Method and device for controlling running electric braking torque of electric mine truck

Abstract

The invention provides a driving electric braking torque control method and device for an electric mine truck, and the method comprises the steps: obtaining the internal air pressure and temperature of a second tire of a target tire of the electric mine truck at the current time; determining a second tire interior air volume of the target tire; determining a volume relative difference between the second tire interior air volume and the first tire interior air volume; when the volume relative difference is larger than the relative difference threshold value, it is determined that the second load state of the electric mine card at the current time is opposite to the first load state; when the volume relative difference is smaller than the relative difference threshold value, it is determined that the second load state of the electric mine card at the current time is the same as the first load state; calling a traveling electric braking torque curve corresponding to the second load state as a current traveling electric braking torque curve of the electric mine truck; according to the invention, under the condition of the same opening degree of the brake pedal, the deceleration is the same as much as possible no matter the mine truck is in a no-load state or a full-load state.

Description

Technical Field

[0001] The present invention relates to the technical field of electric mining truck driving, and in particular to an electric braking torque control method and device for an electric mining truck driving. Background Art

[0002] Mining trucks are specially used in off-road conditions to carry out short-distance transportation of large quantities of materials. Since off-road conditions have large slopes, rugged roads, and low vehicle speeds, in order to adapt to the characteristics of mining areas, mining truck parameters are generally calibrated for each mine, and one of the key points of the calibration is the driving electric brake torque.

[0003] Mining trucks are used for off-road short-distance transportation, such as earthwork and ore handling in mining areas. Mining trucks are either fully loaded or empty, and rarely half-loaded. Mining trucks travel at a low speed, with the maximum speed generally not exceeding 40km / h, and the speed is even lower when fully loaded. The weight of a mining truck is very different when it is empty and fully loaded, and the full-load weight can be 2.5 to 3 times that of an empty truck. This means that if the same driving electric brake torque strategy is used for empty and fully loaded mining trucks, it is definitely not suitable.

[0004] It can be seen that the electric braking torque method of mining truck driving in the related art has technical problems of low efficiency and non-adaptability. Summary of the invention

[0005] The present invention provides an electric brake torque control method and device for an electric mining truck, which are used to solve the defects of low efficiency and non-adaptability of the electric brake torque mode of mining trucks in the prior art, so as to achieve the same deceleration as much as possible regardless of whether the mining truck is in an unloaded state or a fully loaded state under the same brake pedal opening.

[0006] The present invention provides a method for controlling the electric brake torque of an electric mining truck, comprising the following steps: obtaining the first tire internal air volume and the first load state of a target tire of the electric mining truck in a target time period, wherein the first load state includes: a full load state and an empty load state; during the driving process of the electric mining truck, obtaining the second tire internal air pressure and the second tire temperature of the target tire of the electric mining truck at the current time; determining the second tire internal air volume of the target tire based on the second tire internal air pressure and the second tire temperature; determining the relative difference between the second tire internal air volume and the first tire internal air volume; when the relative volume difference is greater than a relative difference threshold, determining that the second load state of the electric mining truck at the current time is opposite to the first load state; when the relative volume difference is less than a relative difference threshold, determining that the second load state of the electric mining truck at the current time is the same as the first load state; calling the driving electric brake torque curve corresponding to the second load state as the current driving electric brake torque curve of the electric mining truck.

[0007] According to a driving electric brake torque control method for an electric mining truck provided by the present invention, the obtaining of the first tire internal air volume and the first load state of the target tire of the electric mining truck in a target time period comprises: during the driving process of the electric mining truck, determining the total vehicle weight of the electric mining truck and the first tire internal air pressure and the first tire temperature of the target tire of the electric mining truck in the target time period; determining the first load state of the electric mining truck in the target time period based on the total vehicle weight; and determining the first tire internal air volume of the target tire based on the first tire internal air pressure and the first tire temperature.

[0008] According to a method for controlling electric brake torque of an electric mining truck provided by the present invention, the determining of the total vehicle weight of the electric mining truck in a target time period comprises: determining the total vehicle weight of the electric mining truck in the target time period based on a dynamics formula, wherein the dynamics formula comprises: ; Wherein, m represents the total vehicle weight of the electric mining truck. Tr represents the output torque of the driving motor of the electric mining truck, η represents the mechanical transmission efficiency of the electric mining truck, represents the gearbox speed ratio of the electric mining truck, represents the bridge speed ratio of the electric mining truck, I W represents the tire rotational inertia of the electric mining truck, r represents the tire rolling radius of the electric mining truck, g represents the acceleration of gravity, α represents the vehicle pitch angle of the electric mining truck, f represents the vehicle rolling resistance coefficient of the electric mining truck, n represents the output speed of the driving motor of the electric mining truck, d n / d t Represents the derivative of the output speed of the driving motor with respect to the target time period t.

[0009] According to a method for controlling electric braking torque of an electric mining truck provided by the present invention, the target time period at least satisfies the following conditions: within the target time period, the driving process of the electric mining truck is on an uphill slope, and the slope of the uphill slope is greater than a preset threshold; within the target time period, the speed of the electric mining truck is greater than a speed threshold, and the acceleration of the electric mining truck is less than an acceleration threshold; within the target time period, the electric mining truck does not shift gears, and the fluctuation amplitude of the output of the drive motor of the electric mining truck does not exceed a preset proportion of the minimum output torque; the target time period is greater than a first duration threshold and less than a second duration threshold.

[0010] According to a method for controlling the electric brake torque of an electric mining truck provided by the present invention, the calling of the electric brake torque curve corresponding to the second load state as the current electric brake torque curve of the electric mining truck comprises: when the second load state is a full load state, using the full load electric brake torque curve as the current electric brake torque curve of the electric mining truck; when the second load state is a no-load state, using the no-load electric brake torque curve as the current electric brake torque curve of the electric mining truck.

[0011] According to a method for controlling electric brake torque of an electric mining truck provided by the present invention, the slope of the full-load electric brake torque curve and the no-load electric brake torque curve is the same as the ratio of the no-load vehicle mass of the electric mining truck to the full-load vehicle mass of the electric mining truck.

[0012] The present invention also provides an electric braking torque control device for an electric mining truck, comprising the following modules: A state acquisition module, used to acquire a first tire internal air volume and a first load state of a target tire of the electric mining truck in a target time period, wherein the first load state includes: a full load state and an empty load state; An air pressure and temperature module, used for obtaining the second tire internal air pressure and the second tire temperature of the target tire of the electric mining truck at the current time during the driving process of the electric mining truck; an air volume module, configured to determine a second tire internal air volume of the target tire based on the second tire internal air pressure and the second tire temperature; a relative difference module, configured to determine a relative difference between the volume of air inside the second tire and the volume of air inside the first tire; a state determination module, configured to determine, when the volume relative difference is greater than a relative difference threshold, that a second load state of the electric mining truck at the current time is opposite to the first load state; The state determination module is further configured to determine that the second load state of the electric mining truck at the current time is the same as the first load state when the volume relative difference is less than the relative difference threshold; The curve calling module is used to call the driving electric braking torque curve corresponding to the second load state as the current driving electric braking torque curve of the electric mining truck.

[0013] The present invention also provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, any of the above-described electric braking torque control methods for electric mining trucks is implemented.

[0014] The present invention also provides a non-transitory computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, the electric braking torque control method for an electric mining truck as described above is implemented.

[0015] The present invention also provides a computer program product, comprising a computer program, wherein when the computer program is executed by a processor, the electric braking torque control method for an electric mining truck as described above is implemented.

[0016] The electric brake torque control method and device for electric mining truck driving provided by the present invention can calculate the internal air volume of the tire by real-time monitoring the internal air pressure and temperature of the target tire during driving of the electric mining truck, and compare it with the air volume in the target time period, which is helpful to find the change of the load state in real time; by comparing the relative difference of the air volume inside the tire with the preset relative difference threshold, it can be judged whether the current load state (full load or no load) of the electric mining truck is opposite to the load state in the target time period; according to the load state judged in real time, the corresponding driving electric brake torque curve can be called, thereby, the electric mining truck can adjust its electric brake performance according to different load states, so as to optimize the braking effect and improve the driving safety and stability; thereby, when the brake pedal opening is the same, the deceleration of the mining truck is as close as possible regardless of whether it is in the no-load state or the fully loaded state. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced one by one below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 It is a flow chart of the electric braking torque control method for an electric mining truck provided by the present invention.

[0019] Figure 2 It is a schematic diagram of the slope of the no-load electric braking torque curve and the full-load electric braking torque curve provided by the present invention.

[0020] Figure 3 It is a schematic diagram of the overall process of the electric braking torque control method for an electric mining truck provided by the present invention.

[0021] Figure 4 It is a structural schematic diagram of the electric braking torque control device for an electric mining truck provided by the present invention.

[0022] Figure 5 It is a schematic diagram of the physical structure of the electronic device provided by the present invention. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] Mining trucks are specially used in off-road conditions to carry out short-distance transportation of large quantities of materials. Since off-road conditions have large slopes, rugged roads, and low vehicle speeds, in order to adapt to the characteristics of mining areas, mining truck parameters are generally calibrated for each mine, and one of the key points of the calibration is the driving electric brake torque.

[0025] The driving electric braking torque is an important part of the driving braking torque. The driving electric braking torque comes from the reverse drag of the motor, that is, the output torque of the drive system is opposite to the direction of vehicle travel. Driving electric braking is a major source of energy recovery for electric mining trucks.

[0026] Mining trucks are used for off-road short-distance transportation, such as earthwork and ore transportation in mining areas. Mining trucks are either fully loaded or empty, and rarely half-loaded. Mining trucks have low driving speeds, with the maximum speed generally not exceeding 40km / h, and even lower speeds when fully loaded. The weight of a mining truck is very different when it is empty and fully loaded, and the fully loaded weight can reach 2.5 to 3 times that of an empty truck.

[0027] This means that if the same driving electric braking torque strategy is used for mining trucks that are empty or fully loaded, it will definitely not be suitable.

[0028] There are many reasons for calibrating the electric brake torque of mining trucks: First, the working conditions of each mining area are different. For example, under heavy-load downhill conditions, the electric brake torque should be larger, preferably reaching the maximum value of the vehicle. On the one hand, it can make the vehicle's braking ability stronger and increase vehicle safety, and on the other hand, it can recover energy as much as possible in the form of electrical energy. In addition, under heavy-load uphill and unloaded downhill conditions, the electric brake torque should be smaller, otherwise the braking force will be too large, affecting the driving experience and driving safety.

[0029] The current solution is to calibrate one mine at a time. For example, if the mine is operating under heavy load uphill, the electric brake torque of the vehicle is adjusted to a smaller value; if it is operating under heavy load downhill, the electric brake torque of the vehicle is adjusted to a larger value. This faces two problems: one is that calibrating one mine at a time consumes manpower and material resources, and the other is that it is not suitable for complex operating conditions with both heavy load uphill and heavy load downhill.

[0030] The embodiment of the present invention provides a method for controlling the electric brake torque of an electric mining truck to achieve two purposes: first, the driver steps on the brake pedal to the same depth, and the deceleration is basically the same whether the vehicle is unloaded or fully loaded, so as to increase the braking smoothness and safety of the mining truck. Second, the electric brake energy recovery is increased as much as possible to increase the economy. To achieve these two purposes, accurately identifying the load state of the vehicle is the key.

[0031] Optionally, the electric braking torque control method for an electric mining truck in an embodiment of the present application can be executed by a server, or by a terminal device, or jointly by a server and a terminal device, taking the electric braking torque control method for an electric mining truck in this embodiment executed by a vehicle-mounted terminal as an example.

[0032] Figure 1 FIG. 1 is a flow chart of the electric braking torque control method for an electric mining truck provided by the present invention, such as Figure 1 As shown, the method includes the following: Step 101, obtaining a first tire internal air volume and a first load state of a target tire of an electric mining truck in a target time period, wherein the first load state includes: a full load state and an empty load state.

[0033] Here, the target tire can be selected according to the actual application situation. For example, the left tire of the rear axle can be selected as the target tire.

[0034] In the embodiment of the present invention, a small segment (target time period) of the electric mining truck during the driving process is selected to identify whether the vehicle is fully loaded or unloaded. Since the speed of the mining truck is low, generally not exceeding 30km / h, air resistance is not considered.

[0035] In some embodiments, the air pressure and temperature inside the tire are recorded in real time or periodically by the preset sensors of the electric mining truck, and the air volume is calculated by a certain algorithm. Within the target time period, these parameters are recorded and the average value of the air volume inside the first tire or the value at a specific time point is calculated.

[0036] In some embodiments, the total vehicle weight m of the electric mining truck is obtained, and it is determined whether the first load state of the electric mining truck is a fully loaded state or an unloaded state. If m>m0+m1 / 2, the vehicle is fully loaded; if m≤m0+m1 / 2, the vehicle is unloaded.

[0037] Among them, m0 is the unloaded mass of the electric mining truck, m1 is the rated load mass of the electric mining truck, and m0 and m1 are the design masses, which are known quantities.

[0038] According to a method for controlling electric braking torque of an electric mining truck provided by the present invention, the target time period at least satisfies the following conditions: During the target time period, the electric mining truck is driving uphill, and the uphill slope is greater than a preset threshold; During the target time period, the speed of the electric mining truck is greater than the speed threshold, and the acceleration of the electric mining truck is less than the acceleration threshold; During the target time period, the electric mining truck does not shift gears, and the fluctuation amplitude of the drive motor output of the electric mining truck does not exceed the preset proportion of the minimum output torque; The target time period is greater than the first time length threshold and less than the second time length threshold.

[0039] In the embodiment of the present invention, in order to reduce the influence of the rolling resistance coefficient and improve the accuracy of vehicle weight recognition, the driving segment (i.e., the target time period) of the electric mining truck is selected to meet the following requirements: The vehicle is on an uphill slope in the driving segment, with a slope of more than 4%; When driving uphill, the weight of the vehicle has a more significant effect on rolling resistance, which helps to more accurately identify the actual weight of the vehicle. Slope measurement can be achieved through GPS devices, map data or dedicated slope sensors.

[0040] The vehicle speed in the driving segment is >5km / h, and the speed is relatively stable, and the acceleration is ≤1m / s 2 ; The vehicle speed should be greater than 5km / h to ensure that the vehicle is in a normal driving state and to avoid atypical driving characteristics at low speeds that interfere with weight recognition. The vehicle speed should be relatively stable and the acceleration should not exceed 1m / s². This helps to reduce the impact of dynamic effects caused by acceleration or deceleration on weight recognition. Speed ​​sensors and acceleration sensors can be used to monitor and record these parameters.

[0041] There is no gear shifting in the driving segment, the output torque of the drive motor is stable, and the fluctuation range does not exceed 10% of the minimum output torque in the segment; In the selected driving segment, the vehicle should not perform gear shifting to keep the output torque of the drive motor stable. The fluctuation of the output torque of the drive motor should not exceed 10% of the minimum output torque in the segment. This can be achieved by monitoring the torque output signal of the motor.

[0042] The driving clip lasts for a period of time, but it should not be too long, for example, 4 seconds can be selected.

[0043] The duration of the driving segment should be moderate, which ensures the adequacy of the data and avoids unnecessary interference caused by excessive time. The duration should be adjusted according to the actual situation to ensure that the vehicle status meets all requirements within the selected time period.

[0044] It should be noted that it is not difficult to meet the above driving requirements during the driving of electric mining trucks.

[0045] According to a method for controlling electric brake torque of an electric mining truck provided by the present invention, the first tire internal air volume and the first load state of a target tire of the electric mining truck in a target time period are obtained, including: During the driving process of the electric mining truck, the gross vehicle weight of the electric mining truck and the first tire internal air pressure and the first tire temperature of the target tire of the electric mining truck are determined in the target time period; Based on the total vehicle weight, determine the first load state of the electric mining truck in the target time period; A first tire internal air volume of the target tire is determined based on the first tire internal air pressure and the first tire temperature.

[0046] In the embodiment of the present invention, the first tire internal air pressure P0 and the first tire temperature T0 of any tire (ie, the target tire) of the electric mining truck in the target time period are obtained. For example, the left tire of the middle bridge (tire number 1) may be selected.

[0047] The gas in the enclosed space satisfies the following formula: Wherein, P represents the internal air pressure of the tire, in units of pa; V represents the internal air volume of the tire, T represents the temperature, in units of K; C represents the determined tire research object, and C is a preset constant.

[0048] From the above formula, it can be seen that by obtaining the first tire internal air pressure P0 and the first tire temperature T0, the tire internal air volume V0 can be obtained. The tire pressure monitoring system currently carried on vehicles has built-in pressure sensors and temperature sensors, which can easily obtain the tire internal air pressure and tire temperature.

[0049] Through the embodiments of the present invention, by real-time monitoring of the total vehicle weight of the electric mining truck, the internal air pressure and temperature of the target tire, the state changes of the vehicle in different time periods can be accurately grasped; the internal air volume of the target tire can be calculated by combining the air pressure and temperature data, and a more comprehensive assessment of the health status of the tire can be made.

[0050] According to a method for controlling electric brake torque of an electric mining truck provided by the present invention, the total vehicle weight of the electric mining truck in a target time period is determined, including: Based on the dynamics formula, the total weight of the electric mining truck in the target time period is determined, where the dynamics formula includes: ; Among them, m represents the total weight of the electric mining truck. Tr represents the output torque of the driving motor of the electric mining truck, η represents the mechanical transmission efficiency of the electric mining truck, Indicates the gearbox ratio of the electric mining truck. Indicates the bridge speed ratio of the electric mining truck, I W represents the moment of inertia of the tire of the electric mining truck, r represents the rolling radius of the tire of the electric mining truck, g represents the acceleration of gravity, α represents the vehicle pitch angle of the electric mining truck, and f represents the vehicle rolling resistance coefficient of the electric mining truck. n Indicates the output speed of the driving motor of the electric mining truck, d n / d t It represents the derivative of the output speed of the drive motor with respect to the target time period t.

[0051] In the embodiment of the present invention, the vehicle mass of a small segment (target time period) of the driving process is selected to identify whether the vehicle is fully loaded or unloaded. Since the speed of the mining truck is low, generally not exceeding 30km / h, air resistance is not considered. The vehicle weight is calculated according to the above dynamic formula.

[0052] In some embodiments, d n / d t It represents the derivative of the output speed n of the drive motor with respect to time t, that is, the acceleration of the motor speed. When applied, it can be approximately replaced by the following formula: Among them, n1 represents the initial speed of the drive motor output in the driving segment, n2 represents the final speed of the drive motor output in the driving segment, Indicates the target time period (a small segment of driving).

[0053] Through the embodiments of the present invention, the total vehicle weight of the electric mining truck can be calculated in real time within a target time period according to the dynamics formula.

[0054] Step 102, during the driving process of the electric mining truck, obtaining the second tire internal air pressure and the second tire temperature of the target tire of the electric mining truck at the current time.

[0055] In the embodiment of the present invention, during the operation of the electric mining truck, the second tire internal air pressure P and the second tire temperature T of the target tire of the electric mining truck are obtained in real time.

[0056] For example, the tire pressure monitoring system currently pre-installed on electric mining trucks has built-in pressure sensors and temperature sensors, which can easily obtain the tire pressure and temperature of each tire.

[0057] Step 103 : determining the second tire internal air volume of the target tire based on the second tire internal air pressure and the second tire temperature.

[0058] The gas in the enclosed space satisfies the following formula: Wherein, P represents the internal air pressure of the tire, in units of pa; V represents the internal air volume of the tire, T represents the temperature, in units of K; C represents the determined tire research object, and C is a preset constant.

[0059] In an embodiment of the present invention, based on the built-in pressure sensor and temperature sensor of the tire pressure monitoring system pre-set on the electric mining truck vehicle, the second tire internal air pressure and the second tire temperature of the target tire in the target time period are obtained, and the second tire internal air volume of the target tire is calculated according to the above formula.

[0060] Step 104 , determining a relative difference between the volume of air inside the second tire and the volume of air inside the first tire.

[0061] In the embodiment of the present invention, when the tire load is large, the internal air is compressed and the volume becomes smaller. The tire load can be determined by comparing the internal air volume V of the second tire of the target tire at the current time with the internal air volume V0 of the first tire of the target tire at the target time period, thereby determining the empty or full load state of the electric mining truck at the current time.

[0062] The relative difference between the air volume inside the second tire at the current time and the air volume inside the first tire at the target time period can be determined by the following formula: ; in, Vper Indicates relative difference in volume, V represents the internal air volume of the second tire of the target tire at the current time, V0 Indicates the air volume inside the first tire during the target time period, T Indicates the second tire temperature of the target tire at the current time, P Indicates the internal air pressure of the second tire of the target tire at the current time; T 0 represents the internal air pressure of the first tire of the target tire during the target time period, P 0 Indicates the first tire temperature of the target tire in the target time period.

[0063] Step 105, when the volume relative difference is greater than the relative difference threshold, it is determined that the second load state of the electric mining truck at the current time is opposite to the first load state; when the volume relative difference is less than the relative difference threshold, it is determined that the second load state of the electric mining truck at the current time is the same as the first load state.

[0064] In the embodiment of the present invention, if the volume is relatively poor Vper If it is greater than the relative difference threshold ε, the volume of the tire at the current time is quite different from that at the target time period, and the empty and full-load states of the electric mining truck are opposite to those at the target time period.

[0065] If the volume is relatively poor Vper If it is less than the relative difference threshold ε, the difference between the tire volume at the current time and the tire volume at the target time period is small, and the empty and full-load states of the electric mining truck are the same as those in the target time period.

[0066] It should be noted that the selection of the specific value of the relative difference threshold ε depends on different types of tires, and can be calibrated before the vehicle leaves the factory, or obtained during the actual operation of the vehicle (electric mining truck).

[0067] For example, referring to the above embodiment, the tire pressure and temperature of the vehicle in the unloaded state are P0empty, T0empty, and the tire pressure and temperature in the fully loaded state are P0full, T0full, then the air volume inside the tire in the unloaded and fully loaded states can be obtained (C represents a preset constant): ; ; Select ε = (V0 full - V0 empty) / V0 full as the boundary to distinguish between empty and full load. It should be noted that after determining ε as the boundary, it can be treated as a constant and does not need to be recalibrated every time.

[0068] Step 106: call the driving electric braking torque curve corresponding to the second load state as the current driving electric braking torque curve of the electric mining truck.

[0069] In the embodiment of the present invention, according to the different load states of the electric mining truck, the vehicle controller calls different driving electric brake torque curves. When the vehicle is fully loaded, the driving electric brake torque curve is steep, and when the vehicle is unloaded, the driving electric brake torque curve is gentle.

[0070] According to a method for controlling electric braking torque of an electric mining truck provided by the present invention, a driving electric braking torque curve corresponding to a second load state is called as a current driving electric braking torque curve of the electric mining truck, including: When the second load state is a full load state, the full load electric brake torque curve is used as the current driving electric brake torque curve of the electric mining truck; When the second load state is the no-load state, the no-load electric brake torque curve is used as the current driving electric brake torque curve of the electric mining truck.

[0071] refer to Figure 2 , Figure 2 It is a schematic diagram of the slope of the no-load electric braking torque curve and the full-load electric braking torque curve provided by the present invention.

[0072] The horizontal axis is the brake pedal opening, and the vertical axis is the electric brake torque, including: a full-load electric brake torque curve and a no-load electric brake torque curve.

[0073] In an embodiment of the present invention, it is necessary to determine the current load state of the electric mining truck. This state can generally be divided into two types: fully loaded state and unloaded state. The fully loaded state means that the vehicle is loaded with a rated or near-rated cargo weight; while the unloaded state means that the vehicle is not loaded or only loaded with a small amount of cargo.

[0074] When the electric mining truck is fully loaded, the required braking force will increase accordingly due to the increase in vehicle weight. Therefore, under full load, the full load electric brake torque curve should be selected as the current driving electric brake torque curve. This curve can ensure that under full load conditions, the electric mining truck can quickly and stably decelerate or stop, thereby ensuring driving safety.

[0075] On the contrary, when the electric mining truck is in an unloaded state, the required braking force will be reduced accordingly due to the reduction in vehicle weight. In order to avoid excessive deceleration or inappropriate braking behavior of the vehicle due to excessive braking force, the unloaded electric braking torque curve should be selected as the current driving electric braking torque curve. This curve can ensure that the electric mining truck can decelerate or stop smoothly under unloaded conditions while maintaining good driving performance.

[0076] Through the embodiments of the present invention, the electric brake torque curve is adjusted according to the load state of the electric mining truck, which can not only improve the braking performance of the vehicle, but also extend the service life of the vehicle to a certain extent and reduce the operating cost.

[0077] According to an electric braking torque control method for an electric mining truck provided by the present invention, the slope of a full-load electric braking torque curve and a no-load electric braking torque curve is the same as the ratio of the no-load vehicle mass of the electric mining truck to the full-load vehicle mass of the electric mining truck.

[0078] In an embodiment of the present invention, the slopes of the no-load electric brake torque curve and the full-load electric brake torque curve may be the same as the ratio of the no-load vehicle mass to the full-load mass, so that the driver feels that the brake pedal is depressed to the same depth and the vehicle deceleration is the same.

[0079] In order to increase the full-load braking energy recovery rate of the vehicle, the full-load electric braking torque curve can be made close to the maximum electric braking power of the power system. The maximum electric braking power of the vehicle power system should comprehensively consider the power battery system, drive motor system, bridge and other assembly parts.

[0080] The following describes an example of a practical application of the electric braking torque control method for an electric mining truck provided by the present invention.

[0081] refer to Figure 3 , Figure 3 It is a schematic diagram of the overall process of the electric braking torque control method for an electric mining truck provided by the present invention.

[0082] Input the unladen mass \(m_0\) of the electric mining truck and the rated full-load mass \(m_1\) of the electric mining truck; and initialize the internal air pressure \(P_{0\text{ empty}}\), the internal temperature \(T_{0\text{ empty}}\) and the internal air volume \(V_{0\text{ empty}}\) of the tires of the electric mining truck.

[0083] S0. Select a small fragment of the driving process, determine the total vehicle weight \(m\), and identify whether the vehicle is fully loaded or unladen. Since the speed of the mining truck is low, generally not exceeding 30 km / h, air resistance is not considered.

[0084] S1. Based on the total vehicle weight \(m\) obtained in S0, determine whether the vehicle is fully loaded or unladen. If \(m > m_0+\frac{m_1}{2}\), the vehicle is fully loaded; if \(m\leq m_0+\frac{m_1}{2}\), the vehicle is unladen. Here, \(m_0\) is the unladen mass of the whole vehicle, \(m_1\) is the total vehicle weight under the rated load of the whole vehicle, and \(m_0\) and \(m_1\) are design masses and are known quantities.

[0085] S2. Obtain \(P_0\) and \(T_0\) of the target tire of the vehicle at the moment when the total vehicle weight \(m\) is calculated in step S0. For example, the left tire of the middle bridge (tire number 1) can be selected.

[0086] S3. During the operation of the vehicle, real-time obtain the tire pressure \(P\) and temperature \(T\) of the target tire, and compare with the values in S2 to determine the empty / full load state of the vehicle.

[0087] S4. According to the different load states of the vehicle, the vehicle controller calls different driving electric braking torque curves.

[0088] S5. When the drive motor enters neutral, repeat S3 and S4; when the drive motor leaves neutral, repeat S3 and S4.

[0089] S6. Repeat steps S0, S1, S2. If the empty / full load state in S1 is the same as the previous empty / full load state in S1, and the internal air volume \(V_1\) of the target tire newly measured and calculated in S2 satisfies \(\frac{V_1 - V_0}{V_0}>\varepsilon\), then use the newly measured and calculated tire pressure \(P_1\), temperature \(T_1\), and internal air volume \(V_1\) in S2 to replace the tire pressure \(P_0\), temperature \(T_0\), and internal air volume \(V_0\); otherwise, still adopt the original \(P_0\), \(T_0\), and \(V_0\).

[0090] S7. Before the vehicle shuts down, record the empty / full load state of the vehicle and the tire pressure, temperature, and internal air volume of the corresponding target tire. After powering on again, adopt the recorded empty / full load state of the vehicle and the tire pressure, temperature, and internal air volume of the corresponding target tire.

[0091] In the embodiment of the present invention, according to the characteristics of the working conditions, a method for roughly calculating the total weight of the mining truck and classifying the total weight of the mining truck into empty or full load is proposed. Since the difference between the empty and full load masses of the mining truck is very large, by applying the vehicle dynamics formula to a small fragment of the vehicle movement that meets the conditions, the vehicle weight is calculated and classified into empty or full load, ensuring the accuracy of the classification.

[0092] In an embodiment of the present invention, the empty and full load states of the vehicle are determined in real time by tire pressure. The real-time determination of the empty and full load states of the vehicle by tires is high. By obtaining the tire pressure and temperature in real time and comparing them with the tire pressure and temperature of the known empty and full load states, the empty and full load states of the vehicle can be quickly determined.

[0093] In the embodiment of the present invention, different driving electric brake torque curves for the mining truck under no-load and full-load conditions are proposed. When the brake pedal opening is the same, the deceleration of the mining truck is as similar as possible regardless of whether it is in an no-load state or a full-load state, thereby increasing the smoothness and safety of the mining truck, and also increasing the energy recovery efficiency of the mining truck's electric brake, thereby increasing economy.

[0094] In the embodiment of the present invention, the mining truck does not need to add other hardware equipment. The tire pressure sensor can transmit tire pressure and temperature. The sensor is mature and is widely used as standard on mining trucks. The angle sensor for measuring the pitch angle of the mining truck is also mostly integrated into the vehicle controller. The cost of the vehicle is not increased.

[0095] In the embodiment of the present invention, the algorithm is adapted to the working conditions of mining trucks, and the algorithm is based on two unique usage conditions of mining trucks: on the one hand, in the reverse short transportation condition, the vehicle is either empty or fully loaded, and is basically not in a half-loaded or other condition; on the other hand, the empty and fully loaded masses of mining trucks differ greatly. Although the error in determining the vehicle mass by tire pressure is large, it is completely impossible to misjudge whether the vehicle is empty or fully loaded.

[0096] In the embodiment of the present invention, there is no need to perform machine learning, which eliminates the disadvantage that the supervised learning algorithm requires a large amount of data for training, and makes the program more generalizable.

[0097] The present invention can be applied to other power drive systems such as electric drive axles, hybrid vehicles, etc.

[0098] The electric braking torque control device for an electric mining truck provided by the present invention is described below. The electric braking torque control device for an electric mining truck described below and the electric braking torque control method for an electric mining truck described above can be referred to each other.

[0099] refer to Figure 4 , Figure 4 It is a structural schematic diagram of the electric braking torque control device for an electric mining truck provided by the present invention.

[0100] The state acquisition module 401 is used to acquire the first tire internal air volume and the first load state of the target tire of the electric mining truck in the target time period, wherein the first load state includes: a full load state and an empty load state; The air pressure and temperature module 402 is used to obtain the second tire internal air pressure and the second tire temperature of the target tire of the electric mining truck at the current time during the driving process of the electric mining truck; The air volume module 403 is used to determine the air volume inside the second tire of the target tire based on the air pressure inside the second tire and the temperature of the second tire; A relative difference module 404 for determining a relative difference between the volume of air inside the second tire and the volume of air inside the first tire; The state determination module 405 is used to determine that the second load state of the electric mining truck at the current time is opposite to the first load state when the volume relative difference is greater than the relative difference threshold; and to determine that the second load state of the electric mining truck at the current time is the same as the first load state when the volume relative difference is less than the relative difference threshold; The curve calling module 406 is used to call the driving electric braking torque curve corresponding to the second load state as the current driving electric braking torque curve of the electric mining truck.

[0101] Specifically, the electric braking torque control device for electric mining truck provided by the present invention can implement all the method steps implemented in the above-mentioned electric braking torque control method embodiment for electric mining truck, and can achieve the same technical effect. The parts and beneficial effects that are the same as those in the method embodiment will not be described in detail herein.

[0102] Figure 5 is a schematic diagram of the physical structure of the electronic device provided by the present invention, such as Figure 5As shown, the electronic device may include: a processor (processor) 510, a communication interface (Communications Interface) 520, a memory (memory) 530 and a communication bus 540, wherein the processor 510, the communication interface 520, and the memory 530 communicate with each other through the communication bus 540. The processor 510 can call the logic instructions in the memory 530 to execute the electric braking torque control method for electric mining truck driving, which includes: obtaining the first tire internal air volume and the first load state of the target tire of the electric mining truck in the target time period, wherein the first load state includes: a full load state and an empty load state; in the driving process of the electric mining truck, obtaining the second tire internal air pressure and the second tire temperature of the target tire of the electric mining truck at the current time; based on the second tire internal air pressure and the second tire temperature, determining the second tire internal air volume of the target tire; determining the relative volume difference between the second tire internal air volume and the first tire internal air volume; when the volume relative difference is greater than the relative difference threshold, determining that the second load state of the electric mining truck at the current time is opposite to the first load state; when the volume relative difference is less than the relative difference threshold, determining that the second load state of the electric mining truck at the current time is the same as the first load state; calling the driving electric braking torque curve corresponding to the second load state as the current driving electric braking torque curve of the electric mining truck.

[0103] In addition, the logic instructions in the above-mentioned memory 530 can be implemented in the form of a software functional unit and can be stored in a computer-readable storage medium when it is sold or used as an independent product. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc. Various media that can store program codes.

[0104] On the other hand, the present invention also provides a computer program product, which includes a computer program, which can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the electric brake torque control method for electric mining truck driving provided by the above methods, which method includes: obtaining the first tire internal air volume and the first load state of the target tire of the electric mining truck in the target time period, wherein the first load state includes: a full load state and an empty load state; during the driving process of the electric mining truck, obtaining the second tire internal air pressure and the second tire temperature of the target tire of the electric mining truck at the current time; based on the second tire internal air pressure and the second tire temperature, determining the second tire internal air volume of the target tire; determining the relative difference between the second tire internal air volume and the first tire internal air volume; when the volume relative difference is greater than the relative difference threshold, determining that the second load state of the electric mining truck at the current time is opposite to the first load state; when the volume relative difference is less than the relative difference threshold, determining that the second load state of the electric mining truck at the current time is the same as the first load state; calling the driving electric brake torque curve corresponding to the second load state as the current driving electric brake torque curve of the electric mining truck.

[0105] On the other hand, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which is implemented by a processor to execute the electric braking torque control method for electric mining truck driving provided by the above methods when the computer program is executed, the method comprising: obtaining the first tire internal air volume and the first load state of the target tire of the electric mining truck in the target time period, wherein the first load state includes: a full load state and an empty load state; during the driving process of the electric mining truck, obtaining the second tire internal air pressure and the second tire temperature of the target tire of the electric mining truck at the current time; determining the second tire internal air volume of the target tire based on the second tire internal air pressure and the second tire temperature; determining the relative volume difference between the second tire internal air volume and the first tire internal air volume; when the volume relative difference is greater than the relative difference threshold, determining that the second load state of the electric mining truck at the current time is opposite to the first load state; when the volume relative difference is less than the relative difference threshold, determining that the second load state of the electric mining truck at the current time is the same as the first load state; calling the driving electric braking torque curve corresponding to the second load state as the current driving electric braking torque curve of the electric mining truck.

[0106] The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without paying creative labor.

[0107] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, can also be implemented by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0108] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for controlling electric braking torque of an electric mining truck, characterized in that: include: Obtaining a first tire internal air volume and a first load state of a target tire of an electric mining truck in a target time period, wherein the first load state includes: a full load state and an empty load state; During the driving process of the electric mining truck, obtaining the second tire internal air pressure and the second tire temperature of the target tire of the electric mining truck at the current time; determining a second tire internal air volume of the target tire based on the second tire internal air pressure and the second tire temperature; determining a relative difference in volume between the second tire interior air volume and the first tire interior air volume; When the volume relative difference is greater than the relative difference threshold, it is determined that the second load state of the electric mining truck at the current time is opposite to the first load state; when the volume relative difference is less than the relative difference threshold, it is determined that the second load state of the electric mining truck at the current time is the same as the first load state; The driving electric braking torque curve corresponding to the second load state is called as the current driving electric braking torque curve of the electric mining truck.

2. The electric braking torque control method for electric mining truck according to claim 1 is characterized in that: The step of obtaining a first tire internal air volume and a first load state of a target tire of an electric mining truck in a target time period includes: During the driving process of the electric mining truck, determining the total vehicle weight of the electric mining truck and the first tire internal air pressure and the first tire temperature of the target tire of the electric mining truck in a target time period; Based on the total vehicle weight, determining a first load state of the electric mining truck in the target time period; A first tire internal air volume of the target tire is determined based on the first tire internal air pressure and the first tire temperature.

3. The electric braking torque control method for electric mining truck according to claim 2 is characterized in that: The determining of the total vehicle weight of the electric mining truck in the target time period includes: Based on the dynamics formula, the total vehicle weight of the electric mining truck in the target time period is determined, wherein the dynamics formula includes: ； Wherein, m represents the total vehicle weight of the electric mining truck. Tr represents the output torque of the driving motor of the electric mining truck, η represents the mechanical transmission efficiency of the electric mining truck, represents the gearbox speed ratio of the electric mining truck, represents the bridge speed ratio of the electric mining truck, I W represents the tire rotational inertia of the electric mining truck, r represents the tire rolling radius of the electric mining truck, g represents the acceleration of gravity, α represents the vehicle pitch angle of the electric mining truck, f represents the vehicle rolling resistance coefficient of the electric mining truck, n represents the output speed of the driving motor of the electric mining truck, d n / d t Represents the derivative of the output speed of the driving motor with respect to the target time period t.

4. The electric braking torque control method for electric mining truck according to claim 1 is characterized in that: The target time period at least meets the following conditions: During the target time period, the electric mining truck is traveling uphill, and the uphill slope is greater than a preset threshold; During the target time period, the speed of the electric mining truck is greater than a speed threshold, and the acceleration of the electric mining truck is less than an acceleration threshold; During the target time period, the electric mining truck does not shift gears, and the fluctuation amplitude of the output of the driving motor of the electric mining truck does not exceed a preset proportion of the minimum output torque; The target time period is greater than a first time threshold and less than a second time threshold.

5. The electric braking torque control method for electric mining truck according to claim 1 is characterized in that: The calling of the driving electric braking torque curve corresponding to the second load state as the current driving electric braking torque curve of the electric mining truck includes: When the second load state is a full load state, the full load electric brake torque curve is used as the current driving electric brake torque curve of the electric mining truck; When the second load state is a no-load state, the no-load electric brake torque curve is used as the current driving electric brake torque curve of the electric mining truck.

6. The electric braking torque control method for electric mining truck according to claim 5 is characterized in that: The slope of the full-load electric brake torque curve and the no-load electric brake torque curve is the same as the ratio of the no-load vehicle mass of the electric mining truck to the full-load vehicle mass of the electric mining truck.

7. An electric braking torque control device for an electric mining truck, characterized in that: include: A state acquisition module, used to acquire a first tire internal air volume and a first load state of a target tire of the electric mining truck in a target time period, wherein the first load state includes: a full load state and an empty load state; An air pressure and temperature module, used for obtaining the second tire internal air pressure and the second tire temperature of the target tire of the electric mining truck at the current time during the driving process of the electric mining truck; an air volume module, configured to determine a second tire internal air volume of the target tire based on the second tire internal air pressure and the second tire temperature; a relative difference module, configured to determine a relative difference between the volume of air inside the second tire and the volume of air inside the first tire; a state determination module, configured to determine that the second load state of the electric mining truck at the current time is opposite to the first load state when the volume relative difference is greater than a relative difference threshold; and to determine that the second load state of the electric mining truck at the current time is the same as the first load state when the volume relative difference is less than the relative difference threshold; The curve calling module is used to call the driving electric braking torque curve corresponding to the second load state as the current driving electric braking torque curve of the electric mining truck.

8. An electronic device comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that: When the processor executes the computer program, the electric braking torque control method for an electric mining truck as claimed in any one of claims 1 to 6 is implemented.

9. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the electric braking torque control method for an electric mining truck as claimed in any one of claims 1 to 6 is implemented.

10. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the electric braking torque control method for an electric mining truck as claimed in any one of claims 1 to 6 is implemented.

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