A mine dump truck power uninterrupted control method based on multi-motor cooperation

Abstract

The application discloses a mine dump truck power uninterrupted control method based on multi-motor cooperation, and relates to the technical field of mine vehicle control.The application comprises vehicle state sensing and pre-triggering of ramp starting mode;calculating a pretightening torque target value based on a dynamic safety coefficient;electing a virtual master motor dynamically and distributing exclusive pretightening torque, establishing an electronic parking anchor point;confirming the establishment of pretightening torque in a closed loop and eliminating transmission chain clearance;based on the throttle opening, performing torque smoothing superposition and dynamic cooperation on the slave motor;after the vehicle speed meets the standard, exiting the virtual master-slave mode and switching to a regular cooperative control mode;and redundant safety control in a fault mode.The application can reduce the risk of vehicle backsliding during ramp starting, eliminate the impact caused by transmission clearance, and improve starting smoothness and system fault tolerance through virtual master-slave cooperation and pretightening torque anchoring.

Description

Technical Field

[0001] This invention belongs to the field of mining vehicle control technology, and in particular relates to a method for uninterrupted power control of mining dump trucks based on multi-motor coordination. Background Technology

[0002] Mining dump trucks are large off-highway transportation equipment used in open-pit mines to transport materials such as ore and rock. Their working environment is characterized by steep slopes, slippery roads, and heavy loads. To meet the increasing demands for transportation efficiency and load capacity, large-tonnage mining dump trucks are gradually adopting new energy drive systems. Among these, multi-motor parallel centralized drive is a practical application solution. This involves mechanically coupling the output shafts of two, three, or four independently controllable drive motors to the same reduction gearbox or transmission. The vehicle controller coordinates the torque output of each motor to jointly drive the vehicle. This solution has already been applied in some electric wheel mining dump trucks with a capacity of over 100 tons, such as those using dual-motor or quad-motor drive axles, aiming to improve peak power and system redundancy.

[0003] In multi-motor parallel drive systems, hill start is a special and demanding operating condition. When a fully loaded vehicle is parked on a steep unpaved road, the downward component of gravity along the slope will cause the vehicle to tend to roll backward. To ensure a smooth start, the controller needs to overcome this downward force before the wheel drive force is established. In existing technologies, for mining dump trucks equipped with multi-motor parallel drive systems, the hill start control method typically follows the traditional centralized drive approach: when the driver releases the brake and depresses the accelerator, the controller simultaneously sends the same torque request to all parallel motors, or distributes torque according to a fixed ratio, so that each motor outputs drive force synchronously to counteract the downward force.

[0004] However, in actual mining operations, the aforementioned synchronous torque output method has significant shortcomings. Due to the uneven adhesion coefficient of the mining road surface, the contact conditions between each drive wheel and the ground vary. Furthermore, the temperature, aging level, and controller response speed of the four motors are not entirely consistent, making it difficult to strictly synchronize the timing and amplitude of the actual output torque of each motor reaching the transmission system. This slight asynchrony can generate impact loads within the transmission system, manifesting as momentary vehicle vibration or gear impact. More seriously, in the initial stage of synchronous torque establishment, if the total driving force fails to reach the value required to overcome the slippage force in time, the vehicle will briefly roll backward during the motor torque rise. This backward rolling not only causes driving shock but may also lead to driver misoperation or even loss of vehicle control. Therefore, the following solutions are proposed to address these problems. Summary of the Invention

[0005] The purpose of this invention is to provide a method for uninterrupted power control of mining dump trucks based on multi-motor cooperation. By dynamically selecting a virtual master motor and independently establishing a pre-tightening torque to form an electronic parking anchor point, and then smoothly superimposing the drive torque by the slave motor, the method can eliminate transmission gap impact and prevent the vehicle from rolling backward when starting on a slope. This solves the problem of starting jerking and the risk of rolling backward caused by response differences in the synchronous output torque of multiple motors in the prior art.

[0006] To solve the above-mentioned technical problems, the present invention is achieved through the following technical solution:

[0007] This invention relates to a method for uninterrupted power control of mining dump trucks based on multi-motor cooperation, comprising the following steps:

[0008] Step S1: The vehicle controller acquires vehicle status parameters in real time and determines whether to enter the hill start pre-trigger mode based on the slope angle, vehicle speed and gear status.

[0009] Step S2: In the hill start pre-trigger mode, calculate the target preload torque required to keep the vehicle stationary on the hill.

[0010] Step S3: Based on the real-time status parameters of each drive motor, dynamically select one motor as the virtual master motor and the remaining motors as slave motors;

[0011] Step S4: Assign an exclusive preload torque command to the virtual main motor, enabling it to independently establish and maintain the target preload torque, thus forming an electronic parking anchor point;

[0012] Step S5: After the virtual main motor successfully establishes preload torque, the torque required by the driver is smoothly distributed to each slave motor according to the driver's accelerator pedal opening, so that the torque of the slave motor increases gradually until the vehicle starts moving.

[0013] Step S6: When the vehicle speed reaches the preset start-up completion threshold, control the virtual main motor torque to decrease to zero, and switch all motors to the normal parallel cooperative drive mode.

[0014] Furthermore, in step S2, the specific formula for calculating the target preload torque is as follows:

[0015]

[0016] In the formula, Preload torque to target; The dynamic safety factor; It is the difference between the component of gravity acting on the vehicle as it slides down the slope and the rolling resistance. The tire's rolling radius; This is the total transmission ratio from the motor output to the wheel; This represents the number of motors that are currently in a healthy and standby state.

[0017] Further, in step S3, the specific method for dynamically selecting the virtual main motor is as follows: the vehicle controller reads the winding temperature, controller DC bus current, current torque output capability, and torque response time constant of each drive motor, calculates the transient response performance score of each motor, and selects the motor with the highest score as the virtual main motor; the formula for calculating the transient response performance score is:

[0018]

[0019] In the formula, For motor Transient response performance score; For motor The current temperature of the winding; This is the upper limit of the motor's protection temperature. For motor The torque response time constant; For motor Current torque output capability; This refers to the rated torque of the motor. All are weighting coefficients.

[0020] Furthermore, in step S4, when assigning an exclusive preload torque command to the virtual main motor, the target torque value of the preload torque command is modified to an absolute preload torque, which is equal to the target preload torque divided by the current number of healthy motors and then superimposed with a positive torque bias. This positive torque bias is used to eliminate transmission system backlash and static friction. After sending the command, the vehicle controller locks the command, prohibiting other controllers from intervening in the torque of the motor, and monitors the actual output torque of the virtual main motor at high frequency.

[0021] Furthermore, in step S4, the criterion for successfully establishing the preload torque of the virtual main motor is: the actual output torque of the virtual main motor reaches the target preload torque and remains stable within the preset error band for a preset stable time; after confirming successful establishment, the vehicle controller further maintains a preset torque holding time, which is determined by the sum of the estimated transmission system clearance elimination time and the hydraulic brake complete release delay time, and strictly maintains the torque output of the virtual main motor unchanged within this time.

[0022] Furthermore, in step S5, the conversion of the driver's required torque is based on a preset nonlinear accelerator pedal opening-MAP diagram; the smooth allocation method is as follows: the vehicle controller calculates the total torque required by the slave motors, which is the smaller of the driver's required torque and the sum of the current surplus capacity of all slave motors; then it allocates the torque proportionally according to the real-time torque response capability of each slave motor, and applies a slope limiter associated with the slope angle to the torque command of each slave motor, wherein the maximum upward slope of the slope limiter increases as the slope angle increases.

[0023] Furthermore, in step S6, the process of controlling the virtual main motor torque to decrease to zero is as follows: the vehicle controller sends a linear decrease command to the virtual main motor, causing its torque to decrease linearly to zero within a preset time; during the decrease process, the torque of the slave motor is increased synchronously to compensate for the decrease in the virtual main motor torque, ensuring that the total output torque is continuous and smooth; when the actual torque of the virtual main motor decays to zero, the vehicle controller releases the exclusive lock state of its virtual main motor.

[0024] Furthermore, the control method also includes redundant safety control in fault mode: at any stage of the hill start process, when the virtual master motor fails, the vehicle controller immediately sends an emergency torque holding command to all slave motors to maintain their current output torque; then, a new virtual master motor is elected from the remaining healthy motors to take over the establishment of the remaining preload torque value and continue the subsequent torque distribution steps; when the fault occurs in the normal parallel cooperative drive mode, the faulty motor is directly disconnected and the upper limit of the total output power of the system is reduced to the preset redundancy power percentage, and the remaining healthy motors continue to work in torque cooperative mode.

[0025] Furthermore, the vehicle status parameters include at least: the slope angle from the slope sensor, the pressure value from the suspension cylinder pressure sensor, the vehicle speed signal from the wheel speed sensor, the gear position from the gear sensor, and the motor winding temperature, controller DC bus current, current torque output capability, and torque response time constant from each drive motor controller; the vehicle controller reads the suspension cylinder pressure value and calculates the current total vehicle mass according to the pre-calibrated load-pressure mapping function, and then calculates the gravitational downward component force.

[0026] Furthermore, the conventional parallel cooperative drive mode is as follows: the vehicle controller redistributes the total required torque to all healthy motors according to the total required torque and the motor efficiency MAP, using a proportional allocation or optimal efficiency allocation algorithm; during the hill start process, as the motor torque increases, the vehicle controller continuously monitors the vehicle speed, and when the vehicle speed reaches the preset start completion threshold and remains there for a preset time, it determines that the hill start phase has ended and executes the mode switch.

[0027] The present invention has the following beneficial effects:

[0028] This invention establishes a pre-tensioned torque anchor point during ramp starts through virtual master-slave collaborative control, reducing the risk of vehicle rollback and improving start-up smoothness. The dynamic torque distribution and closed-loop confirmation mechanism helps eliminate the impact of transmission backlash, reducing driver difficulty. In fault mode, rapid switching and torque maintenance of the main motor provide redundancy and fault tolerance, preventing power interruption and ensuring the vehicle's safe departure from the work surface under complex conditions. This method balances the collaborative efficiency of multi-motor drives with start-up stability, improving the vehicle's adaptability to slippery and steep road surfaces.

[0029] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0030] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a flowchart illustrating a method for uninterrupted power control of a mining dump truck based on multi-motor collaboration, according to the present invention. Detailed Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] Please see Figure 1 As shown, this invention is a method for uninterrupted power control of a mining dump truck based on multi-motor cooperation, comprising the following steps:

[0034] Step S1: The vehicle controller acquires vehicle status parameters in real time and determines whether to enter the hill start pre-trigger mode based on the slope angle, vehicle speed and gear status.

[0035] Step S2: In the hill start pre-trigger mode, calculate the target preload torque required to keep the vehicle stationary on the hill.

[0036] Step S3: Based on the real-time status parameters of each drive motor, dynamically select one motor as the virtual master motor and the remaining motors as slave motors;

[0037] Step S4: Assign exclusive preload torque commands to the virtual main motor, enabling it to independently establish and maintain the target preload torque, thus forming an electronic parking anchor point;

[0038] Step S5: After the virtual main motor successfully establishes preload torque, the torque required by the driver is smoothly distributed to each slave motor according to the driver's accelerator pedal opening, so that the torque of the slave motor increases gradually until the vehicle starts moving.

[0039] Step S6: When the vehicle speed reaches the preset start-up completion threshold, control the virtual main motor torque to decrease to zero, and switch all motors to the normal parallel cooperative drive mode.

[0040] In step S2, the specific formula for calculating the target preload torque is as follows:

[0041]

[0042] In the formula, Preload torque to target; The dynamic safety factor; It is the difference between the component of gravity acting on the vehicle as it slides down the slope and the rolling resistance. The tire's rolling radius; This is the total transmission ratio from the motor output to the wheel; This represents the number of motors that are currently in a healthy and standby state.

[0043] In step S3, the specific method for dynamically selecting the virtual main motor is as follows: the vehicle controller reads the winding temperature, controller DC bus current, current torque output capability, and torque response time constant of each drive motor, calculates the transient response performance score of each motor, and selects the motor with the highest score as the virtual main motor; the formula for calculating the transient response performance score is:

[0044]

[0045] In the formula, For motor Transient response performance score; For motor The current temperature of the winding; This is the upper limit of the motor's protection temperature. For motor The torque response time constant; For motor Current torque output capability; This refers to the rated torque of the motor. All are weighting coefficients.

[0046] In step S4, when assigning an exclusive preload torque command to the virtual main motor, the target torque value of the preload torque command is corrected to an absolute preload torque. The absolute preload torque is equal to the target preload torque divided by the current number of healthy motors, plus a positive torque bias. This positive torque bias is used to eliminate transmission system backlash and static friction. After sending the command, the vehicle controller locks the command, prohibiting other controllers from intervening in the torque of the motor, and monitors the actual output torque of the virtual main motor at high frequency.

[0047] In step S4, the criterion for successfully establishing the preload torque of the virtual main motor is: the actual output torque of the virtual main motor reaches the target preload torque and remains stable within the preset error band for a preset stabilization time; after confirming successful establishment, the vehicle controller further maintains a preset torque holding time, which is determined by the sum of the estimated transmission system clearance elimination time and the hydraulic brake complete release delay time. During this time, the torque output of the virtual main motor is strictly maintained unchanged.

[0048] In step S5, the conversion of the driver's required torque is based on a preset nonlinear throttle pedal opening-MAP diagram. The smooth allocation method is as follows: the vehicle controller calculates the total torque required by the slave motors, which is the smaller of the driver's required torque and the sum of the current surplus capacity of all slave motors. Then, it is allocated proportionally according to the real-time torque response capability of each slave motor, and a slope limiter associated with the slope angle is applied to the torque command of each slave motor. The maximum upward slope of the slope limiter increases as the slope angle increases.

[0049] In step S6, the process of controlling the virtual main motor torque to decrease to zero is as follows: the vehicle controller sends a linear decrease command to the virtual main motor, causing its torque to decrease linearly to zero within a preset time; during the decrease, the torque of the slave motor is increased synchronously to compensate for the decrease in the virtual main motor torque, ensuring that the total output torque is continuous and smooth; when the actual torque of the virtual main motor decays to zero, the vehicle controller releases the exclusive lock state of its virtual main motor.

[0050] The control method also includes redundant safety control in fault mode: at any stage of the hill start process, when the virtual master motor fails, the vehicle controller immediately sends an emergency torque holding command to all slave motors to keep their current output torque unchanged; then, a new virtual master motor is selected from the remaining healthy motors to take over and establish the remaining preload torque value, and continues the subsequent torque distribution steps; when the fault occurs in the normal parallel cooperative drive mode, the faulty motor is directly disconnected and the upper limit of the total output power of the system is reduced to the preset redundancy power percentage, and the remaining healthy motors continue to work in torque cooperative mode.

[0051] The vehicle status parameters include at least: the slope angle from the slope sensor, the pressure value from the suspension cylinder pressure sensor, the vehicle speed signal from the wheel speed sensor, the gear position from the gear sensor, and the motor winding temperature, controller DC bus current, current torque output capability, and torque response time constant from each drive motor controller. The vehicle controller reads the suspension cylinder pressure value and calculates the current total mass of the vehicle according to the pre-calibrated load-pressure mapping function, and then calculates the gravitational downward component force.

[0052] The conventional parallel cooperative drive mode is as follows: the vehicle controller redistributes the total required torque to all healthy motors based on the total required torque and the motor efficiency MAP, using a proportional allocation or optimal efficiency allocation algorithm; during the hill start process, as the motor torque increases, the vehicle controller continuously monitors the vehicle speed. When the vehicle speed reaches the preset start completion threshold and remains there for a preset time, the hill start phase is determined to be over and the mode switch is executed.

[0053] The specific application of this embodiment is as follows:

[0054] Step S1: Vehicle Status Perception and Hill Start Mode Pre-triggering

[0055] During the operation of the mining dump truck at the mining face, the vehicle control unit (VCU) receives multi-source data from the vehicle status perception system in real time at a sampling frequency of no less than 100Hz. The perception system includes: a MEMS dual-axis slope sensor mounted on the chassis, a pressure sensor integrated into the suspension cylinder, wheel speed sensors, and internal status data reported by the controllers of the four drive motors.

[0056] The VCU executes the pre-judgment logic for starting conditions in real time. The VCU analyzes the slope sensor data to obtain the vehicle's current pitch angle, which is recorded as the slope angle. At the same time, the VCU reads the pressure value from the suspension cylinder pressure sensor. ,in These represent four suspension cylinders, based on a pre-calibrated load-pressure mapping function. Calculate the current total mass of the vehicle. The specific expression is as follows:

[0057]

[0058] In the formula, The slope coefficient is determined from two sets of pressure-mass data points, one under no-load and one under full-load conditions. The calibrated intercept represents the equivalent mass of non-suspension loads such as axles and wheels when the vehicle is unloaded.

[0059] VCU continuously monitors vehicle speed signals and gear status The VCU determines that the vehicle has entered the hill start pre-trigger mode if and only if all three of the following conditions are met:

[0060] (a) Gear position This is the forward gear (D).

[0061] (b) Vehicle speed This means that the vehicle is stationary or nearly stationary.

[0062] (c) Slope angle ,in The preset slope threshold is usually 5 degrees to avoid accidental triggering on flat roads;

[0063] Upon entering pre-trigger mode, the VCU immediately executes step S2.

[0064] Step S2: Calculation of the target preload torque based on the dynamic safety factor

[0065] After determining that the vehicle has entered the hill start pre-trigger mode, the VCU immediately calculates the minimum preload torque required to bring the vehicle to a standstill on the slope. This calculation is based on the vehicle's force balance equation.

[0066] First, calculate the component of gravity that causes the vehicle to slide down the slope. The calculation formula is as follows:

[0067]

[0068]

[0069] In the formula, It is the difference between the component of gravity acting on the vehicle along the slope and the rolling resistance, which is the net downward force that the drive motor needs to overcome. The total mass of the vehicle; It is the acceleration due to gravity; The slope angle is measured by a MEMS biaxial slope sensor. For vehicle rolling resistance; This is the rolling resistance coefficient.

[0070] Considering factors such as the uncertainty of the adhesion coefficient on wet and slippery surfaces, sensor noise, and wind disturbance, a dynamic safety factor is introduced. . It's not a fixed value, but rather dynamically adjusted based on the current road surface slip ratio prediction. The VCU calculates the slip ratio change rate of each wheel in the last 0.5 seconds before the vehicle comes to a complete stop using wheel speed sensor data, and thereby estimates the road surface adhesion margin. Safety factor. The calculation formula is:

[0071]

[0072] In the formula, This is a dynamic safety factor used to amplify the calculated minimum preload torque to address road surface uncertainties; The basic safety factor, ranging from 1.1 to 1.2, is determined by the system calibration. This is an adaptive coefficient, ranging from 0.1 to 0.2, used to adjust the influence of road surface adhesion margin; This is the estimated peak adhesion coefficient of the road surface.

[0073] Then, the target preload torque The formula for calculating the total torque (converted to the motor output shaft) is:

[0074]

[0075] In the formula, The target preload torque is the total torque that needs to be generated by all healthy motors when converted to the motor output shaft. The tire's rolling radius; It is the total transmission ratio from the motor output to the wheel, including the product of the fixed-ratio reduction gearbox ratio and the drive axle ratio; This represents the number of motors currently in a healthy and standby state, initially set at 4. The target total torque value is... That is, the VCU requires the basic anti-slip torque generated by the coordinated operation of four motors.

[0076] Step S3: Dynamic election of virtual main motor and exclusive allocation of preload torque

[0077] This step is the core of implementing virtual master-slave control. The VCU does not calculate step S2. Instead of directly assigning them to all motors, a virtual master motor election process is executed.

[0078] The VCU reads the real-time status vectors reported by the four drive motor controllers, including: motor winding temperature. Controller DC bus current Current torque output capability and torque response time constant ,in This represents four motors. The VCU calculates the transient response performance score for each motor. The scoring formula is as follows:

[0079]

[0080] In the formula, For motor The transient response performance score is used to select the virtual master motor; For motor The current temperature of the winding; This is the upper limit of the motor protection temperature; exceeding this value will trigger derating or protection. For motor The torque response time constant characterizes how quickly the actual output torque reaches the target value from receiving the command; For motor The current torque output capability is the maximum sustainable output torque after taking into account temperature and current limitations. This refers to the rated torque of the motor. All are weighting coefficients, and In hill start scenarios, to emphasize rapid response, the following settings are configured: Highest, for example

[0081] VCU selection The motor with the largest value is designated as the virtual main motor for this hill start process, and is denoted as motor X. The remaining three motors are automatically defined as slave motors.

[0082] The VCU then sends a signal to the virtual master motor. The controller sends a high-priority, exclusive preload torque build-up command. The target torque value of this command is not... Instead, it is the corrected absolute value of the preload torque. :

[0083]

[0084] In the formula, The absolute value of the preload torque allocated to the virtual main motor; A small positive torque offset, typically 2%-5% of the rated torque, is used to overcome transmission system backlash and static friction, ensuring unidirectional gear clamping and eliminating clanging and impact. This correction value allows the virtual master motor to independently undertake the entire preload task and actively eliminates transmission chain backlash.

[0085] Simultaneously with sending the command, the VCU locks the command, preventing any other controller, such as the auxiliary brake controller, from intervening in the motor's torque. The VCU then begins high-frequency monitoring of the virtual master motor's actual output torque. .

[0086] Step S4: Confirm the preload torque establishment loop and eliminate transmission chain gaps.

[0087] The VCU performs closed-loop monitoring of the preload torque establishment process of the virtual main motor. When achieve And stabilized at When the error band exceeds 50 milliseconds, the VCU considers the electronic parking anchor point to have been successfully established.

[0088] At this point, the VCU does not immediately respond to the driver's throttle input. Instead, it waits for an additional confirmation signal: either by monitoring the torque sensor on the drive axle input shaft (if installed) or by monitoring the wheel speed signal via wheel speed sensors. The VCU then performs a brief torque sustaining state, lasting for [duration missing]. The calculation formula is:

[0089]

[0090] In the formula, Once the preload torque is established, the system needs to maintain that torque for an additional period of time. The estimated backlash elimination time for the transmission system is obtained by referring to a table based on the backlash calibration values ​​of the gearbox and drive axle gear pairs; The delay time for the hydraulic brake to fully release;

[0091] Here During this time, the VCU strictly maintains a constant torque output from the virtual main motor, ensuring that all rotating components in the entire drivetrain, from the motor rotor to the wheel hub, are tightly meshed, achieving a quasi-static equilibrium state of rigid connection. During this period, the VCU sends a start-preparation warning signal to the driver's instrument panel.

[0092] Step S5: Smooth superposition and dynamic coordination of slave motor torque based on throttle opening

[0093] exist After the time expires, the VCU begins to read the driver's accelerator pedal opening signal in real time. And convert it into total driver-demand torque. The conversion uses a non-linear MAP diagram, calibrated based on the heavy-load start-up characteristics of the mining area.

[0094] The VCU executes a dynamic collaborative algorithm for torque distribution. The core principle is: virtual master motor. Continue to maintain and fine-tune its preload torque in real time. To compensate for the change in downward force caused by the slight shift in the vehicle's center of gravity; all the increased torque required by the driver. All of these tasks are smoothly handled by the other three motors.

[0095] The specific allocation logic is as follows:

[0096] First, the VCU calculates the total torque that the motor needs to handle. :

[0097]

[0098] In the formula, This refers to the total torque that all the motors need to share. To adjust according to the driver's accelerator pedal opening The total required torque is obtained through mapping; The virtual main motor number selected in step S3; For motor Current torque output capability; The absolute value of the preload torque allocated to the virtual main motor;

[0099] That is, the total demand from the motor is the smaller of the driver's demand and the current surplus capacity of the motor.

[0100] VCU will The torque is allocated proportionally according to the real-time torque response capability of each slave motor. Each slave motor... Distributed torque The calculation formula is:

[0101]

[0102] In the formula, To assign to a slave motor The specific torque value, of which ; To sum the index variable, iterate through all slave motors;

[0103] The VCU sends incremental torque commands to each slave motor controller at a refresh rate of 50Hz. To avoid shocks caused by sudden torque changes, the VCU also applies a slope limiter to the torque command of each slave motor, limiting the maximum torque rise slope. With the current slope angle Related: In the formula, This is the baseline slope for starting on a flat road. The steeper the slope, the greater the allowable torque increase slope, allowing for faster overcoming of the downward trend.

[0104] Throughout the entire process of increasing motor torque, the VCU continuously monitors the vehicle speed. Once vehicle speed is detected This signifies that the vehicle has successfully overcome the slope resistance and established a stable driving speed. At this point, the VCU determines that the hill start process is complete.

[0105] Step S6: Exiting virtual master-slave mode and switching to regular collaborative control mode

[0106] When the vehicle speed in step S5 After the conditions are met and remain so for 200 milliseconds, the VCU determines that the ramp start phase has ended and begins to execute the mode switch.

[0107] The mode switching involves two steps:

[0108] Step S61: VCU sends data to the virtual master motor Send a command to make it transfer its torque from 1 second The torque decreases linearly to 0. The decrease curve is linear to avoid sudden torque changes. During this decrease, the VCU synchronously increases the torque of the slave motor to compensate for the decrease in the torque of the virtual master motor, ensuring a smooth transition of the total driving force. The torque dynamic compensation algorithm for this stage is as follows:

[0109]

[0110] In the formula, For the virtual master motor torque reduction process, the additional torque that the slave motor needs to dynamically compensate for changes over time; This represents the actual torque value of the virtual main motor at the current moment during the decreasing process. This represents the number of motors. This formula guarantees the total output torque. The continuity, in the formula, For a moment The sum of the total torque at the output shaft ends of all four drive motors; For a moment The actual output torque of the virtual main motor; For a moment The actual output torque of the motor is taken as the starting point.

[0111] Step S62: Once the actual torque of the virtual master motor decays to zero, the VCU releases the exclusive lock-up state of its virtual master motor. Afterward, all four motors (including the original virtual master motor) enter the standard parallel centralized drive mode. In this normal mode, the VCU redistributes the total required torque to the four motors based on the total required torque and the motor efficiency MAP, using either a proportional allocation or an optimal efficiency allocation algorithm.

[0112] This concludes a complete dynamic control process for ramp anti-slip preload torque based on virtual master-slave collaboration. The system returns to its normal, uninterrupted multi-motor collaborative drive state, awaiting the triggering of the next ramp start-up condition.

[0113] Step S7: Redundant safety control under fault modes

[0114] In any of the above control steps, if the VCU detects a fault in any motor or its controller, such as reporting overcurrent, overtemperature, or communication interruption, the VCU immediately executes redundant safety control logic.

[0115] During the execution of steps S3 to S5, if the virtual main motor In the event of a fault, the VCU will immediately perform a fail-safe switch. The VCU first sends an emergency torque hold command to all slave motors, maintaining their current output torque. The VCU then applies the same transient response performance scoring formula to the remaining slave motors. Re-elect a new virtual master motor The new virtual main motor takes over all the responsibilities of the faulty motor, first establishing the remaining preload torque value, and then continuing with the subsequent torque distribution steps. The entire process is completed within 100 milliseconds, and because of the torque holding action of the slave motor, the vehicle does not experience any power interruption or backward rolling.

[0116] If the fault occurs after step S6 or S7, the VCU will directly disconnect the faulty motor and reduce the system's total output power to 75%, while simultaneously issuing an alarm to the driver. The remaining healthy motors continue to operate in a torque-coordinated manner, ensuring that the entire machine can be smoothly driven away from the work surface for maintenance, thus achieving fail-safe operation.

[0117] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0118] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for uninterrupted power control of a mining dump truck based on multi-motor cooperation, characterized in that, The control method includes the following steps: Step S1: The vehicle controller acquires vehicle status parameters in real time and determines whether to enter the hill start pre-trigger mode based on the slope angle, vehicle speed and gear status. Step S2: In the hill start pre-trigger mode, calculate the target preload torque required to keep the vehicle stationary on the hill. Step S3: Based on the real-time status parameters of each drive motor, dynamically select one motor as the virtual master motor and the remaining motors as slave motors; Step S4: Assign an exclusive preload torque command to the virtual main motor, enabling it to independently establish and maintain the target preload torque, thus forming an electronic parking anchor point; Step S5: After the virtual main motor successfully establishes preload torque, the torque required by the driver is smoothly distributed to each slave motor according to the driver's accelerator pedal opening, so that the torque of the slave motor increases gradually until the vehicle starts moving. Step S6: When the vehicle speed reaches the preset start-up completion threshold, control the virtual main motor torque to decrease to zero, and switch all motors to the normal parallel cooperative drive mode.

2. The method for uninterrupted power control of a mining dump truck based on multi-motor coordination according to claim 1, characterized in that, In step S2, the specific formula for calculating the target preload torque is as follows: ； In the formula, Preload torque to target; The dynamic safety factor; It is the difference between the component of gravity acting on the vehicle as it slides down the slope and the rolling resistance. The tire's rolling radius; This is the total transmission ratio from the motor output to the wheel; This represents the number of motors that are currently in a healthy and standby state.

3. The method for uninterrupted power control of a mining dump truck based on multi-motor cooperation according to claim 1, characterized in that, In step S3, the specific method for dynamically selecting the virtual main motor is as follows: the vehicle controller reads the winding temperature, controller DC bus current, current torque output capability, and torque response time constant of each drive motor, calculates the transient response performance score of each motor, and selects the motor with the highest score as the virtual main motor; the formula for calculating the transient response performance score is: ； In the formula, For motor Transient response performance score; For motor The current temperature of the winding; This is the upper limit of the motor's protection temperature. For motor The torque response time constant; For motor Current torque output capability; This refers to the rated torque of the motor. All are weighting coefficients.

4. The method for uninterrupted power control of a mining dump truck based on multi-motor coordination according to claim 1, characterized in that, In step S4, when assigning an exclusive preload torque command to the virtual master motor, the target torque value of the preload torque command is corrected to an absolute value preload torque, which is equal to the target preload torque divided by the current number of healthy motors and then superimposed with a positive torque bias. This positive torque bias is used to eliminate drivetrain backlash and static friction; After sending the command, the vehicle controller locks the command, prohibiting other controllers from interfering with the torque of the motor, and monitors the actual output torque of the virtual main motor at high frequency.

5. The method for uninterrupted power control of a mining dump truck based on multi-motor coordination according to claim 1, characterized in that, In step S4, the criterion for successfully establishing the preload torque of the virtual main motor is: the actual output torque of the virtual main motor reaches the target preload torque and remains stable within the preset error band for a preset stable time; after confirming successful establishment, the vehicle controller further maintains a preset torque holding time, which is determined by the sum of the estimated transmission system clearance elimination time and the hydraulic brake complete release delay time, and strictly maintains the torque output of the virtual main motor unchanged within this time.

6. The method for uninterrupted power control of a mining dump truck based on multi-motor cooperation according to claim 1, characterized in that, In step S5, the conversion of the driver's required torque is based on a preset nonlinear accelerator pedal opening-MAP diagram. The smooth allocation method is as follows: the vehicle controller calculates the total torque required by the slave motors, which is the smaller of the driver's required torque and the sum of the current spare capacity of all slave motors; then, it is allocated proportionally according to the real-time torque response capability of each slave motor, and a slope limiter associated with the slope angle is applied to the torque command of each slave motor. The maximum upward slope of the slope limiter increases as the slope angle increases.

7. The method for uninterrupted power control of a mining dump truck based on multi-motor cooperation according to claim 1, characterized in that, In step S6, the process of controlling the virtual main motor torque to decrease to zero is as follows: the vehicle controller sends a linear decrease command to the virtual main motor, causing its torque to decrease linearly to zero within a preset time; during the decrease process, the torque of the slave motor is increased synchronously to compensate for the decrease in the virtual main motor torque, ensuring that the total output torque is continuous and smooth; when the actual torque of the virtual main motor decays to zero, the vehicle controller releases the exclusive lock state of its virtual main motor.

8. The method for uninterrupted power control of a mining dump truck based on multi-motor cooperation according to claim 1, characterized in that, The control method also includes redundant safety control in fault mode: at any stage of the hill start process, when the virtual main motor fails, the vehicle controller immediately sends an emergency torque holding command to all slave motors to keep their current output torque unchanged. Then, select a new virtual master motor from the remaining healthy motors. This new virtual master motor will take over the establishment of the remaining preload torque value and continue the subsequent torque distribution steps. When a fault occurs in the normal parallel cooperative drive mode, the faulty motor is directly disconnected, and the upper limit of the total output power of the system is reduced to the preset redundancy power percentage, while the remaining healthy motors continue to work in torque cooperative mode.

9. The method for uninterrupted power control of a mining dump truck based on multi-motor cooperation according to claim 1, characterized in that, The vehicle status parameters include at least: the slope angle from the slope sensor, the pressure value from the suspension cylinder pressure sensor, the vehicle speed signal from the wheel speed sensor, the gear position from the gear sensor, and the motor winding temperature, controller DC bus current, current torque output capability, and torque response time constant from each drive motor controller. The vehicle controller reads the suspension cylinder pressure value and calculates the current total mass of the vehicle according to the pre-calibrated load-pressure mapping function, and then calculates the gravitational downward component force.

10. A method for uninterrupted power control of a mining dump truck based on multi-motor cooperation according to claim 8, characterized in that, The conventional parallel cooperative drive mode is as follows: the vehicle controller redistributes the total required torque to all healthy motors according to the total required torque and the motor efficiency MAP, using a proportional allocation or optimal efficiency allocation algorithm; during the hill start process, as the motor torque increases, the vehicle controller continuously monitors the vehicle speed. When the vehicle speed reaches the preset start completion threshold and remains there for a preset time, the hill start phase is determined to be over and the mode switch is executed.

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