Method and system for calculating reference vehicle speed of cross-country cruise and related equipment

Abstract

The invention relates to the technical field of automobile electronic control, and discloses a reference vehicle speed calculation method and system for cross-country cruise and related equipment, and the method comprises the steps: when a vehicle is in a cross-country cruise function, obtaining wheel speed information and a first reference vehicle speed in real time; calculating the first credibility of the current first reference vehicle speed based on the first reference vehicle speed at the adjacent moment; calculating a second credibility of the current first reference vehicle speed based on the current wheel speed information; calculating a current second reference vehicle speed based on the current wheel speed signal; and calculating a current target reference vehicle speed based on the first credibility, the second credibility, the current first reference vehicle speed and the current second reference vehicle speed. According to the invention, the credibility index is established for the reference vehicle speed, and the reasonable reference vehicle speed is calculated through the credibility index and the second reference vehicle speed calculated based on the wheel speed signal, so that the power output and the driving control of the vehicle under the complex terrain better meet the actual requirements.

Description

Technical Field

[0001] The present disclosure relates to the field of automotive electronic control technology, and in particular to a method and system for calculating a reference vehicle speed for off-road cruising, and related equipment. Background Art

[0002] An off-road vehicle is a type of off-road vehicle specially designed for off-road use on rugged terrain. Its main features are a non-load-bearing body, four-wheel drive, a higher chassis, tires with better grip, a higher exhaust pipe, greater horsepower and thick and sturdy bumpers, which can adapt to various road conditions in the wild.

[0003] However, when the vehicle activates the off-road cruise function under low-speed off-road conditions, the vehicle faces complex and changeable terrain, and the wheel speed will fluctuate violently, causing the reference vehicle speed calculated by the TCS system (Traction Control System) to be seriously overestimated, making it difficult to meet the real-time vehicle speed requirements of off-road driving. Summary of the Invention

[0004] To overcome the problem that when a vehicle faces complex and changeable terrain, the reference speed calculated by the TCS system will be seriously overestimated, making it difficult to meet the real-time speed requirements of off-road driving, the present disclosure provides a reference speed calculation method, system and related equipment for off-road cruising.

[0005] In a first aspect, in order to solve the above technical problems, the present disclosure provides a method for calculating a reference vehicle speed for off-road cruising, comprising:

[0006] When the vehicle is in the off-road cruise function, wheel speed information and a first reference vehicle speed are obtained in real time; wherein the wheel speed information includes the wheel speed of each wheel of the vehicle, and the first reference vehicle speed is the first reference vehicle speed output by the vehicle's TCS system;

[0007] Calculating a first reliability of the current first reference vehicle speed based on the first reference vehicle speed at adjacent moments; wherein the first reliability represents the stability of the first reference vehicle speed;

[0008] Calculating a second reliability of the current first reference vehicle speed based on the current wheel speed information; wherein the second reliability represents the stability of the first reference vehicle speed determined by the wheel speed signal;

[0009] Calculating a current second reference vehicle speed based on the current wheel speed signal;

[0010] A current target reference vehicle speed is calculated based on the first reliability, the second reliability, the current first reference vehicle speed, and the current second reference vehicle speed.

[0011] In a second aspect, the present disclosure provides a reference vehicle speed calculation device for off-road cruising, comprising:

[0012] a first reference vehicle speed acquisition module, configured to acquire wheel speed information and a first reference vehicle speed in real time when the vehicle is in an off-road cruise function; wherein the wheel speed information includes the speed of each wheel of the vehicle, and the first reference vehicle speed is the first reference vehicle speed output by the vehicle's TCS system;

[0013] A first credibility calculation module is configured to calculate a first credibility of a current first reference vehicle speed based on first reference vehicle speeds at adjacent moments; wherein the first credibility represents the stability of the first reference vehicle speed;

[0014] A second credibility calculation module is configured to calculate a second credibility of the current first reference vehicle speed based on the current wheel speed information; wherein the second credibility represents the stability of the first reference vehicle speed determined by the wheel speed signal;

[0015] A second reference vehicle speed calculation module, configured to calculate a current second reference vehicle speed based on the current wheel speed signal;

[0016] The current target reference vehicle speed calculation module is used to calculate the current target reference vehicle speed based on the first credibility, the second credibility, the current first reference vehicle speed and the current second reference vehicle speed.

[0017] In a third aspect, the present disclosure provides a computing device comprising a memory, a processor, and a program stored in the memory and running on the processor. When the processor executes the program, the steps of the reference vehicle speed calculation method for off-road cruising are implemented as described above.

[0018] In a fourth aspect, the present disclosure provides a computer-readable storage medium storing instructions, which, when executed on a terminal device, enable the terminal device to execute the steps of a reference vehicle speed calculation method for off-road cruising as described above.

[0019] The present disclosure provides the following beneficial effects: when a vehicle is in off-road cruise mode, wheel speed information and a first reference speed are acquired, and a first reliability and a second reliability of the first reference speed are calculated to verify the stability of the first reference speed. The second reference speed is then calculated based on the current wheel speed, and the current target reference speed is calculated based on the first reliability, the second reliability, the current first reference speed, and the current second reference speed. The present disclosure establishes a reliability index for the reference speed and calculates a reasonable reference speed using the reliability index and the second reference speed calculated based on the wheel speed signal, thereby ensuring that the vehicle's power output and driving control in complex terrain are more in line with actual needs. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the prior art, the present disclosure is further described below with reference to the accompanying drawings and embodiments.

[0021] Figure 1 Schematic diagram of a flow chart of a method for calculating a reference vehicle speed for off-road cruising according to an embodiment of the present disclosure;

[0022] Figure 2 This is a schematic diagram of multi-signal source acquisition;

[0023] Figure 3 Flowchart for calculating the reliability of wheel speed;

[0024] Figure 4 A flowchart for obtaining a second reference vehicle speed;

[0025] Figure 5 Flowchart for calculating reference vehicle speed output limit;

[0026] Figure 6 A schematic diagram of a reference vehicle speed calculation system for off-road cruising according to an embodiment of the present disclosure

[0027] Figure 7 Schematic diagram of the structure of a computing device according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0028] The following examples are provided to further explain and supplement the present disclosure and do not constitute any limitation to the present disclosure.

[0029] The following describes a reference vehicle speed calculation method, system, and related equipment for off-road cruising according to an embodiment of the present disclosure in conjunction with the accompanying drawings.

[0030] like Figure 1 As shown, an embodiment of the present disclosure provides a method for calculating a reference vehicle speed for off-road cruising, comprising:

[0031] S1. When the vehicle is in off-road cruise mode, wheel speed information and a first reference vehicle speed are obtained in real time; the wheel speed information includes the speed of each wheel of the vehicle, and the first reference vehicle speed is a first reference vehicle speed output by the vehicle's TCS system.

[0032] S2. Calculate a first credibility of the current first reference vehicle speed based on the first reference vehicle speed at adjacent moments; wherein the first credibility represents the stability of the first reference vehicle speed.

[0033] S3. Calculate a second reliability of the current first reference vehicle speed based on the current wheel speed information; wherein the second reliability represents the stability of the first reference vehicle speed determined by the wheel speed signal.

[0034] S4. Calculate a current second reference vehicle speed based on the current wheel speed signal.

[0035] S5. Calculate a current target reference vehicle speed based on the first credibility, the second credibility, the current first reference vehicle speed, and the current second reference vehicle speed.

[0036] In this embodiment, when the vehicle is in off-road cruise mode, wheel speed information and a first reference speed are acquired, and a first reliability and a second reliability of the first reference speed are calculated to verify the stability of the first reference speed. The second reference speed is then calculated based on the current wheel speed. The current target reference speed is then calculated using the first reliability, the second reliability, the current first reference speed, and the current second reference speed. This disclosure establishes a reliability index for the reference speed and uses this reliability index and the second reference speed calculated based on the wheel speed signals to calculate a reasonable reference speed, ensuring that the vehicle's power output and driving control in complex terrain are more aligned with actual needs.

[0037] like Figure 2 As shown, all data is collected by various sensors connected to the vehicle's MCU (Microcontroller Unit) signal acquisition module, as follows:

[0038] Wheel speed signal (wheel speed information) collection: High-precision wheel speed sensors collect wheel speed pulse signals from each of the four wheels, recorded as V_FL (left front wheel speed), V_FR (right front wheel speed), V_RL (left rear wheel speed), and V_RR (right rear wheel speed), in meters per second. The wheel speed sensors are highly sensitive and have a fast response, accurately capturing instantaneous changes in wheel speed.

[0039] TCS Reference Speed ​​Signal (First Reference Speed) Acquisition: This system acquires the TCS reference speed (v_TCS) in meters per second (m / s) through the vehicle's TCS communication interface. The TCS calculates the first reference speed based on the vehicle's overall dynamics and a variety of factors.

[0040] Longitudinal acceleration and yaw rate signal acquisition: Use a high-precision longitudinal acceleration sensor to collect the vehicle's longitudinal acceleration sensor signal a_x in m / s 2 The longitudinal acceleration sensor can accurately measure the acceleration change of the vehicle in the direction of travel, providing important dynamic parameters for subsequent vehicle speed calculation; the high-precision yaw rate sensor is used to collect the vehicle's yaw rate signal dPsi, which is measured in rad / s.

[0041] Off-road cruise target speed signal acquisition: This function acquires the target speed Vx_Tar (in meters per second) entered by the user for the off-road cruise function through the vehicle's off-road cruise system communication interface. The off-road cruise system calculates the target speed based on a combination of factors, including the user-set target speed and the off-road cruise status.

[0042] Inner and outer wheel angle average signal acquisition: The SAS system communication interface collects the average inner and outer wheel angle θ (in rad). The SAS system calculates the average inner and outer wheel angle based on factors such as steering wheel angle input and vehicle posture.

[0043] Wheel braking force signal collection: Through the braking force calculation system communication interface, the actual braking force signals of the four wheels are collected respectively, recorded as Mb_FL (left front wheel braking force), Mb_FR (right front wheel braking force), Mb_RL (left rear wheel braking force), and Mb_RR (right rear wheel braking force), and the unit is rad.

[0044] This embodiment adopts multi-source signal acquisition, fully considering the variability of wheel speed signals under off-road conditions and the limitations of TCS reference speed. In extreme slip conditions, by combining wheel speed signals, reference speed and credibility assessment, the actual vehicle speed can be accurately captured, effectively overcoming the error problem of a single wheel speed reference or simple averaging algorithm when the wheels slip, providing a more accurate speed reference for off-road vehicles, making the vehicle's power output and driving control in complex terrain more in line with actual needs, and avoiding power waste or control errors caused by speed calculation errors.

[0045] Optionally, calculating the first credibility of the current first reference vehicle speed based on the first reference vehicle speed at adjacent moments includes:

[0046] Based on the first reference vehicle speed at adjacent moments, the preset filter coefficient, and the preset operation cycle, the stability of the reference vehicle speed is determined using the following formula:

[0047]

[0048] Wherein, k represents stability, k1 represents the rate of change calculated from the first reference vehicle speed at adjacent moments, dv_TCS represents the difference calculated from the first reference vehicle speed v_TCS at adjacent moments, dt represents the preset operation period, and b0 represents the preset filter coefficient;

[0049] Based on stability, the first credibility is calculated as follows:

[0050] β = 1-min(1, k);

[0051] Wherein, β represents the first credibility.

[0052] In this embodiment, the first reliability can represent the stability of the first reference vehicle speed. If the first reliability is high, it means that the first reference vehicle speed is relatively stable. If the first reliability is low, it means that the vehicle may be on a complex road and the first reference vehicle speed is unstable. In this case, the first reference vehicle speed can be corrected. For example, when the first reliability drops to a set minimum value, it indicates that the first reference vehicle speed output by the TCS system is unreliable, and the first reference vehicle speed needs to be corrected. The correction formula is as follows:

[0053]

[0054] Wherein, v_TCS_1 represents the corrected first reference vehicle speed, and k1+k2+...+k10 represents the change rate of the first reference vehicle speed within ten cycles before the first credibility drops to the lowest value.

[0055] Optionally, calculating the second credibility of the current first reference vehicle speed based on the current wheel speed information includes:

[0056] Preprocessing the wheel speed of each wheel in the current wheel speed information to determine the target wheel speed of each wheel; wherein the preprocessing includes low-pass filtering and wheel speed correction;

[0057] The credibility of the target wheel speeds that do not meet the preset conditions among the target wheel speeds is set to zero;

[0058] Calculate the standard deviation of each target wheel speed corresponding to a non-zero reliability and determine the standard deviation wheel speed. The formula is as follows:

[0059]

[0060] Where σ represents the standard deviation of wheel speed, v_i represents the i-th target wheel speed with non-zero reliability, v_avg represents the first average value of each target wheel speed with non-zero reliability, and i represents the number of target wheel speeds with non-zero reliability.

[0061] Based on the standard deviation wheel speed, the second reliability is calculated as follows:

[0062] α=exp(-σ / 2)

[0063] Here, α represents the second credibility.

[0064] In this embodiment, a second-order Butterworth low-pass filter technology with a cutoff frequency is used to perform low-pass filtering on the wheel speed. The cutoff frequency can be dynamically adjusted according to the first reference vehicle speed output by the TCS, effectively filtering out high-frequency noise and interference signals in the wheel speed signal, retaining the effective signal components that truly reflect the wheel speed, and obtaining the filtered four-wheel speeds V_FL_1 (left front wheel speed), V_FR_1 (right front wheel speed), V_RL_1 (left rear wheel speed), and V_RR_1 (right rear wheel speed), in units of m / s.

[0065] In this embodiment, when the vehicle turns, the outer wheel speed is faster than the inner wheel speed, so the wheel speed needs to be corrected. The wheel speed correction is performed using the average value of the inner and outer wheel turning angles θ to obtain the corrected wheel speeds V_FL_2 (left front wheel speed), V_FR_2 (right front wheel speed), V_RL_2 (left rear wheel speed), and V_RR_2 (right rear wheel speed). The correction method is as follows:

[0066] Using Taylor series to expand θ, we can get sinθ and cosθ, as shown in the following formula:

[0067]

[0068] Correct the wheel speed by sinθ and cosθ:

[0069]

[0070]

[0071] Among them, L_WheelTrack_FA represents the front track, and L_WheelTrack_RA represents the rear track.

[0072] In this embodiment, the calculation process of the standard deviation wheel speed is illustrated by an example. The reliability corresponding to the right rear wheel speed is 0, and the reliability corresponding to the other wheels is 1. In addition, V_FL_2 = 10, V_FR_2 = 11, V_RL_2 = 8, and V_RR_2 = 20. Then:

[0073]

[0074] Optionally, setting the credibility corresponding to the target wheel speed that does not meet the preset condition among the target wheel speeds to zero includes:

[0075] Sort the target wheel speeds, and calculate the average of the target wheel speeds after excluding the maximum and minimum values ​​to determine a second average value;

[0076] Obtain the initial credibility of each wheel. If the absolute value of the difference between the target wheel speed and the second average value is greater than the first threshold, set the credibility of the corresponding wheel to zero, and

[0077] If the braking force of the wheel is greater than the second threshold, the credibility of the corresponding wheel is set to zero.

[0078] For example, V_FL_2=8, V_FR_2=12, V_RL_2=20, and V_RR_2=13. After the target wheel speeds are sorted, V_RL_2=20, V_RR_2=13, V_FR_2=12, and V_FL_2=8. The maximum and minimum values ​​are eliminated to obtain V_RR_2=13 and V_FR_2=12. The average value is calculated, and the second average value is V_Average_1=12.5.

[0079] By default, the initial credibility of each wheel, TV_Pls_FL, TV_Pls_FR, TV_Pls_RL, and TV_Pls_RR, is 1. If the absolute value of the difference between the target wheel speed of a wheel and V_Average_1 is greater than a threshold (5 by default in this embodiment), the credibility of the wheel is set to 0.

[0080] In this embodiment, when a single wheel is braking, the wheel speed may be lower than the actual vehicle speed. In this case, the wheel speed is unreliable and the wheel speed credibility needs to be corrected. If the braking force of any wheel among Mb_FL (left front wheel braking force), Mb_FR (right front wheel braking force), Mb_RL (left rear wheel braking force), and Mb_RR (right rear wheel braking force) is greater than Mb_TV_Max (the second threshold), the credibility of the wheel is corrected to 0.

[0081] like Figure 3 As shown in the figure, the credibility calculation process of the above wheel is as follows:

[0082] start.

[0083] S03-2-1, wheel speed sorting.

[0084] S03-2-2, remove the maximum and minimum values.

[0085] S03-2-3, arithmetic mean.

[0086] S03-2-4, calculate round credibility.

[0087] Finish.

[0088] Optionally, calculating the current second reference vehicle speed based on the current wheel speed signal includes:

[0089] Get the longitudinal acceleration of the vehicle and calculate the dynamic weight based on the longitudinal acceleration. The formula is as follows:

[0090] γ=clip(0.65-0.13*a_x,0.3,0.9)

[0091] Wherein, γ represents the dynamic weight, and 0.3<γ<0.9, clip represents the clipping function, and a_x represents the longitudinal acceleration;

[0092] The second reference vehicle speed is determined based on the dynamic weight, the minimum wheel speed among the target wheel speeds, and the first average value. The formula is as follows:

[0093] v_wheel_Ref=γ*v_avg+(1+γ)*V_min

[0094] Wherein, v_wheel_Ref represents the second reference vehicle speed, γ represents the dynamic weight, V_min represents the minimum wheel speed, and v_avg represents the first average value of each target wheel speed corresponding to a non-zero credibility.

[0095] In this embodiment, the process of obtaining the second reference vehicle speed is as follows: Figure 4 As shown, the details are as follows:

[0096] start.

[0097] S04-1, calculate the basic wheel speed index (calculate the first average value),

[0098] S04-2, dynamic weight calculation.

[0099] S04-3, calculating a reference vehicle speed based on the wheel speed (calculating a second reference vehicle speed).

[0100] In this embodiment, a unique dynamic weight γ is designed to establish a functional relationship with the longitudinal acceleration, and a limiting function is used to ensure that the value is reasonable. This dynamic weight can be automatically adjusted according to the vehicle's acceleration and deceleration status, so that the wheel speed reference calculation is more consistent with the actual vehicle speed under different working conditions.

[0101] Optionally, based on the first credibility, the second credibility, the current first reference vehicle speed, and the current second reference vehicle speed, the current target reference vehicle speed is calculated using the following formula:

[0102]

[0103] Among them, v_ref represents the current target reference speed, α represents the second credibility, v_wheel_Ref represents the second reference speed, β represents the first credibility, V_TCS represents the first reference speed, and δ is a preset constant used for division by zero protection.

[0104] In this embodiment, the average and minimum wheel speeds are fused through dynamic weights, and a first credibility β and a second credibility α based on an exponential function are introduced. A weighted fusion formula in the form of a numerator and denominator is used to comprehensively calculate the final reference vehicle speed. This embodiment has strong robustness and can tolerate severe conditions such as complete failure of a single wheel or temporary slippage of two wheels. When encountering sudden road conditions or wheel failures, the vehicle can still maintain a certain driving ability, reducing the risk of the vehicle being trapped or out of control, and ensuring the safety and reliability of off-road driving.

[0105] Optionally, calculating the current target reference vehicle speed based on the first credibility, the second credibility, the current first reference vehicle speed, and the current second reference vehicle speed further includes:

[0106] Obtain the target speed input by the user and calculate the acceleration amplitude based on the target speed and various target reference speeds within the historical time period;

[0107] Calculate the maximum and minimum boundary limits of the speed adjustment based on the target speed, the target reference speed at the previous moment, and the acceleration amplitude;

[0108] Limiting the current target reference vehicle speed to between the maximum boundary limit and the minimum boundary limit to determine a limited reference vehicle speed;

[0109] The limited reference vehicle speed is low-pass filtered using a first-order low-pass filtering algorithm to determine the final reference vehicle speed.

[0110] In this embodiment, a first-order low-pass filter is performed on the reference vehicle speed to eliminate high-frequency fluctuations and provide a stable and reliable vehicle speed input signal for the cruise control system.

[0111] For example, Figure 5 As shown, the process is as follows:

[0112] start.

[0113] S06-1, acceleration limit.

[0114] The absolute value of the difference between the target vehicle speed (Vx_Tar) and each target reference vehicle speed in the historical time period (in this embodiment, the target reference vehicle speeds at 6 moments in the historical time period are selected) is calculated to obtain the acceleration amplitude dv_TarLimt = [0.1 0.2 0.3 0.5 0.8 1].

[0115] S06-2, Boundary Restrictions.

[0116] Based on the target speed, the target reference speed at the previous moment, and the acceleration amplitude, the maximum boundary limit and the current minimum boundary limit of the speed adjustment are calculated using the following formula:

[0117] Vx_AxTarLimtMax=v_ref_Finish_k1+dv_TarLimt*dt

[0118] Vx_AxTarLimtMin=v_ref_Finish_k1-dv_TarLimt*dt

[0119] Among them, v_ref_Finish_k1 represents the difference between the target vehicle speed and the target reference vehicle speed at the previous moment, Vx_AxTarLimtMax represents the maximum boundary limit, and Vx_AxTarLimtMin represents the minimum boundary limit.

[0120] S06-3 outputs smoothing filtering processing.

[0121] The current target reference vehicle speed is limited between the maximum boundary limit and the minimum boundary limit to obtain the limited reference vehicle speed v_ref_Finish_Raw.

[0122] The limited reference speed is low-pass filtered using a first-order low-pass filtering algorithm to determine the final reference speed. The calculation method is as follows:

[0123] V_ref_Finish=V_ref_Finish_k1+(V_ref_Finish_Raw-V_ref_Finish_k1)*b1

[0124] Among them, b1 is the filter coefficient, the value range is between 0.75-0.9, and V_ref_Finish represents the final reference vehicle speed.

[0125] like Figure 6 As shown, the present disclosure provides a reference vehicle speed calculation device for off-road cruising, comprising:

[0126] a first reference vehicle speed acquisition module, configured to acquire wheel speed information and a first reference vehicle speed in real time when the vehicle is in an off-road cruise function; wherein the wheel speed information includes the speed of each wheel of the vehicle, and the first reference vehicle speed is the first reference vehicle speed output by the vehicle's TCS system;

[0127] A first credibility calculation module is configured to calculate a first credibility of a current first reference vehicle speed based on first reference vehicle speeds at adjacent moments; wherein the first credibility represents the stability of the first reference vehicle speed;

[0128] A second credibility calculation module is configured to calculate a second credibility of the current first reference vehicle speed based on the current wheel speed information; wherein the second credibility represents the stability of the first reference vehicle speed determined by the wheel speed signal;

[0129] A second reference vehicle speed calculation module, configured to calculate a current second reference vehicle speed based on the current wheel speed signal;

[0130] The current target reference vehicle speed calculation module is used to calculate the current target reference vehicle speed based on the first credibility, the second credibility, the current first reference vehicle speed and the current second reference vehicle speed.

[0131] Optionally, the first credibility calculation module is specifically configured to:

[0132] Based on the first reference vehicle speed at adjacent moments, the preset filter coefficient, and the preset operation cycle, the stability of the reference vehicle speed is determined using the following formula:

[0133]

[0134] Wherein, k represents stability, k1 represents the rate of change calculated from the first reference vehicle speed at adjacent moments, dv_TCS represents the difference calculated from the first reference vehicle speed v_TCS at adjacent moments, dt represents the preset operation period, and b0 represents the preset filter coefficient;

[0135] Based on stability, the first credibility is calculated as follows:

[0136] β = 1-min(1, k);

[0137] Wherein, β represents the first credibility.

[0138] Optionally, the second credibility calculation module is specifically configured to:

[0139] Preprocessing the wheel speed of each wheel in the current wheel speed information to determine the target wheel speed of each wheel; wherein the preprocessing includes low-pass filtering and wheel speed correction;

[0140] The credibility of the target wheel speeds that do not meet the preset conditions among the target wheel speeds is set to zero;

[0141] Calculate the standard deviation of each target wheel speed corresponding to a non-zero reliability and determine the standard deviation wheel speed. The formula is as follows:

[0142]

[0143] Where σ represents the standard deviation of wheel speed, v_i represents the i-th target wheel speed with non-zero reliability, v_avg represents the first average value of each target wheel speed with non-zero reliability, and i represents the number of target wheel speeds with non-zero reliability.

[0144] Based on the standard deviation wheel speed, the second reliability is calculated as follows:

[0145] α=exp(-σ / 2)

[0146] Here, α represents the second credibility.

[0147] Optionally, the first credibility calculation module is specifically configured to:

[0148] Sort the target wheel speeds, and calculate the average of the target wheel speeds after excluding the maximum and minimum values ​​to determine a second average value;

[0149] Obtain the initial credibility of each wheel. If the absolute value of the difference between the target wheel speed and the second average value is greater than the first threshold, set the credibility of the corresponding wheel to zero, and

[0150] If the braking force of the wheel is greater than the second threshold, the credibility of the corresponding wheel is set to zero.

[0151] Optionally, the second reference vehicle speed calculation module is specifically configured to:

[0152] Get the longitudinal acceleration of the vehicle and calculate the dynamic weight based on the longitudinal acceleration. The formula is as follows:

[0153] γ=clip(0.65-0.13*a_x,0.3,0.9)

[0154] Wherein, γ represents the dynamic weight, and 0.3<γ<0.9, clip represents the clipping function, and a_x represents the longitudinal acceleration;

[0155] The second reference vehicle speed is determined based on the dynamic weight, the minimum wheel speed among the target wheel speeds, and the first average value. The formula is as follows:

[0156] v_wheel_Ref=γ*v_avg+(1+γ)*V_min

[0157] Wherein, v_wheel_Ref represents the second reference vehicle speed, γ represents the dynamic weight, V_min represents the minimum wheel speed, and v_avg represents the first average value of each target wheel speed corresponding to a non-zero credibility.

[0158] Optionally, the current target reference speed calculation module is specifically configured to:

[0159] Based on the first credibility, the second credibility, the current first reference speed, and the current second reference speed, the current target reference speed is calculated using the following formula:

[0160]

[0161] Among them, v_ref represents the current target reference speed, α represents the second credibility, v_wheel_Ref represents the second reference speed, β represents the first credibility, V_TCS represents the first reference speed, and δ is a preset constant used for division by zero protection.

[0162] Optionally, the system further includes a final reference vehicle speed determination module, specifically configured to:

[0163] Obtain the target speed input by the user and calculate the acceleration amplitude based on the target speed and various target reference speeds within the historical time period;

[0164] Calculate the maximum and minimum boundary limits of the speed adjustment based on the target speed, the target reference speed at the previous moment, and the acceleration amplitude;

[0165] Limiting the current target reference vehicle speed to between the maximum boundary limit and the minimum boundary limit to determine a limited reference vehicle speed;

[0166] The limited reference speed is low-pass filtered using a first-order low-pass filtering algorithm to determine the final reference speed.

[0167] A computing device according to an embodiment of the present disclosure includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the aforementioned method for calculating a reference vehicle speed for off-road cruising is implemented. That is, a computing device according to an embodiment of the present disclosure may include, but is not limited to: a processor and a memory; the memory is used to store the computer program; and the processor is used to execute the method for calculating a reference vehicle speed for off-road cruising shown in any embodiment of the present disclosure by calling the computer program.

[0168] In an alternative embodiment, a computing device is provided, such as Figure 7 As shown, Figure 7 The computing device 4000 shown includes a processor 4001 and a memory 4003. The processor 4001 and the memory 4003 are connected, for example, via a bus 4002. Optionally, the computing device 4000 may also include a transceiver 4004, which can be used for data exchange between the computing device and other computing devices, such as data transmission and / or data reception. It should be noted that in actual applications, the number of transceivers 4004 is not limited to one, and the structure of the computing device 4000 does not constitute a limitation on the embodiments of the present disclosure.

[0169] Processor 4001 can be a CPU (Central Processing Unit), a general-purpose processor, a DSP (Digital Signal Processor), an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. It can implement or execute the various exemplary logic blocks, modules, and circuits described in conjunction with the present disclosure. Processor 4001 can also be a combination that implements computing functions, such as a combination of one or more microprocessors, a combination of a DSP and a microprocessor, etc.

[0170] Bus 4002 may include a path for transmitting information between the above components. Bus 4002 may be a PCI (Peripheral Component Interconnect) bus or an EISA (Extended Industry Standard Architecture) bus. Bus 4002 may be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 7 In the figure, only one thick line is used to represent the bus 4002, but this does not mean that there is only one bus or one type of bus.

[0171] The memory 4003 may be a ROM (Read Only Memory) or other types of static storage devices that can store static information and instructions, a RAM (Random Access Memory) or other types of dynamic storage devices that can store information and instructions, or an EEPROM (Electrically Erasable Programmable Read Only Memory), a CD-ROM (Compact Disc Read Only Memory) or other optical disk storage, optical disk storage (including compact discs, laser discs, optical discs, digital versatile discs, Blu-ray discs, etc.), a magnetic disk storage medium or other magnetic storage device, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and can be accessed by a computer, but is not limited to these.

[0172] The memory 4003 is used to store application code (computer program) for executing the solution of the present disclosure, and the execution is controlled by the processor 4001. The processor 4001 is used to execute the application code stored in the memory 4003 to implement the content shown in the above method embodiment.

[0173] Among them, the computing device can also be a terminal device, and the terminal device can be any device that can install applications, including at least one of a smartphone, a tablet computer, a laptop computer, a desktop computer, a smart speaker, a smart watch, a smart TV, and a smart car device.

[0174] It should be noted that Figure 7 The computing device shown is only an example and should not bring any limitation to the functionality and scope of use of the embodiments of the present disclosure.

[0175] A computer-readable storage medium according to an embodiment of the present disclosure stores a computer program, which, when executed by a processor, implements the above-mentioned reference vehicle speed calculation method for off-road cruising.

[0176] Alternatively, the computer-readable storage medium may be a read-only memory (ROM), a random access memory (RAM), a compact disc (CD-ROM), a magnetic tape, a floppy disk, an optical data storage device, or the like.

[0177] In an exemplary embodiment, a computer program product or computer program is also provided. The computer program product or computer program includes computer instructions stored in a computer-readable storage medium. A processor of a computing device reads the computer instructions from the computer-readable storage medium and executes the computer instructions, causing the computing device to perform the aforementioned method for calculating a reference vehicle speed for off-road cruising.

[0178] Computer program code for performing the operations of the present disclosure may be written in one or more programming languages, or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, C++, and conventional procedural programming languages ​​such as "C" or similar programming languages. The program code may be executed entirely on the user's computer, partially on the user's computer, as a stand-alone software package, partially on the user's computer and partially on a remote computer, or entirely on the remote computer or server. In cases involving a remote computer, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., through the Internet using an Internet service provider).

[0179] It should be understood that the flowcharts and block diagrams in the accompanying drawings illustrate the possible implementation architecture, functions and operations of the methods and computer program products according to various embodiments of the present disclosure. In this regard, each box in the flowchart or block diagram can represent a module, program segment, or a part of code, and the module, program segment, or a part of code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a different order than that marked in the accompanying drawings. For example, two boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or flowchart, and the combination of the boxes in the block diagram and / or flowchart, can be implemented by a dedicated hardware-based system that performs the specified function or operation, or can be implemented by a combination of dedicated hardware and computer instructions.

[0180] The computer-readable storage medium provided in the embodiments of the present disclosure may be, but is not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device or component, or any combination thereof. More specific examples of computer-readable storage media may include, but are not limited to, an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EEPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination thereof. In the present disclosure, a computer-readable storage medium may be any tangible medium containing or storing a program that can be used by or in combination with an instruction execution system, device, or device.

[0181] The computer-readable storage medium carries one or more programs. When the one or more programs are executed by the computing device, the computing device executes the method shown in the above embodiment.

[0182] The above description is merely a preferred embodiment of the present disclosure and an illustration of the technical principles employed. Those skilled in the art should understand that the scope of disclosure involved in the present disclosure is not limited to the technical solutions formed by the specific combination of the above-mentioned technical features, but also includes other technical solutions formed by any combination of the above-mentioned technical features or their equivalents without departing from the above-mentioned disclosed concepts. For example, a technical solution formed by replacing the above-mentioned features with (but not limited to) technical features with similar functions disclosed in this disclosure.

[0183] It should be noted that the terms "first," "second," and the like in the specification and claims of this application are used to distinguish similar objects and to define a specific order or precedence. Where appropriate, the order used for similar objects may be interchanged, such that the embodiments of the present application described herein can be implemented in an order other than the order shown or described.

[0184] Those skilled in the art will appreciate that the present disclosure may be implemented as a system, method, or computer program product. Therefore, the present disclosure may be implemented in the following forms: entirely in hardware, entirely in software (including firmware, resident software, microcode, etc.), or in a combination of hardware and software, generally referred to herein as a "circuit," "module," or "system." Furthermore, in some embodiments, the present disclosure may be implemented in the form of a computer program product embodied in one or more computer-readable media, wherein the computer-readable media contains computer-readable program code.

[0185] Although the embodiments of the present disclosure have been shown and described above, it is understood that the above embodiments are illustrative and are not to be construed as limitations on the present disclosure. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present disclosure.

Claims

1. A method for calculating a reference vehicle speed for off-road cruising, characterized in that: include: When the vehicle is in the off-road cruise function, wheel speed information and a first reference vehicle speed are acquired in real time; wherein the wheel speed information includes the wheel speed of each wheel of the vehicle, and the first reference vehicle speed is the first reference vehicle speed output by the vehicle's TCS system; Calculating a first reliability of a current first reference vehicle speed based on the first reference vehicle speed at adjacent moments; wherein the first reliability represents the stability of the first reference vehicle speed; Calculating a second reliability of the current first reference vehicle speed based on the current wheel speed information; wherein the second reliability represents the stability of the first reference vehicle speed determined by the wheel speed signal; Calculating a current second reference vehicle speed based on the current wheel speed signal; A current target reference vehicle speed is calculated based on the first credibility, the second credibility, the current first reference vehicle speed, and the current second reference vehicle speed.

2. The method according to claim 1, characterized in that The calculating the first credibility of the current first reference vehicle speed based on the first reference vehicle speed at adjacent moments includes: Based on the first reference vehicle speed at adjacent moments, a preset filter coefficient, and a preset operation cycle, the stability of the reference vehicle speed is determined using the following formula: Wherein, k represents stability, k1 represents a rate of change value calculated from the first reference vehicle speed at adjacent moments, dv_TCS represents a difference value calculated from the first reference vehicle speed v_TCS at adjacent moments, dt represents a preset operation period, and d0 represents a preset filter coefficient; Based on the stability, the first credibility is calculated using the following formula: β = 1-min(1, k); Wherein, β represents the first credibility.

3. The method according to claim 1, characterized in that The calculating the second credibility of the current first reference vehicle speed based on the current wheel speed information includes: Preprocessing the wheel speed of each wheel in the current wheel speed information to determine a target wheel speed for each wheel; wherein the preprocessing includes low-pass filtering and wheel speed correction; setting the credibility of the target wheel speeds that do not meet the preset conditions to zero; Calculate the standard deviation of each target wheel speed corresponding to a non-zero reliability and determine the standard deviation wheel speed. The formula is as follows: Where σ represents the standard deviation of wheel speed, v_i represents the i-th target wheel speed with non-zero reliability, v_avg represents the first average value of each target wheel speed with non-zero reliability, and i represents the number of target wheel speeds with non-zero reliability. Based on the standard deviation wheel speed, the second reliability is calculated using the following formula: α=exp(-σ / 2) Here, α represents the second credibility.

4. The method according to claim 3, characterized in that The step of setting the credibility corresponding to the target wheel speeds that do not meet the preset condition among the target wheel speeds to zero includes: sorting the target wheel speeds, and calculating an average of the target wheel speeds after excluding the maximum and minimum values ​​to determine a second average value; Obtaining the initial credibility corresponding to each wheel, if the absolute value of the difference between the target wheel speed and the second average value is greater than a first threshold, setting the credibility of the corresponding wheel to zero, and If the braking force of the wheel is greater than the second threshold, the credibility of the corresponding wheel is set to zero.

5. The method according to claim 4, characterized in that Calculating the current second reference vehicle speed based on the current wheel speed signal includes: The longitudinal acceleration of the vehicle is obtained, and based on the longitudinal acceleration, the dynamic weight is calculated according to the following formula: γ=clip(0.65-0.13*a_x,0.3,0.9) Wherein, γ represents the dynamic weight, and 0.3<γ<0.9, clip represents the clipping function, and a_x represents the longitudinal acceleration; Based on the dynamic weight, the minimum wheel speed among the target wheel speeds, and the first average value, a second reference vehicle speed is determined using the following formula: v_wheel_Ref=γ*v_avg+(1+γ)*V_min Wherein, v_wheel_Ref represents the second reference vehicle speed, γ represents the dynamic weight, V_min represents the minimum wheel speed, and v_avg represents the first average value of each target wheel speed corresponding to a non-zero credibility.

6. The method according to claim 1, characterized in that The current target reference speed is calculated based on the first credibility, the second credibility, the current first reference speed, and the current second reference speed. The formula is as follows: Among them, v_ref represents the current target reference speed, α represents the second credibility, v_wheel_Ref represents the second reference speed, β represents the first credibility, V_TCS represents the first reference speed, and δ is a preset constant used for division by zero protection.

7. The method according to any one of claims 1 to 6, characterized in that The method further includes: Obtaining a target vehicle speed input by a user, and calculating an acceleration magnitude based on the target vehicle speed and various target reference vehicle speeds within a historical time period; Calculating a maximum boundary limit and a minimum boundary limit of the vehicle speed adjustment based on the target vehicle speed, the target reference vehicle speed at the previous moment, and the acceleration amplitude; Limiting the current target reference vehicle speed between the maximum boundary limit and the minimum boundary limit to determine a limited reference vehicle speed; The limited reference vehicle speed is low-pass filtered using a first-order low-pass filtering algorithm to determine the final reference vehicle speed.

8. A reference vehicle speed calculation system for off-road cruising, characterized in that: include: a first reference vehicle speed acquisition module, configured to acquire wheel speed information and a first reference vehicle speed in real time when the vehicle is in an off-road cruise function; wherein the wheel speed information includes the speed of each wheel of the vehicle, and the first reference vehicle speed is the first reference vehicle speed output by the vehicle's TCS system; a first credibility calculation module, configured to calculate a first credibility of a current first reference vehicle speed based on the first reference vehicle speed at adjacent moments; wherein the first credibility represents the stability of the first reference vehicle speed; a second credibility calculation module, configured to calculate a second credibility of the current first reference vehicle speed based on the current wheel speed information; wherein the second credibility represents the stability of the first reference vehicle speed determined by the wheel speed signal; A second reference vehicle speed calculation module, configured to calculate a current second reference vehicle speed based on the current wheel speed signal; The current target reference vehicle speed calculation module is configured to calculate the current target reference vehicle speed based on the first credibility, the second credibility, the current first reference vehicle speed, and the current second reference vehicle speed.

9. A computing device comprising a memory, a processor, and a program stored in the memory and running on the processor, characterized in that: When the processor executes the program, the steps of the method for calculating a reference vehicle speed for off-road cruising as described in any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium, characterized in that The computer-readable storage medium stores instructions, which, when executed on a terminal device, cause the terminal device to execute the steps of a method for calculating a reference vehicle speed for off-road cruising as described in any one of claims 1 to 7.

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