A method for multi-axle vehicle speed fusion calculation and related device

Abstract

This application discloses a method and related apparatus for calculating vehicle speed fusion in multi-axle vehicles, relating to the field of vehicle parameter estimation. The method includes: acquiring the motor-converted vehicle speed, the equivalent vehicle speed of the drive wheels, the corrected longitudinal acceleration integral vehicle speed, the updated rotational speed weights of multiple driven wheels, and the corrected longitudinal acceleration integral vehicle speed weights; calculating the equivalent vehicle speed based on the updated rotational speed weights of multiple driven wheels, the rotational speed of multiple driven wheels in the current cycle, the corrected longitudinal acceleration integral vehicle speed weights, and the corrected longitudinal acceleration integral vehicle speed; calculating the vehicle speed during the fusion transition phase based on preset vehicle speed weights, preset motor-converted vehicle speed weights, the equivalent vehicle speed, and the motor-converted vehicle speed; acquiring the target vehicle speed calculation mode; and searching for the target vehicle speed corresponding to the target vehicle speed calculation mode from the preset correspondence between vehicle speed calculation modes and vehicle speeds. This application is applicable to various low-adhesion road surface conditions and can accurately calculate the target vehicle speed based on sensor information under different vehicle fault states.

Description

Technical Field

[0001] This application relates to the field of vehicle parameter estimation technology, and in particular to a method and related apparatus for fusion calculation of vehicle speed for multi-axle vehicles. Background Technology

[0002] In multi-axle vehicles equipped with wheel speed sensors, the method for calculating vehicle speed is dynamically adjusted based on the vehicle's driving conditions and the reliability of the sensors to improve the accuracy and stability of speed estimation. For example, when the vehicle is driving, the average rotational speed method is typically used to calculate the speed. When the vehicle is braking, the maximum rotational speed method is used. Under low-adhesion conditions or when the wheel speed sensors malfunction, the longitudinal acceleration integral from the accelerometer is used to calculate the speed.

[0003] The maximum speed method described above may result in abnormal vehicle speeds when some wheel speed sensors output abnormally large values; the average speed method described above may result in abnormal vehicle speeds when some wheel speed sensors output abnormally small values ​​or when the hardware is disconnected; the longitudinal acceleration integration method described above may result in abnormal vehicle speeds due to wheel speed sensor noise and insufficient or excessive correction of zero bias effect, leading to deviations in the integration value over a long period of time.

[0004] In summary, the above methods for calculating vehicle speed have low accuracy. Summary of the Invention

[0005] In view of the above problems, this application provides a method and related apparatus for calculating vehicle speed fusion in multi-axle vehicles, so as to achieve the goal of obtaining vehicle speed with high accuracy. The specific solution is as follows:

[0006] The first aspect of this application provides a method for fusion calculation of vehicle speed in multi-axle vehicles, including:

[0007] Based on the fault flags of multiple motors, the equivalent speed of the motors, and the slippage status of multiple motors, the vehicle speed is calculated from the motors.

[0008] Based on the fault flags corresponding to multiple drive wheels and the rotational speeds corresponding to the multiple drive wheels, the equivalent vehicle speed of the drive wheels is calculated.

[0009] Based on the longitudinal acceleration of each cycle, the equivalent vehicle speed of each cycle corresponding to the multiple driven wheels, and the vehicle speed of each cycle corresponding to the multiple driven wheels, the corrected longitudinal acceleration integral vehicle speed is obtained.

[0010] Based on the fault flag bits corresponding to the multiple driven wheels and the rotational speeds of the multiple driven wheels in each cycle, the initial rotational speed weights of the multiple driven wheels are determined.

[0011] For any of the driven wheels, if the driven wheel is in a locked state and the initial speed weight of the driven wheel is not 0, the lock-up level of the driven wheel is determined based on the speed of the driven wheel in each cycle.

[0012] If the locking level of at least one of the driven wheels is not 0, the updated speed weights corresponding to the multiple driven wheels are calculated based on the longitudinal projection of the mounting points of the multiple driven wheels in the vehicle body coordinate system and the initial speed weights of the multiple driven wheels.

[0013] Based on the updated rotational speed weights corresponding to the multiple driven wheels, the corrected longitudinal acceleration integral speed weight is obtained.

[0014] The equivalent vehicle speed is calculated based on the updated rotational speed weights of the multiple driven wheels, the rotational speed of the multiple driven wheels in the current cycle, the corrected longitudinal acceleration integral vehicle speed weights, and the corrected longitudinal acceleration integral vehicle speed.

[0015] Based on the preset vehicle speed weight, the preset motor-converted vehicle speed weight, the equivalent vehicle speed, and the motor-converted vehicle speed, the vehicle speed during the fusion transition phase is calculated.

[0016] Obtain the target vehicle speed calculation mode;

[0017] From the preset vehicle speed calculation mode and the correspondence between vehicle speeds, find the target vehicle speed corresponding to the target vehicle speed calculation mode. The vehicle speed is any one of the corrected longitudinal acceleration integral vehicle speed, the equivalent vehicle speed, the motor converted vehicle speed, the fusion transition stage vehicle speed, and the drive wheel equivalent vehicle speed.

[0018] In one possible implementation, the method for obtaining the vehicle speed calculation mode includes:

[0019] If the fault flag bits of multiple motors, the fault flag bits corresponding to multiple drive wheels, and the fault flag bits corresponding to multiple driven wheels are all FALSE, or if the minimum absolute value of the rotation angle of multiple driven wheels is less than or equal to a preset rotation angle threshold and the number of fault flag bits of multiple driven wheels that are TRUE is within a preset range, the vehicle speed calculation mode is determined based on the equivalent vehicle speed.

[0020] If the minimum absolute value of the rotation angle of multiple driven wheels is less than or equal to the preset rotation angle threshold, and the number of fault flags of multiple driven wheels that are TRUE is greater than the preset range, and the fault flags of multiple motors are all FALSE, then the vehicle speed calculation mode is determined to be the second mode.

[0021] If the minimum absolute value of the rotation angle of multiple driven wheels is greater than the preset rotation angle threshold and the fault flags of the left driven wheel of the first axle and the left driven wheel of the fourth axle are both TRUE or the fault flags of the right driven wheel of the first axle and the right driven wheel of the fourth axle are both TRUE, and the fault flags of multiple motors are not all TRUE, the vehicle speed calculation mode is determined to be the second mode.

[0022] If the fault flag bits of multiple motors, multiple drive wheels, and multiple driven wheels are all TRUE, the vehicle speed calculation mode is determined to be the zeroth mode.

[0023] If the fault flag bits of multiple driven wheels are all TRUE, the fault flag bits of multiple motors are all TRUE, and the fault flag bits of multiple drive wheels are all FALSE, then the vehicle speed calculation mode is determined to be the fourth mode.

[0024] In one possible implementation, determining the vehicle speed calculation mode based on the equivalent vehicle speed includes:

[0025] If the equivalent vehicle speed is less than the lower boundary of the preset fusion interval speed, and the slippage state of multiple motors is not slippage, the vehicle speed calculation mode is determined to be the second mode.

[0026] If the equivalent vehicle speed is greater than or equal to the lower boundary of the preset fusion interval speed and less than or equal to the upper boundary of the preset fusion interval speed, and the slippage state of multiple motors is not slippage, the vehicle speed calculation mode is determined to be the third mode.

[0027] If the equivalent vehicle speed is greater than the upper boundary of the preset fusion interval speed, the vehicle speed calculation mode is determined to be the first mode.

[0028] In one possible implementation, the plurality of motors includes a first motor and a second motor. The step of obtaining the motor-converted vehicle speed based on the fault flag bits of the plurality of motors, the equivalent speed of the motors, and the slippage state of the plurality of motors includes:

[0029] If the fault flags of multiple motors are all FALSE and the first motor and the second motor rotate in the same direction, and the sum of the torque of the first motor and the torque of the second motor is greater than or equal to the first preset torque threshold, or if the fault flags of multiple motors are all FALSE and the first motor and the second motor rotate in different directions, the minimum speed of the first motor and the second motor is determined to be the equivalent speed.

[0030] If the fault flags of multiple motors are all FALSE and the first motor and the second motor rotate in the same direction, and the sum of the torque of the first motor and the torque of the second motor is less than the first preset torque threshold, then the maximum speed of the first motor and the second motor is determined to be the equivalent speed.

[0031] Based on the equivalent rotational speed, determine the motor speed weights corresponding to the first motor and the second motor respectively;

[0032] If the fault flag bits of multiple motors are all FALSE, obtain the first speed gradient of the first motor at multiple cycle intervals and the second speed gradient of the second motor at multiple cycle intervals.

[0033] The maximum value between the first speed gradient and the second speed gradient is determined as the maximum driving speed gradient;

[0034] If the maximum driving speed gradient is greater than or equal to the first preset gradient threshold, the motor speed weights corresponding to the first motor and the second motor are determined to be zero.

[0035] If the maximum driving speed gradient is less than the first preset gradient threshold, the absolute value of the difference between the speed of the first motor and the speed of the second motor is determined to be the separation degree of the front and rear motor speeds.

[0036] If the speed separation of the front and rear motors is less than the preset speed separation threshold, and the maximum driving speed gradient is less than the first preset gradient threshold, the motor speed weights corresponding to the first motor and the second motor are determined to be 1 respectively.

[0037] If the speed separation of the front and rear motors is greater than or equal to the preset speed separation threshold, the speed weights of the first motor and the second motor are determined to be zero.

[0038] If the motor speed weights of the first motor are all zero and the motor speed weights of the second motor are all zero, the converted vehicle speed of the motor is determined to be 0.

[0039] If at least one of the motor speed weights of the first motor and the second motor is not zero, the converted vehicle speed of the motor is calculated based on the tire rolling radius, the transmission ratio from the motor to the wheel end, the turning angle of the left wheel of the front axle, the turning angle of the right wheel of the front axle, the turning angle of the left wheel of the rear axle and the turning angle of the right wheel of the rear axle, the motor speed weight of the first motor and the motor speed weight of the second motor.

[0040] In one possible implementation, the plurality of drive wheels includes a front axle left drive wheel, a front axle right drive wheel, a rear axle left drive wheel, and a rear axle right drive wheel;

[0041] The calculation of the equivalent vehicle speed of the drive wheels based on the fault flag bits corresponding to the multiple drive wheels and the rotational speeds corresponding to the multiple drive wheels includes:

[0042] For each of the drive wheels, if the fault flag bit of the drive wheel is TRUE, the drive wheel speed weight of the drive wheel is determined to be zero.

[0043] For each of the drive wheels, if the fault flag of the drive wheel is FALSE, the absolute value of the difference between the speed of the left drive wheel of the front axle and the speed of the right drive wheel of the front axle is determined as the front axle drive wheel speed difference.

[0044] The absolute value of the difference between the rotational speed of the left drive wheel of the rear axle and the rotational speed of the right drive wheel of the rear axle is determined as the rear axle drive wheel speed difference;

[0045] If the speed difference of the front axle drive wheels is greater than a preset speed threshold, the speed weights of the drive wheels corresponding to the left and right front axle drive wheels are determined to be zero.

[0046] If the speed difference of the front axle drive wheels is less than or equal to the preset speed threshold, the speed weights of the drive wheels corresponding to the left and right front axle drive wheels are determined to be 1.

[0047] If the difference in speed of the rear axle drive wheels is greater than the preset speed threshold, the speed weights of the drive wheels corresponding to the left and right rear axle drive wheels are determined to be zero.

[0048] If the speed difference of the rear axle drive wheels is less than or equal to the preset speed threshold, the speed weights of the drive wheels corresponding to the left and right rear axle drive wheels are determined to be 1.

[0049] The average longitudinal speed of the front axle is calculated based on the rotational speed of the left drive wheel of the front axle, the rotational speed weight of the left drive wheel of the front axle, the rotational speed of the right drive wheel of the front axle, and the rotational speed weight of the right drive wheel of the front axle.

[0050] The average longitudinal speed of the rear axle is calculated based on the speed weights of the left and right drive wheels of the rear axle, the speed of the left and right drive wheels of the rear axle.

[0051] The equivalent vehicle speed of the drive wheels is calculated based on the average longitudinal speed of the front axle and the average longitudinal speed of the rear axle.

[0052] In one possible implementation, the plurality of driven wheels includes a left driven wheel of a single axle, a right driven wheel of a single axle, a left driven wheel of a fourth axle, and a right driven wheel of a fourth axle;

[0053] The method of obtaining the corrected longitudinal acceleration integral speed based on the longitudinal acceleration of each cycle, the equivalent vehicle speed of each cycle corresponding to the multiple driven wheels, and the vehicle speed of each cycle corresponding to the multiple driven wheels includes:

[0054] Obtain real-time longitudinal acceleration;

[0055] For each cycle, if the vehicle is in braking state and the real-time longitudinal acceleration is greater than |first preset acceleration threshold| when the vehicle is in D gear, or the real-time longitudinal acceleration is less than -|first preset acceleration threshold| when the vehicle is in R gear and the real-time longitudinal acceleration is less than the second preset acceleration threshold, the initial longitudinal acceleration of the cycle is set to 0.

[0056] The equivalent vehicle speed of the left driven wheel of the first axle in each cycle, the equivalent vehicle speed of the right driven wheel of the first axle in each cycle, the equivalent vehicle speed of the left driven wheel of the fourth axle in each cycle, the equivalent vehicle speed of the right driven wheel of the fourth axle in each cycle, and the maximum value among the vehicle speeds before each cycle are determined as the starting point for acceleration integration.

[0057] Based on the acceleration integral starting point and the initial longitudinal acceleration of each cycle, the corrected longitudinal acceleration integral speed is calculated.

[0058] One possible implementation also includes:

[0059] Based on the corrected longitudinal acceleration integral vehicle speed, the preset vehicle speed L1 level speed upper limit gain, the preset vehicle speed L1 level speed lower limit gain, and the preset L1 level speed upper and lower limit envelope width, the vehicle speed L1 level upper limit and vehicle speed L1 level lower limit are calculated.

[0060] Based on the corrected longitudinal acceleration integral vehicle speed V ACC The upper and lower limits of vehicle speed at level L2 are calculated by using preset upper and lower speed limit gains, preset lower and upper speed limit envelope widths, and preset upper and lower speed limit gain.

[0061] In one possible implementation, the plurality of driven wheels includes a left driven wheel of a single axle, a right driven wheel of a single axle, a left driven wheel of a fourth axle, and a right driven wheel of a fourth axle;

[0062] The determination of the initial speed weights of the multiple driven wheels based on the fault flag bits corresponding to the multiple driven wheels and the speeds of the multiple driven wheels in each cycle includes:

[0063] For each driven wheel, if the fault flag bit of the driven wheel is TRUE, the initial speed weight of the driven wheel is determined to be 0;

[0064] For each driven wheel, if the fault flag bit of the driven wheel is FALSE, and the difference between the rotational speed of the driven wheel in the current cycle and the rotational speed in the previous cycle is greater than or equal to a preset rotational speed threshold, the initial rotational speed weight of the driven wheel is determined to be 0; otherwise, the initial rotational speed weight is determined to be 1.

[0065] In one possible implementation, determining the lock-up level of the driven wheel based on the rotational speed of the driven wheel in each cycle, if the driven wheel is in a locked state and the initial rotational speed weight of the driven wheel is not 0, includes:

[0066] If the vehicle is under braking, and the maximum absolute value of the rotation angles of the multiple driven wheels is less than a preset steering angle threshold, and the vehicle's real-time speed V x If the vehicle speed exceeds a preset detection threshold and the vehicle is in D or R gear, lock-up detection is enabled.

[0067] For each driven wheel, if the fault flag of the driven wheel is FALSE, obtain the speed reduction gradient of the driven wheel in each cycle interval;

[0068] If the minimum value of the speed decrease gradient of the multiple driven wheels in each cycle interval is greater than the preset speed decrease gradient threshold, the initial lock-up level of the multiple driven wheels is determined to be zero; otherwise, the initial lock-up level of the multiple driven wheels is determined to be 1.

[0069] For each driven wheel, if the rotational speed of the driven wheel is greater than the lower limit of the vehicle speed L1 level and the initial lock-up level of the driven wheel is zero, the lock-up level of the driven wheel is determined to be zero.

[0070] For each driven wheel, if the rotational speed of the driven wheel is greater than or equal to the lower limit of the vehicle speed level L2 and less than or equal to the lower limit of the vehicle speed level L1, the locking level of the driven wheel is determined to be 1.

[0071] For each driven wheel, if the rotational speed of the driven wheel is less than the lower limit of the vehicle speed level L1, the locking level of the driven wheel is determined to be 2.

[0072] A second aspect of this application provides a device for calculating vehicle speed fusion for multi-axle vehicles, comprising:

[0073] The first acquisition module is used to acquire the motor-converted vehicle speed based on the fault flag bits of multiple motors, the equivalent speed of the motors, and the slippage state of multiple motors.

[0074] The first calculation module is used to calculate the equivalent vehicle speed of the drive wheels based on the fault flag bits corresponding to the multiple drive wheels and the rotation speeds corresponding to the multiple drive wheels.

[0075] The second acquisition module is used to obtain the corrected longitudinal acceleration integral speed based on the longitudinal acceleration of each cycle, the equivalent vehicle speed of each cycle corresponding to the multiple driven wheels, and the vehicle speed of each cycle corresponding to the multiple driven wheels.

[0076] The first determining module is used to determine the initial speed weight of the multiple driven wheels based on the fault flag bits corresponding to the multiple driven wheels and the speed of the multiple driven wheels in each cycle.

[0077] The second determining module is used to determine the lock-up level of any driven wheel if the driven wheel is in a locked state and the initial speed weight of the driven wheel is not 0, based on the speed of the driven wheel in each cycle.

[0078] The second calculation module is used to calculate the updated speed weights corresponding to the multiple driven wheels based on the longitudinal projection of the mounting points of the multiple driven wheels in the vehicle body coordinate system and the initial speed weights of the multiple driven wheels if the locking level of at least one of the driven wheels is not 0.

[0079] The third acquisition module is used to acquire the corrected longitudinal acceleration integral speed weight based on the updated rotational speed weights corresponding to the multiple driven wheels.

[0080] The third calculation module is used to calculate the equivalent vehicle speed based on the updated rotational speed weights of the multiple driven wheels, the rotational speed of the multiple driven wheels in the current cycle, the corrected longitudinal acceleration integral vehicle speed weights, and the corrected longitudinal acceleration integral vehicle speed.

[0081] The fourth calculation module is used to calculate the vehicle speed during the fusion transition phase based on the preset vehicle speed weight, the preset motor-converted vehicle speed weight, the equivalent vehicle speed, and the motor-converted vehicle speed.

[0082] The fourth acquisition module is used to acquire the target vehicle speed calculation mode;

[0083] The search module is used to search for the target vehicle speed corresponding to the target vehicle speed calculation mode from the preset vehicle speed calculation mode and vehicle speed correspondence. The vehicle speed is any one of the corrected longitudinal acceleration integral vehicle speed, the equivalent vehicle speed, the motor converted vehicle speed, the fusion transition stage vehicle speed and the drive wheel equivalent vehicle speed.

[0084] A third aspect of this application provides a computer program product, including computer-readable instructions that, when executed on an electronic device, cause the electronic device to implement the method for multi-axle vehicle speed fusion calculation described in the first aspect or any implementation thereof.

[0085] A fourth aspect of this application provides an electronic device, including at least one processor and a memory connected to the processor, wherein:

[0086] The memory is used to store computer programs;

[0087] The processor is used to execute the computer program so that the electronic device can implement the method for multi-axle vehicle speed fusion calculation as described in the first aspect or any implementation thereof.

[0088] The fifth aspect of this application provides a computer storage medium carrying one or more computer programs, which, when executed by an electronic device, enable the electronic device to perform the above-described first aspect or any implementation thereof for a multi-axle vehicle speed fusion calculation method.

[0089] By employing the above technical solution, this application provides a method for calculating vehicle speed fusion in multi-axle vehicles. This method obtains the motor-converted vehicle speed, the equivalent vehicle speed of the drive wheels, the corrected longitudinal acceleration integral vehicle speed, the updated rotational speed weights of multiple driven wheels, and the corrected longitudinal acceleration integral vehicle speed weights. Based on the updated rotational speed weights of multiple driven wheels, the current cycle rotational speed of multiple driven wheels, the corrected longitudinal acceleration integral vehicle speed weights, and the corrected longitudinal acceleration integral vehicle speed, the equivalent vehicle speed is calculated. Based on preset vehicle speed weights, preset motor-converted vehicle speed weights, the equivalent vehicle speed, and the motor-converted vehicle speed, the vehicle speed during the fusion transition phase is calculated. A target vehicle speed calculation mode is obtained. From the preset correspondence between vehicle speed calculation modes and vehicle speeds, the target vehicle speed corresponding to the target vehicle speed calculation mode is found. The embodiments of this application are applicable to various low-adhesion road surface conditions and, under different vehicle fault states, accurately calculate the target vehicle speed based on information from various sensors, providing stable and accurate input parameters for vehicle control to the greatest extent possible. Meanwhile, the method proposed in this application can ensure that the calculation results are stable and that there is no sudden change in vehicle speed, while the calculation time meets the performance requirements of general vehicle controllers. Attached Figure Description

[0090] The above and other features, advantages, and aspects of the embodiments of this disclosure will become more apparent from the accompanying drawings and the following detailed description. Throughout the drawings, the same or similar reference numerals denote the same or similar elements. It should be understood that the drawings are schematic, and the originals and elements are not necessarily drawn to scale.

[0091] Figure 1 A schematic diagram of the architecture of a multi-axle vehicle provided in this application;

[0092] Figure 2 A schematic diagram illustrating the input and output of a method for calculating the speed fusion of multi-axle vehicles provided in this application;

[0093] Figure 3 A flowchart illustrating a method for calculating the speed fusion of multi-axle vehicles, provided as an embodiment of this application;

[0094] Figure 4 A schematic diagram of a multi-axle vehicle speed fusion calculation device provided in this application embodiment;

[0095] Figure 5 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Detailed Implementation

[0096] The embodiments of this application are described below with reference to the accompanying drawings. The terminology used in the implementation section of this application is for explaining specific embodiments only and is not intended to limit the scope of this application.

[0097] The embodiments of this application will now be described with reference to the accompanying drawings. Those skilled in the art will recognize that, with technological advancements and the emergence of new scenarios, the technical solutions provided in the embodiments of this application are equally applicable to similar technical problems.

[0098] The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms are interchangeable where appropriate; this is merely a way of distinguishing objects with the same attributes in the embodiments of this application. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion, so that a process, method, system, product, or apparatus that comprises a series of elements is not necessarily limited to those elements, but may include other elements not explicitly listed or inherent to those processes, methods, products, or apparatuses.

[0099] The following methods can be used to calculate the speed of a vehicle in related technologies.

[0100] The maximum speed method is a method for estimating the reference speed of a vehicle. Its basic principle is to collect the speed signals of multiple wheels of the vehicle in real time and select the maximum value as the reference speed of the vehicle.

[0101] The average speed method is a method for estimating a vehicle's reference speed by calculating the average speed of multiple wheels.

[0102] The acceleration integration method is a method for calculating velocity and displacement by integrating acceleration signals.

[0103] To accurately estimate vehicle speed and provide stable and reliable parameter information for chassis control, it is necessary to dynamically adjust the weights of different sensor data sources under various operating conditions and road surfaces. In related technologies, multi-axle vehicles only allocate signal source weights by a fixed ratio. If some wheel speed sensors output abnormally large values, the maximum speed method will obtain an abnormal vehicle speed much greater than the actual vehicle speed; if some wheel speed sensors produce abnormally small values ​​or experience hardware failure, the average speed method will output an abnormal vehicle speed much less than the actual vehicle speed; if the acceleration integral method is used directly, sensor noise and insufficient or excessive correction due to zero-bias effects will lead to long-term deviations in the integral value.

[0104] None of the related technologies consider wheel angle and yaw rate. Changes in wheel angle and yaw rate significantly impact the vehicle's longitudinal speed during steering and diagonal maneuvers. However, methods in these technologies typically focus only on data from wheel speed and acceleration sensors, neglecting this crucial dynamic information. This results in inaccurate longitudinal vehicle speed estimates during steering and diagonal maneuvers. This is partly because these methods ignore this dynamic information, and partly because, under extreme conditions, they fail to comprehensively utilize sensor information, leading to an overemphasis on certain sensor types in speed calculations and inaccurate speed estimations. Therefore, vehicle speed estimation algorithms in these technologies cannot accurately estimate the vehicle's longitudinal speed (the speed in the vehicle's forward direction in the vehicle's coordinate system) under conditions such as partial wheel speed sensor failure, low-traction drive wheel slippage, low-traction drive or driven wheel lockup, or dead zones in wheel speed sensors. Furthermore, they cannot provide accurate longitudinal vehicle speed (i.e., target speed) during steering and diagonal maneuvers.

[0105] Based on this, this application addresses the practical problems of related technologies being unsuitable for low-adhesion road surfaces, partial sensor failures, and wheel speed sensor dead zones. It proposes a method for fusion calculation of vehicle speed in multi-axle vehicles. By identifying the current sensor status, vehicle speed, vehicle slippage, and vehicle brake lock-up, the method enables switching or fusion calculation of the vehicle speed calculation mode. This application can maximize the accuracy of target vehicle speed calculation even under conditions such as partial wheel speed sensor failure, vehicle slippage on low-adhesion roads, and speed jumps caused by ABS activation.

[0106] See Figure 1 , Figure 1 A schematic diagram of the architecture of a multi-axle vehicle is shown. The multi-axle vehicle may include: wheel speed sensor 100, motor controller 200, steering angle sensor 300, acceleration sensor 400, vehicle controller 500, motor 600, steering mechanism 700, and braking system 800.

[0107] Wheel speed sensors 100 are important sensors used in multi-axle vehicles to measure wheel rotation speed. They are typically mounted on each wheel to monitor the wheel's rotational speed in real time. The output signal of the wheel speed sensor is usually a pulse signal, and the wheel rotation speed is determined by calculating the number of pulses per unit time.

[0108] Wheel speed sensor 100 can provide real-time wheel rotation speed information for vehicle speed calculation, anti-lock braking system (ABS), traction control system (TCS), etc.

[0109] The pulse signal output by the wheel speed sensor 100 can be processed by the vehicle's electronic control unit (ECU).

[0110] For example, the wheels in a multi-axle vehicle may include one or more driven wheels (non-driving wheels) and one or more driving wheels (driving wheels). Driving wheels are directly driven by the vehicle's powertrain, typically connected to an engine or electric motor, and provide driving force. Driven wheels are not directly connected to the powertrain; their primary function is to support the vehicle's weight and provide steering and braking force. Therefore, wheel speed sensors can output the rotational speeds of the driven wheels and the driving wheels.

[0111] For example, one or more drive wheels include: left front drive wheel Drvfl, right front drive wheel Drvfr, left rear drive wheel Drvrl, and right rear drive wheel Drvrr; one or more driven wheels include: left front driven wheel whlfl, right front drive wheel whlfr, left rear drive wheel whlrl, and right rear drive wheel whlrr; then the wheel speed sensor can output the rotational speed n of the left front drive wheel Drvfl. Drvfl The rotational speed n of the right front drive wheel Drvfr Drvfr The rotational speed n of the left rear drive wheel Drvrl Drvrl The rotational speed n of the right rear drive wheel Drvrr Drvrr The rotational speed n of the front driven wheel whlfl whlfl The rotational speed n of the right front drive wheel whlfr whlfr The rotational speed n of the left rear drive wheel whlrl whlrl The rotational speed n of the right rear drive wheel whlrr whlrr .

[0112] The motor controller 200 is one of the core components of a multi-axle vehicle, used to control the operating status of the motor, including parameters such as motor speed and torque. The motor controller receives commands from the vehicle controller and adjusts the motor's output power to achieve vehicle driving and braking.

[0113] For example, the motor controller 200 can output the following signals: motor speed, motor torque, fault flag, etc.

[0114] For example, motor 600 can provide driving force for the vehicle and is typically mounted on the vehicle's drive shaft.

[0115] It is understood that a multi-axle vehicle may include one or more motors 600. For example, the motors in a multi-axle vehicle may include a front drive motor f and a rear drive motor r. For example, the front drive motor is typically mounted at the front of the vehicle and connected to the front drive axle. It provides driving force to the front wheels, enabling front-wheel drive (FF) or all-wheel drive (AWD) of the vehicle. The rear drive motor is mounted at the rear of the vehicle and typically connected to the rear drive axle; it provides driving force to the rear wheels, enabling rear-wheel drive (FR) or all-wheel drive (AWD) of the vehicle. In summary, the motor controller 200 can output the speed of the front drive motor, the speed of the rear drive motor, the torque of the front drive motor, the torque of the rear drive motor, a fault flag for the front drive motor, and a fault flag for the rear drive motor.

[0116] The motor controller 200 can output the drive motor speed n of the front drive motor f. f Fault flag E of the front drive motor f The speed n of the drive motor r of the rear drive motor r Fault flag E of the rear drive motor r r .

[0117] The steering angle sensor 300 is used to measure the rotation angle of the wheel relative to the vehicle's longitudinal axis. It is typically mounted on the steering mechanism 700 to monitor the wheel's steering angle in real time. As can be understood, a wheel includes one or more driven wheels and one or more drive wheels, so the steering angle sensor 300 can output the driven wheel's rotation angle and the drive wheel's rotation angle.

[0118] For example, one or more drive wheels include: left front drive wheel Drvfl, right front drive wheel Drvfr, left rear drive wheel Drvrl, and right rear drive wheel Drvrr; one or more driven wheels include: left front driven wheel whlfl, right front drive wheel whlfr, left rear drive wheel whlrl, and right rear drive wheel whlrr; then the steering angle sensor can output the steering angle α of the left front drive wheel Drvfl. 2l The steering angle α of the right front drive wheel Drvfr 2r The steering angle α of the left rear drive wheel Drvrl 3l The steering angle α of the right rear drive wheel Drvrr 3r The rotation angle α of the front driven wheel whlfl fl The steering angle α of the right front drive wheel whlfr fr The turning angle α of the left rear drive wheel whlrl rl The steering angle α of the right rear drive wheel whlrr rr .

[0119] For example, the steering angle sensor 300 is combined with the vehicle's yaw rate sensor to calculate the vehicle's steering radius and yaw rate.

[0120] Accelerometer 400 is used to measure the longitudinal acceleration A of a vehicle. X And lateral acceleration. It is usually mounted on the vehicle's chassis to monitor the vehicle's acceleration status in real time.

[0121] The accelerometer 400 can provide longitudinal acceleration information of the vehicle for vehicle speed calculation and dynamic control.

[0122] The accelerometer 400 can provide lateral acceleration information of the vehicle for vehicle stability control.

[0123] For example, multi-axle vehicles also include torque sensors, brake sensors, and yaw rate sensors.

[0124] For example, the mounting location of the torque sensor depends on the vehicle's powertrain architecture and control requirements. The torque sensor is mounted on the motor's output shaft, typically between the motor and the reduction gear. The torque sensor provides the motor's torque, such as the drive motor torque T of a front-drive motor. f The torque T of the rear drive motor r .

[0125] For example, a yaw rate sensor can acquire the yaw rate. Yaw rate is one of the key parameters for vehicle dynamic control, reflecting the vehicle's rotational motion on a horizontal plane. Yaw rate sensors are typically installed near the vehicle's center of gravity, usually in the middle of the chassis. This placement ensures that the yaw rate measured by the sensor best reflects the overall rotational motion of the vehicle, reducing measurement errors caused by uneven vehicle structure and load distribution.

[0126] The vehicle controller 500 is the central control unit for multi-axle vehicles, responsible for coordinating and managing the various subsystems of the vehicle. It receives signals from sensors, calculates the vehicle's operating status, and issues control commands to the motor controller, braking system, and other components.

[0127] For example, the vehicle controller 500 can receive signals from wheel speed sensors, steering angle sensors, acceleration sensors, etc. The vehicle controller 500 can calculate the vehicle's real-time speed and dynamic state, issue control commands to the motor controller, braking system, etc., monitor the vehicle's fault status, and perform fault diagnosis.

[0128] For example, the vehicle controller 500 can determine whether the driven wheel and the driving wheel have malfunctioned based on the signals from the wheel speed sensor, steering angle sensor, torque sensor, and brake sensor, and generate a fault flag bit.

[0129] For example, one or more drive wheels include: left front drive wheel Drvfl, right front drive wheel Drvfr, left rear drive wheel Drvrl, and right rear drive wheel Drvrr; one or more driven wheels include: left front driven wheel whlfl, right front drive wheel whlfr, left rear drive wheel whlrl, and right rear drive wheel whlrr; then the vehicle controller 500 can output the fault flag E of the left front drive wheel Drvfl. Drvfl The fault flag E for the right front drive wheel (Drvfr) Drvfr The fault flag E for the left rear drive wheel (Drvrl) Drvrl And the fault flag E of the right rear drive wheel Drvrr Drvrr Fault flag E of the front driven wheel whlfl whlfl The fault indicator E for the right front drive wheel whlfr whlfr The fault indicator E for the left rear drive wheel (whlrl) whlrl And the fault flag E of the right rear drive wheel whlrr whlrr .

[0130] For example, the vehicle controller 500 can obtain the vehicle's gear position G. st .

[0131] For example, the steering mechanism 700 includes a steering column, steering knuckle, etc., for steering the wheels. An angle sensor 300 is mounted in the steering mechanism.

[0132] For example, the braking system 800 includes, but is not limited to, brakes and ABS (Anti-lock Braking System).

[0133] The principle of the method for calculating the speed fusion of multi-axle vehicles provided in the embodiments of this application will be explained below.

[0134] like Figure 2 The diagram shown is a schematic representation of the input and output of the multi-axle vehicle speed fusion calculation method provided in an embodiment of this application.

[0135] like Figure 2 As shown, the driving wheel speed is: the speed n of the left front drive wheel Drvfl. Drvfl The rotational speed n of the right front drive wheel Drvfr Drvfr The rotational speed n of the left rear drive wheel Drvrl Drvrl The rotational speed n of the right rear drive wheel Drvrr DrvrrDriven wheel speed: The speed n of the front driven wheel whlfl whlfl The rotational speed n of the right front drive wheel whlfr whlfr The rotational speed n of the left rear drive wheel whlrl whlrl The rotational speed n of the right rear drive wheel whlrr whlrr This can be obtained through wheel speed sensor 100.

[0136] Drive wheel angle: The angle α of the left front drive wheel (Drvfl) 2l The steering angle α of the right front drive wheel Drvfr 2r The steering angle α of the left rear drive wheel Drvrl 3l The steering angle α of the right rear drive wheel Drvrr 3r Driven wheel rotation angle: The rotation angle α of the front driven wheel whlfl fl The steering angle α of the right front drive wheel whlfr fr The turning angle α of the left rear drive wheel whlrl rl The turning angle α of the right rear drive wheel whlrr rr This can be obtained through the angle sensor 300.

[0137] The speed n of the front drive motor f Fault flag E of the front drive motor f The speed n of the drive motor r of the rear drive motor r Fault flag E of the rear drive motor r r This can be obtained through the motor controller 200.

[0138] Longitudinal acceleration A X The yaw rate φ can be obtained using an accelerometer.

[0139] Vehicle gear G st It can be obtained through the vehicle controller.

[0140] Fault flag E for left front drive wheel Drvfl Drvfl The fault flag E for the right front drive wheel (Drvfr) Drvfr The fault flag E for the left rear drive wheel (Drvrl) Drvrl The fault flag E for the right rear drive wheel (Drvrr) Drvrr Fault flag E of the front driven wheel whlfl whlfl The fault indicator E for the right front drive wheel whlfr whlfr The fault indicator E for the left rear drive wheel (whlrl) whlrl And the fault flag E of the right rear drive wheel whlrr whlrr This can be obtained through the vehicle controller.

[0141] The output of the multi-axle vehicle speed fusion calculation method provided in this application embodiment is the target vehicle speed V. x And the target vehicle speed calculation mode.

[0142] The following is combined with Figure 1 and Figure 2 The method for calculating the speed fusion of multi-axle vehicles provided in the embodiments of this application will be described.

[0143] Reference Figure 3 , Figure 3 This application provides a flowchart illustrating a method for calculating the speed fusion of multi-axle vehicles, as shown in the embodiments below. Figure 3 As shown in the embodiment of this application, a method for calculating the speed fusion of multi-axle vehicles may include steps S301 to S311, which are described in detail below.

[0144] Step S301: Based on the fault flag bits of multiple motors, the equivalent speed of the motors, and the slippage status of multiple motors, obtain the motor-converted vehicle speed V. mtrspd .

[0145] Vehicle speed and motor speed have different units, so converting motor speed to vehicle speed means converting the vehicle speed using the motor speed unit.

[0146] For example, the fault flag can be set to TRUE or FALSE, where FALSE indicates no fault and TRUE indicates a fault.

[0147] For example, the unit for rotational speed is rpm, the unit for velocity is m / s, the unit for rotational angle is deg, the unit for torque is Nm, the unit for angular velocity is deg / s, and the unit for acceleration is m / s². 2 Both the state and mode are dimensionless enumerations.

[0148] For example, this application may be executed once at a preset interval. For example, the preset interval may be determined based on the actual situation, such as 10ms.

[0149] For example, the equivalent speed of the motor is determined based on the fault flags of multiple motors, the torque of multiple motors, and the rotation of multiple motors.

[0150] The reasons for motor slippage include, but are not limited to: low-friction road surface, excessive vehicle acceleration, tire wear or insufficient tire pressure, and uneven vehicle load distribution.

[0151] For example, the slip state can include: no slip or slip.

[0152] For example, if the motor experiences abnormal message loss or a rotary transformer failure, the motor speed and torque signals will not be considered valid information, the motor speed will not be included in the vehicle speed calculation, and the motor fault flag will be set to TRUE.

[0153] For example, multiple motors, including a front drive motor and a rear drive motor, can have their motor speed weights determined based on fault flag bits. Specifically, this can be determined using the following formula:

[0154] Among them, the motor speed weight of the front drive motor is W. fmtr The motor speed weight of the rear drive motor is W. rmtr .

[0155] Step S302: Based on the fault flag bits corresponding to the multiple drive wheels and the rotational speeds corresponding to the multiple drive wheels, calculate the equivalent vehicle speed V of the drive wheels. Drvspd .

[0156] The equivalent speed of the drive wheels reflects the actual speed of the vehicle under specific operating conditions, and is commonly used in fields such as vehicle powertrain control, fault diagnosis, and vehicle dynamic control.

[0157] Step S303: Based on the longitudinal acceleration of each cycle, the equivalent vehicle speed of each cycle corresponding to the multiple driven wheels, and the vehicle speed of each cycle corresponding to the multiple driven wheels, obtain the corrected longitudinal acceleration integral vehicle speed V. ACC .

[0158] The implementation process of step S303 is described below. This method includes the following steps A11 to A14.

[0159] Multiple driven wheels include a left driven wheel on one axle, a right driven wheel on one axle, a left driven wheel on four axles, and a right driven wheel on four axles.

[0160] Step A11: Obtain real-time longitudinal acceleration.

[0161] For example, real-time longitudinal acceleration can be obtained, but the accuracy of real-time longitudinal acceleration may be low, so correction is required.

[0162] Step A12: For each cycle, if the vehicle is in braking state and the real-time longitudinal acceleration is greater than |first preset acceleration threshold| when the vehicle is in D gear, or the real-time longitudinal acceleration is less than -|first preset acceleration threshold| when the vehicle is in R gear, and the real-time longitudinal acceleration is less than the second preset acceleration threshold, set the initial longitudinal acceleration of the cycle to 0.

[0163] For example, the first preset acceleration threshold can be ARevsThrs Characterization. For example, the first preset acceleration threshold can be a positive threshold for detecting the opposite acceleration.

[0164] For example, the second preset acceleration threshold can be determined based on the actual situation, such as 0.15 m / s². 2 .

[0165] For example, step A12 can be represented as the following information: when the vehicle is braking and in D gear, the real-time longitudinal acceleration A x >A RevsThrs Or the real-time longitudinal acceleration A when the vehicle is in reverse gear. x <-A RevsThrs And V x <0.15m / s 2 Set the initial longitudinal acceleration A X It is 0.

[0166] Step A12 is to avoid the influence of sinusoidal noise generated by the vehicle body oscillation on the integral during the final stage of braking of the accelerometer sensor value.

[0167] If the conditions in step A12 are met, the initial longitudinal acceleration of the cycle is set to 0; otherwise, the acceleration correction function is not activated.

[0168] Step A13: Determine the equivalent vehicle speed of the left driven wheel of the first axle in each cycle, the equivalent vehicle speed of the right driven wheel of the first axle in each cycle, the equivalent vehicle speed of the left driven wheel of the fourth axle in each cycle, the equivalent vehicle speed of the right driven wheel of the fourth axle in each cycle, and the maximum value among the vehicle speeds before each cycle as the starting point for acceleration integration.

[0169] For example, the starting point of the acceleration integral V spdst =max{Equivalent vehicle speed V of the left driven wheel of the first axle in each cycle} flprv The equivalent vehicle speed V of the right driven wheel of the bridge in each cycle frprv The equivalent vehicle speed V of the left driven wheel of the four axles in each cycle rlprv The equivalent vehicle speed V of the right driven wheel of the four axles in each cycle rrprv The vehicle speed V before each cycle xprev}

[0170] Step A14: Based on the acceleration integration start point and the initial longitudinal acceleration of each cycle, calculate the corrected longitudinal acceleration integral speed V. ACC .

[0171] For example, the corrected longitudinal acceleration integral vehicle speed V ACC =V spdst +Σ i=n-m n (A)X (i)×△T), where △T is the duration of one period. n is the number of periods at the current time; m is the window length for the acceleration integral.

[0172] For example, the value of △T can be determined based on the actual situation, such as 0.01s, and the value of m can be determined based on the situation, such as m being 10.

[0173] In summary, longitudinal acceleration oscillation correction was achieved through steps A11 to A14.

[0174] Step S304: Determine the initial speed weight of the multiple driven wheels based on the fault flag bits corresponding to the multiple driven wheels and the speed of each cycle corresponding to the multiple driven wheels.

[0175] For example, the method of implementing step S304 includes the following steps C11 to C12.

[0176] Multiple driven wheels include a left driven wheel on one axle, a right driven wheel on one axle, a left driven wheel on four axles, and a right driven wheel on four axles.

[0177] Step C11: For each driven wheel, if the fault flag bit of the driven wheel is TRUE, determine that the initial speed weight of the driven wheel is 0.

[0178] Step C12: For each driven wheel, if the fault flag bit of the driven wheel is FALSE, and the difference between the rotational speed of the driven wheel in the current cycle and the rotational speed in the previous cycle is greater than or equal to a preset rotational speed threshold n... wdiffThrs The initial speed weight of the driven wheel is determined to be 0; otherwise, the initial speed weight is determined to be 1.

[0179] For example, the difference n diff =n f -n fprev Where n f n is the rotational speed of the driven wheel during the current cycle. fprev This represents the rotational speed of the driven wheel in the previous cycle of the current cycle.

[0180] It is understandable that if n diff > n wdiffThrs If n is abnormal, it is considered that the driven wheel speed is abnormal, and the initial speed weight of the corresponding driven wheel is 0; diff ≤ n wdiffThrs If the speed of the driven wheel is normal, the initial speed weight of the driven wheel is 1.

[0181] In summary, steps C11 to C12 were used to calculate the effectiveness of the driven wheel speed.

[0182] Step S305: For any of the driven wheels, if the driven wheel is in a locked state and the initial speed weight of the driven wheel is not 0, determine the lock-up level of the driven wheel based on the speed of the driven wheel in each cycle.

[0183] For example, step S305 can be implemented by including steps D11 to D16.

[0184] Step D11: If the vehicle is in a braking state, and the maximum absolute value of the driving wheel rotation angle of the plurality of driven wheels is less than the preset steering judgment angle threshold α TurnThrs And the vehicle's real-time speed V x If the vehicle speed exceeds a preset detection threshold and the vehicle is in D or R gear, lock-up detection is enabled.

[0185] For example, if the vehicle is in D gear, then A X <0&&A X <A LCKThrs Among them, A LCKThrs This enables the deceleration speed threshold for lock-up detection. For example, if the vehicle is in reverse (R) gear, then A... X >0&&A X >-A LCKThrs .

[0186] For example, the condition for step D11 above can be: the vehicle is in a braking state, and max{|α fl |、|α fr |、|α rl |、|α rr |}<α TurnThrs And V X >V lckThrs And in D or R gear.

[0187] For example, to avoid the influence of vehicle driving braking mode, speed, and steering state on lock-up detection, lock-up detection is enabled when the conditions mentioned in step D11 are met. For example, lock-up detection is steps D12 to D16. If the conditions mentioned in step D11 are not met, the process can proceed to step S306.

[0188] Step D12: For each driven wheel, if the fault flag bit of the driven wheel is FALSE, obtain the speed reduction gradient of the driven wheel in each cycle interval.

[0189] For example, the multiple driven wheels include: the left driven wheel of the front axle (i.e., the left driven wheel of the first axle), the right driven wheel of the front axle (i.e., the right driven wheel of the first axle), the left driven wheel of the rear axle (i.e., the left driven wheel of the fourth axle), and the right driven wheel of the rear axle (i.e., the right driven wheel of the fourth axle).

[0190] For example, the formula for calculating the speed drop gradient of the left driven wheel on the front axle is as follows:

[0191] The rotational speed of the left driven wheel of the front axle is n. whlfl The rotation of the right driven wheel of the front axle is n. whlfr The rotational speed of the left driven wheel of the rear axle is n. whlrl The rotational speed of the right driven wheel of the rear axle is n. whlrr For example, n is the number of periods at the current time, and m is the window length for the mean filter. For instance, m can be 5.

[0192] For example, the formula for calculating the speed drop gradient of the right driven wheel on the front axle is as follows:

[0193] .

[0194] For example, the formula for calculating the speed decrease gradient of the left driven wheel of the rear axle is as follows:

[0195] .

[0196] For example, the formula for calculating the speed decrease gradient of the right driven wheel of the rear axle is as follows:

[0197] .

[0198] Step D13: If the minimum value of the speed decrease gradient of the multiple driven wheels in each cycle interval is greater than the preset speed decrease gradient threshold n whlgrdThrs The initial locking level of the multiple driven wheels is determined to be zero; otherwise, the initial locking level of the multiple driven wheels is determined to be 1.

[0199] For example, if min{n whlflgrd n whlfrgrd n whlrlgrd n whlrrgrd}>n whlgrdThrs The initial locking level is zero, that is, the locking level E of the left driven wheel of the front axle. fllck =0, Lock-up level of the right driven wheel of the front axle E frlck =0, Lock-up level of the left driven wheel of the rear axle E rllck =0, Lock-up level of the right driven wheel of the rear axle E rrlck =0; if min{n whlflgrd n whlfrgrd n whlrlgrd n whlrrgrd}≤n whlgrdThrs The initial locking level is 1, which is the locking level E of the left driven wheel of the front axle. fllck =1, Lock-up level of the right driven wheel of the front axle E frlck=1. Rear axle left driven wheel lock-up level E rllck =1. Rear axle right driven wheel lock-up level E rrlck =1.

[0200] The next step is to determine whether the wheels have a tendency to lock up. This process involves using the integral vehicle speed to draw a double-threshold envelope, as mentioned in steps B11 and B12.

[0201] Step D14: For each driven wheel, if the rotational speed of the driven wheel is greater than the lower limit V of the vehicle speed level L1... dwnL1 Furthermore, the initial locking level of the driven wheel is zero, thus determining that the locking level of the driven wheel is zero.

[0202] It is understandable that if the rotational speed of the driven wheel is greater than the lower limit V of the vehicle speed L1 level, dwnL1 If the initial lock-up level of the driven wheel is zero, then it is considered that no wheel lock-up has occurred, and the lock-up level of the driven wheel is determined to be zero.

[0203] Step D15: For each driven wheel, if the rotational speed of the driven wheel is greater than or equal to the lower limit V of the vehicle speed L2 level... dwnL2 And less than or equal to the lower limit V of the L1 vehicle speed level. dwnL1 The locking level of the driven wheel is determined to be 1.

[0204] It is understandable that if the speed of the driven wheel is between V... dwnL2 and V dwnL1 If the following conditions are met, the driven wheel is considered to have experienced a first-level lock-up, and the lock-up level of the driven wheel is determined to be 1.

[0205] Step D16: For each driven wheel, if the rotational speed of the driven wheel is less than the lower limit V of the vehicle speed level L1... dwnL2 The locking level of the driven wheel is determined to be 2.

[0206] If the speed of the driven wheel is less than V dwnL2 If the following condition is met, it is considered that the driven wheel has undergone secondary seizure, and the seizure level of the driven wheel is determined to be 2.

[0207] Understandably, regardless of whether the driven wheel has a tendency to lock up, the following steps S306 need to be performed.

[0208] Step S306: If the locking level of at least one of the driven wheels is not 0, based on the longitudinal projection of the mounting points of the multiple driven wheels in the vehicle body coordinate system and the initial speed weights of the multiple driven wheels, the updated speed weights corresponding to the multiple driven wheels are calculated respectively.

[0209] For example, if the locking level of at least one driven wheel is not 0, it means that the locking level of at least one driven wheel is 1 or 2, and the wheel speed is redistributed according to the wheel speed deviation.

[0210] For example, the formula for calculating the longitudinal projection of multiple driven wheels is as follows:

[0211] Longitudinal projection V of the left driven wheel of the front axle fl The calculation formula is as follows: .

[0212] For example, the longitudinal projection V of the right driven wheel of the front axle fr The calculation formula is as follows: .

[0213] For example, the longitudinal projection V of the left driven wheel of the rear axle rl The calculation formula is as follows: .

[0214] For example, the longitudinal projection V of the right driven wheel of the rear axle rr The calculation formula is as follows: .

[0215] in, L is the yaw rate. fl L fr L rl L rr These represent the distances from the yaw sensor mounting point to the mounting points of each wheel. For example, the yaw rate uses a right-handed system, meaning counter-clockwise rotation is considered positive.

[0216] For example, the formula for calculating the sum of the deviations of the longitudinal speed of each wheel relative to the longitudinal reference vehicle speed is as follows:

[0217] .

[0218] For example, the updated speed weight can be calculated based on the deviation ratio. The calculation formula for the updated speed weight corresponding to each driven wheel is as follows.

[0219] Update speed weight W of the left driven wheel of the front axle fl The calculation formula is as follows:

[0220] .

[0221] Update speed weight W of the right driven wheel of the front axle fr The calculation formula is as follows:

[0222] .

[0223] Update speed weight W of the left driven wheel of the rear axle rlThe calculation formula is as follows:

[0224] .

[0225] Update speed weight W of the right driven wheel of the rear axle rr The calculation formula is as follows:

[0226] .

[0227] Step S307: Based on the updated rotational speed weights corresponding to the multiple driven wheels, obtain the corrected longitudinal acceleration integral speed weight.

[0228] For example, the corrected longitudinal acceleration integral speed weight W ACC =1-(W fl +W fr +W rl +W rr ).

[0229] Step S308: Based on the updated rotational speed weights of the multiple driven wheels, the rotational speed of the multiple driven wheels in the current cycle, the corrected longitudinal acceleration integral vehicle speed weight, and the corrected longitudinal acceleration integral vehicle speed, calculate the equivalent vehicle speed V. whl .

[0230] For example, equivalent vehicle speed .

[0231] Step S309: Based on the preset vehicle speed weight, the preset motor-converted vehicle speed weight, and the equivalent vehicle speed V whl And the motor-converted vehicle speed V mtrspd The vehicle speed V during the fusion transition phase was calculated. mrg .

[0232] For example, the vehicle speed V is calculated by converting the motor speed. mtrspd The updated rotational speed weights of the equivalent vehicle speed of the driven wheel ensure the smoothness of vehicle speed calculation mode switching.

[0233] For example, vehicle speed weight W whl The calculation formula is as follows: For example, C is a gain coefficient used to adjust the upward trend of the function curve; in this embodiment, C = 200. bl V is the lower boundary of the fusion interval velocity. bh The upper boundary of the fusion interval velocity.

[0234] For example, the motor-to-vehicle-speed conversion weight W mtr The calculation formula is as follows: W mtr =1-W whl .

[0235] For example, the vehicle speed V during the fusion transition phase mrg =W whl ×V whl + W mtr× V mtrspd .

[0236] Step S310: Obtain the target vehicle speed calculation mode.

[0237] Step S311: From the preset correspondence between vehicle speed calculation modes and vehicle speeds, find the target vehicle speed corresponding to the target vehicle speed calculation mode, where the vehicle speed is the corrected longitudinal acceleration integral vehicle speed V. ACC The equivalent vehicle speed V whl The motor converted vehicle speed V mtrspd The vehicle speed V during the fusion transition phase mrg and the equivalent vehicle speed V of the drive wheels Drvspd Any one of them.

[0238] For example, vehicle speed calculation mode C mode The correspondence between speed and vehicle speed is as follows:

[0239] Target speed .

[0240] This application provides a method for calculating vehicle speed fusion in multi-axle vehicles. The method involves obtaining the motor-converted vehicle speed, the equivalent vehicle speed of the drive wheels, the corrected longitudinal acceleration integral vehicle speed, the updated rotational speed weights of multiple driven wheels, and the corrected longitudinal acceleration integral vehicle speed weights. Based on the updated rotational speed weights of the multiple driven wheels, the rotational speed of the multiple driven wheels in the current cycle, the corrected longitudinal acceleration integral vehicle speed weights, and the corrected longitudinal acceleration integral vehicle speed, the equivalent vehicle speed is calculated. Based on preset vehicle speed weights, preset motor-converted vehicle speed weights, the equivalent vehicle speed, and the motor-converted vehicle speed, the vehicle speed during the fusion transition phase is calculated. A target vehicle speed calculation mode is obtained. The target vehicle speed corresponding to the target vehicle speed calculation mode is found from a preset correspondence between vehicle speed calculation modes and vehicle speeds.

[0241] The embodiments of this application are applicable to various low-adhesion road conditions and accurately calculate the target vehicle speed based on information from various sensors under different vehicle fault states, providing stable and accurate input parameters for vehicle control to the greatest extent possible. Furthermore, the method proposed in this application ensures stable calculation results without speed jumps, while the calculation time meets the performance requirements of general vehicle controllers.

[0242] In an alternative implementation, the integral vehicle speed can be used to draw a dual-threshold envelope for subsequent wheel lock-up detection. The specific process includes steps B11 to B12.

[0243] Step B11: Integrate vehicle speed V based on the corrected longitudinal acceleration ACC The vehicle speed L1 level upper limit gain, the vehicle speed L1 level lower limit gain, and the preset L1 level speed upper and lower limit envelope widths are used to calculate the vehicle speed L1 level upper limit V. upL1 and the lower limit of vehicle speed at level L1, V dwnL1 .

[0244] For example, the upper limit of vehicle speed at L1 level V upL1 =max{C u1 ×V ACC V ACC +V TolL1}. The speed limit gain for vehicle speed level L1 is C. u1 The preset L1 level velocity upper and lower limit envelope width is V. TolL1 .

[0245] For example, the lower limit of vehicle speed for L1 level is V dwnL1 =max{C l1 ×V ACC V ACC -V TolL1}. The lower limit gain for vehicle speed level L1 is C. l1 .

[0246] Step B12: Integrate vehicle speed V based on the corrected longitudinal acceleration ACC The vehicle speed L2 level upper limit gain, the vehicle speed L2 level lower limit gain, and the preset L2 level speed upper and lower limit envelope widths are used to calculate the vehicle speed L2 level upper limit V. upL2 And the lower limit of vehicle speed at Level 2 (V) dwnL2 .

[0247] For example, the upper limit of vehicle speed at Level L2 is V upL2 =max{C u2 ×V ACC V ACC +V TolL2 The speed limit gain for vehicle speed level L2 is C. u2 The preset L2 level velocity upper and lower limit envelope width is V. TolL2 .

[0248] For example, the lower limit of vehicle speed for Level L2 is V dwnL2 =max{C l2 ×V ACC V ACC -V TolL2}. The lower limit gain for vehicle speed at level L2 is C. l2 .

[0249] The process of obtaining the vehicle speed calculation mode is described below. This process includes the following steps E11 to E15.

[0250] Step E11: If the fault flag bits of multiple motors, the fault flag bits corresponding to multiple drive wheels, and the fault flag bits corresponding to multiple driven wheels are all FALSE, or if the minimum absolute value of the rotation angle of multiple driven wheels is less than or equal to a preset rotation angle threshold and the number of fault flag bits of multiple driven wheels that are TRUE is within a preset range, determine the vehicle speed calculation mode based on the equivalent vehicle speed.

[0251] For example, the preset corner threshold can be α. Turn Characterization.

[0252] For example, the preset range can be determined based on the actual situation, which will not be elaborated here. For example, the preset range is [1,3].

[0253] For example, determining the vehicle speed calculation mode based on the equivalent vehicle speed includes the following steps E111 to E113.

[0254] To avoid the impact of wheel speed sensor acquisition delay and wheel speed sensor dead zone on vehicle speed calculation at low vehicle speeds, a fusion calculation will be performed, as detailed in steps E111 to E113.

[0255] Step E111: If the equivalent vehicle speed V whl The velocity V is less than the lower boundary of the preset fusion range. bl Furthermore, if the slippage state of multiple motors is not slippage, the vehicle speed calculation mode is determined to be the second mode.

[0256] Step E112: If the equivalent vehicle speed V whl Greater than or equal to the lower boundary V of the preset fusion interval velocity bl And less than or equal to the upper boundary V of the preset fusion interval velocity. bh Furthermore, since the slippage state of multiple motors is not slippage, the vehicle speed calculation mode is determined to be the third mode.

[0257] Step E113: If the equivalent vehicle speed V whl The velocity V greater than the preset fusion interval upper boundary bh The vehicle speed calculation mode is determined to be the first mode.

[0258] Step E12: If the minimum absolute value of the rotation angle of the multiple driven wheels is less than or equal to the preset rotation angle threshold, and the number of fault flags of the multiple driven wheels that are TRUE is greater than the preset range, and the fault flags of the multiple motors are all FALSE, then the vehicle speed calculation mode is determined to be the second mode.

[0259] Step E13: If the minimum absolute value of the rotation angle of the multiple driven wheels is greater than the preset rotation angle threshold and the fault flags of the left driven wheel of the first axle and the left driven wheel of the fourth axle are both TRUE or the fault flags of the right driven wheel of the first axle and the right driven wheel of the fourth axle are both TRUE, and the fault flags of the multiple motors are not all TRUE, then the vehicle speed calculation mode is determined to be the second mode.

[0260] Step E14: If the fault flag bits of multiple motors, multiple drive wheels, and multiple driven wheels are all TRUE, determine that the vehicle speed calculation mode is the zero mode.

[0261] Step E15: If the fault flag bits of multiple driven wheels are all TRUE, the fault flag bits of multiple motors are all TRUE, and the fault flag bits of multiple drive wheels are all FALSE, then the vehicle speed calculation mode is determined to be the fourth mode.

[0262] In one optional implementation, the plurality of motors includes a first motor and a second motor, and step S301 specifically includes the following steps F01 to F11.

[0263] Step F01: If the fault flags of multiple motors are all FALSE and the first motor and the second motor rotate in the same direction, and the torque T of the first motor is... f and the second motor T r The sum of the torques is greater than or equal to a first preset torque threshold; or, if the fault flags of multiple motors are all FALSE and the rotation directions of the first motor and the second motor are different, the minimum speed of the first motor and the second motor is determined to be the equivalent speed.

[0264] For example, the first preset torque threshold can be represented by T. Drvgrd Characterization. The first preset torque threshold is the minimum effective torque gradient of the motor, used to determine whether the motor generates effective positive torque. For example, the first preset torque threshold is 50 Nm.

[0265] Step F01 includes two conditions. One condition is that the fault flags of both the first and second motors are FALSE, and the rotation directions of the first and second motors are the same, and T... f +T r ≥T Drvgrd Another condition is that the fault flags of the first motor and the second motor are both FALSE and the rotation directions of the first motor and the second motor are different.

[0266] For example, the equivalent rotational speed n mtr =min{n f nr}, where the rotational speed of the first motor is n. f The second motor's speed is n r .

[0267] Step F02: If the fault flags of multiple motors are all FALSE and the first motor and the second motor rotate in the same direction, and the sum of the torque of the first motor and the torque of the second motor is less than the first preset torque threshold, determine the maximum speed of the first motor and the second motor as the equivalent speed.

[0268] Understandably, at high torque, the motor speed is slightly higher than the actual vehicle speed due to slip ratio or slippage. Therefore, the minimum speed of the first and second motors is determined as the equivalent speed. At low torque, the slip ratio has little impact on the motor speed, especially at the start where it may be affected by sensor dead zones. In this case, the maximum speed of the first and second motors is relatively accurate.

[0269] For example, the equivalent rotational speed n mtr =max{n f n r}

[0270] Step F03: Based on the equivalent rotational speed, determine the motor speed weights corresponding to the first motor and the second motor respectively.

[0271] For example, the motor speed weight of the first motor is represented by W. fmtr The motor speed weight of the second motor is represented by W. rmtr Characterization. The formula for calculating the motor speed weight is as follows:

[0272] .

[0273] Step F04: If the fault flag bits of multiple motors are all FALSE, obtain the first speed gradient of the first motor at multiple cycle intervals and the second speed gradient of the second motor at multiple cycle intervals.

[0274] For example, the first rotational speed gradient n fgrd The calculation formula is as follows:

[0275] .

[0276] For example, the second rotational speed gradient n rgrd The calculation formula is as follows:

[0277] .

[0278] In summary, the rate of change of motor speed, i.e., the gradient, is estimated by calculating the difference in motor speed at different time windows.

[0279] Step F05: Determine the maximum value between the first speed gradient and the second speed gradient, which is the maximum driving speed gradient.

[0280] For example, the maximum driving speed gradient n grd =max{n fgrd , n rgrd}

[0281] Step F06: If the maximum driving speed gradient is greater than or equal to the first preset gradient threshold, determine that the motor speed weights corresponding to the first motor and the second motor are zero.

[0282] For example, the first preset gradient threshold is n slipgrd Characterization.

[0283] If the maximum driving speed gradient is ≥ n slipgrd If this is the case, it is identified that there is slippage in both the first and second motors. The rotational speeds of the first and second motors cannot accurately represent the vehicle's speed, therefore W is set... fmtr =0, W rmtr =0.

[0284] Step F07: If the maximum driving speed gradient is less than the first preset gradient threshold, the absolute value of the difference between the speed of the first motor and the speed of the second motor is determined to be the separation degree of the front and rear motor speeds.

[0285] If the maximum driving speed gradient is < n slipgrd If this is not the case, it is identified that there is no slippage between the first and second motors, and further calculation of the speed separation degree n between the front and rear motors is required. diff =|n f -n r |

[0286] Step F08: If the separation degree of the front and rear motor speeds is less than the preset speed separation threshold, and the maximum drive speed gradient is less than the first preset gradient threshold, determine that the motor speed weights corresponding to the first motor and the second motor are 1 respectively.

[0287] For example, the preset speed separation threshold can be n mdiffThrs Characterization.

[0288] If the speed separation of the front and rear motors is n diff <n mdiffThrs And the maximum driving speed gradient n grd <n slipgrd If the first motor and the second motor do not slip, it is assumed that there is no slippage.

[0289] Step F09: If the speed separation of the front and rear motors is greater than or equal to the preset speed separation threshold, determine that the speed weights of the first motor and the second motor are respectively zero.

[0290] If the speed separation of the front and rear motors is n diff ≥n mdiffThrs If the first motor and / or the second motor slips, it is considered that the first motor and / or the second motor cannot accurately represent the vehicle speed.

[0291] Step F10: If the motor speed weights of the first motor are both zero and the motor speed weights of the second motor are both zero, determine the converted vehicle speed V of the motor. mtrspd It is 0.

[0292] It is understandable that multiple motor speed weights of the first motor and multiple motor speed weights of the second motor can be obtained through steps F01 to F09.

[0293] Step F11: If at least one of the motor speed weights of the first motor and the second motor is not zero, calculate the motor-converted vehicle speed V based on the tire rolling radius, the motor-to-wheel-end transmission ratio, the steering angle of the left and right wheels of the front axle, the steering angles of the left and right wheels of the rear axle, the motor speed weights of the first motor and the second motor. mtrspd .

[0294] For example, calculate the vehicle speed V converted from the motor. mtrspd The formula is as follows:

[0295] , where r is the tire rolling radius and i is the transmission ratio from the motor to the wheel end.

[0296] In one optional implementation, the multiple drive wheels include a front axle left drive wheel, a front axle right drive wheel, a rear axle left drive wheel, and a rear axle right drive wheel; the implementation method of step S302 includes the following steps G01 to G10.

[0297] Step G01: For each drive wheel, if the fault flag bit of the drive wheel is TRUE, determine that the drive wheel speed weight of the drive wheel is zero.

[0298] For example, if the fault flag of the drive wheel is FALSE, the drive wheel speed weight is 1; if the fault flag of the drive wheel is TRUE, the drive wheel speed weight is 0.

[0299] Step G02: For each drive wheel, if the fault flag of the drive wheel is FALSE, determine the absolute value of the difference between the speed of the left drive wheel of the front axle and the speed of the right drive wheel of the front axle, which is the front axle drive wheel speed difference.

[0300] Front axle drive wheel speed difference n Drvfdiff =|n Drvfl -n Drvfr | n Drvfl n is the rotational speed of the left wheel of the front drive axle. Drvfr This refers to the rotational speed of the right wheel of the front drive axle.

[0301] Step G03: Determine the absolute value of the difference between the rotational speed of the left drive wheel of the rear axle and the rotational speed of the right drive wheel of the rear axle, which is the rear axle drive wheel speed difference.

[0302] Since the transfer case may cause the drive wheels to distribute all the drive torque to the low-resistance side when the drive wheels are on a split road or when one wheel is suspended in the air, resulting in excessively high wheel speed on one side, the wheel speed difference between the left and right wheels of the drive axle is used to determine whether there is a fault.

[0303] A transfer case is an important gear transmission device, typically used in four-wheel drive or multi-axle vehicles. Its main function is to distribute the power output from the transmission to each drive axle.

[0304] Rear axle drive wheel speed difference n Drvrdiff =|n Drvrl -n Drvrr | n Drvrl n is the rotational speed of the left wheel of the rear drive axle. Drvrr This refers to the rotational speed of the right wheel of the rear drive axle.

[0305] Step G04: If the speed difference of the front axle drive wheels is greater than a preset speed threshold, determine that the speed weights of the drive wheels corresponding to the left and right front axle drive wheels are zero.

[0306] If the speed difference between the front axle drive wheels is n Drvfdiff >Preset speed threshold n DdiffThrs Therefore, it is believed that the wheel speed of the front axle drive wheel cannot accurately represent the vehicle speed.

[0307] Step G05: If the speed difference of the front axle drive wheels is less than or equal to the preset speed threshold, determine that the speed weights of the drive wheels corresponding to the left and right front axle drive wheels are 1 respectively.

[0308] If the front axle drive wheel speed is less than or equal to the preset speed threshold n DdiffThrs Therefore, it is believed that the wheel speed of the front axle drive wheel can accurately represent the vehicle speed.

[0309] Step G06: If the speed difference of the rear axle drive wheels is greater than the preset speed threshold, determine that the speed weights of the drive wheels corresponding to the left and right rear axle drive wheels are zero.

[0310] Step G07: If the speed difference of the rear axle drive wheels is less than or equal to the preset speed threshold, determine that the speed weights of the drive wheels corresponding to the left and right rear axle drive wheels are 1 respectively.

[0311] Step G08: Calculate the average longitudinal speed of the front axle based on the rotational speed of the left drive wheel of the front axle, the rotational speed weight of the left drive wheel of the front axle, the rotational speed of the right drive wheel of the front axle, and the rotational speed weight of the right drive wheel of the front axle.

[0312] For example, the average longitudinal speed n of the front axle Drvf The calculation formula is as follows:

[0313] .

[0314] Step G09: Calculate the average longitudinal speed of the rear axle based on the speed weights of the left and right drive wheels of the rear axle, the speed of the left and right drive wheels of the rear axle.

[0315] For example, the average longitudinal speed n of the rear axle Drvr The calculation formula is as follows:

[0316] .

[0317] Step G10: Based on the average longitudinal speed of the front axle and the average longitudinal speed of the rear axle, calculate the equivalent vehicle speed V of the drive wheel. Drvspd .

[0318] For example, the formula for calculating the equivalent vehicle speed of the drive wheels is as follows:

[0319] .

[0320] The above describes a method for calculating the speed of multi-axle vehicles according to embodiments of this application. The following describes the apparatus for performing the above method for calculating the speed of multi-axle vehicles.

[0321] Please see Figure 4 , Figure 4 This is a schematic diagram of a device for calculating the speed fusion of multi-axle vehicles, provided as an embodiment of this application. Figure 4 As shown, the device for multi-axle vehicle speed fusion calculation includes:

[0322] The first acquisition module 401 is used to acquire the motor-converted vehicle speed based on the fault flag bits of multiple motors, the equivalent speed of the motors, and the slippage state of multiple motors.

[0323] The first calculation module 402 is used to calculate the equivalent vehicle speed of the drive wheels based on the fault flag bits corresponding to the multiple drive wheels and the rotation speeds corresponding to the multiple drive wheels.

[0324] The second acquisition module 403 is used to obtain the corrected longitudinal acceleration integral speed based on the longitudinal acceleration of each cycle, the equivalent vehicle speed of each cycle corresponding to the multiple driven wheels, and the vehicle speed of each cycle corresponding to the multiple driven wheels.

[0325] The first determining module 404 is used to determine the initial speed weight of the multiple driven wheels based on the fault flag bits corresponding to the multiple driven wheels and the speed of the multiple driven wheels in each cycle.

[0326] The second determining module 405 is used to determine the lock-up level of any driven wheel if the driven wheel is in a locked state and the initial speed weight of the driven wheel is not 0, based on the speed of the driven wheel in each cycle.

[0327] The second calculation module 406 is used to calculate the updated speed weights corresponding to the multiple driven wheels based on the longitudinal projection of the mounting points of the multiple driven wheels in the vehicle body coordinate system and the initial speed weights of the multiple driven wheels if the locking level of at least one of the driven wheels is not 0.

[0328] The third acquisition module 407 is used to acquire the corrected longitudinal acceleration integral vehicle speed weight based on the updated rotation speed weights corresponding to the multiple driven wheels respectively.

[0329] The third calculation module 408 is used to calculate the equivalent vehicle speed based on the updated rotational speed weights of the multiple driven wheels, the rotational speed of the multiple driven wheels in the current cycle, the corrected longitudinal acceleration integral vehicle speed weights, and the corrected longitudinal acceleration integral vehicle speed.

[0330] The fourth calculation module 409 is used to calculate the vehicle speed during the fusion transition phase based on the preset vehicle speed weight, the preset motor-converted vehicle speed weight, the equivalent vehicle speed, and the motor-converted vehicle speed.

[0331] The fourth acquisition module 410 is used to acquire the target vehicle speed calculation mode;

[0332] The lookup module 411 is used to look up the target vehicle speed corresponding to the target vehicle speed calculation mode from the preset vehicle speed calculation mode and vehicle speed correspondence relationship. The vehicle speed is any one of the corrected longitudinal acceleration integral vehicle speed, the equivalent vehicle speed, the motor converted vehicle speed, the fusion transition stage vehicle speed and the drive wheel equivalent vehicle speed.

[0333] In one optional implementation, the fourth acquisition module includes:

[0334] The first determining unit is configured to determine the vehicle speed calculation mode based on the equivalent vehicle speed if the fault flag bits of the multiple motors, the fault flag bits corresponding to the multiple drive wheels, and the fault flag bits corresponding to the multiple driven wheels are all FALSE, or if the minimum absolute value of the rotation angle of the multiple driven wheels is less than or equal to a preset rotation angle threshold and the number of the fault flag bits of the multiple driven wheels being TRUE is within a preset range.

[0335] The second determining unit is used to determine the vehicle speed calculation mode as the second mode if the minimum absolute value of the rotation angle of the plurality of driven wheels is less than or equal to the preset rotation angle threshold, the number of fault flag bits of the plurality of driven wheels that are TRUE is greater than the preset range, and the fault flag bits of the plurality of motors are all FALSE.

[0336] The third determining unit is used to determine the vehicle speed calculation mode as the second mode if the minimum absolute value of the rotation angle of the plurality of driven wheels is greater than the preset rotation angle threshold and the fault flags of the left driven wheel of the first axle and the left driven wheel of the fourth axle are both TRUE or the fault flags of the right driven wheel of the first axle and the right driven wheel of the fourth axle are both TRUE, and the fault flags of the plurality of motors are not all TRUE.

[0337] The fourth determining unit is used to determine the vehicle speed calculation mode as the zero mode if the fault flag bits of multiple motors, multiple drive wheels, and multiple driven wheels are all TRUE.

[0338] The fifth determining unit is used to determine the vehicle speed calculation mode as the fourth mode if the fault flag bits of multiple driven wheels are all TRUE, the fault flag bits of multiple motors are all TRUE, and the fault flag bits of multiple drive wheels are all FALSE.

[0339] In one alternative implementation, the first determining unit includes:

[0340] The first determining subunit is used to determine the vehicle speed calculation mode as the second mode if the equivalent vehicle speed is less than the lower boundary of the preset fusion interval speed and the slippage state of multiple motors is not slippage.

[0341] The second determining subunit is used to determine the vehicle speed calculation mode as the third mode if the equivalent vehicle speed is greater than or equal to the lower boundary of the preset fusion interval speed and less than or equal to the upper boundary of the preset fusion interval speed, and the slippage state of multiple motors is non-slippage.

[0342] The third determining subunit is used to determine the vehicle speed calculation mode as the first mode if the equivalent vehicle speed is greater than the upper boundary of the preset fusion interval speed.

[0343] In one optional implementation, the plurality of motors includes a first motor and a second motor, and the first acquisition module includes:

[0344] The fourth determining subunit is used to determine the minimum speed of the first motor and the second motor as the equivalent speed if the fault flag bits of multiple motors are all FALSE and the rotation directions of the first motor and the second motor are the same, and the sum of the torque of the first motor and the torque of the second motor is greater than or equal to a first preset torque threshold, or if the fault flag bits of multiple motors are all FALSE and the rotation directions of the first motor and the second motor are different.

[0345] The fifth determining subunit is used to determine the maximum speed of the first motor and the second motor as the equivalent speed if the fault flag bits of multiple motors are all FALSE, the rotation direction of the first motor and the second motor are the same, and the sum of the torque of the first motor and the torque of the second motor is less than the first preset torque threshold.

[0346] The sixth determining subunit is used to determine the motor speed weights corresponding to the first motor and the second motor respectively based on the equivalent speed.

[0347] The first acquisition subunit is used to acquire the first speed gradient of the first motor at multiple cycle intervals and the second speed gradient of the second motor at multiple cycle intervals if the fault flag bits of multiple motors are all FALSE.

[0348] The seventh determining subunit is used to determine the maximum value of the first speed gradient and the second speed gradient, which is the maximum driving speed gradient;

[0349] The eighth determining subunit is used to determine that the motor speed weights corresponding to the first motor and the second motor are zero if the maximum driving speed gradient is greater than or equal to the first preset gradient threshold.

[0350] The ninth determining subunit is used to determine the absolute value of the difference between the speed of the first motor and the speed of the second motor as the separation degree of the front and rear motor speeds if the maximum driving speed gradient is less than the first preset gradient threshold.

[0351] The tenth determining subunit is used to determine the motor speed weights of the first motor and the second motor as 1 if the separation degree of the front and rear motor speeds is less than the preset speed separation threshold and the maximum driving speed gradient is less than the first preset gradient threshold.

[0352] The eleventh determining subunit is used to determine that the motor speed weights corresponding to the first motor and the second motor are zero if the speed separation degree of the front and rear motors is greater than or equal to a preset speed separation threshold.

[0353] The twelfth determining subunit is used to determine the converted vehicle speed of the motor as 0 if the motor speed weights of the first motor are all zero and the motor speed weights of the second motor are all zero.

[0354] The first calculation subunit is used to calculate the converted vehicle speed of the motor based on the tire rolling radius, the transmission ratio from the motor to the wheel end, the turning angle of the left wheel of the front axle, the turning angle of the right wheel of the front axle, the turning angle of the left wheel of the rear axle, the turning angle of the right wheel of the rear axle, the motor speed weight of the first motor, and the motor speed weight of the second motor if at least one of the motor speed weight of the first motor and the motor speed weight of the second motor is not zero.

[0355] In one optional implementation, the plurality of drive wheels includes a front axle left drive wheel, a front axle right drive wheel, a rear axle left drive wheel, and a rear axle right drive wheel; the first calculation module includes:

[0356] The sixth determining unit is used to determine that the driving wheel speed weight of each driving wheel is zero if the fault flag bit of the driving wheel is TRUE.

[0357] The seventh determining unit is used to determine, for each of the drive wheels, if the fault flag bit of the drive wheel is FALSE, the absolute value of the difference between the rotational speed of the left drive wheel of the front axle and the rotational speed of the right drive wheel of the front axle, which is the front axle drive wheel rotational speed difference;

[0358] The eighth determining unit is used to determine the absolute value of the difference between the rotational speed of the left drive wheel of the rear axle and the rotational speed of the right drive wheel of the rear axle, which is the difference in rotational speed of the rear axle drive wheels;

[0359] The ninth determining unit is used to determine that the speed weights of the drive wheels corresponding to the left and right drive wheels of the front axle are zero if the speed difference of the front axle drive wheels is greater than a preset speed threshold.

[0360] The tenth determining unit is used to determine the speed weights of the drive wheels corresponding to the left and right drive wheels of the front axle as 1 if the speed difference of the front axle drive wheels is less than or equal to the preset speed threshold.

[0361] The eleventh determining unit is used to determine that the speed weights of the drive wheels corresponding to the left and right drive wheels of the rear axle are zero if the speed difference of the rear axle drive wheels is greater than the preset speed threshold.

[0362] The twelfth determining unit is used to determine the speed weights of the drive wheels corresponding to the left and right drive wheels of the rear axle as 1 if the speed difference of the rear axle drive wheels is less than or equal to the preset speed threshold.

[0363] The first calculation unit is used to calculate the average longitudinal speed of the front axle based on the speed of the left drive wheel of the front axle, the speed weight of the drive wheel of the left drive wheel of the front axle, the speed of the right drive wheel of the front axle, and the speed weight of the drive wheel of the right drive wheel of the front axle.

[0364] The second calculation unit is used to calculate the average longitudinal speed of the rear axle based on the speed weight of the left drive wheel of the rear axle, the speed weight of the right drive wheel of the rear axle, the speed of the left drive wheel of the rear axle, and the speed of the right drive wheel of the rear axle.

[0365] The third calculation unit is used to calculate the equivalent vehicle speed of the drive wheel based on the average longitudinal speed of the front axle and the average longitudinal speed of the rear axle.

[0366] In one optional implementation, the multiple driven wheels include a left driven wheel of a single axle, a right driven wheel of a single axle, a left driven wheel of a four-axle axle, and a right driven wheel of a four-axle axle; the second acquisition module includes:

[0367] The first acquisition unit is used to acquire real-time longitudinal acceleration;

[0368] The setting unit is used to, for each cycle, if the vehicle is in braking state and the real-time longitudinal acceleration of the vehicle is greater than |first preset acceleration threshold| when the vehicle is in D gear or the real-time longitudinal acceleration of the vehicle is less than -|first preset acceleration threshold| when the vehicle is in R gear and the real-time longitudinal acceleration is less than second preset acceleration threshold, set the initial longitudinal acceleration of the cycle to 0.

[0369] The fourteenth determining unit is used to determine the equivalent vehicle speed of the left driven wheel of the first axle in each cycle, the equivalent vehicle speed of the right driven wheel of the first axle in each cycle, the equivalent vehicle speed of the left driven wheel of the fourth axle in each cycle, the equivalent vehicle speed of the right driven wheel of the fourth axle in each cycle, and the maximum value among the vehicle speeds before each cycle as the starting point of acceleration integration.

[0370] The fourth calculation unit is used to calculate the corrected longitudinal acceleration integral speed based on the acceleration integral starting point and the initial longitudinal acceleration of each cycle.

[0371] In one alternative implementation, it also includes:

[0372] The fifth calculation module is used to calculate the upper limit of vehicle speed L1 and the lower limit of vehicle speed L1 based on the corrected longitudinal acceleration integral vehicle speed, the preset upper limit gain of vehicle speed L1, the preset lower limit gain of vehicle speed L1, and the preset envelope width of vehicle speed L1.

[0373] The sixth calculation module is used to integrate the vehicle speed V based on the corrected longitudinal acceleration. ACC The upper and lower limits of vehicle speed at level L2 are calculated by using preset upper and lower speed limit gains, preset lower and upper speed limit envelope widths, and preset upper and lower speed limit gain.

[0374] In one optional implementation, the multiple driven wheels include a left driven wheel of a single axle, a right driven wheel of a single axle, a left driven wheel of a fourth axle, and a right driven wheel of a fourth axle; the first determining module includes:

[0375] The fifteenth determining unit is used to determine the initial speed weight of each driven wheel as 0 if the fault flag bit of the driven wheel is TRUE.

[0376] The sixteenth determining unit is used to determine the initial speed weight of the driven wheel as 0 if the fault flag bit of the driven wheel is FALSE and the difference between the speed of the current cycle and the speed of the previous cycle is greater than or equal to a preset speed threshold for each driven wheel; otherwise, it determines the initial speed weight as 1.

[0377] In one alternative implementation, the second determining module includes:

[0378] The enabling unit is configured to enable the vehicle if it is in a braking state, and the maximum absolute value of the driving wheel rotation angles of the plurality of driven wheels is less than a preset steering judgment angle threshold, and the real-time vehicle speed V x If the vehicle speed exceeds a preset detection threshold and the vehicle is in D or R gear, lock-up detection is enabled.

[0379] The second acquisition unit is used to acquire the speed decrease gradient of each driven wheel in each cycle interval if the fault flag bit of the driven wheel is FALSE.

[0380] The seventeenth determining unit is used to determine that the initial locking level of the multiple driven wheels is zero if the minimum value of the speed decrease gradient of the multiple driven wheels in each cycle interval is greater than a preset speed decrease gradient threshold; otherwise, it determines that the initial locking level of the multiple driven wheels is 1.

[0381] The eighteenth determining unit is used to determine that the lock-up level of each driven wheel is zero if the rotational speed of the driven wheel is greater than the lower limit of the vehicle speed level L1 and the initial lock-up level of the driven wheel is zero.

[0382] The nineteenth determining unit is used to determine the locking level of each driven wheel as 1 if the rotational speed of the driven wheel is greater than or equal to the lower limit of the vehicle speed level L2 and less than or equal to the lower limit of the vehicle speed level L1.

[0383] The twentieth determining unit is used to determine the locking level of each driven wheel as 2 if the rotational speed of the driven wheel is less than the lower limit of the vehicle speed level L1.

[0384] This application also provides an electronic device in its embodiments. (See reference...) Figure 5 The diagram illustrates a structural schematic suitable for implementing the electronic device in the embodiments of this application. The electronic device in the embodiments of this application may include, but is not limited to, fixed terminals such as mobile phones, laptops, PDAs (personal digital assistants), PADs (tablet computers), desktop computers, etc. Figure 5 The electronic device shown is merely an example and should not impose any limitation on the functionality and scope of use of the embodiments of this application.

[0385] like Figure 5 As shown, the electronic device may include a processing unit (e.g., a central processing unit, a graphics processing unit, etc.) 501, which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM) 502 or a program loaded from a storage device 508 into a random access memory (RAM) 503. When the electronic device is powered on, the RAM 503 also stores various programs and data required for the operation of the electronic device. The processing unit 501, ROM 502, and RAM 503 are interconnected via a bus 504. An input / output (I / O) interface 505 is also connected to the bus 504.

[0386] Typically, the following devices can be connected to I / O interface 505: input devices 506 including, for example, touchscreens, touchpads, keyboards, mice, cameras, microphones, accelerometers, gyroscopes, etc.; output devices 507 including, for example, liquid crystal displays (LCDs), speakers, vibrators, etc.; storage devices 508 including, for example, memory cards, hard drives, etc.; and communication devices 509. Communication device 509 allows electronic devices to communicate wirelessly or wiredly with other devices to exchange data. Although Figure 5 Electronic devices with various devices are shown, but it should be understood that it is not required to implement or have all of the devices shown. More or fewer devices may be implemented or have alternatively.

[0387] This application also provides a computer program product including computer-readable instructions, which, when executed on an electronic device, cause the electronic device to implement any of the multi-axle vehicle speed fusion calculation methods provided in this application.

[0388] This application also provides a computer-readable storage medium carrying one or more computer programs. When the one or more computer programs are executed by an electronic device, the electronic device can implement any of the vehicle speed fusion calculation methods for multi-axle vehicles provided in this application.

[0389] It should also be noted that the device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. In addition, in the device embodiment drawings provided in this application, the connection relationship between modules indicates that they have a communication connection, which can be implemented as one or more communication buses or signal lines.

[0390] Through the above description of the embodiments, those skilled in the art can clearly understand that this application can be implemented by means of software plus necessary general-purpose hardware, or it can be implemented by special-purpose hardware including application-specific integrated circuits, special-purpose CPUs, special-purpose memory, special-purpose components, etc. Generally, any function performed by a computer program can be easily implemented by corresponding hardware, and the specific hardware structure used to implement the same function can also be diverse, such as analog circuits, digital circuits, or special-purpose circuits. However, for this application, software program implementation is more often the preferred implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a readable storage medium, such as a computer floppy disk, USB flash drive, mobile hard disk, ROM, RAM, magnetic disk, or optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, training equipment, or network device, etc.) to execute the methods described in the various embodiments of this application.

[0391] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented in software, it can be implemented, in whole or in part, as a computer program product.

[0392] The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions may be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions may be transmitted from one website, computer, training device, or data center to another website, computer, training device, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium may be any available medium that a computer can store or a data storage device such as a training device or data center that integrates one or more available media. The available media may be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., DVDs), or semiconductor media (e.g., solid-state drives (SSDs)).

Claims

1. A method for fusion calculation of vehicle speed in multi-axle vehicles, characterized in that, include: Based on the fault flags of multiple motors, the equivalent speed of the motors, and the slippage status of multiple motors, the vehicle speed is calculated from the motors. Based on the fault flags corresponding to multiple drive wheels and the rotational speeds corresponding to the multiple drive wheels, the equivalent vehicle speed of the drive wheels is calculated. Based on the longitudinal acceleration of each cycle, the equivalent vehicle speed of each cycle corresponding to the multiple driven wheels, and the vehicle speed of each cycle corresponding to the multiple driven wheels, the corrected longitudinal acceleration integral vehicle speed is obtained. Based on the fault flag bits corresponding to the multiple driven wheels and the rotational speeds of the multiple driven wheels in each cycle, the initial rotational speed weights of the multiple driven wheels are determined. For any of the driven wheels, if the driven wheel is in a locked state and the initial speed weight of the driven wheel is not 0, the lock-up level of the driven wheel is determined based on the speed of the driven wheel in each cycle. If the locking level of at least one of the driven wheels is not 0, the updated speed weights corresponding to the multiple driven wheels are calculated based on the longitudinal projection of the mounting points of the multiple driven wheels in the vehicle body coordinate system and the initial speed weights of the multiple driven wheels. Based on the updated rotational speed weights corresponding to the multiple driven wheels, the corrected longitudinal acceleration integral speed weight is obtained. The equivalent vehicle speed is calculated based on the updated rotational speed weights of the multiple driven wheels, the rotational speed of the multiple driven wheels in the current cycle, the corrected longitudinal acceleration integral vehicle speed weights, and the corrected longitudinal acceleration integral vehicle speed. Based on the preset vehicle speed weight, the preset motor-converted vehicle speed weight, the equivalent vehicle speed, and the motor-converted vehicle speed, the vehicle speed during the fusion transition phase is calculated. Obtain the target vehicle speed calculation mode; From the preset vehicle speed calculation mode and the correspondence between vehicle speeds, find the target vehicle speed corresponding to the target vehicle speed calculation mode. The vehicle speed is any one of the corrected longitudinal acceleration integral vehicle speed, the equivalent vehicle speed, the motor converted vehicle speed, the fusion transition stage vehicle speed, and the drive wheel equivalent vehicle speed.

2. The method for calculating vehicle speed fusion for multi-axle vehicles according to claim 1, characterized in that, The target vehicle speed calculation mode includes: If the fault flag bits of multiple motors, the fault flag bits corresponding to multiple drive wheels, and the fault flag bits corresponding to multiple driven wheels are all FALSE, or if the minimum absolute value of the rotation angle of multiple driven wheels is less than or equal to a preset rotation angle threshold and the number of fault flag bits of multiple driven wheels that are TRUE is within a preset range, the target vehicle speed calculation mode is determined based on the equivalent vehicle speed. If the minimum absolute value of the rotation angle of multiple driven wheels is less than or equal to the preset rotation angle threshold, and the number of fault flags of multiple driven wheels that are TRUE is greater than the preset range, and the fault flags of multiple motors are all FALSE, then the target vehicle speed calculation mode is determined to be the second mode. If the minimum absolute value of the rotation angle of the multiple driven wheels is greater than the preset rotation angle threshold and the fault flags of the left driven wheel of the first axle and the left driven wheel of the fourth axle are both TRUE or the fault flags of the right driven wheel of the first axle and the right driven wheel of the fourth axle are both TRUE, and the fault flags of the multiple motors are not all TRUE, then the target vehicle speed calculation mode is determined to be the second mode. If the fault flag bits of multiple motors, multiple drive wheels, and multiple driven wheels are all TRUE, the target vehicle speed calculation mode is determined to be the zeroth mode. If the fault flags of multiple driven wheels are all TRUE, the fault flags of multiple motors are all TRUE, and the fault flags of multiple drive wheels are all FALSE, then the target vehicle speed calculation mode is determined to be the fourth mode.

3. The method for calculating vehicle speed fusion for multi-axle vehicles according to claim 2, characterized in that, The method for determining the target vehicle speed based on the equivalent vehicle speed includes: If the equivalent vehicle speed is less than the lower boundary of the preset fusion interval speed, and the slippage state of multiple motors is not slippage, the target vehicle speed calculation mode is determined to be the second mode. If the equivalent vehicle speed is greater than or equal to the lower boundary of the preset fusion interval speed and less than or equal to the upper boundary of the preset fusion interval speed, and the slippage state of multiple motors is not slippage, the target vehicle speed calculation mode is determined to be the third mode. If the equivalent vehicle speed is greater than the upper boundary of the preset fusion interval speed, the target vehicle speed calculation mode is determined to be the first mode.

4. The method for calculating vehicle speed fusion for multi-axle vehicles according to claim 1, characterized in that, The plurality of motors includes a first motor and a second motor. The step of obtaining the motor-converted vehicle speed based on the fault flags of the plurality of motors, the equivalent speed of the motors, and the slippage state of the plurality of motors includes: If the fault flags of multiple motors are all FALSE and the first motor and the second motor rotate in the same direction, and the sum of the torque of the first motor and the torque of the second motor is greater than or equal to the first preset torque threshold, or if the fault flags of multiple motors are all FALSE and the first motor and the second motor rotate in different directions, the minimum speed of the first motor and the second motor is determined to be the equivalent speed. If the fault flags of multiple motors are all FALSE and the first motor and the second motor rotate in the same direction, and the sum of the torque of the first motor and the torque of the second motor is less than the first preset torque threshold, then the maximum speed of the first motor and the second motor is determined to be the equivalent speed. Based on the equivalent rotational speed, determine the motor speed weights corresponding to the first motor and the second motor respectively; If the fault flag bits of multiple motors are all FALSE, obtain the first speed gradient of the first motor at multiple cycle intervals and the second speed gradient of the second motor at multiple cycle intervals. The maximum value between the first speed gradient and the second speed gradient is determined as the maximum driving speed gradient; If the maximum driving speed gradient is greater than or equal to the first preset gradient threshold, the motor speed weights corresponding to the first motor and the second motor are determined to be zero. If the maximum driving speed gradient is less than the first preset gradient threshold, the absolute value of the difference between the speed of the first motor and the speed of the second motor is determined to be the separation degree of the front and rear motor speeds. If the speed separation of the front and rear motors is less than a preset speed separation threshold, and the maximum driving speed gradient is less than the first preset gradient threshold, the motor speed weights corresponding to the first motor and the second motor are determined to be 1 respectively. If the speed separation degree of the front and rear motors is greater than or equal to the preset speed separation threshold, the motor speed weights corresponding to the first motor and the second motor are determined to be zero. If the motor speed weights of the first motor are all zero and the motor speed weights of the second motor are all zero, the converted vehicle speed of the motor is determined to be 0. If at least one of the motor speed weights of the first motor and the second motor is not zero, the converted vehicle speed of the motor is calculated based on the tire rolling radius, the transmission ratio from the motor to the wheel end, the turning angle of the left wheel of the front axle, the turning angle of the right wheel of the front axle, the turning angle of the left wheel of the rear axle and the turning angle of the right wheel of the rear axle, the motor speed weight of the first motor and the motor speed weight of the second motor.

5. The method for fusion calculation of vehicle speed for multi-axle vehicles according to claim 1, characterized in that, The plurality of drive wheels includes a front axle left drive wheel, a front axle right drive wheel, a rear axle left drive wheel, and a rear axle right drive wheel; The calculation of the equivalent vehicle speed of the drive wheels based on the fault flag bits corresponding to the multiple drive wheels and the rotational speeds corresponding to the multiple drive wheels includes: For each of the drive wheels, if the fault flag bit of the drive wheel is TRUE, the drive wheel speed weight of the drive wheel is determined to be zero. For each of the drive wheels, if the fault flag of the drive wheel is FALSE, the absolute value of the difference between the speed of the left drive wheel of the front axle and the speed of the right drive wheel of the front axle is determined as the front axle drive wheel speed difference. The absolute value of the difference between the rotational speed of the left drive wheel of the rear axle and the rotational speed of the right drive wheel of the rear axle is determined as the rear axle drive wheel speed difference; If the speed difference of the front axle drive wheels is greater than a preset speed threshold, the speed weights of the drive wheels corresponding to the left and right front axle drive wheels are determined to be zero. If the speed difference of the front axle drive wheels is less than or equal to the preset speed threshold, the speed weights of the drive wheels corresponding to the left and right front axle drive wheels are determined to be 1. If the difference in speed of the rear axle drive wheels is greater than the preset speed threshold, the speed weights of the drive wheels corresponding to the left and right rear axle drive wheels are determined to be zero. If the speed difference of the rear axle drive wheels is less than or equal to the preset speed threshold, the speed weights of the drive wheels corresponding to the left and right rear axle drive wheels are determined to be 1. The average longitudinal speed of the front axle is calculated based on the rotational speed of the left drive wheel of the front axle, the rotational speed weight of the left drive wheel of the front axle, the rotational speed of the right drive wheel of the front axle, and the rotational speed weight of the right drive wheel of the front axle. The average longitudinal speed of the rear axle is calculated based on the speed weights of the left and right drive wheels of the rear axle, the speed of the left and right drive wheels of the rear axle. The equivalent vehicle speed of the drive wheels is calculated based on the average longitudinal speed of the front axle and the average longitudinal speed of the rear axle.

6. The method for calculating vehicle speed fusion for multi-axle vehicles according to any one of claims 1 to 5, characterized in that, The plurality of driven wheels includes a left driven wheel of a single axle, a right driven wheel of a single axle, a left driven wheel of a fourth axle, and a right driven wheel of a fourth axle; The method of obtaining the corrected longitudinal acceleration integral speed based on the longitudinal acceleration of each cycle, the equivalent vehicle speed of each cycle corresponding to the multiple driven wheels, and the vehicle speed of each cycle corresponding to the multiple driven wheels includes: Obtain real-time longitudinal acceleration; For each cycle, if the vehicle is in braking state and the real-time longitudinal acceleration is greater than |first preset acceleration threshold| when the vehicle is in D gear, or the real-time longitudinal acceleration is less than -|first preset acceleration threshold| when the vehicle is in R gear and the real-time longitudinal acceleration is less than the second preset acceleration threshold, the initial longitudinal acceleration of the cycle is set to 0. The equivalent vehicle speed of the left driven wheel of the first axle in each cycle, the equivalent vehicle speed of the right driven wheel of the first axle in each cycle, the equivalent vehicle speed of the left driven wheel of the fourth axle in each cycle, the equivalent vehicle speed of the right driven wheel of the fourth axle in each cycle, and the maximum value among the vehicle speeds before each cycle are determined as the starting point for acceleration integration. Based on the acceleration integral starting point and the initial longitudinal acceleration of each cycle, the corrected longitudinal acceleration integral speed is calculated.

7. The method for calculating vehicle speed fusion for multi-axle vehicles according to claim 6, characterized in that, Also includes: Based on the corrected longitudinal acceleration integral vehicle speed, the preset vehicle speed L1 level speed upper limit gain, the preset vehicle speed L1 level speed lower limit gain, and the preset L1 level speed upper and lower limit envelope width, the vehicle speed L1 level upper limit and vehicle speed L1 level lower limit are calculated. Based on the corrected longitudinal acceleration integral vehicle speed, the preset upper limit gain of vehicle speed L2 level, the preset lower limit gain of vehicle speed L2 level, and the preset envelope width of the upper and lower limits of vehicle speed L2 level, the upper limit of vehicle speed L2 level and the lower limit of vehicle speed L2 level are calculated.

8. The method for calculating vehicle speed fusion for multi-axle vehicles according to claim 7, characterized in that, The plurality of driven wheels includes a left driven wheel of a single axle, a right driven wheel of a single axle, a left driven wheel of a fourth axle, and a right driven wheel of a fourth axle; The determination of the initial speed weights of the multiple driven wheels based on the fault flag bits corresponding to the multiple driven wheels and the speeds of the multiple driven wheels in each cycle includes: For each driven wheel, if the fault flag bit of the driven wheel is TRUE, the initial speed weight of the driven wheel is determined to be 0; For each driven wheel, if the fault flag bit of the driven wheel is FALSE, and the difference between the rotational speed of the driven wheel in the current cycle and the rotational speed in the previous cycle is greater than or equal to a preset rotational speed threshold, the initial rotational speed weight of the driven wheel is determined to be 0; otherwise, the initial rotational speed weight is determined to be 1.

9. The method for calculating vehicle speed fusion for multi-axle vehicles according to claim 8, characterized in that, If the driven wheel is in a locked state and the initial speed weight of the driven wheel is not 0, the locking level of the driven wheel is determined based on the speed of the driven wheel in each cycle, including: If the vehicle is in braking state, and the maximum absolute value of the rotation angle of the driven wheels of the multiple driven wheels is less than the preset steering judgment angle threshold, and the real-time vehicle speed is greater than the preset detection speed threshold, and the vehicle is in D or R gear, then lock-up detection is enabled. For each driven wheel, if the fault flag of the driven wheel is FALSE, obtain the speed reduction gradient of the driven wheel in each cycle interval; If the minimum value of the speed decrease gradient of the multiple driven wheels in each cycle interval is greater than the preset speed decrease gradient threshold, the initial lock-up level of the multiple driven wheels is determined to be zero; otherwise, the initial lock-up level of the multiple driven wheels is determined to be 1. For each driven wheel, if the rotational speed of the driven wheel is greater than the lower limit of the vehicle speed L1 level and the initial lock-up level of the driven wheel is zero, the lock-up level of the driven wheel is determined to be zero. For each driven wheel, if the rotational speed of the driven wheel is greater than or equal to the lower limit of the vehicle speed level L2 and less than or equal to the lower limit of the vehicle speed level L1, the locking level of the driven wheel is determined to be 1. For each driven wheel, if the rotational speed of the driven wheel is less than the lower limit of the vehicle speed level L1, the locking level of the driven wheel is determined to be 2.

10. A device for calculating vehicle speed fusion in multi-axle vehicles, characterized in that, include: The first acquisition module is used to acquire the motor-converted vehicle speed based on the fault flag bits of multiple motors, the equivalent speed of the motors, and the slippage state of multiple motors. The first calculation module is used to calculate the equivalent vehicle speed of the drive wheels based on the fault flags corresponding to the multiple drive wheels and the rotational speeds corresponding to the multiple drive wheels. The second acquisition module is used to obtain the corrected longitudinal acceleration integral speed based on the longitudinal acceleration of each cycle, the equivalent vehicle speed of each cycle corresponding to the multiple driven wheels, and the vehicle speed of each cycle corresponding to the multiple driven wheels. The first determining module is used to determine the initial speed weight of the multiple driven wheels based on the fault flag bits corresponding to the multiple driven wheels and the speed of the multiple driven wheels in each cycle. The second determining module is used to determine the lock-up level of any driven wheel if the driven wheel is in a locked state and the initial speed weight of the driven wheel is not 0, based on the speed of the driven wheel in each cycle. The second calculation module is used to calculate the updated speed weights corresponding to the multiple driven wheels based on the longitudinal projection of the mounting points of the multiple driven wheels in the vehicle body coordinate system and the initial speed weights of the multiple driven wheels if the locking level of at least one of the driven wheels is not 0. The third acquisition module is used to acquire the corrected longitudinal acceleration integral speed weight based on the updated rotational speed weights corresponding to the multiple driven wheels. The third calculation module is used to calculate the equivalent vehicle speed based on the updated rotational speed weights of the multiple driven wheels, the rotational speed of the multiple driven wheels in the current cycle, the corrected longitudinal acceleration integral vehicle speed weights, and the corrected longitudinal acceleration integral vehicle speed. The fourth calculation module is used to calculate the vehicle speed during the fusion transition phase based on the preset vehicle speed weight, the preset motor-converted vehicle speed weight, the equivalent vehicle speed, and the motor-converted vehicle speed. The fourth acquisition module is used to acquire the target vehicle speed calculation mode; The search module is used to search for the target vehicle speed corresponding to the target vehicle speed calculation mode from the preset vehicle speed calculation mode and vehicle speed correspondence. The vehicle speed is any one of the corrected longitudinal acceleration integral vehicle speed, the equivalent vehicle speed, the motor converted vehicle speed, the fusion transition stage vehicle speed and the drive wheel equivalent vehicle speed.

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