Road surface gradient determination method and vehicle

Abstract

The invention relates to the technical field of vehicles, in particular to the technical field of vehicle motion control, in particular to a road surface gradient determination method and a vehicle, and aims to more accurately determine the gradient. Based on the road adhesion coefficient of the slope road and the slip rate of wheels in a target axle of the vehicle, target cornering stiffness and target residual torque corresponding to the target axle are determined; the target cornering stiffness and the target residual moment are the slope and the intercept of an equivalent linear relation curve of the lateral force of the virtual center wheel of the target axis at the target slip angle relative to the slip angle of the virtual center wheel respectively; determining a vehicle body inclination angle of the vehicle based on the target cornering stiffness, the target residual moment and the running speed information of the vehicle; the gradient of the slope pavement is determined based on the vehicle body inclination angle, and gradient determination precision is improved.

Description

A method for determining road slope and a vehicle Technical Field

[0001] This application relates to the field of vehicle technology, and more particularly to the field of vehicle motion control technology, specifically to a method for determining road slope and a vehicle. Background Technology

[0002] Currently, with the rapid development of vehicle intelligence, road surface slope, as a key parameter affecting vehicle dynamics control and driving safety, has made accurate estimation of road surface slope a core requirement for vehicle intelligence. In related technologies, road surface slope estimation is typically performed by directly determining the slope using data from onboard sensors or inertial measurement units combined with the vehicle's kinematics model.

[0003] However, this method of determining the slope does not take into account the nonlinear effects of longitudinal slippage and lateral slippage on the vehicle when it is on a sloping road surface, thus reducing the accuracy of the road slope estimation. Summary of the Invention

[0004] This application provides a method for determining road slope and a vehicle to at least solve the technical problem of insufficient accuracy in slope determination in related technologies. The technical solution adopted in this application is as follows: Firstly, this application provides a method for determining road slope, including: when the vehicle is on a sloping road surface, determining the target lateral stiffness and target residual moment corresponding to the target axle based on the road adhesion coefficient of the sloping road surface and the slip ratio of the wheel in the target axle of the vehicle; the target lateral stiffness and target residual moment are respectively the slope and intercept of the equivalent linear relationship curve of the lateral force of the virtual center wheel of the target axle at the target lateral angle with respect to the lateral angle of the virtual center wheel; the target lateral angle is determined based on the lateral angle of the wheel in the target axle; the vehicle body tilt angle is determined based on the target lateral stiffness, target residual moment and vehicle operating speed information; and the slope of the sloping road surface is determined based on the vehicle body tilt angle.

[0005] Based on the aforementioned technical means, this application can more accurately determine the lateral stiffness and residual moment of the target axle of the vehicle (e.g., the front axle or the rear axle) by using the wheel slip ratio of the vehicle on the sloping road surface and the road surface adhesion coefficient of the sloping road surface. The lateral stiffness and residual moment can effectively reflect the influence of lateral slip and longitudinal slip when the vehicle is on the sloping road surface. Based on this, the vehicle body tilt angle and the slope of the sloping road surface are determined by combining the running speed information. This not only improves the accuracy of the road slope determination, but also reduces the hardware resource cost of slope determination by using only basic on-board sensor data.

[0006] In one possible implementation, the target lateral stiffness and target residual moment of the target axle are determined based on the road adhesion coefficient of the sloping road surface and the slip ratio of the wheels on the target axle of the vehicle. This includes: estimating the lateral force of each wheel at a specified slip angle based on the road adhesion coefficient and the slip ratio of each wheel on the target axle; wherein the specified slip angle includes the slip angle of each wheel and a first slip angle and a second slip angle adjacent to the slip angle of each wheel; determining the first slope and a first intercept of the equivalent linear relationship curve of the lateral force of each wheel at the specified slip angle with respect to the slip angle of each wheel based on the lateral force of each wheel at the specified slip angle; and determining the target lateral stiffness and target residual moment based on the first slope and the first intercept.

[0007] Based on the above technical means, this application determines the lateral forces of the first and second slip angles near the slip angle of the wheel, and uses equivalent linear calculation to determine the target slip stiffness and target residual moment corresponding to the slip angle of the wheel. This not only simplifies the complex nonlinear problem in the calculation of the slip stiffness and residual moment of the slip angle and improves the calculation efficiency, but also enables more accurate determination of the target slip stiffness and target residual moment.

[0008] In one possible implementation, the lateral force of each wheel at a specified sideslip angle is estimated based on the road adhesion coefficient and the slip ratio of each wheel on the target axle, including: determining the theoretical maximum longitudinal force of each wheel based on the standard longitudinal stiffness and slip ratio of each wheel; determining the theoretical maximum lateral force of the target wheel based on the standard sideslip stiffness, slip ratio, and specified sideslip angle of each wheel; determining the theoretical maximum resultant force between each wheel and the slope road surface based on the theoretical longitudinal force and the theoretical lateral force; determining the actual road adhesion force between each wheel and the slope road surface based on the theoretical maximum resultant force, the vertical load of each wheel, and the road adhesion coefficient; and determining the lateral force of each wheel at a specified sideslip angle based on the actual road adhesion force, the theoretical maximum lateral force, and the theoretical maximum resultant force.

[0009] Based on the above-mentioned technical means, this application determines the theoretical longitudinal force and theoretical lateral force of the wheel by parameters such as longitudinal stiffness, lateral stiffness, slip ratio and lateral angle, which can more clearly and accurately determine the wheel's stress condition. The wheel's stress condition is combined with the wheel's vertical load and road surface adhesion coefficient to obtain the wheel's actual road surface adhesion force, thereby effectively determining the wheel's lateral force at a specified lateral angle.

[0010] In one possible implementation, the slip angle of the wheels on the target axle is characterized by the vehicle's lateral velocity; the vehicle body angle includes longitudinal body angle and lateral body angle; the operating speed information includes longitudinal vehicle speed and yaw rate; the target axle includes the front axle and the rear axle, and the vehicle body angle is determined based on the target slip stiffness, the target residual torque, and the vehicle's operating speed information, including: determining the observed values ​​of the vehicle's lateral acceleration based on the front axle lateral force and the rear axle lateral force; calling the vehicle's motion acceleration observation equation; wherein, the motion acceleration observation equation includes the longitudinal motion acceleration observation equation and the lateral motion acceleration observation equation, and is structured with the vehicle lateral velocity, the vehicle longitudinal body angle, and the vehicle lateral body angle as state variables, and the observed values ​​of the vehicle longitudinal speed, the vehicle longitudinal motion acceleration, and the vehicle yaw rate as observation variables; the longitudinal body angle and the lateral body angle are determined based on the observed values ​​of the longitudinal speed, the yaw rate, the longitudinal motion acceleration, the lateral motion acceleration, and the motion acceleration observation equation.

[0011] Based on the aforementioned technical means, this application uses the front axle lateral force and the rear axle lateral force as intermediate variables to establish the correlation between longitudinal vehicle speed, yaw rate, longitudinal motion acceleration, lateral motion acceleration and vehicle body roll angle, and shows the correlation through the motion acceleration observation equation, which can more accurately determine the longitudinal body roll angle and lateral body roll angle of the vehicle.

[0012] In one possible implementation, the constraints satisfied by the motion acceleration observation equations include: the front axle lateral force, the rear axle lateral force, and the yaw rate satisfy the yaw moment balance equation; and the derivatives of the lateral body roll angle and the longitudinal body roll angle are both 0.

[0013] Based on the above technical means, this application can enhance the anti-interference ability of the lateral and longitudinal vehicle body tilt angles determined by the motion acceleration observation equations under different driving conditions by adding constraints to the motion acceleration observation equations, thereby improving the effectiveness of the lateral and longitudinal vehicle body tilt angles.

[0014] In one possible implementation, the sideslip angle of the wheels on the front axle is equal to the difference between a first target value and the vehicle's front axle steering angle; the first target value is the ratio of the sum of the lateral velocity and the product of the first target value to the longitudinal velocity; the first target product is the product of the yaw rate and the distance between the front axle and the vehicle's center of mass; the sideslip angle of the wheels on the rear axle is equal to a second target value; the second target value is the ratio of the difference between the lateral velocity and the product of the second target value to the longitudinal velocity; the second target product is the product of the yaw rate and the distance between the rear axle and the center of mass.

[0015] Based on the aforementioned technical means, this application determines the slip angle of the wheels on the front and rear axles by using lateral velocity, longitudinal velocity, yaw rate, distance between the front axle and the vehicle's center of gravity, distance between the rear axle and the vehicle's center of gravity, and front axle rotation angle. This allows for a more effective determination of the wheel slip angle based on the actual operating state of the vehicle.

[0016] In one possible implementation, the longitudinal vehicle roll angle and the lateral vehicle roll angle are determined based on the observed values ​​of longitudinal vehicle speed, yaw rate, longitudinal motion acceleration, lateral motion acceleration, and the motion acceleration observation equation. This includes substituting the observed values ​​of longitudinal vehicle speed, yaw rate, longitudinal motion acceleration, and lateral motion acceleration into the motion acceleration observation equation, solving it using constraint conditions, and obtaining the longitudinal vehicle roll angle and the lateral vehicle roll angle.

[0017] Based on the aforementioned technical means, this application determines the longitudinal body roll angle and the lateral body roll angle by using vehicle speed information, observed values ​​of longitudinal motion acceleration, observed values ​​of lateral motion acceleration, and motion acceleration observation equations, which can more realistically and meticulously reflect the vehicle's roll angle situation.

[0018] In one possible implementation, determining the slope of the sloping road surface based on the vehicle body tilt angle includes: determining the vehicle's suspension pitch angle and suspension roll angle; and determining the slope of the sloping road surface based on a first tilt angle difference between the longitudinal vehicle body tilt angle and the suspension pitch angle, and a second tilt angle difference between the lateral vehicle body tilt angle and the suspension roll angle.

[0019] Based on the aforementioned technical means, this application determines the longitudinal slope angle of the sloping road surface by using the longitudinal vehicle body tilt angle and the suspension pitch angle, and determines the lateral slope angle of the sloping road surface by using the lateral vehicle body tilt angle and the suspension roll angle, which can filter out the interference of the vehicle's suspension tilt angle on the determination of the road surface slope angle.

[0020] In one possible implementation, determining the vehicle's suspension pitch angle and roll angle includes: substituting the vehicle's center of gravity height, mass, and acceleration into the pitch angle fitting regression curve to determine the suspension pitch angle; and substituting the center of gravity height, mass, and acceleration into the roll angle fitting regression curve to determine the suspension roll angle. The regression equation for the pitch angle fitting regression curve is established with the product of the center of gravity height, mass, and longitudinal acceleration as a constant term, and the first-order coefficient, first-order differential coefficient, and second-order differential coefficient of the suspension pitch stiffness, pitch damping, and equivalent moment of inertia as the coefficients of the first-order, first-order differential, and second-order differential terms, respectively. The regression equation for the roll angle fitting regression curve is established with the product of the center of gravity height, mass, and lateral acceleration as a constant term, and the first-order coefficient, first-order differential coefficient, and second-order differential coefficient of the suspension roll stiffness, roll damping, and equivalent moment of inertia as the coefficients of the first-order, first-order differential, and second-order differential terms, respectively.

[0021] Based on the aforementioned technical means, this application determines the suspension roll angle and suspension pitch angle by fitting regression curves of the vehicle's center of gravity height, mass, motion acceleration, and suspension tilt angle. This enables effective determination of the suspension tilt angle without the need for a suspension height sensor, thereby reducing sensor deployment costs and minimizing suspension tilt angle deviations caused by sensor data failures or transmission delays.

[0022] In one possible implementation, the fitting process for the pitch angle fitting regression curve and the roll angle fitting regression curve includes: determining multiple sets of sample data; wherein each set of sample data includes: the sample vehicle body longitudinal tilt angle, the sample vehicle body lateral tilt angle, and the sample motion acceleration when the vehicle is on a flat road surface; the sample vehicle body longitudinal tilt angle is equivalent to the sample suspension pitch angle; the sample vehicle body lateral tilt angle is equivalent to the sample suspension roll angle; and using the multiple sets of sample data, fitting the pitch angle fitting regression curve and the roll angle fitting regression curve.

[0023] Based on the aforementioned technical means, this application uses vehicle sample data from flat road surfaces to fit the pitch angle fitting regression curve and the roll angle fitting regression curve, thereby using existing data to determine the suspension pitch angle and suspension roll angle. This reduces the cost of determining the suspension pitch angle and suspension roll angle, and also avoids data errors in the sensor monitoring and transmission process caused by using sensors to monitor the suspension pitch angle and suspension roll angle.

[0024] In one possible implementation, the method further includes adjusting the vehicle torque based on the operating speed information and the slope of the sloping road surface until the vehicle torque reaches the required torque of the vehicle.

[0025] Based on the aforementioned technical means, this application can more accurately determine the required torque of a vehicle on a sloping road by using operating speed information and the slope of the sloping road. Based on this, adjusting the engine torque of the vehicle can improve the matching between the engine torque and the required torque of the vehicle, thereby significantly improving the operating stability and safety of the vehicle on complex sloping roads.

[0026] Secondly, this application provides a road slope determination device, comprising: a parameter determination module, used to determine the target lateral stiffness and target residual moment corresponding to the target axle based on the road adhesion coefficient of the slope and the slip ratio of the wheel in the target axle of the vehicle when the vehicle is on a slope; the target lateral stiffness and target residual moment are respectively the slope and intercept of the equivalent linear relationship curve of the lateral force of the virtual center wheel of the target axle at the target lateral angle with respect to the lateral angle of the virtual center wheel; the target lateral angle is determined based on the lateral angle of the wheel in the target axle; a tilt angle determination module, used to determine the vehicle body tilt angle based on the target lateral stiffness, the target residual moment and the vehicle's running speed information; and a slope determination module, used to determine the slope of the slope based on the vehicle body tilt angle.

[0027] In one possible implementation, a parameter determination module is used to estimate the lateral force of each wheel at a specified slip angle based on the road adhesion coefficient and the slip ratio of each wheel on the target axle; wherein the specified slip angle includes the slip angle of each wheel and a first slip angle and a second slip angle adjacent to the slip angle of each wheel; based on the lateral force of each wheel at the specified slip angle, a first slope and a first intercept of the equivalent linear relationship curve of the lateral force of each wheel at the slip angle with respect to the slip angle of each wheel are determined; based on the first slope and the first intercept, the target slip stiffness and the target residual moment are determined.

[0028] In one possible implementation, the parameter determination module is specifically used to determine the theoretical maximum longitudinal force of each wheel based on the standard longitudinal stiffness and slip ratio of each wheel; to determine the theoretical maximum lateral force of the target wheel based on the standard lateral stiffness, slip ratio, and specified slip angle of each wheel; to determine the theoretical maximum resultant force between each wheel and the slope road surface based on the theoretical longitudinal force and the theoretical lateral force; to determine the actual road surface adhesion between each wheel and the slope road surface based on the theoretical maximum resultant force, the vertical load of each wheel, and the road surface adhesion coefficient; and to determine the lateral force of each wheel at the specified slip angle based on the actual road surface adhesion, the theoretical maximum lateral force, and the theoretical maximum resultant force.

[0029] In one possible implementation, the slip angle of the wheels in the target axle is characterized by the vehicle's lateral velocity; the vehicle body angle includes longitudinal body angle and lateral body angle; the operating speed information includes longitudinal vehicle speed and yaw rate; the target axle includes the front axle and the rear axle; the inclination angle determination module is used to determine the observed value of the vehicle's lateral motion acceleration based on the front axle lateral force and the rear axle lateral force; the vehicle's motion acceleration observation equation is invoked; wherein, the motion acceleration observation equation includes the longitudinal motion acceleration observation equation and the lateral motion acceleration observation equation, and is structured with the vehicle's lateral velocity, vehicle longitudinal body angle, and vehicle lateral body angle as state variables, and the observed values ​​of the vehicle's longitudinal speed, vehicle longitudinal motion acceleration, and vehicle yaw rate as observation variables; the longitudinal body angle and lateral body angle are determined based on the observed values ​​of the longitudinal speed, yaw rate, longitudinal motion acceleration, lateral motion acceleration, and the motion acceleration observation equation.

[0030] In one possible implementation, the constraints satisfied by the motion acceleration observation equations include: the front axle lateral force, the rear axle lateral force, and the yaw rate satisfy the yaw moment balance equation; and the derivatives of the lateral body roll angle and the longitudinal body roll angle are both 0.

[0031] In one possible implementation, the sideslip angle of the wheels on the front axle is equal to the difference between a first target value and the vehicle's front axle steering angle; the first target value is the ratio of the sum of the lateral velocity and the product of the first target value to the longitudinal velocity; the first target product is the product of the yaw rate and the distance between the front axle and the vehicle's center of mass; the sideslip angle of the wheels on the rear axle is equal to a second target value; the second target value is the ratio of the difference between the lateral velocity and the product of the second target value to the longitudinal velocity; the second target product is the product of the yaw rate and the distance between the rear axle and the center of mass.

[0032] In one possible implementation, the tilt angle determination module is specifically used to substitute the observed values ​​of longitudinal vehicle speed, yaw rate, longitudinal motion acceleration, and lateral motion acceleration into the motion acceleration observation equation, and solve it using constraint conditions to obtain the longitudinal vehicle tilt angle and the lateral vehicle tilt angle.

[0033] In one possible implementation, a slope determination module is used to determine the vehicle's suspension pitch angle and suspension roll angle; based on a first camber difference between the longitudinal vehicle body camber angle and the suspension pitch angle, and a second camber difference between the lateral vehicle body camber angle and the suspension roll angle, the slope of the sloping road surface is determined.

[0034] In one possible implementation, the slope determination module is further used to substitute the vehicle's center of gravity height, mass, and acceleration into the pitch angle fitting regression curve to determine the suspension pitch angle; and to substitute the center of gravity height, mass, and acceleration into the roll angle fitting regression curve to determine the suspension roll angle; wherein, the regression relationship of the pitch angle fitting regression curve is established with the product of the center of gravity height, mass, and longitudinal acceleration as a constant term, and the first-order coefficient, first-order differential coefficient, and second-order differential coefficient of the pitch angle as the suspension pitch stiffness, pitch damping, and equivalent moment of inertia, respectively; the regression relationship of the roll angle fitting regression curve is established with the product of the center of gravity height, mass, and lateral acceleration as a constant term, and the first-order coefficient, first-order differential coefficient, and second-order differential coefficient of the roll angle as the suspension roll stiffness, roll damping, and equivalent moment of inertia, respectively.

[0035] In one possible implementation, the fitting process for the pitch angle fitting regression curve and the roll angle fitting regression curve includes: determining multiple sets of sample data; wherein each set of sample data includes: the sample vehicle body longitudinal tilt angle, the sample vehicle body lateral tilt angle, and the sample motion acceleration when the vehicle is on a flat road surface; the sample vehicle body longitudinal tilt angle is equivalent to the sample suspension pitch angle; the sample vehicle body lateral tilt angle is equivalent to the sample suspension roll angle; and using the multiple sets of sample data, fitting the pitch angle fitting regression curve and the roll angle fitting regression curve.

[0036] In one possible implementation, the device is also used to adjust the vehicle torque based on the operating speed information and the slope of the sloping road surface until the vehicle torque reaches the required torque of the vehicle.

[0037] Thirdly, this application provides a vehicle that includes the road slope determination device described in the second aspect.

[0038] Fourthly, this application provides an electronic device, including: a processor and a memory, wherein the memory stores at least one computer program, and the at least one computer program is loaded and executed by the processor to implement the method described in the first aspect and any possible implementation thereof.

[0039] Fifthly, this application provides a computer-readable storage medium that, when the instructions in the computer-readable storage medium are executed by a processor of an electronic device, enables the electronic device to perform the methods described in the first aspect and any possible implementation thereof.

[0040] In a sixth aspect, this application provides a computer program product comprising computer instructions that, when executed on an electronic device, cause the electronic device to perform the method described in the first aspect and any of its possible implementations.

[0041] It should be noted that the technical effects of any of the implementation methods in aspects two through six can be found in the technical effects of the corresponding implementation methods in aspect one, and will not be repeated here.

[0042] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0043] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application, and do not constitute an undue limitation of this application.

[0044] Figure 1 is a schematic diagram of a vehicle structure according to an embodiment of this application; Figure 2 is a flowchart of a method for determining road slope according to an embodiment of this application; Figure 3 is a flowchart of a method for determining vehicle body tilt angle according to an embodiment of this application; Figure 4 is a line graph of a longitudinal slope angle according to an embodiment of this application; Figure 5 is a line graph of a lateral slope angle according to an embodiment of this application; Figure 6 is a block diagram of a road slope determination device according to an embodiment of this application; Figure 7 is a block diagram of an electronic device according to an embodiment of this application. Detailed Implementation

[0045] To enable those skilled in the art to better understand the technical solutions of this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings.

[0046] It should be noted that the terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0047] In the embodiments of this application, the words "exemplary," "for example," or "for instance" are used to indicate examples, illustrations, or explanations. Any embodiment or design described as "exemplary," "for example," or "for instance" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of the words "exemplary," "for example," or "for instance" is intended to present the relevant concepts in a specific manner.

[0048] The technical solutions of the embodiments of this application will be described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0049] The road slope determination device provided in this application embodiment is used to determine the vehicle body tilt angle and the road slope for vehicles (especially intelligent driving vehicles) on sloping roads. Vehicles can also be referred to as vehicles, mobile carriers, electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), fuel cell vehicles (FCVs), autonomous vehicles, intelligent and connected vehicles (ICVs), driverless vehicles, etc.

[0050] In this application, the vehicle can be a sedan, a sport utility vehicle (SUV), a truck, a special vehicle (such as an ambulance, fire truck, police car, etc.), a driverless taxi, a smart connected bus, an autonomous logistics vehicle, an electric truck, etc. Furthermore, this method is also applicable to various special-purpose vehicles, such as agricultural vehicles, mining vehicles, forestry vehicles, airport vehicles, and port vehicles. This application does not impose specific limitations in this regard.

[0051] Figure 1 is a schematic diagram of the structure of a vehicle shown in an embodiment of this application.

[0052] In one possible implementation, as shown in Figure 1, the vehicle 100 includes a road slope determination device 101 and a sensor 102.

[0053] The road slope determination device 101 is used to determine the lateral stiffness and residual moment of a vehicle when the vehicle is on a sloping road surface, based on the road surface adhesion coefficient of the sloping road surface and the wheel slip ratio of the vehicle.

[0054] The road slope determination device 101 is also used to receive the vehicle's running speed information collected by the sensor 102, and combine it with the lateral stiffness and residual moment to obtain the vehicle's body tilt angle and determine the slope of the sloping road surface.

[0055] Sensor 102 is used to collect vehicle speed information and transmit it to road slope determination device 101.

[0056] The aforementioned operating speed information includes longitudinal acceleration, lateral acceleration, yaw rate, longitudinal vehicle speed, front wheel steering angle, tire rotational speed, vehicle gear status, and motor / engine torque information.

[0057] The aforementioned sensor 102 includes a speed sensor, an acceleration sensor, an angular velocity sensor, a front wheel steering angle sensor, and a motor / engine torque sensor, etc.

[0058] In practical applications, the road slope determination device 101 can communicate with one or more sensors 102.

[0059] For ease of understanding, this application uses the communication connection between a road surface slope determination device 101 and a sensor 102 as an example for illustration.

[0060] As one possible approach, the road slope determination device 101 in Figure 1 can be installed inside or outside the vehicle, while the sensor 102 is installed inside the vehicle. The road slope determination device 101 and the sensor 102 are independently installed devices.

[0061] As one possible approach, the road slope determination device 101 in Figure 1 can be installed on a terminal, a server, or other types of electronic devices.

[0062] When the road slope determination device 101 is installed at a terminal, the terminal can be a device providing data connectivity to vehicle users or vehicle owners, a handheld device with wireless connectivity, or other processing devices connected to a wireless modem. The terminal can communicate with one or more core networks via a radio access network (RAN). The terminal can be a mobile terminal, such as a computer with a mobile terminal, or a mobile device that exchanges voice and / or data with the radio access network, such as a mobile phone, tablet, laptop, netbook, or personal digital assistant (PDA). This application does not impose any limitations on this.

[0063] When the road slope determination device 101 is installed on a server, the server can be a single server or a server cluster consisting of multiple servers. In some embodiments, the server cluster can also be a distributed cluster. This application does not impose any limitations on this.

[0064] It should be noted that the structure illustrated in this application embodiment does not constitute a limitation on the road slope determining device 101. It may include more or fewer components than illustrated, or combine some components, or split some components, or have different component arrangements. The illustrated components may be implemented in hardware, software, or a combination of both.

[0065] For ease of understanding, the method for determining road slope provided in this application will be described in detail below with reference to the accompanying drawings.

[0066] Figure 2 is a flowchart of a road slope determination method according to an embodiment of this application. Referring to Figure 2, the road slope determination method includes: S201, when the vehicle is on a sloping road surface, determining the target lateral stiffness and target residual moment corresponding to the target axle based on the road surface adhesion coefficient of the sloping road surface and the slip ratio of the wheel in the target axle of the vehicle.

[0067] The aforementioned sloping road surface refers to a road surface that has a certain angle of inclination with the horizontal plane. When a vehicle is driving on a road surface with an inclination angle, the vehicle's operating state and stress conditions are different from those on a horizontal road surface, and situations such as wheel slippage or vehicle body tilting may occur.

[0068] The aforementioned coefficient of adhesion is a parameter that measures the adhesion between the wheel and the road surface. The coefficient of adhesion reflects the ratio of the maximum frictional force that the road surface can provide to the wheel to the vertical load experienced by the tire.

[0069] For example, different road surface conditions have different road surface adhesion coefficients. Under otherwise identical road conditions, the road surface adhesion coefficient of a wet road surface is less than that of a dry road surface; for example, the road surface adhesion coefficient of a wet road surface is 0.4, while that of a dry road surface is 0.7.

[0070] In some embodiments, the road surface adhesion coefficient can be determined based on Coulomb's law of friction, the friction coefficient of the tire material, and the road surface roughness.

[0071] In other embodiments, the road surface adhesion coefficient can be estimated using historical test data.

[0072] In other embodiments, the road surface adhesion coefficient can also be determined by combining vehicle driving status information collected by vehicle sensors with vehicle dynamics model and road surface information.

[0073] In other embodiments, when the vehicle chassis stability control function is activated, the road adhesion coefficient is entirely reflected in the acceleration value; therefore, it can be used... To approximate the road surface adhesion coefficient, where, It is the acceleration due to gravity. For longitudinal acceleration, This is lateral acceleration.

[0074] In other embodiments, when the vehicle's Anti-lock Braking System (ABS), Traction Control System (TCS), Electronic Stability Program (ESP), and other functions are not activated, the road adhesion coefficient can be reduced. This is the preset road surface adhesion coefficient. The preset road surface adhesion coefficient is the standard road surface adhesion coefficient corresponding to this road surface type. The standard road surface adhesion coefficient is set in advance, for example, the preset road surface adhesion coefficient is 0.8.

[0075] The slip ratio described above is used to describe the degree of slippage of a wheel during driving, and is the degree of difference between the actual speed of the wheel and the theoretical speed when the wheel is rolling.

[0076] In some embodiments, the slip ratio of the aforementioned wheel is calculated using the following formula:

[0077] in, This represents the slip ratio of the i-th tire. The effective rolling radius of the wheel, Let be the rotational angular velocity of the i-th wheel. This represents the vehicle's longitudinal speed. The effective rolling radius of the wheels mentioned above was pre-calibrated through real-vehicle testing.

[0078] The target axle mentioned above is either the front axle or the rear axle of the vehicle.

[0079] In some embodiments, the target lateral stiffness and the target residual moment are the slope and intercept of the equivalent linear relationship curve of the lateral force of the virtual center wheel of the target axle at the target lateral angle with respect to the lateral angle of the virtual center wheel, respectively.

[0080] The slip angle mentioned above refers to the angle between the wheel's direction of travel and the wheel's plane. When a wheel is subjected to a lateral force, it will deviate laterally, thus creating the slip angle.

[0081] In some embodiments, the target slip angle is determined based on the slip angle of the wheel on the target axle. Since there are two wheels on either the front or rear axle of the vehicle, the front axle slip angle is the average of the slip angles of the two wheels on the front axle, and the rear axle slip angle is the average of the slip angles of the two wheels on the rear axle.

[0082] In other embodiments, the front axle slip angle is the larger of the slip angles of the two wheels on the front axle of the vehicle, and the rear axle slip angle is the larger of the slip angles of the two wheels on the rear axle of the vehicle.

[0083] In other embodiments, when the vehicle is considered to have only one virtual axle and only one virtual center wheel, the target sideslip angle of the target axle is the average of the sideslip angles of the four wheels of the vehicle.

[0084] The aforementioned virtual center wheel is an equivalent virtual wheel located at the center of the target axle, which is used to analyze the force situation of the target axle.

[0085] The aforementioned target lateral stiffness is a mechanical characteristic parameter used to describe the lateral force of the tire. It is the lateral force required for the tire to generate a unit slip angle. For example, the lateral stiffness of a truck tire can be 60% of the vertical load.

[0086] The aforementioned target residual torque is used to reflect the sum of internal torques or external disturbance torques that still exist in the wheel when the wheel sideslip angle is zero.

[0087] The aforementioned equivalent linear relationship refers to the method used to determine the target lateral stiffness and target residual moment, which approximates the relationship between the lateral force and the lateral angle of the wheel as a linear relationship within a small range of wheel slip angles. The slope of the equivalent linear relationship corresponds to the wheel's lateral stiffness.

[0088] In some embodiments, the slip angle of the wheels on the front axle is equal to the difference between a first target value and the vehicle's front axle steering angle; the first target value is the ratio of the sum of the lateral velocity and the product of the first target value to the longitudinal velocity; the first target product is the product of the yaw rate and the distance between the front axle and the vehicle's center of mass. The slip angle of the wheels on the rear axle is equal to a second target value; the second target value is the ratio of the difference between the lateral velocity and the product of the second target value to the longitudinal velocity; the second target product is the product of the yaw rate and the distance between the rear axle and the center of mass. The slip angle of the wheels on the target axle is characterized using the vehicle's lateral velocity.

[0089] As one feasible method, the formulas for calculating the slip angle of the front axle wheels and the slip angle of the rear axle wheels are as follows:

[0090]

[0091] in, The slip angle of the wheel on the front axle. The slip angle of the wheel on the rear axle. For lateral velocity, For longitudinal velocity, This is the distance from the front axle to the vehicle's center of gravity. The yaw rate is angular velocity. Front axle steering angle, This is the distance from the rear axle to the vehicle's center of gravity.

[0092] The lateral velocity, longitudinal velocity, yaw rate, and front axle angle mentioned above are obtained by vehicle sensors. The distances from the front axle to the vehicle's center of gravity and the distances from the rear axle to the vehicle's center of gravity are parameters of the vehicle that have been pre-calibrated through real vehicle testing.

[0093] As one feasible approach, based on the road adhesion coefficient of the sloping road surface and the slip ratio of the wheels on the target axle of the vehicle, the target lateral stiffness and target residual moment of the target axle are determined, including: estimating the lateral force of each wheel at a specified slip angle based on the road adhesion coefficient and the slip ratio of each wheel on the target axle; wherein the specified slip angle includes the slip angle of each wheel and a first slip angle and a second slip angle adjacent to the slip angle of each wheel; based on the lateral force of each wheel at the specified slip angle, determining the first slope and the first intercept of the equivalent linear relationship curve of the lateral force of each wheel at the slip angle of each wheel with respect to the slip angle of each wheel; and determining the target lateral stiffness and target residual moment based on the first slope and the first intercept.

[0094] In some embodiments, determining the target lateral stiffness and target residual moment based on the first and second sideslip angles includes: calculating the first sideslip angle. Second side deflection angle and the corresponding lateral force and The difference and division yield the lateral stiffness of the i-th tire corresponding to the first and second slip angles. The first intercept of the i-th tire , Let be the slip angle of the i-th tire. This represents the change in the sideslip angle.

[0095]

[0096] in, Let be the lateral stiffness of the i-th tire.

[0097] The target residual torques of the vehicle's front and rear axles can be expressed as:

[0098] in, The target lateral stiffness of the front axle. The target lateral stiffness of the rear axle. The target residual torque of the front axle. The target residual torque of the rear axle, This is the intercept of the front axle. This is the intercept of the rear axle.

[0099] In some embodiments, the front axle intercept is the average of the first intercepts of the two wheels on the front axle, and the rear axle intercept is the average of the first intercepts of the two wheels on the rear axle.

[0100] In some embodiments, the front axle intercept is the larger of the first intercepts of the two wheels on the front axle, and the rear axle intercept is the larger of the first intercepts of the two wheels on the rear axle.

[0101] As another feasible approach, the aforementioned front axle lateral forces and rear axle lateral forces can be determined using a linear tire model. The calculation formula expressed using a linear tire model is as follows:

[0102]

[0103] in, For front axle lateral stiffness, Front axle side slip angle, For rear axle lateral stiffness, This refers to the rear axle side slip angle.

[0104] As a feasible approach, the process of determining lateral forces based on a nonlinear tire model involves estimating the lateral force of each wheel at a specified slip angle based on the road adhesion coefficient and the slip ratio of each wheel on the target axle. This includes: determining the theoretical maximum longitudinal force of each wheel based on its standard longitudinal stiffness and slip ratio; determining the theoretical maximum lateral force of the target wheel based on its standard slip stiffness, slip ratio, and specified slip angle; determining the theoretical maximum resultant force between each wheel and the sloping road surface based on the theoretical longitudinal force and theoretical lateral force; determining the actual road adhesion force between each wheel and the sloping road surface based on the theoretical maximum resultant force, the vertical load of each wheel, and the road adhesion coefficient; and determining the lateral force of each wheel at a specified slip angle based on the actual road adhesion force, the theoretical maximum lateral force, and the theoretical maximum resultant force.

[0105] In some embodiments, the lateral forces of the front axle and the rear axle can be determined according to the following formula.

[0106]

[0107] in, Let i be the longitudinal force of the i-th tire. Let be the lateral force of the i-th tire. For standard longitudinal stiffness, For standard lateral stiffness, This represents the wheel slip ratio of the i-th tire. This represents the actual road surface adhesion. For the theoretical maximum resultant force, Let be the slip angle of the i-th tire. The road surface adhesion coefficient, Let be the vertical load of the i-th tire.

[0108] The standard longitudinal stiffness and standard lateral stiffness are pre-calibrated through actual vehicle testing.

[0109] S202. Based on the target lateral stiffness, target residual moment and vehicle operating speed information, determine the vehicle body tilt angle.

[0110] In some embodiments, the vehicle body camber angle includes longitudinal vehicle body camber angle and lateral vehicle body camber angle.

[0111] In other embodiments, the vehicle body camber angle is a combined angle formed by the longitudinal vehicle body camber angle and the lateral vehicle body camber angle.

[0112] As one feasible approach, the vehicle body tilt angle is determined based on the target lateral stiffness of the front axle, the target residual moment of the front axle, the target lateral stiffness of the rear axle, the target residual moment of the rear axle, and the vehicle's operating speed information.

[0113] As one feasible approach, the vehicle's body roll angle can be determined based on the lateral stiffness, residual torque, and vehicle speed information of each wheel.

[0114] As another feasible approach, the target lateral stiffness and target residual moment of the front and rear axles can be combined to obtain the central lateral stiffness and central residual moment of the virtual central axis, which can then be used to determine the vehicle's body tilt angle in conjunction with the vehicle's operating speed information.

[0115] As another feasible method, when the vehicle is on a slope and stationary, the vehicle's body roll angle can be directly determined based on its speed information. The longitudinal body roll angle is calculated directly using the following formula. and lateral body roll angle .

[0116]

[0117]

[0118] in, The longitudinal body tilt angle, This refers to the lateral body roll angle. It is the acceleration due to gravity. For longitudinal acceleration, This is lateral acceleration.

[0119] For example, if the vehicle is in parking gear (P) or the longitudinal speed and the actual braking torque of the motor / engine are both 0, then the vehicle is stationary.

[0120] S203. Determine the slope of the sloping road surface based on the vehicle body tilt angle.

[0121] In some embodiments, the slope of a sloping road surface includes a longitudinal slope angle and / or a lateral slope angle.

[0122] In other embodiments, the slope of the sloping road surface is a combined angle formed by the longitudinal slope angle and the lateral slope angle.

[0123] As an achievable method, when a vehicle is on a longitudinal slope (horizontally parallel to the vehicle's direction of travel), and there is no lateral acceleration affecting the vehicle, the longitudinal slope angle of the slope is the longitudinal vehicle body tilt angle.

[0124] As another possible approach, when a vehicle is on a lateral slope (or transverse slope) and traveling at a constant speed, and there is no longitudinal acceleration affecting the vehicle, the lateral slope angle of the slope is the lateral body roll angle.

[0125] As an feasible method, the process of determining the slope of a sloping road surface includes: determining the vehicle's suspension pitch angle and suspension roll angle; and determining the slope of the sloping road surface based on the first angle difference between the longitudinal vehicle body roll angle and the suspension pitch angle, and the second angle difference between the lateral vehicle body roll angle and the suspension roll angle. The formula for calculating the slope is as follows:

[0126]

[0127] in, This refers to the suspension pitch angle. This refers to the suspension roll angle. The longitudinal slope angle, The lateral slope angle, The longitudinal body tilt angle, This refers to the lateral body roll angle.

[0128] Based on the aforementioned technical means, this application can more accurately determine the lateral stiffness and residual torque of the front or rear axle of a vehicle based on the wheel slip ratio of the vehicle on the sloping road surface and the road surface adhesion coefficient of the sloping road surface. This, combined with the vehicle's operating speed information, can determine the vehicle body tilt angle and the slope of the sloping road surface. This not only improves the accuracy of the road slope determination, but also reduces the hardware resource cost of slope determination by using only existing vehicle-mounted sensor data.

[0129] In some embodiments, determining the vehicle's suspension pitch angle and suspension roll angle includes: substituting the vehicle's center of gravity height, mass, and motion acceleration into the pitch angle fitting regression curve to determine the suspension pitch angle.

[0130] Furthermore, by substituting the center of gravity height, mass, and acceleration into the roll angle fitting regression curve, the suspension roll angle can be determined, enabling effective determination of the suspension roll angle without the need for a suspension height sensor.

[0131] The regression equation for the pitch angle fitting regression curve is established with the product of center of mass height, mass, and longitudinal acceleration as a constant term, and the first-order coefficients, first-order differential coefficients, and second-order differential coefficients of the pitch angle as the suspension pitch stiffness, pitch damping, and equivalent moment of inertia, respectively. The regression equation for the roll angle fitting regression curve is established with the product of center of mass height, mass, and lateral acceleration as a constant term, and the first-order coefficients, first-order differential coefficients, and second-order differential coefficients of the roll angle as the suspension roll stiffness, roll damping, and equivalent moment of inertia, respectively.

[0132] As one possible approach, the aforementioned suspension pitch angle The calculation formula is as follows:

[0133] in, This refers to the suspension pitch angle. The height of the vehicle's center of gravity. For equivalent rotational inertia, For the longitudinal acceleration of the vehicle, For pitch stiffness, For pitch damping, Let be the first-order differential term of the suspension pitch angle. The pitch angle of the suspension is a second-order differential term.

[0134] As one possible approach, the aforementioned suspension roll angle The calculation formula is as follows:

[0135] in, For roll stiffness, For roll damping, The lateral acceleration of the vehicle. This is the first-order differential term of the suspension roll angle. The suspension roll angle is a second-order differential term.

[0136] The aforementioned parameters, such as pitch stiffness, pitch damping, roll stiffness, roll damping, center of gravity height, and equivalent moment of inertia, were determined based on vehicle sample data and test calibration.

[0137] As one possible approach, the above calibration process includes steps 1-5.

[0138] Step 1: Continuously accelerate, decelerate, or turn on a flat road with no longitudinal or lateral slope to collect data with sufficient excitation.

[0139] Step 2: Calculate the vehicle body tilt angle using the collected data through offline simulation. Since the actual road slope is 0, the calculated angles are actually the suspension pitch angle and the suspension roll angle.

[0140] Step 3: After aligning the acceleration data and vehicle tilt angle data in time, use MATLAB's system identification toolbox to identify the reference value of each parameter of the second-order model.

[0141] Step 4: Repeat the above steps for each different suspension setting on the vehicle to obtain the parameter calibration values ​​for each set of settings.

[0142] Step 5: Convert the reference values ​​of parameters at continuous time points into parameter values ​​of the discrete model, and then calculate the suspension pitch angle and suspension roll angle based on the acceleration data.

[0143] As one possible approach, the fitting process for the above-mentioned pitch angle fitting regression curve and roll angle fitting regression curve includes: determining multiple sets of sample data.

[0144] Each set of sample data includes: the longitudinal tilt angle, lateral tilt angle, and acceleration of the vehicle body when it is on a flat road surface. The longitudinal tilt angle is equivalent to the pitch angle of the suspension. The lateral tilt angle is equivalent to the roll angle of the suspension.

[0145] Using multiple sets of sample data, we fitted regression curves for pitch angle and roll angle.

[0146] This application can more accurately determine the lateral stiffness and residual moment of the target axle of a vehicle (e.g., the front or rear axle) based on the wheel slip ratio of the vehicle on the sloping road surface and the road surface adhesion coefficient of the sloping road surface. By combining lateral slip, longitudinal slip and running speed information, the vehicle body tilt angle and the slope of the sloping road surface can be determined. This not only improves the accuracy of the road slope determination, but also reduces the hardware resource cost of slope determination based only on the data of basic on-board sensors.

[0147] In some embodiments, FIG3 is a flowchart of a vehicle body tilt angle determination method according to an embodiment of the present application. Referring to FIG3, the vehicle body tilt angle determination method includes: S301, determining the observed value of the lateral motion acceleration of the vehicle based on the front axle lateral force of the front axle and the rear axle lateral force of the rear axle.

[0148] The observed values ​​of motion acceleration mentioned above refer to the lateral motion acceleration of the vehicle predicted based on the front axle lateral force and the rear axle lateral force.

[0149] S302, invoke the vehicle's motion acceleration observation equation.

[0150] The motion acceleration observation equation includes a longitudinal motion acceleration observation equation and a lateral motion acceleration observation equation. It is structured with the vehicle's lateral velocity, vehicle's longitudinal body tilt angle, and vehicle's lateral body tilt angle as state variables, and the observed values ​​of the vehicle's longitudinal speed, vehicle's longitudinal motion acceleration, and vehicle's yaw rate as observation variables.

[0151] S303. Based on the observed values ​​of longitudinal vehicle speed, yaw rate, longitudinal motion acceleration, lateral motion acceleration, and the motion acceleration observation equation, determine the longitudinal vehicle body tilt angle and the lateral vehicle body tilt angle.

[0152] As one feasible approach, the observed value of longitudinal acceleration is... The observed values ​​of lateral acceleration Based on the observed values ​​of longitudinal acceleration, lateral acceleration, longitudinal vehicle speed, yaw rate, and the observed equations for acceleration, the calculation formulas for longitudinal vehicle roll angle and lateral vehicle roll angle are determined as follows:

[0153]

[0154] in, For longitudinal vehicle speed, Lateral speed, ω represents the yaw rate.

[0155] As another feasible approach, the observed values ​​of the vehicle's lateral acceleration are determined based on the front axle lateral force and the rear axle lateral force to obtain the longitudinal body roll angle. and lateral body roll angle .

[0156]

[0157]

[0158]

[0159] in, This is the distance from the front axle to the vehicle's center of gravity. For the lateral force on the front axle, This is the distance from the rear axle to the vehicle's center of gravity. This is the lateral force on the rear axle. For the moment of inertia of yaw rotation, For vehicle quality.

[0160] As one feasible approach, the observed values ​​of longitudinal vehicle speed, yaw rate, longitudinal motion acceleration, and lateral motion acceleration are substituted into the motion acceleration observation equation. The constraint conditions are then used to solve the equation to obtain the longitudinal vehicle body tilt angle and the lateral vehicle body tilt angle.

[0161] In some embodiments, the constraints satisfied by the motion acceleration observation equation include: the front axle lateral force, the rear axle lateral force, and the yaw rate satisfy the yaw moment balance equation; and the derivatives of the lateral body roll angle and the longitudinal body roll angle are both 0.

[0162] Then the longitudinal body camber angle and lateral body roll angle Add to state variables:

[0163] The equations for the observed acceleration of motion are obtained. :

[0164] in, For longitudinal velocity, For lateral velocity, The yaw rate is angular velocity. The longitudinal body tilt angle, This refers to the lateral body roll angle. It is the acceleration due to gravity. For the roll stiffness of the front axle, For the roll stiffness of the rear axle, Front axle steering angle, This is the distance from the front axle to the vehicle's center of gravity. This is the distance from the rear axle to the vehicle's center of gravity. This is the first intercept corresponding to the front axle. This is the first intercept corresponding to the rear axle. For vehicle quality.

[0165] Because of the coupling between state variables in the motion acceleration observation equation, linearization is required. The system matrix is ​​obtained by calculating the Jacobian matrix of the motion acceleration observation equation. :

[0166] The discretized system matrix is ​​obtained by discretizing the system using the backward Euler method. , Where I is the identity matrix, Sampling time.

[0167] Select output variables: The system's output equation can be expressed as: :

[0168] Based on this, the Jacobian matrix of the motion acceleration observation equation is calculated to obtain the output matrix. And select the observation as The estimation process for expanding the state variables using the Extended Kalman Filter (EKF) is as follows: Step a: Calculate the prior estimate using the estimate from the previous time step: Step b: Calculate the prior error covariance: Step c: Calculate the Kalman gain: Step d: Posterior estimation: Step e: Calculate the posterior error covariance: ;in, and These are the model noise covariance matrix and the observation noise covariance matrix of the system, respectively. This is the state estimate at time k-1. Let k be the prior state estimate at time k. Sampling time, Let be the posterior state estimate at time k. Let be the prior error covariance matrix at time k. Let be the posterior error covariance matrix at time k. The system matrix represents the state transition from time k-1 to time k. Let be the transpose of the posterior error covariance matrix at time k. Let K be the Kalman gain matrix at time k. Let k be the observation at time k.

[0169] As an feasible approach, given that the observation noise covariance matrix R is a diagonal matrix, sequential Kalman filtering can be considered. This involves performing steps c to e sequentially at each sampling time using each observation, which transforms the n-dimensional matrix operation into n scalar operations, where n is the number of observations.

[0170] When the road surface slope is determined according to the above-mentioned road surface slope determination method, the angular errors between the determined longitudinal slope angle and lateral slope angle and those obtained by directly using the vehicle body tilt angle collected by the vehicle sensor as the longitudinal slope angle and / or lateral slope angle are shown in Figures 4 and 5.

[0171] Figure 4 is a line graph of a longitudinal slope angle shown in an embodiment of this application; Figure 5 is a line graph of a lateral slope angle shown in an embodiment of this application.

[0172] As an feasible approach, after determining the slope of the sloping road surface where the vehicle is located according to the above method, the vehicle torque is adjusted based on the vehicle's operating speed information and the slope of the sloping road surface until the vehicle torque reaches the required torque of the vehicle; the vehicle torque can be engine torque or drive motor torque; this can improve the matching between engine torque or drive motor torque and the required torque of the vehicle, thereby significantly improving the vehicle's operating stability and safety on complex sloping roads.

[0173] The engine torque mentioned above is the rotational torque output from the crankshaft end of the engine. It is a core parameter for measuring the engine's acceleration and load-bearing capacity. Its physical essence is the product of force and lever arm, and its unit is Newton-meter (N·m). Under the condition of fixed power, engine torque is inversely proportional to engine speed: the faster the speed, the smaller the torque; the lower the speed, the larger the torque.

[0174] The aforementioned required torque is the engine output torque value required by the vehicle under the current driving conditions.

[0175] For example, when a vehicle is climbing a hill, the engine torque is increased in time to overcome the resistance of gravity, and when the vehicle is going downhill, the engine torque is actively reduced to cooperate with engine braking and reduce the braking load.

[0176] Figure 6 is a block diagram of a road slope determination device according to an embodiment of this application. Referring to Figure 6, the road slope determination device includes: a parameter determination module 601, an inclination angle determination module 602, and a slope determination module 603.

[0177] The parameter determination module 601 is used to determine the target lateral stiffness and target residual moment of the target axle based on the road adhesion coefficient of the slope and the slip ratio of the wheels in the target axle of the vehicle when the vehicle is on a slope.

[0178] The target lateral stiffness and target residual moment are the slope and intercept of the equivalent linear relationship curve of the lateral force of the virtual center wheel of the target axle at the target lateral angle with respect to the lateral angle of the virtual center wheel, respectively; the target lateral angle is determined based on the lateral angle of the wheel in the target axle.

[0179] The tilt angle determination module 602 is used to determine the vehicle body tilt angle based on the target lateral stiffness, target residual moment and vehicle running speed information.

[0180] The slope determination module 603 is used to determine the slope of a sloping road surface based on the vehicle body tilt angle.

[0181] In one possible implementation, the parameter determination module 601 is used to estimate the lateral force of each wheel at a specified slip angle based on the road adhesion coefficient and the slip ratio of each wheel on the target axle; wherein the specified slip angle includes the slip angle of each wheel and a first slip angle and a second slip angle adjacent to the slip angle of each wheel; based on the lateral force of each wheel at the specified slip angle, a first slope and a first intercept of the equivalent linear relationship curve of the lateral force of each wheel at the slip angle with respect to the slip angle of each wheel are determined; based on the first slope and the first intercept, the target slip stiffness and the target residual moment are determined.

[0182] In one possible implementation, the parameter determination module 601 is specifically used to determine the theoretical maximum longitudinal force of each wheel based on the standard longitudinal stiffness and slip ratio of each wheel; to determine the theoretical maximum lateral force of the target wheel based on the standard lateral stiffness, slip ratio, and specified slip angle of each wheel; to determine the theoretical maximum resultant force between each wheel and the slope road surface based on the theoretical longitudinal force and the theoretical lateral force; to determine the actual road surface adhesion between each wheel and the slope road surface based on the theoretical maximum resultant force, the vertical load of each wheel, and the road surface adhesion coefficient; and to determine the lateral force of each wheel at the specified slip angle based on the actual road surface adhesion, the theoretical maximum lateral force, and the theoretical maximum resultant force.

[0183] In one possible implementation, the slip angle of the wheel in the target axle is characterized by the vehicle's lateral velocity; the vehicle body tilt angle includes the longitudinal vehicle body tilt angle and the lateral vehicle body tilt angle; the operating speed information includes the longitudinal vehicle speed and the yaw rate; the target axle includes the front axle and the rear axle; the tilt angle determination module 602 is used to determine the observed value of the vehicle's lateral motion acceleration based on the front axle lateral force of the front axle and the rear axle lateral force of the rear axle; and to call the vehicle's motion acceleration observation equation; wherein, the motion acceleration observation equation includes the longitudinal motion acceleration observation equation and the lateral motion acceleration observation equation, and is structured with the vehicle lateral velocity, the vehicle longitudinal vehicle body tilt angle and the vehicle lateral vehicle body tilt angle as state variables, and the observed values ​​of the vehicle longitudinal speed, the vehicle longitudinal motion acceleration and the vehicle yaw rate as observation variables; and the longitudinal vehicle body tilt angle and the lateral vehicle body tilt angle are determined based on the observed values ​​of the longitudinal speed, the yaw rate, the longitudinal motion acceleration, the lateral motion acceleration and the motion acceleration observation equation.

[0184] In one possible implementation, the constraints satisfied by the motion acceleration observation equations include: the front axle lateral force, the rear axle lateral force, and the yaw rate satisfy the yaw moment balance equation; and the derivatives of the lateral body roll angle and the longitudinal body roll angle are both 0.

[0185] In one possible implementation, the sideslip angle of the wheels on the front axle is equal to the difference between a first target value and the vehicle's front axle steering angle; the first target value is the ratio of the sum of the lateral velocity and the product of the first target value to the longitudinal velocity; the first target product is the product of the yaw rate and the distance between the front axle and the vehicle's center of mass; the sideslip angle of the wheels on the rear axle is equal to a second target value; the second target value is the ratio of the difference between the lateral velocity and the product of the second target value to the longitudinal velocity; the second target product is the product of the yaw rate and the distance between the rear axle and the center of mass.

[0186] In one possible implementation, the tilt angle determination module 602 is specifically used to substitute the observed values ​​of longitudinal vehicle speed, yaw rate, longitudinal motion acceleration and lateral motion acceleration into the motion acceleration observation equation, and solve it using the constraint conditions to obtain the longitudinal vehicle tilt angle and the lateral vehicle tilt angle.

[0187] In one possible implementation, the slope determination module 603 is used to determine the vehicle's suspension pitch angle and suspension roll angle; based on the first angle difference between the longitudinal vehicle body roll angle and the suspension pitch angle, and the second angle difference between the lateral vehicle body roll angle and the suspension roll angle, the slope of the sloping road surface is determined.

[0188] In one possible implementation, the slope determination module 603 is further used to substitute the vehicle's center of gravity height, mass, and acceleration into the pitch angle fitting regression curve to determine the suspension pitch angle; and to substitute the center of gravity height, mass, and acceleration into the roll angle fitting regression curve to determine the suspension roll angle; wherein, the regression relationship of the pitch angle fitting regression curve is established with the product of the center of gravity height, mass, and longitudinal acceleration as a constant term, and the first-order coefficient, first-order differential coefficient, and second-order differential coefficient of the pitch angle as the pitch stiffness, pitch damping, and equivalent moment of inertia of the suspension, respectively; the regression relationship of the roll angle fitting regression curve is established with the product of the center of gravity height, mass, and lateral acceleration as a constant term, and the first-order coefficient, first-order differential coefficient, and second-order differential coefficient of the roll angle as the roll stiffness, roll damping, and equivalent moment of inertia of the suspension, respectively.

[0189] In one possible implementation, the fitting process for the pitch angle fitting regression curve and the roll angle fitting regression curve includes: determining multiple sets of sample data; wherein each set of sample data includes: the sample vehicle body longitudinal tilt angle, the sample vehicle body lateral tilt angle, and the sample motion acceleration when the vehicle is on a flat road surface; the sample vehicle body longitudinal tilt angle is equivalent to the sample suspension pitch angle; the sample vehicle body lateral tilt angle is equivalent to the sample suspension roll angle; and using the multiple sets of sample data, fitting the pitch angle fitting regression curve and the roll angle fitting regression curve.

[0190] In one possible implementation, the device is also used to adjust the vehicle torque based on the operating speed information and the slope of the sloping road surface until the vehicle torque reaches the required torque of the vehicle; the vehicle torque is the engine torque or the drive motor torque.

[0191] Regarding the apparatus in the above embodiments, the specific methods of execution of each module have been described in detail in the embodiments of the road slope determination method, and will not be elaborated here.

[0192] Figure 7 is a block diagram of an electronic device according to an embodiment of this application. As shown in Figure 7, the electronic device includes, but is not limited to, a processor 701 and a memory 702.

[0193] The aforementioned memory 702 is used to store the executable instructions of the aforementioned processor 701. It is understood that the aforementioned processor 701 is configured to execute instructions to implement the road slope determination method in the above embodiments.

[0194] It should be noted that those skilled in the art will understand that the electronic device structure shown in FIG7 does not constitute a limitation on the electronic device. The electronic device may include more or fewer components than shown in FIG7, or combine certain components, or have different component arrangements.

[0195] Processor 701 is the control center of the electronic device. It connects various parts of the electronic device via various interfaces and lines. By running or executing software programs and / or modules stored in memory 702, and by calling data stored in memory 702, it performs various functions and processes data, thereby providing overall monitoring of the electronic device. Processor 701 may include one or more processing units. Processor 701 may integrate an application processor and a modem processor. The application processor mainly handles the operating system, user interface, and applications, while the modem processor mainly handles wireless communication. It is understood that the modem processor may not be integrated into processor 701.

[0196] The memory 702 can be used to store software programs and various data. The memory 702 may primarily include a program storage area and a data storage area. The program storage area may store the operating system, application programs required by at least one functional module (such as deterministic components, integrated components, etc.), etc. Furthermore, the memory 702 may include high-speed random access memory, and may also include non-volatile memory, such as at least one disk storage device, flash memory device, or other volatile solid-state storage device.

[0197] In an exemplary embodiment, a computer-readable storage medium including instructions is also provided, such as a memory 702 including instructions, which can be executed by a processor 701 of an electronic device to implement the methods in the above embodiments.

[0198] In actual implementation, the functions of the parameter determination module 601, tilt angle determination module 602, and slope determination module 603 in Figure 6 can all be implemented by the processor 701 in Figure 7 calling the computer program stored in the memory 702. The specific execution process can be found in the description of the method section in the above embodiment, and will not be repeated here.

[0199] Optionally, the computer-readable storage medium may be a non-transitory computer-readable storage medium, such as a read-only memory (ROM), random access memory (RAM), compact disc read-only memory (CD-ROM), magnetic tape, floppy disk, and optical data storage device. In an exemplary embodiment, this application also provides a computer program product including one or more instructions, which can be executed by the processor 701 of an electronic device to perform the methods in the above embodiments.

[0200] It should be noted that when one or more instructions in the computer-readable storage medium or computer program product are executed by the processor of an electronic device, they implement the various processes of the above method embodiments and achieve the same technical effect as the above method. To avoid repetition, they will not be described again here.

[0201] Through the above description of the embodiments, those skilled in the art can clearly understand that, for the sake of convenience and brevity, only the division of the above functional modules is used as an example. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above.

[0202] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another apparatus, or some features may be ignored or not executed. Furthermore, the mutual coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0203] The units described as separate components may or may not be physically separate. A component shown as a unit can be one or more physical units; that is, it can be located in one place or distributed in multiple different locations. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0204] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0205] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a readable storage medium. Based on this understanding, the technical solutions of the embodiments of this application, essentially, or the parts that contribute to the prior art, or all or part of the technical solutions, can be embodied in the form of a software product. This software product is stored in a storage medium and includes several instructions to cause a device (which may be a microcontroller, chip, etc.) or processor to execute all or part of the steps of the methods of the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, ROM, RAM, magnetic disks, or optical disks.

[0206] This application provides a computer program product containing instructions that, when run on a computer, cause the computer to perform the methods described in the above method embodiments.

[0207] This application also provides a computer-readable storage medium storing instructions that, when executed on a computer, cause the computer to perform the method in the method flow shown in the above method embodiments.

[0208] The computer-readable storage medium can be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of computer-readable storage media (a non-exhaustive list) include: an electrical connection having one or more wires, a portable computer disk, a hard disk, a random access memory, a read-only memory, an erasable programmable read-only memory, a register, a hard disk, an optical fiber, a portable compact disk read-only memory, an optical storage device, a magnetic storage device, or any suitable combination thereof, or any other form of computer-readable storage medium known in the art. An exemplary storage medium is coupled to a processor, enabling the processor to read information from and write information to the storage medium. Of course, the storage medium can also be a component of the processor. The processor and the storage medium can reside in an application-specific integrated circuit (ASIC). In embodiments of this application, the computer-readable storage medium can be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, apparatus, or device.

[0209] Since the power control device, computer-readable storage medium, and computer program product of the heat pump air conditioner in the embodiments of this application can be applied to the above method, the technical effects that can be obtained can also be referred to the above method embodiments. The embodiments of this application will not be repeated here.

[0210] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for determining road surface slope, characterized in that, The method for determining the road surface slope includes: when the vehicle is on a sloping road surface, determining the target lateral stiffness and target residual moment corresponding to the target axle based on the road adhesion coefficient of the sloping road surface and the slip ratio of the wheel in the target axle of the vehicle; the target lateral stiffness and the target residual moment are respectively the slope and intercept of the equivalent linear relationship curve of the lateral force of the virtual center wheel of the target axle at the target lateral angle with respect to the lateral angle of the virtual center wheel; the target lateral angle is determined based on the lateral angle of the wheel in the target axle; determining the vehicle body tilt angle based on the target lateral stiffness, the target residual moment and the vehicle's operating speed information; and determining the slope of the sloping road surface based on the vehicle body tilt angle.

2. The method for determining road slope according to claim 1, characterized in that, The determination of the target lateral stiffness and target residual moment corresponding to the target axle based on the road adhesion coefficient of the sloped road surface and the slip ratio of the wheels on the target axle of the vehicle includes: estimating the lateral force of each wheel at a specified slip angle based on the road adhesion coefficient and the slip ratio of each wheel on the target axle; wherein the specified slip angle includes the slip angle of each wheel and a first slip angle and a second slip angle adjacent to the slip angle of each wheel; determining the first slope and a first intercept of the equivalent linear relationship curve of the lateral force of each wheel at the specified slip angle with respect to the slip angle of each wheel based on the lateral force of each wheel at the specified slip angle; and determining the target lateral stiffness and the target residual moment based on the first slope and the first intercept.

3. The method for determining road slope according to claim 2, characterized in that, The method of estimating the lateral force of each wheel at a specified sideslip angle based on the road surface adhesion coefficient and the slip ratio of each wheel on the target axle includes: determining the theoretical maximum longitudinal force of each wheel based on the standard longitudinal stiffness and slip ratio of each wheel; determining the theoretical maximum lateral force of the target wheel based on the standard sideslip stiffness, slip ratio of each wheel, and the specified sideslip angle; determining the theoretical maximum resultant force between each wheel and the slope road surface based on the theoretical longitudinal force and the theoretical lateral force; determining the actual road surface adhesion force between each wheel and the slope road surface based on the theoretical maximum resultant force, the vertical load of each wheel, and the road surface adhesion coefficient; and determining the lateral force of each wheel at the specified sideslip angle based on the actual road surface adhesion force, the theoretical maximum lateral force, and the theoretical maximum resultant force.

4. The method for determining road slope according to any one of claims 1-3, characterized in that, The slip angle of the wheels in the target axle is characterized by the lateral velocity of the vehicle; the vehicle body roll angle includes longitudinal vehicle roll angle and lateral vehicle roll angle; the operating speed information includes longitudinal vehicle speed and yaw rate; the target axle includes the front axle and the rear axle; determining the vehicle body roll angle based on the target slip stiffness, the target residual moment, and the vehicle's operating speed information includes: determining the observed value of the vehicle's lateral acceleration based on the front axle lateral force of the front axle and the rear axle lateral force of the rear axle; and calling the vehicle's acceleration observation method. The process; wherein the motion acceleration observation equation includes a longitudinal motion acceleration observation equation and a lateral motion acceleration observation equation, and is structured with the vehicle lateral velocity, the vehicle longitudinal body tilt angle and the vehicle lateral body tilt angle as state variables, and the observed values ​​of the vehicle longitudinal speed, the vehicle longitudinal motion acceleration and the vehicle yaw rate as observation variables; based on the observed values ​​of the longitudinal speed, the yaw rate, the longitudinal motion acceleration and the lateral motion acceleration and the motion acceleration observation equation, the longitudinal body tilt angle and the lateral body tilt angle are determined.

5. The method for determining road slope according to claim 4, characterized in that, The constraints satisfied by the motion acceleration observation equation include: the front axle lateral force, the rear axle lateral force, and the yaw rate satisfy the yaw moment balance equation; and the derivatives of the lateral body roll angle and the longitudinal body roll angle are both 0.

6. The method for determining road slope according to claim 5, characterized in that, The sideslip angle of the wheels on the front axle is equal to the difference between a first target value and the front axle steering angle of the vehicle; the first target value is the ratio of the sum of the product of the lateral velocity and the first target value to the longitudinal velocity; the first target product is the product of the yaw rate and the distance between the front axle and the center of mass of the vehicle; the sideslip angle of the wheels on the rear axle is equal to a second target value; the second target value is the ratio of the difference between the product of the lateral velocity and the second target value to the longitudinal velocity; the second target product is the product of the yaw rate and the distance between the rear axle and the center of mass.

7. The method for determining road slope according to claim 5, characterized in that, The determination of the longitudinal vehicle roll angle and the lateral vehicle roll angle based on the observed values ​​of the longitudinal vehicle speed, the yaw rate, the longitudinal acceleration, the lateral acceleration, and the acceleration observation equation includes: substituting the observed values ​​of the longitudinal vehicle speed, the yaw rate, the longitudinal acceleration, and the lateral acceleration into the acceleration observation equation, and solving the equation using the constraint conditions to obtain the longitudinal vehicle roll angle and the lateral vehicle roll angle.

8. The method for determining road slope according to any one of claims 1-3, characterized in that, The step of determining the slope of the sloping road surface based on the vehicle body tilt angle includes: determining the vehicle's suspension pitch angle and suspension roll angle; and determining the slope of the sloping road surface based on a first angle difference between the longitudinal vehicle body tilt angle and the suspension pitch angle, and a second angle difference between the lateral vehicle body tilt angle and the suspension roll angle.

9. The method for determining road slope according to claim 8, characterized in that, Determining the vehicle's suspension pitch angle and roll angle includes: substituting the vehicle's center of gravity height, mass, and acceleration into a pitch angle fitting regression curve to determine the suspension pitch angle; and substituting the center of gravity height, mass, and acceleration into a roll angle fitting regression curve to determine the suspension roll angle; wherein the regression equation for the pitch angle fitting regression curve is based on the product of the center of gravity height, mass, and longitudinal acceleration. The constant term is established with the pitch stiffness, pitch damping, and equivalent moment of inertia of the suspension as the first-order coefficients, first-order differential coefficients, and second-order differential coefficients of the pitch angle, respectively. The regression relationship of the roll angle fitting regression curve is established with the product of the center of gravity height, the mass, and the lateral acceleration as the constant term, and with the roll stiffness, roll damping, and equivalent moment of inertia of the suspension as the first-order coefficients, first-order differential coefficients, and second-order differential coefficients of the roll angle, respectively.

10. The method for determining road slope according to claim 9, characterized in that, The fitting process of the pitch angle fitting regression curve and the roll angle fitting regression curve includes: determining multiple sets of sample data; wherein, each set of sample data includes: the sample vehicle body longitudinal tilt angle, the sample vehicle body lateral tilt angle, and the sample motion acceleration when the vehicle is on a flat road surface; the sample vehicle body longitudinal tilt angle is equivalent to the sample suspension pitch angle; the sample vehicle body lateral tilt angle is equivalent to the sample suspension roll angle; and using the multiple sets of sample data, fitting the pitch angle fitting regression curve and the roll angle fitting regression curve.

11. The method for determining road surface slope according to any one of claims 1-3, characterized in that, The method further includes: adjusting the vehicle torque based on the operating speed information and the slope of the sloping road surface until the vehicle torque reaches the required torque of the vehicle.

12. A vehicle, characterized in that, The vehicle uses the road slope determination method as described in any one of claims 1-11 to determine the road slope.

Images