Active charging warning and remaining mileage calculation method for electric excavator

Abstract

The present invention discloses an active charging warning and remaining mileage calculation method for an electric excavator, comprising the following steps: grouping and calibrating the battery power, calculating the driving distance that can be achieved by consuming the power of each group of intervals, and establishing a remaining mileage fitting function, based on the fitting function, calculating the remaining mileage that can be satisfied by the remaining power, selecting a reliability coefficient, and setting a charging warning trigger condition based on the remaining mileage and the distance between the work site and the charging pile. After the warning, the excavator goes to the charging pile to charge, and the remaining mileage during the charging process is calculated in real time. The present invention can improve construction efficiency and effective working time.

Description

Technical Field

[0001] The invention relates to an active charging early warning and a remaining mileage calculation method for an electric excavator, and belongs to the technical field of electric excavator testing. Background Art

[0002] At present, the requirements for non-road mobile machinery to emit pollutants are becoming increasingly stringent, and excavators are also gradually being electrified. Unlike internal combustion engine-driven excavators, electric excavators have limited working hours, battery packs are greatly affected by the environment, and charging facilities are required. Electric excavators only display the remaining power on the instrument, not the remaining mileage. Even if the remaining power cannot drive to the charging station, the driver will not be reminded, which seriously affects the construction progress. At present, the remaining mileage calculation method in the electric vehicle industry is relatively mature and can be used as a reference, but the electric excavator travel motor is hydraulically driven, and the estimation method used in the electric vehicle industry has a large error.

[0003] Currently, there are few methods for estimating the remaining mileage of electric excavators. The characteristics of the battery pack and the working principle of the travel motor are not considered enough, the estimation accuracy is not high, and the active charging warning device is rarely mentioned. The remaining power on the meter is of little reference value for reminding the driver to charge at the charging station. Drawing on the electric vehicle industry, displaying the remaining mileage and active charging warning are issues that need to be solved. Summary of the invention

[0004] In order to solve the deficiencies of the prior art, the purpose of the present invention is to provide an active charging warning and remaining mileage calculation method for an electric excavator, which solves the problem of low accuracy in estimating the remaining mileage of an electric excavator in the prior art.

[0005] In order to achieve the above object, the present invention adopts the following technical solution:

[0006] A method for active charging warning and remaining mileage calculation of an electric excavator comprises the following steps:

[0007] Calibrate the battery SOC in groups;

[0008] Calculate the driving distance that can be achieved by consuming each group of interval SOC, and establish the remaining driving mileage fitting function;

[0009] Calculate the remaining power SOC based on the fitting function 剩 The remaining mileage that can be satisfied is L 剩 ;

[0010] Select the reliability coefficient based on the remaining mileage L 剩 The distance L between the work site and the charging pile 距 , set the charging warning trigger conditions;

[0011] Based on the charging warning, go to the charging station to charge and calculate the remaining mileage of the excavator during charging in real time.

[0012] Furthermore, the aforementioned step of grouping and calibrating the battery power SOC includes:

[0013] Select the calibration step size Δ;

[0014] [0, SOC] is grouped and calibrated, with the interval of each group being Δ, totaling SOC / Δ groups, and recorded as: [0, Δ], [Δ, 2Δ], …, [(i-1)Δ, iΔ]…, [SOC-Δ, SOC].

[0015] Furthermore, the calibration step length Δ of the battery power SOC from 20% to 0 is 1%.

[0016] Furthermore, the driving distance L that can be achieved by consuming the SOC of the i-th group interval is 行i The expression is:

[0017]

[0018] Among them, n 行 is the speed of the travel motor, Z 链 is the number of teeth of the driving sprocket, L 履 is the length of a single track shoe, It is the time taken for SOC to be consumed from iΔ to (i-1)Δ.

[0019] Furthermore, the consumption time of the SOC in the aforementioned single group interval is obtained by using a timer in the most energy-consuming mode;

[0020] The most energy-consuming method is: on a solid and flat road, the excavator moves forward and backward at the highest gear and maximum speed without making any turns.

[0021] Furthermore, the expression of the remaining mileage fitting function L(i) is:

[0022]

[0023] Furthermore, the above-mentioned remaining power SOC is calculated based on the fitting function 剩 The remaining mileage that can be satisfied is L 剩 The steps include:

[0024] Determine SOC 剩 The group interval [INT(SOC 剩 ), SOC 剩 ],

[0025] The interpolation method is used to obtain [INT(SOC 剩 ), SOC剩 ] The mileage of the interval L 插值 ,

[0026] Then we have:

[0027]

[0028] Furthermore, the aforementioned step of setting the charging warning triggering condition includes:

[0029] Enter the distance L between the work site and the charging pile 距 ;

[0030] Select the reliability coefficient K, when L 剩 =KL 距 When the system is in operation, it will issue an active warning to remind the driver to charge at the charging station.

[0031] Furthermore, the above also includes: after the system active warning is triggered, a pressure sensor is used to collect pedal pressure in real time. If the pressure sensor continues to receive pulses, it is considered that the driver is charging and the warning signal can be turned off, otherwise it remains on.

[0032] Furthermore, the remaining mileage of the aforementioned excavator during charging is expressed as:

[0033]

[0034]

[0035] In the formula, For driving T j The remaining capacity after the time period, Remaining capacity The remaining mileage that can be traveled; U j ,I j Respectively represent the voltage and current sensors collected by T j-1 ~T j Real-time voltage and current across the battery pack during the time period; T j-1 ~T j The speed of the travel motor during the time period.

[0036] The beneficial effects achieved by the present invention are:

[0037] 1. Use an encoder to test the speed of the travel motor, and then calibrate the SOC and mileage. The user can input the distance between the charging pile and the work site. Under a certain reliability coefficient, when the remaining power is enough for the user to drive to the charging pile, the active charging warning is turned on, and the remaining mileage is displayed in real time, providing auxiliary reference for the driver to drive the electric excavator. When the power is appropriate to meet the walking distance, the driver can drive the excavator to a fixed charging pile for charging, which can improve construction efficiency and effective working time.

[0038] 2. The method for estimating the remaining mileage of an electric excavator does not require adding any hardware to the electric excavator and does not increase costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is an architecture diagram of the system of the present invention;

[0040] Figure 2 This is a flow chart of calculating the remaining mileage before warning according to the present invention;

[0041] Figure 3 This is a flow chart of calculating the remaining mileage after early warning according to the present invention. DETAILED DESCRIPTION

[0042] The technical solution of the present invention is described in detail below through the accompanying drawings and specific embodiments. It should be understood that the embodiments of the present application and the specific features in the embodiments are detailed descriptions of the technical solution of the present application, rather than limitations on the technical solution of the present application. In the absence of conflict, the embodiments of the present application and the technical features in the embodiments can be combined with each other.

[0043] This embodiment discloses a method for active charging warning and remaining mileage calculation of an electric excavator. Figure 2 , Figure 3 As shown, the problem of active charging warning and remaining mileage display of electric excavators is solved.

[0044] 1. Calibrate the battery power in groups.

[0045] The battery capacity is recorded as SOC, and a calibration step length Δ is selected. [0, SOC] is grouped and calibrated. Each group of intervals is the selected calibration step length, totaling SOC / Δ groups: [0, Δ], [Δ, 2Δ], …, [(i-1)Δ, iΔ] …, [SOC-Δ, SOC]. In this embodiment, it is preferred to calibrate the battery capacity SOC from 20% to 0, with a calibration step length of 1%, for a total of 20 groups. The 20 groups of SOC are divided into intervals, such as [0, 1%], [1%, 2%], …, [19%, 20%].

[0046] 2. Calculate the driving distance that can be achieved by consuming the SOC in each group of intervals and establish a fitting function for the remaining mileage.

[0047] The most energy-consuming method is used to predict the driving distance that can be achieved by consuming the SOC of each group of intervals mentioned above. The most energy-consuming method is: on a solid and flat road, the excavator moves forward and backward at the highest gear and maximum speed (reverse means that the upper rotating body moves backward without rotating), without turning. The encoder is used to collect the speed n of the travel motor. 行 , the driving distance in the i-th group SOC interval is recorded as L 行i , as shown in formula 1:

[0048]

[0049] Among them, Z 链 --Number of teeth of driving sprocket; L 履 --The length of a single track shoe; It is the time taken by SOC to be consumed from iΔ to (i-1)Δ, and a timer is used to obtain the consumption time.

[0050] By analogy, the relationship between the consumption Δ of the SOC in a single interval and the driving distance can be accurately obtained, and it can be fitted into a function L(i), as shown in Formula 2:

[0051]

[0052] 3. Calculate the remaining power SOC based on the fitting function 剩 The remaining mileage that can be satisfied is L 剩 .

[0053] Determine SOC 剩 The group interval [INT(SOC 剩 ), SOC 剩 ],

[0054] The interpolation method is used to obtain [INT(SOC 剩 ), SOC 剩 ] The mileage of the interval L 插值 , and then add the remaining mileage obtained by the fitting function. This method can reduce the accuracy of SOC to within Δ, as shown in Formula 3:

[0055]

[0056] 4. Select the reliability coefficient and set the charging warning trigger conditions.

[0057] The driver enters the distance L between the work site and the charging pile 距 , the reliability coefficient K is 1.4, when the remaining mileage L 剩 For L 距 If the battery is 1.4 times higher than the normal level, it will automatically warn the driver to go to the charging station to charge.

[0058] 5. Based on the charging warning, go to the charging station to charge, and calculate the remaining mileage of the excavator during charging in real time.

[0059] When the active charging warning is triggered, a pressure sensor is used to collect pedal pressure. If the pressure sensor continues to receive pulses, it is considered that the driver is charging and the alarm signal can be turned off, otherwise it will remain on.

[0060] During the charging process of driving to the charging station, the driver may change gears and use different gears to move forward on different sections of the road at different time periods. Since the interval between each time period is relatively small, the remaining distance that can be traveled with the remaining capacity can be estimated based on the driving distance per unit power consumption.

[0061] Taking driving time 0 to T1 as an example, collect the speed of the travel motor at the current gear and current speed Calculate the driving distance in the time period from 0 to T1 respectively Remaining capacity after driving for T1 period and remaining capacity Remaining mileage

[0062]

[0063]

[0064]

[0065] Wherein, U1 and I1 represent the real-time voltage and current at both ends of the battery pack during the time period 0 to T1 collected by the voltage and current sensors, respectively.

[0066] Driving time T1~T2, collect the speed of the travel motor at the current gear and speed Calculate the driving distance in the time period T1 to T2 respectively Remaining capacity after driving for T2 time period and remaining capacity Remaining mileage

[0067]

[0068]

[0069]

[0070] In the formula, U2 and I2 represent the real-time voltage and current at both ends of the battery pack during the time period T1 to T2 collected by the voltage and current sensors, respectively. 总is the initial total capacity.

[0071] And so on:

[0072]

[0073]

[0074] For driving T j The remaining capacity after the time period, Remaining capacity The remaining mileage that can be traveled, U j ,I j Respectively represent the voltage and current sensors collected by T j-1 ~T j The real-time voltage and current at both ends of the battery pack during the time period, T j-1 ~T j The speed of the travel motor at the gear and speed within the time period.

[0075] Figure 1 This is a structural diagram of an active charging warning and remaining mileage device for electric excavators. The algorithm for the remaining mileage before and after the warning is written into module 1 in the form of a piecewise function, and the active warning device is embedded in module 2, and both are communicated to the instrument to facilitate the driver's query.

[0076] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for active charging warning and remaining mileage calculation of an electric excavator, characterized in that: The following steps are involved: Calibrate the battery SOC in groups; Calculate the driving distance that can be achieved by consuming each group of interval SOC, and establish the remaining driving mileage fitting function; Calculate the remaining power based on the fitting function The remaining mileage that can be satisfied ; Select reliability factor, based on remaining mileage The distance between the work site and the charging station , set the charging warning trigger conditions; Based on the charging warning, the excavator goes to the charging station to charge and calculates the remaining mileage of the excavator during charging in real time; The step of grouping and calibrating the battery power SOC comprises: Select the calibration step size ; Set [0, SOC ] for group calibration, each group interval is ,total Groups are recorded as: ； Consumption i The driving distance that can be achieved by the group interval SOC The expression is: ;in, is the speed of the travel motor, is the number of teeth of the driving sprocket, is the length of a single track shoe, For SOC Consume to the time taken; The remaining driving range fitting function The expression is: ; The remaining mileage of the excavator during charging is expressed as: ； In the formula, For driving The remaining capacity after the time period, Remaining capacity The remaining mileage that can be traveled; U j ,I j Respectively represent the voltage and current sensors collected Real-time voltage and current across the battery pack during the time period; for The speed of the travel motor during the time period; is the initial total capacity.

2. The method for active charging warning and remaining mileage calculation of an electric excavator according to claim 1 is characterized in that: The battery power SOC is calibrated from 20% to 0, and the calibration step length is 1%.

3. The method for active charging warning and remaining mileage calculation of an electric excavator according to claim 1 is characterized in that: The consumption time of SOC in a single group interval is obtained by using a timer in the most energy-consuming mode; The most energy-consuming mode is: on a solid and flat road surface, the excavator moves forward and backward at the highest gear and maximum speed without turning.

4. The method for active charging warning and remaining mileage calculation of an electric excavator according to claim 1, characterized in that: The remaining power is calculated based on the fitting function. The remaining mileage that can be satisfied The steps include: Sure The group interval , Using interpolation method, we get Mileage of the interval , Then we have: .

5. The method for active charging warning and remaining mileage calculation of an electric excavator according to claim 4 is characterized in that: The step of setting the charging warning triggering condition comprises: Enter the distance between the work site and the charging station ; Select the reliability coefficient K, when When the system is in operation, it will issue an active warning to remind the driver to charge at the charging station.

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