Intelligent four-wheel drive control method and system for electric trackless rubber-tyred vehicle

Abstract

The application provides an intelligent four-wheel drive control method and system for an electric trackless rubber-tyred vehicle, and relates to the field of underground trackless transportation, which comprises the following steps: collecting signals of a brake pedal and an electronic accelerator pedal to calculate required torque, and then acquiring real-time rotating speeds of front and rear drive motors to calculate a rotating speed difference; when the absolute value of the rotating speed difference is greater than or equal to a preset threshold, the high-speed motor is controlled to reduce the rotating speed to a value less than the preset threshold, otherwise, the next step is entered; according to the current rotating speed of the motor and the required torque of the vehicle, a preset rotating speed-torque-efficiency corresponding table is inquired to obtain the motor efficiency under different torques at the current rotating speed; the single-motor and double-motor working efficiencies are compared, the required torque is distributed to the single motor or distributed to the double motor in proportion, and the total efficiency is maximized; meanwhile, the temperature of the motor and the controller is detected in real time, and when the temperature does not meet the adaptation requirement, a torque reduction strategy is executed, and after meeting the requirement, the efficiency distribution step is returned to. According to the efficiency under different torques at the current rotating speed, the application reasonably distributes the front and rear drive motor torques, and improves the system efficiency.

Description

Technical Field

[0001] This invention relates to the field of underground trackless transportation technology, specifically to an intelligent four-wheel drive control method and system for an electric trackless rubber-wheeled vehicle. Background Technology

[0002] Existing pure electric trackless rubber-tired vehicles mainly employ the following types of drive systems. The first type replaces the internal combustion engine in the original fuel-powered vehicle with a single motor, transmitting power to the front and rear axles via a torque converter and multi-speed gearbox. However, due to the low efficiency of the torque converter and gearbox, this technology results in high energy consumption and poor range. The second type uses a single motor drive, eliminating the torque converter and achieving rear-wheel drive through a direct connection between the reducer and the rear drive axle. The third type also uses a single motor drive, eliminating the torque converter and achieving four-wheel drive by connecting the front and rear drive axles via a transfer case. The second and third technologies eliminate the torque converter, but require high motor torque and have high motor costs. Under complex underground working conditions, such as steep inclines, low-speed heavy loads, or high-speed no-load conditions, the motor efficiency is low, and energy consumption remains high. Furthermore, prolonged operation of a single motor leads to severe overheating, causing shutdown protection. After a single motor stops, a tow truck is required to return the vehicle to a repair point.

[0003] Existing trackless rubber-tired vehicle control technologies, such as the control method and system for a mining trackless rubber-tired vehicle disclosed in publication number CN118144585A, feature two independently driveable electric drive axles. These axles can switch between single-motor and dual-motor drive in real time based on operating conditions, motor efficiency MAP, and motor temperature, thereby improving system efficiency. However, the control system in CN118144585A has the following problems:

[0004] 1) It distributes torque proportionally based on the front and rear load collectors. When the front or rear wheels slip, it may cause the slippage to worsen, resulting in insufficient power and inability to get out of trouble.

[0005] 2) When the total torque demand is at the efficiency critical point of a single motor, frequent switching of the drive motor causes frequent system shocks and reduces motor life.

[0006] 3) When driving on bumpy roads, the front and rear load collectors will fluctuate frequently, causing torque distribution fluctuations, making the vehicle ride unstable. In addition, the front and rear load collectors increase costs and the failure rate.

[0007] 4) The drive motor is switched according to the motor temperature. When the temperature is at the critical point, it is switched to another motor. However, in actual operation, the motor temperature is likely to hover near the critical point, resulting in frequent switching and greater impact when driving.

[0008] 5) The dual motors use a two-in-one motor controller. When one motor controller malfunctions, it is not easy to repair or replace it, and it is also not easy to determine whether the problem affects the other controller or whether the vehicle can be towed. Summary of the Invention

[0009] This invention provides an intelligent four-wheel drive control method and system for an electric trackless rubber-wheeled vehicle, which solves at least one of the technical problems mentioned in the background art.

[0010] To address the aforementioned technical problems, this invention discloses an intelligent four-wheel drive control method for an electric trackless rubber-wheeled vehicle. In automatic mode, the control method includes:

[0011] Step 1: Collect signals from the brake pedal and electronic accelerator pedal of the electric trackless rubber-wheeled vehicle, and calculate the current torque demand of the vehicle;

[0012] Step 2: Collect the real-time speeds of the front and rear drive motors of the electric trackless rubber-wheeled vehicle and calculate the speed difference;

[0013] When the absolute value of the speed difference is greater than or equal to a preset threshold, the high-speed drive motor is controlled to reduce its speed until the absolute value of the speed difference is less than the preset threshold.

[0014] When the speed difference is less than the preset threshold, proceed to step 3;

[0015] Step 3: Based on the current speeds of the front drive motor and the rear drive motor and the current torque demand of the vehicle, look up the preset motor speed-motor torque-motor efficiency correspondence table to obtain the motor efficiency corresponding to different motor torques at the current speed;

[0016] Step 4: Compare the efficiency values ​​of single-motor operation and dual-motor operation, and allocate all the required torque to the front drive motor or the rear drive motor, or proportionally to the front drive motor and the rear drive motor, in order to maximize the overall efficiency.

[0017] Step 5: Monitor the motor temperature and motor controller temperature in real time. If a motor does not meet the temperature adaptation requirements, implement a motor torque reduction strategy until both motors meet the temperature adaptation requirements, and then return to step 4.

[0018] The temperature adaptation requirement is that the motor temperature and the corresponding motor controller temperature are both lower than the corresponding preset temperature.

[0019] Preferably, in step 4, the total efficiency is the average of the efficiency of the front drive motor and the efficiency of the rear drive motor.

[0020] Preferably, the motor torque reduction strategy is as follows:

[0021] If any motor fails to meet the temperature adaptation requirements, the distributed torque value of the motor that fails to meet the temperature adaptation requirements shall be reduced.

[0022] If neither motor meets the temperature matching requirements, then reduce the torque distribution value of the motor with the higher temperature.

[0023] Preferably, the control mode of the electric trackless rubber-wheeled vehicle also includes a manual mode, in which it operates in either front axle drive or rear axle drive mode.

[0024] Preferably, the speeds of both the front drive motor and the rear drive motor are detected using a rotary transformer; both the front drive motor and the rear drive motor are switched reluctance motors.

[0025] Preferably, the control method further includes: the vehicle controller calculating the vehicle acceleration in real time, identifying the driving direction, and monitoring the fault status of the electric trackless rubber-wheeled vehicle's control system; the vehicle controller sending control signals containing vehicle acceleration, driving direction, and fault status to the lighting controller via the CAN bus, and the lighting controller controlling the corresponding indicator lights to work according to the control signals.

[0026] Preferably, during the operation of the electric trackless rubber-wheeled vehicle, a dynamic monitoring and adjustment process for motor temperature and torque is performed, specifically including:

[0027] Step B1: During the operation of the electric trackless rubber-wheeled vehicle, the motor temperature is collected, and the average temperature rise rate is obtained in each time window, as well as the average motor torque in each time window;

[0028] Step B2: When the motor temperature triggers the pre-analysis condition, perform a motor temperature pre-analysis;

[0029] Pre-analysis conditions: The motor temperature reaches the corresponding preset temperature at a preset ratio and the motor temperature rise rate is greater than the preset temperature rise rate.

[0030] Motor temperature pre-analysis includes:

[0031] Step B21: Obtain the average temperature rise rate and average motor torque of the latest M historical time windows of the trigger motor; construct an average temperature rise rate sequence in the order of temperature acquisition time; construct an average motor torque sequence in the order of torque acquisition time; the trigger motor is the motor for the current trigger temperature pre-analysis.

[0032] Step B22: Determine the equivalent torque temperature rise effect factor based on the average temperature rise rate sequence and the average motor torque sequence;

[0033] Step B23: Extract the torque data of the trigger motor from the latest N target historical time windows, and extract the average temperature rise rate of the latest preset number of historical time windows after the end of each target historical time window in the latest N target historical time windows, and determine the equivalent torque temperature rise lag factor; in the target historical time windows, the ratio of the torque standard deviation to the torque average value is greater than the preset ratio;

[0034] Step B3: Combine the equivalent torque temperature rise effect factor and the equivalent torque temperature rise lag factor to determine the equivalent predicted temperature after a preset time. When the equivalent predicted temperature is greater than the preset temperature of the motor, reduce the output torque of the motor.

[0035] Preferably, the method further includes step B4: constructing a curve of motor continuous working time - equivalent torque temperature rise effect factor, judging the motor state based on the change of the curve slope, and executing a response processing strategy.

[0036] This invention also discloses an intelligent four-wheel drive control system for an electric trackless rubber-tired vehicle, including a front motor controller and a rear motor controller: each is communicatively connected to the vehicle controller, and the front motor controller and the rear motor controller control the operation of the front drive motor and the rear drive motor respectively; the front drive motor and the rear drive motor drive the front wheel and the rear wheel of the electric trackless rubber-tired vehicle to rotate respectively; the vehicle controller is also connected to the brake pedal, the electronic accelerator pedal, the mode selection knob, and the lighting controller signals respectively;

[0037] The intelligent four-wheel drive control system for the electric trackless rubber-wheeled vehicle is used to execute the intelligent four-wheel drive control method for the electric trackless rubber-wheeled vehicle described above.

[0038] Preferably, it also includes a battery management system that is communicatively connected to the vehicle controller. The battery management system is electrically connected to the power battery and is used to collect the status parameters of the power battery and feed them back to the vehicle controller. The power battery supplies power to the front motor controller, the rear motor controller and the vehicle controller through the power distribution unit.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] 1) The system adopts a dual-motor drive system, which drives the front and rear drive axles separately, eliminating the torque converter and gearbox and improving system efficiency;

[0041] 2) The dual-motor drive requires less motor torque and can switch operation according to actual conditions, reducing energy consumption and heat generation; the dual motors use independent motor controllers, so if one motor or motor controller fails, the other motor can be used to return to the repair point without towing.

[0042] 3) Manual mode can be selected according to actual needs, and it will run in either front axle drive or rear axle drive mode, which reduces energy consumption and avoids frequent motor switching.

[0043] 4) By using the preset relationship between motor speed / torque and motor efficiency, the efficiency of different torques at the current speed is obtained, so as to reasonably allocate the torque of the front and rear drive motors and further improve the system efficiency;

[0044] 5) By using the rotary transformer of the motor to detect the speed difference between the front and rear drive motors, the adhesion of the front and rear ground is determined, and the speed and torque of the front and rear drive motors are adjusted in real time, which has a limited slip function.

[0045] 6) A switched reluctance motor is adopted, which has strong high temperature resistance, resulting in a higher temperature critical point for the front and rear motors, thus avoiding frequent switching and frequent start-stop.

[0046] 7) The lighting controller connected via CAN bus automatically controls the corresponding brake lights, reversing lights, warning lights, etc. to illuminate, which can prevent the brake lights from not illuminating due to excessive deceleration during the control process (without pressing the brake pedal). Attached Figure Description

[0047] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0048] Figure 1 This is a schematic diagram of the process of the present invention;

[0049] Figure 2 This is a schematic diagram of the control system of the present invention;

[0050] Figure 3 This is a schematic diagram of one embodiment of the motor speed-motor torque-motor efficiency correspondence table of the present invention. Detailed Implementation

[0051] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0052] Furthermore, in this invention, the use of terms such as "first" and "second" is for descriptive purposes only and does not specifically refer to any order or sequence, nor is it intended to limit the invention. They are merely used to distinguish components or operations described using the same technical terms and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions and features of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If a combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0053] The present invention provides the following embodiments: Example 1

[0054] Embodiment 1 of the present invention provides an intelligent four-wheel drive control method for an electric trackless rubber-wheeled vehicle, such as... Figures 1-3 As shown, in automatic mode, the control methods include:

[0055] Step 1: Collect signals from the brake pedal and electronic accelerator pedal of the electric trackless rubber-wheeled vehicle, and calculate the current torque demand of the vehicle;

[0056] Step 1 is an existing technology. For example, in automatic mode, the vehicle controller can drive the brake pedal and electronic accelerator pedal to generate corresponding opening degrees through electronic actuators (such as stepper motors and electromagnetic push rods). The position sensor built into the pedal converts the opening degree into a 0-5V voltage signal. The vehicle controller collects this signal through an AD sampling circuit. After filtering and calibration preprocessing, it combines the vehicle's current operating status such as vehicle speed, slope, and battery charge, and calls a preset torque mapping algorithm to convert the pedal opening degree signal into the total torque required by the vehicle in N·m, providing the core input for subsequent torque distribution.

[0057] Step 2: Collect the real-time speeds of the front and rear drive motors of the electric trackless rubber-wheeled vehicle and calculate the speed difference;

[0058] When the absolute value of the speed difference is greater than or equal to a preset threshold (e.g., 200 rpm), it is determined that the front / rear tires are slipping. The high-speed drive motor (the motor with the higher real-time speed among the front and rear drive motors) is controlled to reduce its speed until the absolute value of the speed difference is less than the preset threshold. The purpose of this step is to avoid slipping and to prevent the slipping from being aggravated by unreasonable torque distribution in subsequent steps.

[0059] When the speed difference is less than the preset threshold, proceed to step 3;

[0060] Step 3: Based on the current speeds of the front and rear drive motors and the vehicle's current torque requirements, find the preset motor speed-motor torque-motor efficiency correspondence table (a typical example is...). Figure 3 ), to obtain the motor efficiency corresponding to different motor torques at the current speed;

[0061] Step 4: Compare the efficiency values ​​of single-motor operation and dual-motor operation, and allocate all the required torque to the front drive motor or the rear drive motor, or proportionally to the front drive motor and the rear drive motor, in order to maximize the overall efficiency.

[0062] For example: the current speed is 1500 rpm and the required total torque is 600 N·m. If 600 N·m is given to a single motor, the corresponding total efficiency is 89%. If it is distributed as 300 N·m each to the front and rear drive motors, the average efficiency is 94%. Therefore, it is decided to distribute the required torque as 300 N·m each.

[0063] For example, if the current speed is 2500 rpm and the required total torque is 300 N·m, and the 300 N·m is given to a single motor, the total efficiency is 93%. If the torque is distributed to the front / rear drive motors at 100 N·m / 200 N·m, the average efficiency is (90.5%+91.5%) / 2=91%. Therefore, it is decided to give the required torque to a single motor.

[0064] The above examples are only integer values ​​for illustrative purposes. In actual operation, the values ​​are calculated in real time according to the motor speed-motor torque-motor efficiency correspondence table and computer programming language.

[0065] Step 5: Monitor the motor temperature and motor controller temperature in real time. If a motor does not meet the temperature adaptation requirements, implement a motor torque reduction strategy until both motors meet the temperature adaptation requirements, and then return to step 4.

[0066] The temperature adaptation requirement is that the motor temperature and the corresponding motor controller temperature are both lower than the corresponding preset temperature.

[0067] Specifically, in step 4, the overall efficiency is the average of the efficiency of the front drive motor and the efficiency of the rear drive motor.

[0068] The strategy for reducing motor torque is as follows:

[0069] If any motor fails to meet the temperature adaptation requirements, the allocated torque value of the motor that fails to meet the temperature adaptation requirements is reduced; if both motors fail to meet the temperature adaptation requirements, the allocated torque value of the motor with the higher temperature is reduced.

[0070] Temperature adaptation requirements are as follows: the motor temperature and the corresponding motor controller temperature are both lower than the corresponding preset temperature: that is, the motor temperature is lower than the corresponding preset temperature (the preset temperature of the switched reluctance motor can be 110~150℃, which does not reach the motor's limit temperature), and the temperature of the motor controller corresponding to the motor is lower than the corresponding preset temperature (the preset temperature of the motor controller can be set to 70~90℃).

[0071] All of the above steps involve closed-loop control with dynamic real-time adjustments.

[0072] The control method further includes: the vehicle controller calculating vehicle acceleration in real time, identifying the driving direction, and monitoring the fault status of the electric trackless rubber-wheeled vehicle's control system; the vehicle controller sending control signals containing vehicle acceleration, driving direction, and fault status to the lighting controller via the CAN bus, and the lighting controller controlling the corresponding indicator lights (such as brake lights, reversing lights, and warning lights) to operate according to the control signals. For example, when the electronic accelerator pedal is released, and the required torque decreases, if the deceleration is greater than a preset value, the brake lights will automatically illuminate;

[0073] The speeds of both the front and rear drive motors are detected using rotary transformers; both the front and rear drive motors are switched reluctance motors, which have strong high-temperature resistance, resulting in a higher preset temperature in step 5, thus avoiding frequent switching and starting / stopping of the motors.

[0074] The front drive motor and the rear drive motor can also be replaced by permanent magnet synchronous motors.

[0075] Select the working mode using the mode selection button. Under stable road conditions and gentle slopes, you can select manual mode, which will operate in either front axle drive or rear axle drive mode, reducing energy consumption and avoiding frequent motor switching.

[0076] The front and rear drive motors use independent motor controllers, so that if one set of motors or motor controllers fails, the other set can be used to drive back to the repair point; furthermore, the independent motor controllers can use independent explosion-proof housings, or they can use a single explosion-proof housing.

[0077] This invention also discloses an intelligent four-wheel drive control system for an electric trackless rubber-wheeled vehicle, comprising a front motor controller and a rear motor controller: which are respectively connected to the vehicle controller for communication; the front motor controller and the rear motor controller control the operation of the front drive motor and the rear drive motor respectively; the front drive motor and the rear drive motor drive the front wheel and the rear wheel of the electric trackless rubber-wheeled vehicle to rotate respectively; the vehicle controller is also connected to the brake pedal, the electronic accelerator pedal and the mode selection knob for signal connection respectively.

[0078] The intelligent four-wheel drive control system for the electric trackless rubber-wheeled vehicle is used to execute the intelligent four-wheel drive control method for the electric trackless rubber-wheeled vehicle.

[0079] The intelligent four-wheel drive control system for the electric trackless rubber-wheeled vehicle also includes a battery management system and a lighting controller that are communicatively connected to the vehicle controller. The battery management system is electrically connected to the power battery and is used to collect the status parameters of the power battery and feed them back to the vehicle controller. The power battery supplies power to the front motor controller, the rear motor controller, and the vehicle controller through the power distribution unit.

[0080] The implementation principle of this application embodiment is as follows: In automatic mode, by using a preset motor speed-motor torque-motor efficiency correspondence table, the efficiency of different torques at the current speed is obtained, and the torques of the front and rear motors are reasonably allocated to make the efficiency most ideal.

[0081] In automatic mode, the speed difference between the front and rear motors is detected by the motor's rotary transformer to determine the adhesion to the ground and adjust the speed and torque of the front and rear motors in real time, thus providing a limited-slip function.

[0082] A switched reluctance motor is used, which has strong high temperature resistance, thus reducing the temperature difference between the front and rear motors;

[0083] The vehicle controller (VCU) uses two independent motor controllers that are electrically connected to the CAN bus. After calculating the required torque through the brake pedal, electronic accelerator pedal, and current torque signal, the VCU sends the allocated target torque / speed to the independent motor controllers through two independent CAN connection lines to drive the front and rear drive motors respectively.

[0084] The power battery and power distribution unit are connected by high-voltage cables. The power battery and power distribution unit deliver high-voltage DC power to two independent motor controllers. After calculation and inversion, the front / rear motor controllers deliver the required AC power to the front / rear drive motors through high-voltage cables.

[0085] The power battery management system (BMS) is electrically connected to the CAN bus. It sends the battery status information to the vehicle controller (VCU). After the vehicle controller obtains information such as the battery's charge and temperature, it controls the power battery discharge in real time and limits the discharge based on the battery's charge, temperature, alarm information, etc.

[0086] Furthermore, a lighting controller electrically connected to the CAN bus is used. During the aforementioned motor control process, the vehicle control unit (VCU) determines the vehicle's acceleration, direction of travel, and fault conditions, and then sends these information to the lighting controller via the CAN connection line to illuminate the corresponding brake lights, reversing lights, warning lights, etc.

[0087] The beneficial effects of the above technical solution are as follows:

[0088] 1) The system adopts a dual-motor drive, which drives the front and rear drive axles respectively, eliminating the torque converter and gearbox and improving system efficiency;

[0089] 2) The dual-motor drive requires less motor torque and can switch operation according to actual conditions, reducing energy consumption and heat generation; the dual motors use independent motor controllers, so if one motor or motor controller fails, the other motor can be used to return to the repair point without towing.

[0090] 3) Manual mode can be selected according to actual needs, and it will run in either front axle drive or rear axle drive mode, which reduces energy consumption and avoids frequent motor switching.

[0091] 4) By using the preset relationship between motor speed / torque and motor efficiency, the efficiency of different torques at the current speed is obtained, so as to reasonably distribute the torque of the front and rear motors and further improve the system efficiency;

[0092] 5) By using the rotary transformer of the motor to detect the speed difference between the front and rear drive motors, the adhesion of the front and rear ground is determined, and the speed and torque of the front and rear drive motors are adjusted in real time, which has a limited slip function.

[0093] 6) A switched reluctance motor is adopted, which has strong high temperature resistance, resulting in a higher temperature critical point for the front and rear drive motors, thus avoiding frequent switching and frequent start-stop.

[0094] 7) The lighting controller connected via CAN bus automatically controls the corresponding brake lights, reversing lights, warning lights, etc. to illuminate, which can prevent the brake lights from not illuminating due to excessive deceleration during the control process (without pressing the brake pedal). Example 2

[0095] Based on Example 1, the control method further includes: when the motor speed is stable (specifically: the real-time speed fluctuation of the drive motor is ≤ the preset speed fluctuation amplitude and the duration of this stable state is ≥ the preset stable duration; the preset speed fluctuation amplitude is such as 5% to 8%; the preset stable duration is 500ms to 1500ms), the vehicle is in an effective driving state (driving speed ≥ 1.5km / h and ≤ the design maximum vehicle speed, not parked, not idling, not turning in place), and there is no short-term driver intervention, a current dynamic monitoring and adjustment process is executed, specifically including:

[0096] Step A1: Collect dynamic motor current, motor speed, and motor output torque data for the front drive motor and the rear drive motor;

[0097] Step A2: Execute when the motor current fluctuation analysis conditions are met (either the motor current sensor detects that the current motor current fluctuation amplitude is greater than or equal to the preset motor current fluctuation amplitude (8%~12%), or the current motor current change rate is greater than the preset motor current change rate (60~120A / s)).

[0098] Extract the current amplitude of the target motor (the motor that meets the conditions for motor current fluctuation analysis); calculate the current rate of change of the target motor using a first-order difference algorithm (take the current values ​​of two adjacent samples of the target motor (e.g., with an interval of 50 milliseconds), calculate the difference between the two currents, and then divide it by the sampling interval time to obtain the instantaneous rate of change of the current (take the absolute value of the result)); for the motor current data within a time window (e.g., 2 seconds), calculate the interval time between adjacent peak / valley values ​​(i.e., the fluctuation period T), and calculate the current current fluctuation frequency of the target motor using the formula f=1 / T;

[0099] Collect the current speed of the electric trackless rubber-wheeled vehicle;

[0100] Collect the current output torque of the target motor;

[0101] Step A3: Determine the target motor torque buffer coefficient based on the target motor's current torque and the target motor's current current change rate; determine the target motor torque impact suppression coefficient based on the target motor's current current amplitude and the electric trackless rubber-wheeled vehicle's current speed.

[0102] Step A4: Based on the current motor torque buffer coefficient, the current motor torque impact suppression coefficient, and the preset motor torque buffer coefficient-motor torque impact suppression coefficient-torque suppression ratio mapping table, determine the current torque suppression ratio of the target motor, determine the target output torque of the target motor based on the current torque suppression ratio of the target motor, and determine the current torque difference;

[0103] Step A5: Obtain the preset torque difference-target frequency response coefficient mapping table, and determine the current target torque response time of the target motor by combining the current torque difference and the current current fluctuation frequency of the target motor.

[0104] Step A6: Based on the current target torque response time of the target motor, constrain the rate of change of the target motor's torque, and send the constraint to the target motor's motor controller to complete the dynamic torque adjustment.

[0105] In step A3:

[0106] Current motor torque buffer coefficient = ;

[0107] Current motor torque shock suppression coefficient = ;

[0108] Current torque difference = Target output torque of target motor - Current actual total output torque of target motor;

[0109] Target output torque of the target motor = current actual output torque of the target motor × current torque suppression ratio of the target motor;

[0110] Reference current change rate: This is a preset value that represents the typical value of the current change rate when the motor is running under normal operating conditions (without drastic current fluctuations) (e.g., 80A / s for medium power motors). It is usually obtained through bench testing or actual vehicle calibration.

[0111] Standard operating conditions: Under relatively stable power supply conditions, the motor operates at a typical, commonly used speed (usually set to 10–15 km / h) as the baseline (corresponding to the baseline travel speed). The baseline travel speed of the electric trackless rubber-wheeled vehicle is 10–15 km / h.

[0112] Current motor torque buffering coefficient: This quantifies the torque buffering strength required for fluctuations in the motor's own current. A larger coefficient indicates more severe fluctuations, requiring stronger torque buffering.

[0113] Current motor torque shock suppression coefficient: used to dynamically adjust the strength of torque shock suppression; it first converts the motor current fluctuation amplitude into a relative value (with the rated current as the denominator), and then combines it with the ratio of the current driving speed to the reference speed, so that the system adopts a smoother suppression strategy at high speeds to ensure stability, and allows for a faster response speed at low speeds.

[0114] Rated current / rated output torque: The rated operating current and rated output torque marked on the motor nameplate are inherent parameters of the motor.

[0115] In step A4, the process for obtaining the mapping table of motor torque buffer coefficient, motor torque impact suppression coefficient, and torque suppression ratio is as follows: First, under different current fluctuation intensities and driving speeds in industrial and mining scenarios, multiple sets of matching data of motor torque buffer coefficient intervals, motor torque impact suppression coefficient intervals, and corresponding optimal torque suppression ratio intervals are collected on a test bench or actual vehicle. Then, through cluster analysis and interval fitting, the continuous experimental data are divided into discrete coefficient intervals, and the correspondence between each interval combination and the torque suppression ratio interval is established to generate an initial interval mapping table. Next, full-condition verification is carried out in the actual operating scenario in the mining area, and the interval boundaries and corresponding ratios are iteratively optimized based on the performance of transmission system vibration, driving smoothness, etc. Finally, the verified interval mapping table is solidified into the vehicle control program. When the system is running, the corresponding torque suppression ratio interval can be quickly obtained by matching the interval to which the current coefficient belongs, thereby achieving efficient and accurate torque control.

[0116] In step A5:

[0117] Current target frequency response coefficient = ;

[0118] Current target frequency response coefficient: Used to match the frequency characteristics of the motor's own current fluctuations and dynamically adjust the motor's torque response speed. It compares the current fluctuation frequency with the reference frequency to determine whether the fluctuation is a high-frequency disturbance or a low-frequency fluctuation; then, combined with the ratio of the motor's reference response time to the target response time, it allows the system to shorten the response time to quickly follow the fluctuation during high-frequency fluctuations and extend the response time to avoid resonance during low-frequency fluctuations, thereby improving the smoothness and stability of torque adjustment.

[0119] Reference torque response time: An inherent characteristic parameter of the motor, referring to the standard time from when the motor receives the torque adjustment command from the controller to when the output torque stably reaches the command requirement value under rated electrical conditions. It is determined only by the motor body structure, winding characteristics and controller control algorithm, and is unrelated to the vehicle driving conditions.

[0120] The preset torque difference-target frequency response coefficient mapping table is obtained by calibrating the optimal response coefficients under different motor current fluctuation frequencies and different torque differences during bench and vehicle testing.

[0121] Response time: refers to the time it takes for a motor to receive a torque adjustment command and for the output torque to stabilize and reach the required output torque value.

[0122] Step A6, as the final execution stage of dynamic torque adjustment, uses the current target torque response time of the motor determined in step A5 as the core constraint, transforming it into a specific torque change rate threshold. This strictly limits the adjustment speed of the current required output torque. Subsequently, the vehicle controller generates a smooth torque command curve without abrupt changes according to this rate threshold and simultaneously sends it to the controller corresponding to the target motor. This ensures that the motor output torque transitions smoothly according to the preset rhythm. It avoids the mechanical impact of torque abrupt changes on the transmission system through rate constraints, and combines the dynamic characteristics of the target response time to make the torque adjustment accurately adapt to the frequency characteristics of the motor's own current fluctuations. Ultimately, it achieves closed-loop control of the smoothness and stability of the vehicle's power output.

[0123] The beneficial effects of the above technical solution are as follows:

[0124] This solution overcomes the limitations of traditional torque control that relies solely on the steady-state output parameters of the motor. For the first time, it directly incorporates the time-domain and frequency-domain dynamic characteristics of the motor current into the dual-motor torque control logic. By precisely quantifying the rate of change and dominant frequency of the motor current, and combining this with a dual-factor model of torque buffering / suppression coefficients, a preset mapping table is used to transform the current fluctuation characteristics into a precise torque suppression ratio. This is coupled with the motor response time constraining the rate of torque change, fundamentally solving the torque impact problem caused by current fluctuations in the motor itself under industrial and mining conditions, effectively reducing fatigue damage to the motor and transmission system.

[0125] This solution overcomes the drawbacks of traditional torque control's single-parameter adjustment, creatively constructing a three-dimensional dynamically coupled torque response system of "speed-frequency-torque". Addressing the complex operating conditions of motors in industrial and mining scenarios, including high-frequency start-stop, current fluctuations, and operating condition switching, it achieves full-scenario adaptive matching of torque adjustment. Based on the main frequency of current fluctuations, it dynamically adjusts the motor's target response time, providing a rapid response during high-frequency fluctuations to offset current impact energy, and a delayed response during low-frequency fluctuations to avoid transmission resonance. This achieves optimal synergy between motor output smoothness and power responsiveness, fully adapting to the stable operation requirements of motors under complex industrial and mining conditions.

[0126] While ensuring the core objectives of optimal efficiency, temperature protection, and anti-slip control in Embodiment 1, this embodiment further improves the smoothness of motor torque output, ultimately achieving efficient, stable, and reliable operation of the vehicle's power system under complex industrial and mining conditions. Example 3

[0127] Based on Example 1 or 2, the process of dynamically monitoring and adjusting the motor temperature and torque during the operation of the electric trackless rubber-wheeled vehicle specifically includes:

[0128] Step B1: During the operation of the electric trackless rubber-wheeled vehicle, the motor temperature is collected, and the average temperature rise rate is obtained in each time window, as well as the average motor torque in each time window;

[0129] Step B2: When the motor temperature triggers the pre-analysis condition, perform a motor temperature pre-analysis;

[0130] Pre-analysis conditions: The motor temperature reaches the corresponding preset temperature at a preset ratio and the motor temperature rise rate is greater than the preset temperature rise rate.

[0131] Motor temperature pre-analysis includes:

[0132] Step B21: Obtain the average temperature rise rate and average motor torque of the latest M historical time windows of the trigger motor; construct an average temperature rise rate sequence in the order of temperature acquisition time; construct an average motor torque sequence in the order of torque acquisition time; the trigger motor is the motor for the current trigger temperature pre-analysis.

[0133] Step B22: Determine the equivalent torque temperature rise effect factor based on the average temperature rise rate sequence and the average motor torque sequence;

[0134] Step B23: Extract the torque data of the trigger motor from the latest N target historical time windows, and extract the average temperature rise rate of the latest preset number of historical time windows after the end of each target historical time window in the latest N target historical time windows, and determine the equivalent torque temperature rise lag factor; in the target historical time windows, the ratio of the torque standard deviation to the torque average value is greater than the preset ratio;

[0135] Step B3: Combine the equivalent torque temperature rise effect factor and the equivalent torque temperature rise lag factor to determine the equivalent predicted temperature after a preset time. When the equivalent predicted temperature is greater than the preset temperature of the trigger motor, reduce the output torque of the motor.

[0136] There is a preset mapping relationship between the equivalent torque temperature rise effect factor and the torque reduction ratio. Based on the current equivalent torque temperature rise lag factor determined in step B23, the current output torque is adjusted according to the current torque reduction ratio determined by the mapping relationship between the equivalent torque temperature rise effect factor and the torque reduction ratio.

[0137] Specifically, in step B1:

[0138] The duration of the time window is set to 1 / 5 to 1 / 3 of the thermal response time (the thermal response time is the characteristic time for the motor to go from load change to temperature stability; it is usually taken as 60s to 300s). This setting ensures that the data within the window can capture the dynamic changes in temperature rise, and does not obscure the trend details due to the window being too long. The average temperature rise rate is obtained by calculating the difference between the motor temperature at the end and the beginning of the time window and dividing it by the duration of the time window. The average temperature rise rate reflects the trend of motor temperature change during this period.

[0139] In step B2: the preset ratio of the preset temperature can be 75% to 90%; the typical range of the preset temperature rise rate is 0.5℃ / min to 2℃ / min.

[0140] Step B22: Determine the equivalent torque temperature rise effect factor based on the average temperature rise rate sequence and the average motor torque sequence; specifically:

[0141] Obtain the torque temperature rise effect factor for each of the M historical time windows (values ​​range from 2 to 5):

[0142] Current time window torque temperature rise effect factor = ;

[0143] The equivalent torque temperature rise effect factor is the maximum value of the torque temperature rise effect factor corresponding to all M historical time windows;

[0144] The unit torque is 1 N·m; the torque temperature rise effect factor quantifies the rate of temperature rise caused by each 1 N·m of torque within a certain period of time, directly reflecting the contribution effect of the current load on the motor's heating. The unit temperature rise rate is 1℃ / min.

[0145] In step B23: the preset ratio range is 0.08 to 0.2; the N range is 3 to 10; the preset number range is 1 to 3; in the preset number of time windows extracted after each target historical time window, the end time of the time window in which the average temperature rise rate changes for the first time (relative to the average temperature rise rate of the previous historical time window, the increase is ≥3% to 8%) is determined.

[0146] The torque temperature rise lag factor corresponding to the current target historical time window = (the end time of the time window in which the average temperature rise rate changes for the first time among the preset time windows extracted after the current target historical time window - the end time of the current target historical time window) ÷ the duration of the time window;

[0147] The equivalent torque temperature rise lag factor is the average value of the torque temperature rise lag factors corresponding to all target historical time windows.

[0148] In step B3, the preset duration = torque adjustment effective time + temperature rise buffer time + torque temperature rise lag time;

[0149] Torque adjustment effective time: The actual time from the issuance of the torque adjustment command to the completion of the adjustment of the motor's actual output torque and the start of the decrease in load heat rate (motor control terminal calibration value, such as the total time of the electronic control system response + the actuator action).

[0150] Temperature rise buffer time: The time it takes for the motor temperature to continue to rise slightly after the torque adjustment takes effect, before it changes from the current temperature rise trend to a stable or falling trend; Temperature rise buffer time = Torque temperature rise lag factor × Single time window duration;

[0151] Equivalent predicted temperature = current motor temperature + equivalent torque temperature rise effect factor × current output torque × preset duration.

[0152] In step B3, when the equivalent predicted temperature is greater than the preset temperature of the trigger motor, the output torque of the motor is reduced. Specifically, when the equivalent predicted temperature is greater than the preset temperature of the trigger motor, the system will actively reduce the output torque of the motor in a gradient before the temperature reaches the threshold. The core objective of the adjustment is to reduce the equivalent predicted temperature to 90% to 95% of the preset temperature.

[0153] In the actual operation of electric trackless rubber-tired vehicles, the value range of the equivalent torque temperature rise effect factor is directly related to the operating conditions: when unloaded or cruising at low speed, the factor is usually in the low range of 0.05 to 0.2, and the motor thermal state is stable; when driving at a constant speed under medium load, the factor is maintained in the medium range of 0.2 to 0.6, which can maintain the current output torque; when climbing hills under heavy load, the factor rises to 0.6 to 1.5, and a torque reduction strategy needs to be triggered; under fluctuating operating conditions such as frequent starts and stops or rapid acceleration, the factor can reach 1.2 to 2.2, and torque limiting needs to be strengthened.

[0154] The beneficial effects of the above technical solution are as follows:

[0155] In step B1, the time window duration is set to 1 / 5 to 1 / 3 of the thermal response time, which ensures that subtle changes in temperature rise can be captured without obscuring key dynamic features due to an excessively long window.

[0156] By calculating the average temperature rise rate and average torque within the time window, a quantitative correlation between load output and heat generation rate is directly established. This not only provides a basis for subsequent temperature rise prediction but also allows the system to perceive the motor's thermal load status in real time, providing precise input variables for dynamic adjustment.

[0157] In step B2, the temperature prediction trigger condition implements a tiered prediction with dual thresholds. This avoids ineffective intervention due to occasional temperature fluctuations and enables timely analysis when the temperature rise trend is clear, balancing response speed and prediction accuracy.

[0158] The temperature rise rate sequence and torque sequence constructed in step B21, and the equivalent torque temperature rise effect factor calculated in step B22, accurately quantify the "contribution of unit torque to temperature rise". This allows the system to distinguish the differences in thermal risk of torque under different operating conditions. For example, the high factor value during heavy-load climbing directly reflects the high thermal contribution of the current load, providing a quantitative basis for subsequent precise torque reduction.

[0159] The equivalent torque temperature rise lag factor extracted in step B23 compensates for the thermal inertia delay of the motor from load change to temperature stabilization. By capturing the time difference of the first change in the temperature rise rate, the system can more accurately predict the timing of temperature changes, breaking through the limitations of traditional methods that only compensate for thermal lag based on a fixed time. It can dynamically capture the real change law of thermal lag under different operating conditions, avoiding prediction deviations caused by thermal inertia, and making the timing of torque adjustment more precise.

[0160] The equivalent predicted temperature integrates the current thermal state, load thermal contribution, and thermal inertia delay, achieving multi-dimensional temperature prediction. When the equivalent predicted temperature exceeds the limit, the system actively reduces the output torque, aiming to control the temperature below 90% to 95% of the preset value.

[0161] By presetting the mapping relationship between the equivalent torque temperature rise effect factor and the torque reduction ratio, and combining it with the equivalent torque temperature rise lag factor for dynamic correction, a quantitative and precise torque control mechanism is constructed. This mechanism not only achieves precise matching between thermal risk and torque reduction magnitude, but also compensates for the control deviation caused by the motor's thermal inertia, avoiding over-adjustment or under-adjustment, and ensuring that the timing and magnitude of torque adjustment perfectly match the actual thermal response characteristics of the motor. Example 4

[0162] Based on Example 3, the following step may also be included: Step B4: Construct a curve of motor continuous working time - equivalent torque temperature rise effect factor, determine the motor state based on the change of curve slope, and execute a response processing strategy.

[0163] When the slope of the equivalent torque temperature rise effect factor curve is greater than the preset slope threshold for heat accumulation (e.g., 0.08 / min), it is determined that the motor heat load is in a state of rapid accumulation. At this time, the temperature rise rate is too high and the temperature pre-analysis has been triggered. The current torque reduction strategy should be maintained, and the curve slope and temperature rise rate should be continuously monitored to prevent further accumulation of heat load.

[0164] When the preset slope threshold for thermal stability (e.g., 0.005 / min) < the continuous slope of the equivalent torque temperature rise effect factor curve ≤ the preset slope threshold for thermal accumulation (e.g., 0.08 / min): it is determined that the motor is in the thermal equilibrium transition stage. At this time, the temperature rise rate drops and the temperature pre-analysis trigger condition has been released. It is necessary to combine the current equivalent predicted temperature and gradually increase the motor output torque according to the preset mapping relationship, and continuously monitor the slope change during the recovery process.

[0165] When the slope of the equivalent torque temperature rise effect factor curve is consistently less than or equal to the preset slope threshold for thermal stability (e.g., 0.005 / min), and the fluctuation of the equivalent factor is within the stable range, it is determined that the motor has entered a thermally stable state. At this time, the temperature rise rate is stable below the safety threshold, and the rated output torque of the motor can be restored. However, it is still necessary to continuously monitor the slope of the curve to avoid thermal state fluctuations caused by sudden load changes.

[0166] The beneficial effects of the above technical solution are as follows: By constructing a correlation curve between the continuous working time of the motor and the equivalent torque temperature rise effect factor, the solution can accurately classify and determine the thermal state of the motor based on the dynamic changes in the slope of the curve. It can maintain a torque reduction strategy to prevent the risk of thermal runaway when the heat load accumulates rapidly, gradually increase the torque during the thermal equilibrium transition stage to ensure power efficiency, and safely restore the rated torque output and continuously monitor fluctuations in the thermally stable state. At the same time, it reduces thermal fatigue and mechanical shock to extend the life of core components, providing key support for the intelligent and stable operation of electric trackless rubber-tired vehicles under complex working conditions.

[0167] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method for intelligent four-wheel drive control of an electric trackless rubber-wheeled vehicle, characterized in that: In automatic mode, the control methods include: Step 1: Collect signals from the brake pedal and electronic accelerator pedal of the electric trackless rubber-wheeled vehicle, and calculate the current torque demand of the vehicle; Step 2: Collect the real-time speeds of the front and rear drive motors of the electric trackless rubber-wheeled vehicle and calculate the speed difference; When the absolute value of the speed difference is greater than or equal to a preset threshold, the high-speed drive motor is controlled to reduce its speed until the absolute value of the speed difference is less than the preset threshold. When the speed difference is less than the preset threshold, proceed to step 3; Step 3: Based on the current speeds of the front drive motor and the rear drive motor and the current torque demand of the vehicle, look up the preset motor speed-motor torque-motor efficiency correspondence table to obtain the motor efficiency corresponding to different motor torques at the current speed; Step 4: Compare the efficiency values ​​of single-motor operation and dual-motor operation, and allocate all the required torque to the front drive motor or the rear drive motor, or proportionally to the front drive motor and the rear drive motor, in order to maximize the overall efficiency. Step 5: Monitor the motor temperature and motor controller temperature in real time. If a motor does not meet the temperature adaptation requirements, implement a motor torque reduction strategy until both motors meet the temperature adaptation requirements, and then return to step 4. The temperature adaptation requirement is that the motor temperature and the corresponding motor controller temperature are both lower than the corresponding preset temperature.

2. The intelligent four-wheel drive control method for an electric trackless rubber-wheeled vehicle according to claim 1, characterized in that: In step 4, the total efficiency is the average of the efficiency of the front drive motor and the efficiency of the rear drive motor.

3. The intelligent four-wheel drive control method for an electric trackless rubber-wheeled vehicle according to claim 1, characterized in that: The strategy for reducing motor torque is as follows: If any motor fails to meet the temperature adaptation requirements, the distributed torque value of the motor that fails to meet the temperature adaptation requirements shall be reduced. If neither motor meets the temperature matching requirements, then reduce the torque distribution value of the motor with the higher temperature.

4. The intelligent four-wheel drive control method for an electric trackless rubber-wheeled vehicle according to claim 1, characterized in that: The control modes of the electric trackless rubber-wheeled vehicle also include a manual mode, in which it is fixed to operate in either front axle drive or rear axle drive mode.

5. The intelligent four-wheel drive control method for an electric trackless rubber-wheeled vehicle according to claim 1, characterized in that: The speeds of both the front and rear drive motors are detected using rotary transformers; both the front and rear drive motors are switched reluctance motors.

6. The intelligent four-wheel drive control method for an electric trackless rubber-wheeled vehicle according to claim 1, characterized in that: The control method further includes: the vehicle controller calculates the vehicle acceleration in real time, identifies the driving direction, and monitors the fault status of the electric trackless rubber-wheeled vehicle's control system; the vehicle controller sends control signals containing vehicle acceleration, driving direction, and fault status to the lighting controller via the CAN bus, and the lighting controller controls the corresponding indicator lights to work according to the control signals.

7. The intelligent four-wheel drive control method for an electric trackless rubber-wheeled vehicle according to claim 1, characterized in that: During the operation of the electric trackless rubber-wheeled vehicle, a dynamic monitoring and adjustment process for motor temperature and torque is performed, which specifically includes: Step B1: During the operation of the electric trackless rubber-wheeled vehicle, the motor temperature is collected, and the average temperature rise rate is obtained in each time window, as well as the average motor torque in each time window; Step B2: When the motor temperature triggers the pre-analysis condition, perform a motor temperature pre-analysis; Pre-analysis conditions: The motor temperature reaches the corresponding preset temperature at a preset ratio and the motor temperature rise rate is greater than the preset temperature rise rate. Motor temperature pre-analysis includes: Step B21: Obtain the average temperature rise rate and average motor torque of the latest M historical time windows of the trigger motor; construct an average temperature rise rate sequence in the order of temperature acquisition time; construct an average motor torque sequence in the order of torque acquisition time; the trigger motor is the motor for the current trigger temperature pre-analysis. Step B22: Determine the equivalent torque temperature rise effect factor based on the average temperature rise rate sequence and the average motor torque sequence; Step B23: Extract the torque data of the trigger motor from the latest N target historical time windows, and extract the average temperature rise rate of the latest preset number of historical time windows after the end of each target historical time window in the latest N target historical time windows, and determine the equivalent torque temperature rise lag factor; in the target historical time windows, the ratio of the torque standard deviation to the torque average value is greater than the preset ratio; Step B3: Combine the equivalent torque temperature rise effect factor and the equivalent torque temperature rise lag factor to determine the equivalent predicted temperature after a preset time. When the equivalent predicted temperature is greater than the preset temperature of the motor, reduce the output torque of the motor.

8. The intelligent four-wheel drive control method for an electric trackless rubber-wheeled vehicle according to claim 7, characterized in that: It also includes step B4: constructing the motor continuous working time-equivalent torque temperature rise effect factor curve, judging the motor status based on the change in the curve slope, and executing the response processing strategy.

9. An intelligent four-wheel drive control system for an electric trackless rubber-wheeled vehicle, characterized in that: include: Front motor controller and rear motor controller: They are respectively connected to the vehicle controller and control the front drive motor and the rear drive motor respectively. The front drive motor and the rear drive motor drive the front wheel and the rear wheel of the electric trackless rubber-wheeled vehicle to rotate, respectively; the vehicle controller is also connected to the brake pedal, electronic accelerator pedal, mode selection knob and light controller, respectively. The intelligent four-wheel drive control system for the electric trackless rubber-wheeled vehicle is used to execute the intelligent four-wheel drive control method for the electric trackless rubber-wheeled vehicle as described in any one of claims 1-8.

10. The intelligent four-wheel drive control system for an electric trackless rubber-wheeled vehicle according to claim 9, characterized in that: It also includes a battery management system that is communicatively connected to the vehicle controller. The battery management system is electrically connected to the power battery and is used to collect the status parameters of the power battery and feed them back to the vehicle controller. The power battery supplies power to the front motor controller, the rear motor controller and the vehicle controller through the power distribution unit.

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