Slope estimation method and system for abrupt slope slow descent and computer storage medium

Abstract

The invention discloses a gradient estimation method and system for abrupt slope slow descent and a computer storage medium, and the gradient estimation method for abrupt slope slow descent comprises the steps that the yaw velocity of a vehicle is obtained according to kinematics parameters of the vehicle; determining the acceleration of the mass center of the vehicle based on the yaw velocity; calculating an acceleration deviation caused by the yaw velocity according to the acceleration measured by an inertial sensor and the yaw velocity; calculating an initial gradient acceleration value based on the acceleration of the vehicle mass center, the acceleration measured by the inertial sensor and the acceleration deviation; on the basis of the initial gradient acceleration value and the pitch angle of the vehicle, gradient estimation is compensated, and a compensated gradient value is obtained.

Description

TECHNICAL FIELD

[0001] Embodiments of the present specification relate to the technical field of vehicle control, and particularly relate to a slope estimation method, system and computer storage medium for steep slope slow descent. BACKGROUND

[0002] Hill Descent Control (HDC) is an important vehicle auxiliary driving function, which automatically controls brake pressure when descending steep slopes to keep the vehicle at a constant low speed, thereby reducing the burden on the driver. The stable operation of the HDC system depends highly on the accurate estimation of the current slope.

[0003] Generally, the combination of off-road driving and steep slope descent is difficult for ordinary drivers to handle. In these cases, the HDC function of the vehicle can help the driver keep the vehicle speed constant, so that the driver only needs to concentrate on the steering wheel. HDC is a comfort function that helps the driver to descend by active brake intervention. Therefore, the vehicle speed can be limited without driver intervention, and most of the slope calculations on the market are estimated based on inertial sensors (IMU) and vehicle kinematics, so the accuracy of slope estimation is a basic condition to ensure the stable operation of HDC. SUMMARY

[0004] Therefore, the present specification provides a slope estimation method, system and computer storage medium for steep slope slow descent to solve the problem of inaccurate slope estimation caused by vehicle pitch motion in the prior art.

[0005] The embodiments of the present specification adopt the following technical solutions:

[0006] The embodiments of the present specification provide a slope estimation method for steep slope slow descent, which comprises:

[0007] According to the kinematic parameters of the vehicle, the yaw angular velocity of the vehicle is obtained;

[0008] Based on the yaw angular velocity, the acceleration of the vehicle center of mass is determined;

[0009] According to the acceleration measured by the inertial sensor and the yaw angular velocity, the acceleration deviation caused by the yaw angular velocity is calculated;

[0010] Based on the acceleration of the vehicle center of mass, the acceleration measured by the inertial sensor and the acceleration deviation, an initial slope acceleration value is calculated;

[0011] Compensate the slope estimation based on the initial slope acceleration value and the pitch angle of the vehicle to obtain a compensated slope value.

[0012] The embodiment of the present specification also provides a slope estimation system for steep slope slow descent, which comprises:

[0013] An acquisition module is configured to acquire a yaw rate of the vehicle according to kinematic parameters of the vehicle.

[0014] A determination module is configured to determine an acceleration of a mass center of the vehicle based on the yaw rate.

[0015] A first calculation module is configured to calculate an acceleration deviation caused by the yaw rate according to an acceleration measured by an inertial sensor and the yaw rate.

[0016] A second calculation module is configured to calculate an initial slope acceleration value based on the acceleration of the mass center of the vehicle, the acceleration measured by the inertial sensor and the acceleration deviation.

[0017] A compensation module is configured to compensate the slope estimation based on the initial slope acceleration value and the pitch angle of the vehicle to obtain a compensated slope value.

[0018] The embodiment of the present specification also provides a computer storage medium comprising a program used in combination with an electronic device, and the program can be executed by a processor to complete the following steps:

[0019] Acquire a yaw rate of the vehicle according to kinematic parameters of the vehicle.

[0020] Determine an acceleration of a mass center of the vehicle based on the yaw rate.

[0021] Calculate an acceleration deviation caused by the yaw rate according to an acceleration measured by an inertial sensor and the yaw rate.

[0022] Calculate an initial slope acceleration value based on the acceleration of the mass center of the vehicle, the acceleration measured by the inertial sensor and the acceleration deviation.

[0023] Compensate the slope estimation based on the initial slope acceleration value and the pitch angle of the vehicle to obtain a compensated slope value.

[0024] The above at least one technical scheme adopted by the embodiment of the present specification can achieve the following beneficial effects:

[0025] The acceleration of the vehicle mass center is determined by the yaw angular velocity of the vehicle, the acceleration deviation caused by the yaw angular velocity is calculated according to the acceleration measured by the inertial sensor and the yaw angular velocity, the initial slope acceleration value is calculated based on the acceleration of the vehicle mass center, the acceleration measured by the inertial sensor and the acceleration deviation, and then the slope estimation is compensated based on the initial slope acceleration value and the pitch angle of the vehicle to obtain the compensated slope value.

[0026] In this way, by introducing the vehicle pitch angle compensation, the interference of the lifting and nodding motion caused by vehicle acceleration and braking on the measurement of the inertial sensor is effectively eliminated, and the accuracy of the slope estimation is greatly improved; accurate slope estimation ensures that the HDC system can be activated and exited at the correct time, avoids frequent switching on the critical slope, improves driving comfort and system reliability, and can also provide a more accurate estimation method for other functional modules that need to use the slope signal, and has high engineering application value. BRIEF DESCRIPTION OF DRAWINGS

[0027] The drawings described herein are used to provide further understanding of the embodiments of the present specification, and form a part of the present specification. The schematic embodiments of the present specification and their descriptions are used to explain the present application, and do not constitute an improper limitation on the present application. In the drawings:

[0028] Figure 1 A flowchart of a slope estimation method for steep slope slow descent provided by the embodiments of the present specification;

[0029] Figure 2 A principle diagram of vehicle kinematic acceleration calculation corresponding to a slope estimation method for steep slope slow descent provided by the embodiments of the present specification;

[0030] Figure 3 A principle diagram of slope estimation compensation corresponding to a slope estimation method for steep slope slow descent provided by the embodiments of the present specification;

[0031] Figure 4 A structure diagram of a slope estimation system for steep slope slow descent provided by the embodiments of the present specification;

[0032] Figure 5 A structure diagram of a computer storage medium corresponding to a slope estimation method for steep slope slow descent provided by the embodiments of the present specification. DETAILED DESCRIPTION

[0033] At present, the slope of HDC is estimated according to the inertial sensor (IMU) and vehicle kinematics. This estimation method is easily affected by the acceleration and deceleration of the vehicle, resulting in inaccurate slope estimation, which causes the HDC to frequently activate and exit on the critical slope, affecting the work of the HDC.

[0034] Therefore, the embodiment of the present specification provides a slope estimation method, system and computer storage medium for steep slope slow descent, the acceleration of the vehicle mass center is determined through the yaw angular velocity of the vehicle, the acceleration deviation caused by the yaw angular velocity is calculated according to the acceleration measured by the inertial sensor and the yaw angular velocity, the initial slope acceleration value is calculated based on the acceleration of the vehicle mass center, the acceleration measured by the inertial sensor and the acceleration deviation, and then the slope estimation is compensated based on the initial slope acceleration value and the pitch angle of the vehicle, and the compensated slope value is obtained.

[0035] In this way, by introducing the vehicle pitch angle compensation, the interference of the lifting and nodding motion caused by the vehicle acceleration and braking on the measurement of the inertial sensor is effectively eliminated, and the accuracy of the slope estimation is greatly improved; accurate slope estimation ensures that the HDC system can be activated and exited at the correct time, avoids frequent switching on the critical slope, improves driving comfort and system reliability, and can also provide a more accurate estimation method for other function modules that need to use the slope signal, which has high engineering application value.

[0036] In order to make the purpose, technical scheme and advantages of the present application clearer, the technical scheme of the present application will be described clearly and completely in combination with the specific embodiments of the present specification and the corresponding drawings. Obviously, the described embodiments are only part of the embodiments of the present specification, not all. Based on the embodiments in the present specification, all other embodiments obtained by those skilled in the art without creative labor belong to the scope of protection of the present application.

[0037] The technical scheme provided by each embodiment of the present specification will be described in detail below in combination with the drawings.

[0038] As shown in Figure 1 Fig. 1 is a flowchart of a slope estimation method for steep slope slow descent provided by an embodiment of the present specification.

[0039] In the embodiment of the present specification, the slope estimation method for steep slope slow descent can specifically include the following steps:

[0040] S101: obtaining the yaw angular velocity of the vehicle according to the kinematic parameters of the vehicle;

[0041] S103: determining the acceleration of the vehicle mass center based on the yaw angular velocity;

[0042] S105: calculating the acceleration deviation caused by the yaw angular velocity according to the acceleration measured by the inertial sensor and the yaw angular velocity;

[0043] S107: Calculate an initial slope acceleration value based on the acceleration of the vehicle center of mass, the acceleration measured by the inertial sensor, and the acceleration deviation;

[0044] S109: Compensate the slope estimation based on the initial slope acceleration value and the pitch angle of the vehicle to obtain a compensated slope value.

[0045] As an application example of the present specification, for the step S101, the yaw rate of the vehicle is obtained according to the kinematic parameters of the vehicle, including:

[0046] According to the yaw rate = wheel linear speed * trigonometric function of corresponding wheel angle / vehicle wheelbase, the yaw rates of the four wheels are calculated;

[0047] Based on the calculated yaw rates of the four wheels, the yaw rate of the vehicle is obtained by weighted average or filtering.

[0048] In the embodiments of the present specification, the yaw rate (Yaw Rate) refers to the rotational speed of the vehicle around its vertical axis during driving, which reflects the dynamic characteristics of the vehicle during steering, and is usually expressed in units of "degrees / second" or "radians / second". The calculation of the yaw rate involves factors such as the longitudinal speed of the vehicle and the steering radius, and can usually be estimated by sensor data or mathematical models.

[0049] Generally, the yaw rate can be calculated according to the following formula (1):

[0050] Yaw Rate = V / R = tanθ / L*V, formula (1)

[0051] Where Yaw Rate is the yaw rate, V is the vehicle speed, R is the steering radius, L is the vehicle wheelbase, and θ is the average front wheel angle.

[0052] Specifically, the vehicle wheelbase L (unit, meters) can be calculated according to the following formula (2):

[0053] L = a + b formula (2)

[0054] Where a is the distance from the center of mass of the vehicle to the front axle, and b is the distance from the center of mass of the vehicle to the rear axle.

[0055] The vehicle wheelbase L is equal to the sum of the distance from the center of mass to the front axle and the distance from the center of mass to the rear axle. By calculating the vehicle wheelbase, the geometric dimension parameters of the vehicle are determined, providing a basis for subsequent steering calculations.

[0056] Specifically, θ can be calculated according to the following Ackerman formula:

[0057] θ = (θR+ θL) / 2 Equation (3)

[0058] wherein θR is the right front wheel steering angle (unit: radian), and θL is the left front wheel steering angle (unit: radian).

[0059] By Ackerman formula, the actual double front wheel steering system can be simplified as a single track model, because in the actual steering, the inner and outer wheels have different steering angles (Ackerman geometry), and the average value can well approximate the whole vehicle steering characteristics. Therefore, θ can be equivalent to the single track model steering angle, which is used for simplifying calculation.

[0060] In general, the steering radius R can be calculated according to the following formula (4):

[0061] tan θ = L / R, Equation (4)

[0062] wherein θ is the average front wheel steering angle, and L is the vehicle wheelbase.

[0063] In order to improve the accuracy of vehicle steering geometry calculation, the trigonometric functions of left and right wheel steering angles can be used to calculate the exact speed vector of each wheel, so as to more accurately calculate the yaw rate of the vehicle and be used for correcting the wheel speed signal.

[0064] In actual application scenarios, when the vehicle is steering, it is moving around a transient steering center. The design goal of Ackerman steering geometry is to make the axes of the four wheels intersect at this point in the ideal case, so as to realize pure rolling.

[0065] In order to determine the speed of each wheel, the distance from each wheel to the transient steering center, i.e. the steering radius R, that is, the radius of the circle in which the center of mass of the vehicle is located when the vehicle is steering, needs to be known.

[0066] In the embodiments of the present specification, the steering radius of each wheel can be calculated according to the following formula (5).

[0067] Right front wheel steering radius R_RF = L / sin θR

[0068] Left front wheel steering radius R_LF = L / sin θL

[0069] Right rear wheel steering radius R_RR = L / tan θR

[0070] Left rear wheel steering radius R_LR = L / tan θL Equation (5)

[0071] wherein sin θR, sin θL, tan θR, and tan θL are the trigonometric functions of the left and right wheel steering angles, respectively.

[0072] Further, the linear speed of each wheel can be calculated according to the relationship between the linear speed of the wheel and the yaw rate and the wheel steering radius.

[0073] Wherein, the relationship between the linear velocity of the wheel and the yaw rate, the steering radius of the wheel is that the linear velocity of the wheel = the yaw rate * the steering radius of the wheel.

[0074] In the actual application scenario, the linear velocity of each wheel can be measured by the wheel speed sensor, so that the yaw rate can be inversely deduced by the relationship between the linear velocity of the wheel and the yaw rate, the steering radius of the wheel.

[0075] In theory, the yaw rate can be calculated from the linear velocity of the four wheels, but because the inner and outer wheels have different paths, the yaw rates calculated by them should be consistent. In the actual algorithm, the linear velocity signals and the steering angle signals of the four wheels are comprehensively utilized to obtain an optimal and reliable yaw rate estimation value through weighted average or filtering.

[0076] Compared with the simple single-track model, the double-track model is used and the steering angle of each wheel is considered, so that the real yaw rate of the vehicle can be more accurately calculated, especially in large steering angles or dynamic working conditions.

[0077] As an application example of the present specification, for the step S103, determining the acceleration of the vehicle mass center based on the yaw rate can specifically include:

[0078] Correcting the wheel speed signal of the vehicle based on the yaw rate;

[0079] Calculating the speed of the vehicle mass center according to the corrected wheel speed signal;

[0080] Differencing and filtering the speed of the vehicle mass center to obtain the acceleration of the vehicle mass center.

[0081] In the embodiment of the present specification, because the inner and outer wheels have different speeds when steering, the yaw rate, that is, the yaw rate, needs to be compensated to accurately calculate the mass center speed.

[0082] The yaw rate is used to correct the four wheel speeds to eliminate the influence of the speed difference between the inner and outer wheels when steering, so as to calculate a more accurate mass center speed of the vehicle.

[0083] In a specific application scenario, the speed of the vehicle mass center can be calculated according to the following formula (6):

[0084]

[0085] V y = Yaw Rate * b Formula (6)

[0086] Wherein, V COGV is the speed of the vehicle's center of mass x V is the speed of the vehicle y V is the speed of the vehicle's center of mass COG b is the distance from the center of mass to the rear axle, and Yaw Rate is the yaw rate, i.e., the yaw rate.

[0087] Further, by differentiating the center of mass speed and low-pass filtering, a smooth acceleration of the vehicle's center of mass can be obtained.

[0088] In a specific application scenario, the acceleration of the vehicle's center of mass can be calculated according to the following formula (7):

[0089] AxF = dot*V COG Formula (7)

[0090] AxF is the acceleration of the center of mass, V is the speed of the vehicle's center of mass, and dot represents the derivative with respect to time.

[0091] As an application example of the present specification, for the step S105, according to the acceleration measured by the inertial sensor and the yaw rate, the acceleration deviation caused by the yaw rate is calculated, which can be calculated according to the following formula (8):

[0092] AxSlopeYawOffset = vGiF*vGiF*ScaleAxSlopeYawOffset Formula (8)

[0093] vGiF is the filtered yaw rate of the inertial optical sensor, and ScaleAxSlopeYawOffset is a preset scale factor.

[0094] In the embodiment of the present specification, when the vehicle is turning, the yaw rate will cause the slope estimation to be overestimated, causing the HDC to be activated on flat ground, so as to suppress the influence of the yaw rate on the slope estimation, by calculating the acceleration deviation caused by the yaw rate, the disturbance to the slope estimation caused by centrifugal force and other factors when the vehicle is turning can be suppressed.

[0095] As an application example of the present specification, for the step S107, based on the acceleration of the vehicle's center of mass, the acceleration measured by the inertial sensor, and the acceleration deviation, an initial slope acceleration value is calculated, which can be calculated according to the following formula (9) and formula (10):

[0096] AxSlope = AxF - Ax - AxSlopeOffset; Formula (9)

[0097] AxSlope = -AxF - Ax + AxSlopeOffset; Formula (10)

[0098] wherein, AxSlope is the initial slope acceleration value, AxF is the filtered vehicle center of mass acceleration, Ax is the longitudinal acceleration measured by the inertial sensor, and AxSlopeOffset is a preset slope acceleration offset.

[0099] In the embodiments of the present specification, the slope estimation formula calculation process of the vehicle during inertial driving is divided into forward gear and reverse gear, and can be calculated according to the above formula (9) and formula (10) respectively.

[0100] As an application embodiment of the present specification, for the step S109, the slope estimation is compensated based on the initial slope acceleration value and the pitch angle of the vehicle to obtain a compensated slope value, and specifically can include:

[0101] When the vehicle is subjected to an acceleration operation, the compensated slope value is calculated according to the following formula (11):

[0102] SlopeAngle = AxSlope(rad) - pitch; formula (11)

[0103] When the vehicle is subjected to a braking operation, the compensated slope value is calculated according to the following formula (12):

[0104] SlopeAngle = AxSlope(rad) + pitch; formula (12)

[0105] wherein, SlopeAngle is the compensated slope value, AxSlope(rad) is the value converted from the initial slope acceleration value to radian system, and pitch is the pitch angle of the vehicle.

[0106] In the embodiments of the present specification, when the driver actively controls the vehicle, such as stepping on the accelerator pedal or braking, the attitude of the inertial sensor of the vehicle will appear to lift the head or nod, which affects the measurement value of the inertial sensor and also affects the normal work of the HDC, so it is necessary to eliminate the influence of stepping on the accelerator pedal or braking on slope estimation.

[0107] Specifically, when the vehicle is subjected to an acceleration operation, that is, when the driver steps on the accelerator pedal, the vehicle lifts the head, and in this case, the compensated slope value can be calculated according to the above formula (11).

[0108] When the vehicle is subjected to a braking operation, that is, when the driver steps on the brake pedal, the vehicle nods, and in this case, the compensated slope value can be calculated according to the above formula (12).

[0109] Further, the pitch angle of the vehicle can be calculated according to the following formula (13):

[0110] pitch = arcsin(vx_dot - ax - yawrate * vy) / g ≈ (vx_dot - ax - yawrate * vy) / g; formula (13)

[0111] wherein pitch is the pitch angle of the vehicle, vx_dot is the longitudinal acceleration of the vehicle mass center, ax is the longitudinal acceleration measured by the inertial sensor, yawrate is the yaw rate, vy is the lateral speed of the vehicle, and g is the gravitational acceleration.

[0112] Further, since the initial slope acceleration value calculated according to the above formula (9) and formula (10) is in the unit of acceleration, not in the unit of angle, it is necessary to convert the slope size of the slope calculated above into the unit of angle.

[0113] Therefore, in another application of the embodiment of the present specification, after the initial slope acceleration value is calculated, the method further comprises:

[0114] converting the initial slope acceleration value into a corresponding slope angle value through a preset acceleration and angle conversion relationship.

[0115] In the embodiment of the present specification, the preset acceleration and angle conversion relationship can be that the vehicle is respectively parked on a 5%, 7%, 10%, 15%, and 20% slope to collect the size of the signal AxSlope, and the least square method is used to fit these groups of data to obtain the relationship between acceleration and angle, and through the curve, the size of the slope Slope can be obtained according to the calculated AxSlope.

[0116] The slope estimation method for steep slope gentle descent provided by the embodiment of the present specification determines the acceleration of the vehicle mass center through the yaw rate of the vehicle, calculates the acceleration deviation caused by the yaw rate according to the acceleration measured by the inertial sensor and the yaw rate, calculates the initial slope acceleration value based on the acceleration of the vehicle mass center, the acceleration measured by the inertial sensor, and the acceleration deviation, and then compensates the slope estimation based on the initial slope acceleration value and the pitch angle of the vehicle to obtain the compensated slope value.

[0117] In this way, by introducing the vehicle pitch angle compensation, the interference of the head-raising and nodding motion caused by vehicle acceleration and braking on the measurement of the inertial sensor is effectively eliminated, and the accuracy of the slope estimation is greatly improved. The accurate slope estimation ensures that the HDC system can be stably activated and exited at the correct time, avoids frequent switching on the critical slope, improves the driving comfort and system reliability, and can also provide a more accurate estimation method for other function modules that need to use the slope signal, and has high engineering application value.

[0118] It should be noted that the above specific slope estimation method for steep slope slow descent is only used as a specific application example, and does not limit the scope of the embodiments of the present application, and other specific embodiments can also be included, which will not be described one by one here.

[0119] In another application embodiment of the present application, in addition to using the vehicle kinematics estimation method, the slope estimation method can also be calculated according to the following vehicle dynamics formula (14) according to the vehicle dynamics estimation:

[0120]

[0121] Where m is the vehicle mass, p is the air density, C d is the wind resistance coefficient, A is the windward area, g is the gravitational acceleration, θ is the road slope, and f is the road rolling resistance coefficient.

[0122] Where the road slope θ is the parameter to be solved, and the recursive least square estimation method can be used to estimate the size of the slope θ.

[0123] Based on the same inventive concept, the embodiments of the present application also provide a specific application embodiment of the above traffic instruction conflict detection method.

[0124] As Figure 2 shown, a vehicle kinematics acceleration calculation principle block diagram corresponding to a slope estimation method for steep slope slow descent provided by the embodiments of the present application.

[0125] In the embodiments of the present application, the specific process of vehicle kinematics acceleration calculation is as follows:

[0126] 1. Calculate the yaw rate vGiAck through the Ackerman steering model;

[0127] 2. Combine the wheel speed signal to correct the yaw rate;

[0128] 3. Calculate the center of mass speed Vx;

[0129] 4. Perform speed difference calculation;

[0130] 5. Determine the original acceleration dVxRaw;

[0131] Nonlinear filtering processing is performed:

[0132] 6. Calculate the deviation delta_dVxRawFlt;

[0133] 7. Determine whether the deviation is less than or equal to 0;

[0134] 8. If not, keep the original value;

[0135] 9. If yes, calculate the adjustment step dVxF_AbsIncr;

[0136] Further determine whether the deviation is less than 0, if yes, adjust dVxF upward, if not, adjust dVxF downward;

[0137] 10. Get the filtered acceleration AxF.

[0138] As shown in FIG. 1, a schematic diagram of a slope estimation compensation principle corresponding to a slope estimation method for steep slope slow descent provided by an embodiment of the present specification is shown. Figure 3

[0139] In the embodiment of the present specification, the process of the slope estimation compensation can specifically include the following steps:

[0140] 1. Utilize IMU sensor data to perform yaw rate compensation;

[0141] 2. Combine vehicle kinematics acceleration AxF and yaw rate compensation to perform initial slope calculation, and obtain an initial slope value AxSlope;

[0142] 3. Perform acceleration-angle conversion on the initial slope value AxSlope, and obtain a slope angle value AxSlope_rad;

[0143] 4. Utilize vehicle dynamics model to perform vehicle pitch angle calculation, and obtain a real-time pitch angle pitch;

[0144] 5. Detect driver operation, and perform operation type judgment;

[0145] 6. Combine the slope angle value AxSlope_rad, the real-time pitch angle pitch, and the operation type judgment to perform slope compensation calculation;

[0146] 7. Determine whether to perform acceleration by stepping on the accelerator;

[0147] 8. If yes, calculate the compensated slope value based on the formula SlopeAngle = AxSlope_rad - pitch;

[0148] 9. If not, further determine whether to decelerate by stepping on the brake; ​

[0149] 10: If the deceleration is caused by braking, the compensated slope value is calculated based on the formula SlopeAngle = AxSlope_rad + pitch;

[0150] 11: If the deceleration is not caused by braking, the compensated slope value is determined based on the formula SlopeAngle = AxSlope_rad;

[0151] 12: The compensated slope value SlopeAngle is obtained.

[0152] The specific implementation process of the embodiments of the present specification can refer to the respective implementation steps corresponding to the above-mentioned embodiments, which will not be repeated here.

[0153] Based on the same inventive concept, the embodiments of the present specification also provide a slope estimation system for steep slope slow descent. As shown in the Figure 4 structure diagram of the slope estimation system for steep slope slow descent provided by the embodiments of the present specification.

[0154] The slope estimation system for steep slope slow descent can specifically include:

[0155] The acquisition module 401 acquires the yaw angular velocity of the vehicle according to the kinematic parameters of the vehicle.

[0156] The determination module 402 determines the acceleration of the vehicle mass center based on the yaw angular velocity.

[0157] The first calculation module 403 calculates the acceleration deviation caused by the yaw angular velocity according to the acceleration measured by the inertial sensor and the yaw angular velocity.

[0158] The second calculation module 404 calculates the initial slope acceleration value based on the acceleration of the vehicle mass center, the acceleration measured by the inertial sensor, and the acceleration deviation.

[0159] The compensation module 405 compensates the slope estimation based on the initial slope acceleration value and the pitch angle of the vehicle to obtain the compensated slope value.

[0160] Based on the system Figure 4 , the embodiments of the present specification also provide some specific implementation schemes of the system, which are described below.

[0161] Further, the yaw angular velocity of the vehicle is acquired according to the kinematic parameters of the vehicle, which includes:

[0162] The yaw angular velocities of the four wheels are calculated according to the formula: yaw angular velocity = wheel linear speed * trigonometric function of corresponding wheel rotation angle / vehicle wheelbase.

[0163] Based on the calculated yaw rate of the four wheels, the yaw rate of the vehicle is obtained by weighted average or filtering.

[0164] Further, the acceleration of the vehicle mass center is determined based on the yaw rate, including:

[0165] The wheel speed signal of the vehicle is corrected based on the yaw rate;

[0166] The speed of the vehicle mass center is calculated according to the corrected wheel speed signal;

[0167] The speed of the vehicle mass center is differentiated and filtered to obtain the acceleration of the vehicle mass center.

[0168] Further, the acceleration deviation caused by the yaw rate is calculated according to the acceleration measured by the inertial sensor and the yaw rate, and is calculated according to the following formula:

[0169] AxSlopeYawOffset=vGiF*vGiF*ScaleAxSlopeYawOffset;

[0170] Wherein, vGiF is the filtered yaw rate of the inertial optical sensor, and ScaleAxSlopeYawOffset is a preset scale factor.

[0171] Further, based on the acceleration of the vehicle mass center, the acceleration measured by the inertial sensor and the acceleration deviation, an initial slope acceleration value is calculated, and is calculated according to the following formula:

[0172] When the vehicle is in forward gear, AxSlope=AxF-Ax-AxSlopeOffset;

[0173] When the vehicle is in reverse gear, AxSlope=-AxF-Ax+AxSlopeOffset;

[0174] Wherein, AxSlope is the initial slope acceleration value, AxF is the filtered acceleration of the vehicle mass center, Ax is the longitudinal acceleration measured by the inertial sensor, and AxSlopeOffset is a preset slope acceleration offset.

[0175] Further, based on the initial slope acceleration value and the pitch angle of the vehicle, the slope estimation is compensated to obtain a compensated slope value, including:

[0176] When the vehicle is accelerated, the compensated slope value is calculated according to the following formula:

[0177] SlopeAngle=AxSlope(rad)-pitch;

[0178] When the vehicle is performing a braking operation, a compensated slope value is calculated according to the following formula:

[0179] SlopeAngle = AxSlope(rad) + pitch;

[0180] wherein, SlopeAngle is the compensated slope value, AxSlope(rad) is a value converted from the initial slope acceleration value to radian system, and pitch is the pitch angle of the vehicle.

[0181] Further, the pitch angle of the vehicle is calculated according to the following formula:

[0182] pitch = arcsin(vx_dot - ax - yawrate * vy) / g ≈ (vx_dot - ax - yawrate * vy) / g;

[0183] wherein, pitch is the pitch angle of the vehicle, vx_dot is the longitudinal acceleration of the vehicle mass center, ax is the longitudinal acceleration measured by the inertial sensor, yawrate is the yaw rate, vy is the lateral speed of the vehicle, and g is the gravitational acceleration.

[0184] Further, after the initial slope acceleration value is calculated, the system further comprises:

[0185] converting the initial slope acceleration value into a corresponding slope angle value through a preset acceleration and angle conversion relationship.

[0186] The slope estimation system for steep slope slow descent provided by the embodiments of the present specification determines the acceleration of the vehicle mass center through the yaw rate of the vehicle, calculates the acceleration deviation caused by the yaw rate based on the acceleration measured by the inertial sensor and the yaw rate, calculates the initial slope acceleration value based on the acceleration of the vehicle mass center, the acceleration measured by the inertial sensor and the acceleration deviation, and compensates the slope estimation based on the initial slope acceleration value and the pitch angle of the vehicle to obtain a compensated slope value.

[0187] In this way, by introducing the vehicle pitch angle compensation, the interference of the head-raising and nodding motion caused by the vehicle acceleration and braking on the measurement of the inertial sensor is effectively eliminated, and the accuracy of the slope estimation is greatly improved. The accurate slope estimation ensures that the HDC system can be stably activated and exited at the correct time, avoids frequent switching on the critical slope, improves the driving comfort and system reliability, and can also provide a more accurate estimation method for other functional modules that need to use the slope signal, and has high engineering application value.

[0188] Based on the same inventive concept, the embodiments of the present specification also provide an electronic device, comprising at least one processor and a memory, the memory storing a program and being configured to perform the following steps by the at least one processor:

[0189] According to the kinematic parameters of the vehicle, the yaw angular velocity of the vehicle is obtained;

[0190] Based on the yaw angular velocity, the acceleration of the vehicle mass center is determined;

[0191] According to the acceleration measured by the inertial sensor and the yaw angular velocity, the acceleration deviation caused by the yaw angular velocity is calculated;

[0192] Based on the acceleration of the vehicle mass center, the acceleration measured by the inertial sensor, and the acceleration deviation, an initial slope acceleration value is calculated;

[0193] Based on the initial slope acceleration value and the pitch angle of the vehicle, the slope estimation is compensated to obtain a compensated slope value.

[0194] Wherein, the other functions of the processor can also refer to the contents described in the above embodiments, which will not be repeated here.

[0195] Based on the same inventive concept, the embodiments of the present specification also provide a computer readable storage medium, comprising a program used in combination with an electronic device, the program can be executed by a processor to complete the following steps:

[0196] According to the kinematic parameters of the vehicle, the yaw angular velocity of the vehicle is obtained;

[0197] Based on the yaw angular velocity, the acceleration of the vehicle mass center is determined;

[0198] According to the acceleration measured by the inertial sensor and the yaw angular velocity, the acceleration deviation caused by the yaw angular velocity is calculated;

[0199] Based on the acceleration of the vehicle mass center, the acceleration measured by the inertial sensor, and the acceleration deviation, an initial slope acceleration value is calculated;

[0200] Based on the initial slope acceleration value and the pitch angle of the vehicle, the slope estimation is compensated to obtain a compensated slope value.

[0201] Wherein, the other functions of the processor can also refer to the contents described in the above embodiments, which will not be repeated here.

[0202] As Figure 5 shown, the embodiments of the present specification also provide a structural schematic diagram of a computer storage medium.

[0203] The systems, apparatuses, modules, or units disclosed in the above embodiments can be implemented by computer chips or entities, or by products with certain functions. A typical implementation device is a computer. Specifically, the computer can be, for example, a personal computer, a laptop computer, a cellular phone, a camera phone, a smart phone, a personal digital assistant, a media player, a navigation device, an email device, a game console, a tablet computer, a wearable device, or a combination of any of these devices.

[0204] For the sake of description, the above apparatuses are described in various units respectively according to functions. Of course, the functions of the units can be implemented in one or more software and / or hardware in the implementation of the present application.

[0205] Those skilled in the art should understand that embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROMs, optical storage devices, etc.) containing computer-usable program code.

[0206] The present application is described with reference to the flowcharts and / or block diagrams of the methods, apparatuses (systems), and computer program products according to the embodiments of the present application. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, and the combination of flows and / or blocks in the flowcharts and / or block diagrams can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing apparatus to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing apparatus produce the functions specified in the flowcharts and / or block diagrams. Figure 1 The functions specified in a flow or multiple flows and / or blocks Figure 1 The functions specified in a flow or multiple flows and / or blocks

[0207] These computer program instructions can also be stored in a computer-readable memory that can direct the computer or other programmable data processing apparatus to work in a specific manner, so that the instructions stored in the computer-readable memory produce the manufactured product including the instruction apparatus that implements the functions specified in the flowcharts and / or block diagrams. Figure 1 The functions specified in a flow or multiple flows and / or blocks Figure 1 The functions specified in a flow or multiple flows and / or blocks

[0208] These computer program instructions can also be loaded into a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks. Figure 1 Figure 1 The flowchart blocks or blocks in the multiple flows and / or blocks

[0209] In one typical configuration, the computing device includes one or more processors (CPUs), input / output interfaces, network interfaces, and memory.

[0210] The memory can include non-persistent memory and / or volatile memory, such as random access memory (RAM) about which the computer stores information about an operating system, application software, and / or the like. Memory is an example of computer readable media.

[0211] Computer readable media includes permanent and non-permanent, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read only memory (ROM), electrically erasable programmable read only memory (EEPROM), flash memory or other memory technology, compact disc read only memory (CD-ROM), digital versatile disc (DVD), or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transmission medium that can be used to store information accessible to a computing device. According to the definition herein, computer readable media does not include transitory media, such as modulated data signals and carrier waves.

[0212] It should also be noted that the terms "comprising", "containing", or any other variant thereof, are intended to encompass a non-exclusive inclusion, such that a process, method, article or apparatus that comprises a list of elements does not include only those elements recited, but can also include other elements not expressly listed or inherent to such process, method, article or apparatus. Without more limitations, an element defined by the statement "comprising a" does not exclude the presence of additional identical elements in the process, method, article or apparatus that includes the element.

[0213] ​The application can be described in the general context of computer-executable instructions, such as program modules, being executed by a computer. Generally, program modules include routines, programs, objects, components, data structures, and the like, that perform particular tasks or implement particular abstract data types. The application can also be practiced in distributed computing environments where tasks are performed by remote processing devices that are linked through a communications network. In a distributed computing environment, program modules can be located in local and remote computer storage media including memory storage devices.

[0214] Each of the embodiments in the specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other. Each embodiment focuses on the difference from other embodiments. In particular, the system embodiments are described simply because they are basically similar to the method embodiments, and the relevant parts can be referred to the description of the method embodiments.

[0215] The above only describes the embodiments of the application and is not intended to limit the application. The application can have various changes and modifications for those skilled in the art. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the application shall be included in the protection scope of the claims of the application.

Claims

1. A method for estimating the slope of a steep slope for a steep slope gradual descent, characterized by, The slope estimation method for steep slope gentle descent comprises: According to the kinematic parameters of the vehicle, the yaw rate of the vehicle is obtained; Based on the yaw rate, the acceleration of the vehicle mass center is determined; According to the acceleration measured by the inertial sensor and the yaw rate, the acceleration deviation caused by the yaw rate is calculated; Based on the acceleration of the vehicle mass center, the acceleration measured by the inertial sensor and the acceleration deviation, the initial slope acceleration value is calculated; Based on the initial slope acceleration value and the pitch angle of the vehicle, the slope estimation is compensated to obtain the compensated slope value.

2. The method of claim 1, wherein, According to the kinematic parameters of the vehicle, the yaw rate of the vehicle is obtained, comprising: According to the yaw rate = wheel linear speed * trigonometric function of corresponding wheel angle / vehicle wheelbase, the yaw rates corresponding to the four wheels are calculated; Based on the calculated yaw rates corresponding to the four wheels, the yaw rate of the vehicle is obtained by weighted average or filtering.

3. The method of claim 1, wherein, Based on the yaw rate, the acceleration of the vehicle mass center is determined, comprising: Based on the yaw rate, the wheel speed signal of the vehicle is corrected; According to the corrected wheel speed signal, the speed of the vehicle mass center is calculated; The speed of the vehicle mass center is differentiated and filtered to obtain the acceleration of the vehicle mass center.

4. The method of claim 1, wherein, According to the acceleration measured by the inertial sensor and the yaw rate, the acceleration deviation caused by the yaw rate is calculated according to the following formula: AxSlopeYawOffset = vGiF * vGiF * ScaleAxSlopeYawOffset; Wherein, vGiF is the filtered yaw rate of inertial optical sensor, ScaleAxSlopeYawOffset is the preset proportion coefficient.

5. The method of claim 4, wherein, Based on the acceleration of the vehicle mass center, the acceleration measured by the inertial sensor and the acceleration deviation, the initial slope acceleration value is calculated according to the following formula: When the vehicle is in forward gear, AxSlope = AxF - Ax - AxSlopeOffset; When the vehicle is in reverse gear, AxSlope = -AxF - Ax + AxSlopeOffset; Wherein, AxSlope is the initial slope acceleration value, AxF is the filtered acceleration of the vehicle mass center, Ax is the longitudinal acceleration measured by the inertial sensor, and AxSlopeOffset is the preset slope acceleration offset.

6. The method of claim 1, wherein, Based on the initial slope acceleration value and the pitch angle of the vehicle, the slope estimation is compensated to obtain the compensated slope value, comprising: When the vehicle is accelerated, the compensated slope value is calculated according to the following formula: SlopeAngle = AxSlope(rad) - pitch; When the vehicle is braked, the compensated slope value is calculated according to the following formula: SlopeAngle = AxSlope(rad) + pitch; Wherein, the slope angle is the compensated slope value, AxSlope(rad) is the value converted from the initial slope acceleration value to radian system, and the pitch is the pitch angle of the vehicle.

7. The method of claim 6, wherein, The pitch angle of the vehicle is calculated according to the following formula: pitch=arcsin(vx_dot–ax-yawrate*vy) / g≈(vx_dot–ax-yawrate*vy) / g; Wherein, the pitch is the pitch angle of the vehicle, vx_dot is the longitudinal acceleration of the vehicle mass center, ax is the longitudinal acceleration measured by the inertial sensor, yawrate is the yaw rate, vy is the lateral speed of the vehicle, and g is the gravity acceleration.

8. The method of claim 6, wherein, After the initial slope acceleration value is calculated, the method further comprises: Converting the initial slope acceleration value into a corresponding slope angle value through a preset acceleration and angle conversion relationship.

9. A slope estimation system for steep slope slow down, characterized by, The slope estimation system for steep slope slow descent comprises: An acquisition module configured to acquire the yaw rate of the vehicle according to the kinematic parameters of the vehicle; A determination module configured to determine the acceleration of the vehicle mass center based on the yaw rate; A first calculation module configured to calculate the acceleration deviation caused by the yaw rate according to the acceleration measured by the inertial sensor and the yaw rate; A second calculation module configured to calculate the initial slope acceleration value based on the acceleration of the vehicle mass center, the acceleration measured by the inertial sensor, and the acceleration deviation; A compensation module configured to compensate the slope estimation based on the initial slope acceleration value and the pitch angle of the vehicle, and obtain a compensated slope value. 10.A computer storage medium comprising a program used in conjunction with an electronic device, the program executable by a processor to perform the following steps: acquiring the yaw rate of the vehicle according to the kinematic parameters of the vehicle; determining the acceleration of the vehicle mass center based on the yaw rate; calculating the acceleration deviation caused by the yaw rate according to the acceleration measured by the inertial sensor and the yaw rate; calculating the initial slope acceleration value based on the acceleration of the vehicle mass center, the acceleration measured by the inertial sensor, and the acceleration deviation; compensating the slope estimation based on the initial slope acceleration value and the pitch angle of the vehicle, and obtaining a compensated slope value.

Images