the start of the current statistical period is less than the pressure value collected at the end of the sampling period, it indicates that the main pump pressure increased from the start to the end of the sampling period, and the real-time pressure gradient change rate is a positive real-time pressure gradient change rate. If the pressure value collected at the start of the current statistical period is greater than the pressure value collected at the end of the sampling period, it indicates that the main pump pressure decreased from the start to the end of the sampling period, and the real-time pressure gradient change rate is a negative real-time pressure gradient change rate.

[0066] It should be noted that although a new real-time pressure gradient change rate may be calculated at any moment within the statistical period, the positive and negative directions are always determined based on the pressure values ​​at the start and end sampling times of the statistical period.

[0067] In this embodiment, by calculating the real-time pressure gradient change rate, load mutations within the current statistical period can be quickly identified.

[0068] Step 4: Determine the real-time pressure cutoff amplitude within the current statistical period based on the real-time pressure value and real-time pressure gradient change rate of the excavator's main pump.

[0069] Step 4.1: Obtain the pressure cutoff amplitude corresponding to the pressure value of the excavator's main pump in the previous statistical period, and use it as the initial value of the pressure cutoff amplitude for the current statistical period.

[0070] Step 4.2: Initialize the pressure threshold range.

[0071] The minimum value of the pressure threshold range is the constant power pump pressure setting value of the excavator.

[0072] The maximum value of the pressure threshold range is the average of the maximum pressure values ​​for multiple statistical periods in the database.

[0073] Step 4.3: In response to the real-time pressure value of the excavator's main pump being within the pressure threshold range, determine whether the real-time pressure gradient change rate exceeds the preset change threshold.

[0074] Specifically, if the real-time pressure value of the excavator's main pump does not reach the excavator's constant power pump pressure setting value, the initial value of the pressure cutoff amplitude for the current statistical period is the real-time pressure cutoff amplitude.

[0075] Specifically, if the real-time pressure value of the excavator's main pump exceeds the maximum value of the pressure threshold range, the maximum value of the output pressure cutoff amplitude is the real-time pressure cutoff amplitude. This process continues until the real-time pressure value of the excavator's main pump decreases and falls within the pressure threshold range, at which point the determination of whether the real-time pressure gradient change rate exceeds the preset change threshold in step 4.3 is repeated.

[0076] Step 4.4: If the threshold is exceeded, calculate the magnitude of the real-time pressure gradient change rate exceeding the preset change threshold, and use the calculated magnitude to correct the initial value of the pressure cut-off amplitude to obtain the real-time pressure cut-off amplitude; if the threshold is not exceeded, use the preset safety adjustment coefficient to correct the initial value of the pressure cut-off amplitude to obtain the real-time pressure cut-off amplitude.

[0077] When the duration of the real-time pressure gradient change rate exceeding the preset change threshold reaches the preset time threshold, the maximum value of the output pressure cutoff amplitude is the real-time pressure cutoff amplitude, until the real-time pressure value of the excavator's main pump decreases and falls within the pressure threshold range.

[0078] For example, the initial value of the pressure cutoff amplitude (the initial value of the pressure cutoff amplitude is the initial amplitude) is "the main pump pressure starts to cut off at 300 bar, the current starts to decrease, and for every 10 bar increase in pressure, the current decreases by 50 mA". The real-time pressure gradient change rate is 0.8, exceeding the preset change threshold of 0.5, and lasting for 2 statistical cycles, but not reaching the preset time threshold. The calculated amplitude of the real-time pressure gradient change rate exceeding the preset change threshold is (0.8-0.5) / 0.5=0.6. This calculated amplitude of 0.6 is used to correct the initial value of the pressure cutoff amplitude. If it is a positive pressure gradient change rate, the main pump pressure starts to cut off at 300 bar, the current starts to decrease, and for every 10 bar increase in pressure, the current decreases by 50+50×0.6=80 mA. If it is a negative pressure gradient change rate, the main pump pressure starts to cut off at 300 bar, the current starts to decrease, and for every 10 bar increase in pressure, the current decreases by 50-50×0.6=20 mA.

[0079] For example, the initial value of the pressure cutoff amplitude is "the main pump pressure starts to cut off at 300 bar, the current begins to decrease, and for every 10 bar increase in pressure, the current decreases by 50 mA". The real-time pressure gradient change rate is 0.2, which does not exceed the preset change threshold of 0.5. The initial value of the pressure cutoff amplitude is corrected using the preset safety adjustment coefficient t=0.1. If it is a positive pressure gradient change rate, the main pump pressure starts to cut off at 300 bar, the current begins to decrease, and for every 10 bar increase in pressure, the current decreases by 50 + 50 × 0.1 = 55 mA. If it is a negative pressure gradient change rate, the main pump pressure starts to cut off at 300 bar, the current begins to decrease, and for every 10 bar increase in pressure, the current decreases by 50 - 50 × 0.1 = 45 mA.

[0080] In this embodiment, the real-time pressure cutoff amplitude within the current statistical period is determined based on the real-time pressure value and real-time pressure gradient change rate of the excavator's main pump. This enables precise adaptive control for different working conditions, avoids overflow losses caused by the traditional fixed amplitude pressure cutoff mode, and significantly reduces the overall energy consumption of the machine.

[0081] In this embodiment, the dynamic step size combined with real-time pressure gradient calculation can accurately determine the pressure cutoff amplitude, avoiding the overflow energy waste caused by "insufficient cutoff" or "excessive cutoff" under the traditional fixed step size.

[0082] Step 5: Based on the real-time pressure cutoff range within the current statistical period, adjust the real-time current of the excavator's main pump to control the main pump opening.

[0083] This embodiment can adaptively adjust the opening of the excavator's main pump according to different working conditions, which can effectively reduce hydraulic overflow loss and fuel consumption, reduce carbon emissions, conform to the industry development trend of green manufacturing and energy conservation, reduce user operating costs, and reduce energy loss.

[0084] Example 2

[0085] This embodiment provides an excavator that uses a load-based main pump control method provided in Embodiment 1 to adjust the real-time current of the excavator's main pump for main pump opening control.

[0086] 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. A load-based main pump control method, characterized in that, include: Obtain the real-time pressure value of the excavator's main pump and the pressure value of the excavator's main pump in the previous statistical period; Based on the pressure value of the excavator's main pump in the previous statistical period, determine the step size of the current statistical period; Based on the real-time pressure value of the excavator's main pump and the step size of the current statistical period, calculate the real-time pressure gradient change rate within the current statistical period; wherein, calculating the real-time pressure gradient change rate within the current statistical period based on the real-time pressure value of the excavator's main pump and the step size of the current statistical period includes: Within the time interval from the start of the current statistical period to the real-time sampling time, select the maximum pressure value Pmax and the minimum pressure value Pmin; The real-time pressure gradient change rate kt is calculated using the following formula: kt = (Pmax - Pmin) / t, Where t represents the duration of the time interval from the start sampling time to the real-time sampling time in the current statistical period, and t is less than or equal to the step size of the current statistical period; Based on the real-time pressure value and real-time pressure gradient change rate of the excavator's main pump, the real-time pressure cutoff amplitude within the current statistical period is determined; including: Obtain the pressure cutoff amplitude corresponding to the pressure value of the excavator's main pump in the previous statistical period, and use it as the initial value of the pressure cutoff amplitude for the current statistical period; Initialize the pressure threshold range; In response to the real-time pressure value of the excavator's main pump being within the pressure threshold range, it is determined whether the real-time pressure gradient change rate exceeds the preset change threshold. If it exceeds the threshold, calculate the magnitude of the real-time pressure gradient change rate exceeding the preset change threshold, and use the calculated magnitude to correct the initial value of the pressure cutoff amplitude to obtain the real-time pressure cutoff amplitude. If the limit is not exceeded, the initial value of the pressure cutoff amplitude is corrected using a preset safety adjustment coefficient to obtain the real-time pressure cutoff amplitude; Based on the real-time pressure cutoff range within the current statistical period, the real-time current of the excavator's main pump is adjusted to control the main pump opening.

2. The load-based main pump control method according to claim 1, characterized in that, The step size for determining the current statistical period based on the excavator's main pump pressure value in the previous statistical period includes: Select the time points when the pressure value is the highest and the pressure value is the lowest from the pressure values ​​of the excavator's main pump in the previous statistical period; The time interval between the time point when the pressure value is at its maximum and the time point when the pressure value is at its minimum is used as the step size of the current statistical period. Among them, when the pressure value at its maximum in the previous statistical period is less than the main pump overflow pressure, the pressure value of the excavator's main pump in the previous statistical period is invalid data. The step size of the statistical period before confirming the pressure value of the excavator's main pump in the previous statistical period based on the invalid data is determined.

3. The load-based main pump control method according to claim 1, characterized in that, The minimum value of the pressure threshold range is the constant power pump pressure setting value of the excavator, and the maximum value of the pressure threshold range is the average of the maximum values ​​of pressure values ​​for multiple statistical periods in the database.

4. The load-based main pump control method according to claim 1, characterized in that, In response to the fact that the real-time pressure value of the excavator's main pump has not reached the excavator's constant power pump pressure setting value, the initial value of the pressure cut-off amplitude for the current statistical period is output as the real-time pressure cut-off amplitude.

5. The load-based main pump control method according to claim 1, characterized in that, In response to the real-time pressure value of the excavator's main pump exceeding the maximum value of the pressure threshold range, the maximum value of the output pressure cutoff amplitude is the real-time pressure cutoff amplitude; when the real-time pressure value of the excavator's main pump decreases and is within the pressure threshold range, a judgment is made on whether the real-time pressure gradient change rate exceeds the preset change threshold.

6. The load-based main pump control method according to claim 3, characterized in that, The database is updated through the following steps: When the pressure value of the excavator's main pump reaches the excavator's constant power pump pressure set value, data recording is initiated. The recorded data includes the recording statistical period, sampling time point, and pressure value. A sliding window mechanism is used to retain data from the most recent N statistical periods and remove old data that is outside the window range.

7. The load-based main pump control method according to claim 1, characterized in that, When the duration of the real-time pressure gradient change rate exceeding the preset change threshold reaches the preset time threshold, the maximum value of the output pressure cutoff amplitude is the real-time pressure cutoff amplitude, until the real-time pressure value of the excavator's main pump decreases and falls within the pressure threshold range.

8. An excavator, characterized in that, The main pump opening is controlled by adjusting the real-time current of the excavator's main pump using any one of claims 1-7.

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