CN119190047A

CN119190047A - Vehicle speed estimation method, device, equipment, storage medium, program product and vehicle

Info

Publication number: CN119190047A
Application number: CN202411217862.XA
Authority: CN
Inventors: 江彪; 赖日飞
Original assignee: Guangzhou Xiaopeng Motors Technology Co Ltd
Current assignee: Guangzhou Xiaopeng Motors Technology Co Ltd
Priority date: 2024-08-30
Filing date: 2024-08-30
Publication date: 2024-12-27

Abstract

The invention relates to the technical field of vehicles, and discloses a vehicle speed estimation method, a device, equipment, a storage medium, a program product and a vehicle. The vehicle speed estimation method comprises the steps of converting a first longitudinal acceleration under a vehicle body consolidation coordinate system into a second longitudinal acceleration under a vehicle relative coordinate system, converting a first lateral acceleration under the vehicle body consolidation coordinate system into a second lateral acceleration under the vehicle relative coordinate system, decomposing the longitudinal vehicle speed and the lateral vehicle speed under the vehicle relative coordinate system from the combined speed of the vehicle under the navigation coordinate system, estimating a longitudinal reference vehicle speed based on the longitudinal vehicle speed and the second longitudinal acceleration, and estimating a lateral reference vehicle speed based on the lateral vehicle speed and the second lateral acceleration. Compared with the related art, the method and the device improve the accuracy of the reference vehicle speed estimation.

Description

Vehicle speed estimation method, device, equipment, storage medium, program product and vehicle

Technical Field

The invention relates to the technical field of vehicles, in particular to a vehicle speed estimation method, a device, equipment, a storage medium, a program product and a vehicle.

Background

For vehicles, obtaining accurate vehicle speed is the basis for accurate dynamics control. Taking four-wheel drive automobiles as an example, each wheel can output power, so that, for example, under the scenes of low-speed road surface or extreme dynamic driving and the like, all wheels can possibly slip or slide, especially when the automobiles work in a steering-in-place function or a transverse movement function, all wheel speed signals can not reflect the actual movement speed of the automobiles at the moment, the real-time speed under the scenes is obtained, and the control method is important for anti-skid control, lateral stability control, transverse movement speed and movement track control of the vehicles during transverse movement and mass center deviation inhibition of the vehicles during steering-in-place. Although the related art can directly measure the vehicle speed through sensing devices such as a pentameter or a Doppler radar, the sensing devices have high cost and cannot be widely applied. Therefore, how to obtain an accurate vehicle speed at a low cost has become an important point of study for those skilled in the art.

Disclosure of Invention

In view of the above, the present invention provides a vehicle speed estimation method, apparatus, device, storage medium, program product, and vehicle, so as to be able to obtain an accurate vehicle speed at low cost.

In a first aspect, the invention provides a vehicle speed estimation method comprising the steps of converting a first longitudinal acceleration under a vehicle body consolidation coordinate system into a second longitudinal acceleration under a vehicle relative coordinate system, converting the first lateral acceleration under the vehicle body consolidation coordinate system into a second lateral acceleration under the vehicle relative coordinate system, decomposing a longitudinal vehicle speed and a lateral vehicle speed under the vehicle relative coordinate system from the combined speed of the vehicle under a navigation coordinate system, estimating a longitudinal reference vehicle speed based on the longitudinal vehicle speed and the second longitudinal acceleration, and estimating a lateral reference vehicle speed based on the lateral vehicle speed and the second lateral acceleration.

The vehicle speed estimation method based on the Doppler radar and the vehicle speed estimation utilizes the longitudinal speed decomposed from the combined speed under the navigation coordinate system and the second longitudinal acceleration converted from the first longitudinal acceleration under the vehicle body consolidation coordinate system to estimate the longitudinal reference vehicle speed under the vehicle relative coordinate system, and utilizes the lateral vehicle speed decomposed from the combined speed under the navigation coordinate system and the second lateral acceleration converted from the first lateral acceleration under the vehicle body consolidation coordinate system to estimate the lateral reference vehicle speed, so that the vehicle speed estimation method based on the Doppler radar and the vehicle speed estimation system integrates the vehicle movement information under the vehicle body consolidation coordinate system and the vehicle movement information under the navigation coordinate system in the reference vehicle speed estimation process, improves the accuracy of the reference vehicle speed estimation, does not need high-cost sensing equipment such as the Doppler radar, and the like, and achieves the purpose of obtaining accurate vehicle speed under the premise of low cost. The invention realizes the function of respectively estimating the longitudinal reference vehicle speed and the lateral reference vehicle speed, thereby being directly applied to the dynamics control of the vehicle, having low calculation force requirement on the vehicle controller and being easy for engineering application. In addition, the invention does not depend on wheel speed signals, so that the invention not only can estimate the longitudinal reference vehicle speed and the lateral reference vehicle speed of a conventional driving scene, but also can accurately estimate the reference vehicle speed of a tire in a strong nonlinear scene such as a large slip angle, a high slip rate and the like, especially the longitudinal reference vehicle speed and the lateral reference vehicle speed of a four-wheel drive automobile in a transverse movement and in-situ steering scene, thereby providing necessary control basis for controlling the transverse movement speed and the direction of the automobile in transverse movement and inhibiting the mass center offset of the automobile in-situ steering.

In an alternative embodiment, the longitudinal speed and the lateral speed of the vehicle under the relative coordinate system are decomposed from the combined speed of the vehicle under the navigation coordinate system, and the method comprises the steps of utilizing the course angle under the navigation coordinate system and the yaw angle under the fixed coordinate system of the vehicle body to determine the centroid side deflection angle, and decomposing the combined speed into the longitudinal speed and the lateral speed according to the centroid side deflection angle.

The invention takes the centroid side deflection angle as the decomposition basis of the combined speed under the navigation coordinate system, so as to decompose the longitudinal speed and the lateral speed from the combined speed, and provide a reliable basis for accurate estimation of the reference speed.

In an alternative embodiment, decomposing the resultant velocity into a longitudinal vehicle speed and a lateral vehicle speed based on the centroid slip angle includes determining a first product of the cosine of the centroid slip angle and the resultant velocity as the longitudinal vehicle speed and determining a second product of the sine of the centroid slip angle and the resultant velocity as the lateral vehicle speed.

The mode for determining the longitudinal speed and the lateral speed can accurately obtain the longitudinal speed and the lateral speed under the relative coordinate system of the vehicle, and provide a data basis for correction of the reference speed.

In an alternative embodiment, the method for determining the centroid side deflection angle by utilizing the course angle under the navigation coordinate system and the yaw angle under the vehicle body consolidation coordinate system comprises the steps of obtaining the yaw angle by integrating the yaw angle speed under the vehicle body consolidation coordinate system, and determining a first difference value between the course angle and the yaw angle as the centroid side deflection angle.

The invention accurately calculates the mass center side deflection angle based on two data in the navigation coordinate system and the vehicle body consolidation coordinate system, thereby providing a data basis for accurate decomposition of the combination speed.

In an alternative embodiment, estimating the longitudinal reference vehicle speed based on the longitudinal vehicle speed and the second longitudinal acceleration comprises determining the sum of the longitudinal vehicle speed at the current time and the second longitudinal acceleration as the longitudinal reference vehicle speed if the longitudinal vehicle speed at the current time is different from the longitudinal vehicle speed at the previous time, and estimating the lateral reference vehicle speed based on the lateral vehicle speed and the second lateral acceleration comprises determining the sum of the lateral vehicle speed at the current time and the second lateral acceleration as the lateral reference vehicle speed if the lateral vehicle speed at the current time is different from the lateral vehicle speed at the previous time, wherein the second difference between the current time and the previous time is the vehicle controller scheduling period.

When the data acquired by the positioning equipment is updated, the reference vehicle speed is determined by utilizing the current updated data, so that the direct fusion of the data acquired by different equipment is realized, the error caused by a long-time acceleration integration mode based on the reference vehicle speed at the previous moment is avoided, and the accuracy of the reference vehicle speed estimation is improved.

In an alternative embodiment, if the longitudinal speed at the current moment is different from the longitudinal speed at the previous moment, determining the sum of the longitudinal speed at the current moment and the second longitudinal acceleration as the longitudinal reference speed comprises determining a third difference value between the longitudinal speed at the current moment and the longitudinal speed at the previous moment, if the third difference value is not 0, setting a first correction mark position as 1, setting the sum of the longitudinal speed at the current moment and the second longitudinal acceleration as the longitudinal reference speed according to a first correction mark position as 1, and if the lateral speed at the current moment is different from the lateral speed at the previous moment, determining the sum of the lateral speed at the current moment and the second lateral acceleration as the lateral reference speed, wherein the sum of the lateral speed at the current moment and the lateral speed at the previous moment is determined to be a fourth difference value, and if the fourth difference value is not 0, setting a second correction mark position as 1, and setting the sum of the lateral speed at the current moment and the second lateral acceleration as the lateral reference speed according to a second correction mark position as 1.

The invention takes the longitudinal or lateral vehicle speed at the current moment and the previous moment as the basis for determining the corresponding first or second correction zone bit, further corrects the longitudinal reference vehicle speed under the condition that the first correction zone bit is 1, and takes the second correction zone bit as the basis for determining the corresponding first or second correction zone bit under the condition that the second correction zone bit is 1, the method can effectively correct the longitudinal reference vehicle speed and the lateral reference vehicle speed according to the updating of the signals acquired by the positioning equipment, and improves the accuracy of the reference vehicle speed estimation.

In an alternative implementation mode, the method further comprises the steps of setting the first correction mark position to 0 if the third difference value is 0, taking the sum of the longitudinal reference vehicle speed and the second longitudinal acceleration at the previous moment as the longitudinal reference vehicle speed according to the first correction mark position being 0, setting the second correction mark position to 0 if the fourth difference value is 0, and taking the sum of the lateral reference vehicle speed and the second lateral acceleration at the previous moment as the lateral reference vehicle speed according to the second correction mark position being 0.

The invention uses the acceleration integration mode to determine the reference vehicle speed, uses the signal measured by the positioning equipment to periodically correct the reference vehicle speed, greatly improves the accuracy of vehicle speed estimation, and has low complexity of the calculation process, so the invention can reduce the calculation force requirement on the vehicle controller.

In an alternative embodiment, converting the first longitudinal acceleration in the vehicle body consolidation coordinate system to the second longitudinal acceleration in the vehicle relative coordinate system includes determining a third product of the yaw rate in the vehicle body consolidation coordinate system and the lateral reference vehicle speed at the previous time, determining a sum of the first longitudinal acceleration and the third product as the second longitudinal acceleration, and converting the first lateral acceleration in the vehicle body consolidation coordinate system to the second lateral acceleration in the vehicle relative coordinate system includes determining a fourth product of the yaw rate in the vehicle body consolidation coordinate system and the longitudinal reference vehicle speed at the previous time, and determining a difference between the first lateral acceleration and the fourth product as the second lateral acceleration.

The method estimates the second longitudinal acceleration and the second lateral acceleration of the vehicle under the relative coordinate system based on the kinematics method, and improves the accuracy of longitudinal and lateral acceleration estimation.

In an alternative implementation mode, the method further comprises the steps of obtaining absolute longitudinal acceleration, absolute lateral acceleration and absolute yaw rate under a vehicle body consolidation coordinate system measured by the inertial navigation device, obtaining the combined speed and heading angle under the navigation coordinate system measured by the positioning device, and carrying out Kalman filtering processing on the absolute longitudinal acceleration, the absolute lateral acceleration and the absolute yaw rate to obtain first longitudinal acceleration, first lateral acceleration and yaw rate.

The invention also provides a reference vehicle speed estimation method which fuses the information acquired by the inertial navigation equipment and the information acquired by the positioning equipment, and the deviation and noise of the measured value of the inertial navigation equipment compared with the true value are greatly reduced in a Kalman filtering mode, so that the accuracy of the reference vehicle speed estimation is further improved.

In an alternative embodiment, the method further comprises the steps of performing low-pass filtering on the longitudinal reference vehicle speed to obtain a final estimation result of the longitudinal reference vehicle speed, and performing low-pass filtering on the lateral reference vehicle speed to obtain a final estimation result of the lateral reference vehicle speed.

The invention can also avoid the problem of jump possibly occurring in the longitudinal and lateral reference vehicle speeds after correction by respectively carrying out low-pass filtering processing on the obtained longitudinal and lateral reference vehicle speeds, and improves the accuracy of the final estimation results of the longitudinal and lateral reference vehicle speeds.

In an alternative implementation mode, the longitudinal reference vehicle speed is subjected to low-pass filtering processing to obtain a final estimation result of the longitudinal reference vehicle speed, wherein the final estimation result comprises the steps of determining the ratio of the longitudinal reference vehicle speed to a first preset value as a final estimation result of the longitudinal reference vehicle speed, and the lateral reference vehicle speed is subjected to low-pass filtering processing to obtain a final estimation result of the lateral reference vehicle speed, and the final estimation result comprises the step of determining the ratio of the lateral reference vehicle speed to a second preset value as a final estimation result of the lateral reference vehicle speed, wherein the first preset value is the sum of a first filtering time constant and 1, the second preset value is the sum of a second filtering time constant and 1, and the first filtering time constant and the second filtering time constant are the same or different.

The low-pass filtering processing means provided by the invention has the advantages of simple calculation process and easy realization, and can finish the low-pass filtering of the longitudinal and lateral reference vehicle speeds under the condition of occupying less or even negligible calculation force resources.

In a second aspect, the invention provides a vehicle speed estimation device, which comprises a conversion module, a decomposition module and an estimation module, wherein the conversion module is used for converting a first longitudinal acceleration under a vehicle body consolidation coordinate system into a second longitudinal acceleration under a vehicle relative coordinate system and converting a first lateral acceleration under the vehicle body consolidation coordinate system into a second lateral acceleration under the vehicle relative coordinate system, the decomposition module is used for decomposing a longitudinal vehicle speed and a lateral vehicle speed under the vehicle relative coordinate system from the combined speed of the vehicle under a navigation coordinate system, and the estimation module is used for estimating a longitudinal reference vehicle speed based on the longitudinal vehicle speed and the second longitudinal acceleration and estimating a lateral reference vehicle speed based on the lateral vehicle speed and the second lateral acceleration.

In a third aspect, the present invention provides an electronic device, including a memory and a processor, where the memory and the processor are communicatively connected to each other, and the memory stores computer instructions, and the processor executes the computer instructions, thereby executing the vehicle speed estimation method according to the first aspect or any one of the corresponding embodiments.

In a fourth aspect, the present invention provides a computer-readable storage medium having stored thereon computer instructions for causing a computer to execute the vehicle speed estimation method of the first aspect or any one of its corresponding embodiments.

In a fifth aspect, the present invention provides a computer program product comprising computer instructions for causing a computer to perform the vehicle speed estimation method of the first aspect or any of its corresponding embodiments.

In a sixth aspect, the present invention provides a vehicle comprising a vehicle controller for performing the vehicle speed estimation method of the first aspect or any one of its corresponding embodiments.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the related art, the drawings that are required to be used in the description of the embodiments or the related art will be briefly described, and it is apparent that the drawings in the description below are some embodiments of the present invention, and other drawings may be obtained according to the drawings without inventive effort for those skilled in the art.

Fig. 1 is a flowchart of a vehicle speed estimation method according to an embodiment of the present invention.

Fig. 2 is a schematic diagram of a vehicle speed estimation algorithm architecture according to an embodiment of the present invention.

Fig. 3 is a flowchart of another vehicle speed estimation method according to an embodiment of the invention.

FIG. 4 is a schematic diagram of a body consolidation coordinate system, a vehicle relative coordinate system, and a navigation coordinate system according to an embodiment of the present invention.

Fig. 5 is a flowchart of still another vehicle speed estimation method according to an embodiment of the present invention.

Fig. 6 is a schematic view of lateral movement of a vehicle according to an embodiment of the invention.

FIG. 7 is a schematic illustration of a vehicle in-situ steering according to an embodiment of the present invention.

Fig. 8 is a block diagram of a vehicle speed estimating device according to an embodiment of the invention.

Fig. 9 is a schematic diagram of a hardware structure of an electronic device according to an embodiment of the present invention.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments of the present invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

In the related art, a technique for estimating a real-time speed of a vehicle by a technical means is generally referred to as a reference vehicle speed estimation, wherein the reference vehicle speed specifically refers to an actual movement speed of a centroid of the vehicle.

For example, the dynamic slope method based on kinematics judges the slip state of wheels through wheel speed and acceleration, when at least one wheel is not slipped, the reference vehicle speed is obtained by selecting (low selection or high selection) all wheel speeds through driving or braking states, when all wheels are slipped, the reference vehicle speed when all wheels are slipped is obtained by integrating acceleration by taking the reference vehicle speed at the moment before slipping as the basic vehicle speed, the method can estimate the reference vehicle speed, but has low accuracy and is difficult to directly serve as the control parameter of a vehicle dynamics control system, and the error accumulation in the integration process is easy to be caused due to the lack of effective suppression means for measuring noise, in addition, the method can only estimate the longitudinal reference vehicle speed and can not estimate the lateral reference vehicle speed.

In order to improve accuracy of reference vehicle speed estimation, a modeling method of vehicle dynamics and tire force is adopted in the related technology, but the method needs to perform high-dimensional matrix operation, and often needs to perform on-line solution of a jacobian matrix, so that the method has very high requirement on computing capacity of a vehicle-mounted controller, engineering application is difficult, the method cannot be directly applied to a plurality of vehicles provided with vehicle-mounted controllers with low computing force, and only longitudinal reference vehicle speeds cannot be estimated in the method, and lateral reference vehicle speeds cannot be estimated.

According to an embodiment of the present invention, there is provided an embodiment of a vehicle speed estimation method, it being noted that the steps shown in the flowchart of the drawings may be performed in a computer system such as a set of computer executable instructions, and that although a logical order is shown in the flowchart, in some cases the steps shown or described may be performed in an order other than that shown or described herein.

The invention can provide a vehicle speed estimation method which can be used for a vehicle controller, such as a VCU (Vehicle Control Unit, vehicle controller). Fig. 1 is a flowchart of a vehicle speed estimation method according to an embodiment of the present invention, as shown in fig. 1, including the following steps S101 to S103.

Step S101, converting the first longitudinal acceleration in the vehicle body consolidation coordinate system into the second longitudinal acceleration in the vehicle relative coordinate system, and converting the first lateral acceleration in the vehicle body consolidation coordinate system into the second lateral acceleration in the vehicle relative coordinate system.

Wherein the body frame (the body frame) refers to a coordinate system in which the inertial navigation device measures yaw rate and absolute acceleration of the vehicle, and the vehicle relative coordinate system (THE VEHICLE FRAME) is a coordinate system characterizing the vehicle relative acceleration. Referring to FIG. 2, the present invention may determine the longitudinal acceleration and lateral acceleration of the vehicle in the relative coordinate system based on kinematic relative acceleration estimates, the first longitudinal acceleration may be expressed asThe first lateral acceleration can be expressed asThe second longitudinal acceleration can be expressed asThe second lateral acceleration can be expressed asThe method can convert the collected acceleration under the vehicle body consolidation coordinate system into the acceleration under the vehicle relative coordinate system based on the kinematic relative acceleration estimation mode.

In some alternative embodiments, converting the first longitudinal acceleration in the consolidated coordinate system of the vehicle to the second longitudinal acceleration in the relative coordinate system of the vehicle includes determining a third product of yaw rate in the consolidated coordinate system of the vehicle and the lateral reference vehicle speed at a previous time, and determining a sum of the first longitudinal acceleration and the third product as the second longitudinal acceleration.

In particular, the sensor for acquiring longitudinal and lateral accelerations and yaw rates according to the present invention may be mounted at the vehicle centroid position, and the relationship between the measured first longitudinal acceleration and second longitudinal acceleration is expressed as:

as shown in connection with fig. 2, the second longitudinal acceleration (iterative process) is determined as follows:

Wherein, A second longitudinal acceleration is indicated and is indicated,A first longitudinal acceleration (longitudinal acceleration in the consolidated coordinate system of the vehicle body at the present moment) is represented,Indicating the lateral reference vehicle speed at the previous time,Indicating yaw rate.

In some alternative embodiments, converting the first lateral acceleration in the consolidated coordinate system of the vehicle to the second lateral acceleration in the relative coordinate system of the vehicle includes determining a fourth product of yaw rate in the consolidated coordinate system of the vehicle and the longitudinal reference vehicle speed at a previous time, and determining a difference between the first lateral acceleration and the fourth product as the second lateral acceleration.

In particular, the sensor for acquiring longitudinal and lateral accelerations and yaw rates according to the present invention may be mounted at the vehicle centroid position, and the relationship between the measured first lateral acceleration and second lateral acceleration is expressed as:

as shown in connection with fig. 2, the second lateral acceleration is determined (iterative process) as follows:

Wherein, Indicating a second lateral acceleration of the vehicle,Represents a first lateral acceleration (lateral acceleration in the consolidated coordinate system of the vehicle body at the present moment),A longitudinal reference vehicle speed indicating the previous time,Indicating yaw rate.

The method converts the longitudinal acceleration and the lateral acceleration of the vehicle body under the fixed coordinate system into the longitudinal acceleration and the lateral acceleration of the vehicle under the relative coordinate system based on the kinematics, determines the second longitudinal acceleration and the second lateral acceleration of the vehicle under the relative coordinate system, and improves the accuracy of the estimation of the longitudinal acceleration and the lateral acceleration.

In some optional embodiments, before step S101, the vehicle speed estimation method further includes obtaining an absolute longitudinal acceleration, an absolute lateral acceleration and an absolute yaw rate under a vehicle body consolidation coordinate system measured by the inertial navigation device, and obtaining a combined speed and a course angle under the navigation coordinate system measured by the positioning device, and performing kalman filtering processing on the absolute longitudinal acceleration, the absolute lateral acceleration and the absolute yaw rate to obtain a first longitudinal acceleration, a first lateral acceleration and a yaw rate.

The inertial navigation device is, for example, an INS (Inertial Navigation System ), the INS signal update frequency can be 100 times/second, the positioning device is, for example, a GPS (Global Position System, global positioning system), the GPS signal update frequency is generally 1 time/second, and of course, the positioning device related to the present invention may also be a device capable of directly acquiring the combined speed and heading angle of the vehicle under the navigation coordinate system of the vehicle, such as a beidou positioning system, a gnonass satellite navigation system or a galileo satellite navigation system.

The navigational coordinate system may also be referred to as a "northeast" coordinate system (the east north up frame), such as a GPS measurement coordinate system.

Specifically, the inertial navigation device includes a longitudinal acceleration sensor for acquiring absolute longitudinal acceleration, a lateral acceleration sensor for acquiring absolute lateral acceleration, and a yaw rate sensor for acquiring absolute yaw rate. The GPS and other positioning equipment can provide accurate information of the combined speed and the course angle, but has the problems of low sampling frequency and time delay, so that the combined speed and the course angle cannot be directly used as control parameters of a dynamics control system in the related technology.

Referring to fig. 4, the abscissa and ordinate of the navigation coordinate system are denoted as X _e and Y _e, respectively, the abscissa and ordinate of the vehicle body consolidation coordinate system are denoted as X _b and Y _b, respectively, and the abscissa and ordinate of the vehicle relative coordinate system are denoted as X _v and Y _v, respectively. Wherein, Represents the absolute yaw rate, ψ represents the yaw angle, V represents the direction of the vehicle speed,And represents the heading angle, and beta represents the centroid slip angle. The INS of the invention is used for consolidating absolute longitudinal acceleration of a vehicle body under a coordinate systemAbsolute lateral accelerationAbsolute yaw rateThe measurements are taken with the absolute longitudinal, lateral and speed of the vehicle being affected by both translational and rotational movement of the vehicle in the horizontal plane.

Because the absolute longitudinal acceleration, the absolute lateral acceleration and the absolute yaw rate measured by the INS have deviation and noise compared with the true values, if the reference vehicle speed is estimated by directly using the measured result of the INS, the estimation result error of the longitudinal reference vehicle speed and the lateral reference vehicle speed obtained by long-time integration is larger. In order to reduce the estimation result errors of the longitudinal reference vehicle speed and the lateral reference vehicle speed, the invention carries out filtering treatment on the INS measurement result through a Kalman filter (such as a classical Kalman filter), and weakens the deviation and noise of the absolute longitudinal acceleration, the absolute lateral acceleration and the absolute yaw rate, thereby improving the accuracy of vehicle speed estimation.

For example, absolute longitudinal acceleration input to a Kalman filterAbsolute lateral accelerationAbsolute yaw rateRepresented asThen the first longitudinal acceleration is obtained after Kalman filtering processingFirst lateral accelerationYaw rate

Specifically, the selected state quantity and observed quantity are The state equation used by the kalman filter is: The observation equation is y _k＝x_k +.

Wherein, Representing an a priori estimate of time k, a represents a state transition matrix,Representing a posterior estimate at time k-1, B representing the input matrix, u _k-1 representing the control input vector, W representing the normal distributed process noise and having zero mean and covariance Q (i.e., process noise covariance matrix), y _k representing the observed value at time k, H representing the observed matrix, x _k representing the actual value at time k, V representing the normal distributed measurement noise and having zero mean and covariance R (i.e., observed noise covariance matrix).

The working principle of the Kalman filter can be understood as that a state space model (comprising the state equation and the observation equation) of signals and noise is adopted by taking the minimum mean square error as the optimal estimation criterion, the estimated value of the current state and the estimated value of the error covariance are calculated by utilizing the estimated value of the previous moment, and then the correction of the state and the error covariance is carried out by combining the observed value of the current moment, so that the classical Kalman filter is formed by an iterative loop.

The invention provides a reference vehicle speed estimation method integrating INS information and GPS information, which greatly reduces the deviation and noise of the measured value of the INS compared with a true value in a Kalman filtering mode, thereby improving the accuracy of the reference vehicle speed estimation.

In combination with the foregoing embodiment, since the relevant information of the motion state of the vehicle measured by the INS and the GPS respectively belong to different coordinate systems, the present invention realizes effective fusion of the INS information and the GPS information by converting and unifying the information in the different coordinate systems.

Step S102, the longitudinal speed and the lateral speed of the vehicle in the relative coordinate system are decomposed from the combined speed of the vehicle in the navigation coordinate system.

The combined speed comprises a longitudinal speed and a lateral speed. Referring to fig. 2, the present invention represents the total speed of the vehicle in the navigation coordinate system as v _e and the longitudinal speed of the vehicle in the relative coordinate system asRepresenting the lateral speed of a vehicle in a relative coordinate system asThe longitudinal speed of the vehicle is obtained under the relative coordinate system of the vehicle by decomposing the involution speed v _e And lateral vehicle speed

Step S103, estimating a longitudinal reference vehicle speed based on the longitudinal vehicle speed and the second longitudinal acceleration, and estimating a lateral reference vehicle speed based on the lateral vehicle speed and the second lateral acceleration.

The reference vehicle speeds of the present invention include a longitudinal reference vehicle speed and a lateral reference vehicle speed, and vehicles using the vehicle speed estimation method provided by the present invention include, but are not limited to, four-wheel drive vehicles. The longitudinal reference vehicle speed and the lateral reference vehicle speed related to the invention can be real-time vehicle speeds. The longitudinal vehicle speed and the second longitudinal acceleration are used when the longitudinal reference vehicle speed is estimated, and the lateral vehicle speed and the second lateral acceleration are used when the lateral reference vehicle speed is estimated, so that the estimation process of the reference vehicle speed of the invention takes both the information acquired by the positioning equipment and the information acquired by the inertial navigation equipment into account.

In some alternative embodiments, after step S103, the vehicle speed estimation method may further include performing a low-pass filtering process on the longitudinal reference vehicle speed to obtain a final estimation result of the longitudinal reference vehicle speed, and performing a low-pass filtering process on the lateral reference vehicle speed to obtain a final estimation result of the lateral reference vehicle speed.

Specifically, the longitudinal reference vehicle speed and the lateral reference vehicle speed are respectively passed through corresponding low-pass filters, so that final estimation results of the longitudinal reference vehicle speed and the lateral reference vehicle speed are obtained.

The invention can avoid the problem of possible jump of the corrected longitudinal and lateral reference vehicle speeds by respectively carrying out low-pass filtering processing on the obtained longitudinal and lateral reference vehicle speeds, and improves the accuracy of the final estimation results of the longitudinal and lateral reference vehicle speeds.

The method comprises the steps of carrying out low-pass filtering processing on a longitudinal reference vehicle speed to obtain a final estimation result of the longitudinal reference vehicle speed, determining the ratio of the longitudinal reference vehicle speed to a first preset value as the final estimation result of the longitudinal reference vehicle speed, and carrying out low-pass filtering processing on a lateral reference vehicle speed to obtain the final estimation result of the lateral reference vehicle speed, wherein the ratio of the lateral reference vehicle speed to a second preset value is determined as the final estimation result of the lateral reference vehicle speed, the first preset value is the sum of a first filtering time constant and 1, the second preset value is the sum of a second filtering time constant and 1, and the first filtering time constant and the second filtering time constant are the same or different.

The low-pass filtering treatment process of the invention is as follows:

Wherein, Represents the final estimation result of the longitudinal reference vehicle speed,Representing a longitudinal reference vehicle speed, T _s1 represents a first filter time constant,Representing the final estimation of the lateral reference vehicle speed,The lateral reference vehicle speed is represented, T _s2 represents a second filtering time constant, and T _s1＝_s2 is less than or equal to 0.1.

Based on the low-pass filtering processing, the low-pass filtering processing method provided by the invention has the advantages that the calculation process is simple and easy to realize, and the low-pass filtering of the longitudinal and lateral reference vehicle speeds is completed under the condition of occupying less or even negligible calculation force resources.

According to the vehicle speed estimation method, the vehicle motion information under the vehicle body consolidation coordinate system and the vehicle motion information under the navigation coordinate system are fused, the accuracy of reference vehicle speed estimation is improved, and high-cost sensing equipment such as Doppler radars is not needed, so that the accurate vehicle speed is obtained on the premise of low cost. The invention realizes the function of respectively estimating the longitudinal reference vehicle speed and the lateral reference vehicle speed, thereby being directly applied to the dynamics control of the vehicle, having low calculation force requirement on the vehicle controller and being easy for engineering application. In addition, the invention does not depend on wheel speed signals, so the invention not only can estimate the longitudinal reference vehicle speed and the lateral reference vehicle speed of a conventional driving scene, but also can accurately estimate the reference vehicle speed of a tire in a strong nonlinear scene such as a large slip angle, a high slip rate and the like, especially the longitudinal reference vehicle speed and the lateral reference vehicle speed of a four-wheel drive automobile in a transverse movement and in-situ steering scene, and provides necessary control basis for controlling the transverse movement speed and the direction of the vehicle in transverse movement and inhibiting the mass center deviation of the vehicle in-situ steering.

The invention can provide a vehicle speed estimation method which can be used for a vehicle controller, such as a VCU (Vehicle Control Unit, vehicle controller). Fig. 3 is a flowchart of a vehicle speed estimation method according to an embodiment of the present invention, as shown in fig. 3, including the following steps S301 to S303.

Step S301, converting the first longitudinal acceleration in the vehicle body consolidation coordinate system into the second longitudinal acceleration in the vehicle relative coordinate system, and converting the first lateral acceleration in the vehicle body consolidation coordinate system into the second lateral acceleration in the vehicle relative coordinate system. Please refer to step S101 in the embodiment shown in fig. 1 in detail, which is not described herein.

Step S302, the longitudinal speed and the lateral speed of the vehicle in the relative coordinate system are resolved from the combined speed of the vehicle in the navigation coordinate system.

Specifically, the above step S302 includes step S3021 and step S3022.

In step S3021, the centroid side offset angle is determined using the heading angle in the navigation coordinate system and the yaw angle in the vehicle body consolidation coordinate system.

In particular, the centroid slip angle may be the difference of the heading angle and the yaw angle.

In some alternative embodiments, step S3021 described above includes step a1 and step a2.

Step a1, obtaining a yaw angle by integrating the yaw rate in the vehicle body consolidation coordinate system.

As shown in connection with figure 2 of the drawings,

Wherein, psi represents the yaw angle,Indicating yaw rate.

And a step a2, determining a first difference value of the course angle and the yaw angle as a centroid slip angle.

As shown in connection with figure 2 of the drawings,

Where β represents the heading angle.

The invention can accurately calculate the mass center side deflection angle based on the course angle under the navigation coordinate system and the yaw rate under the vehicle body consolidation coordinate system, thereby providing a data basis for the accurate decomposition of the combination speed.

Step S3022, decomposing the combined speed into a longitudinal vehicle speed and a lateral vehicle speed according to the centroid slip angle.

The invention takes the centroid side deflection angle as the decomposition basis of the combined speed, and the longitudinal speed and the lateral speed of the vehicle under the relative coordinate system are separated from the combined speed under the navigation coordinate system.

In some alternative embodiments, step S3022 includes determining a first product of the cosine of the centroid slip angle and the resultant speed as the longitudinal vehicle speed and determining a second product of the sine of the centroid slip angle and the resultant speed as the lateral vehicle speed.

As shown in fig. 2, in combination with the previous embodiment,Wherein, Represents the longitudinal vehicle speed, v _e represents the combined speed,Indicating the lateral vehicle speed.

Specifically, the speed resolution relationship between the GPS measured composite speed v _e and the vehicle relative coordinate system can be expressed as follows: The centroid slip angle is the arctangent value of the ratio of the lateral speed to the longitudinal speed of the vehicle in the relative coordinate system of the vehicle, namely: The method can decompose the GPS measured combined speed v _e under the relative coordinate system of the vehicle to obtain the longitudinal speed and the lateral speed of the vehicle under the relative coordinate system of the vehicle, and can convert the sampling period of the decomposed GPS measured speed, particularly convert the GPS signal updating period (for example, 1 second) into the scheduling period (for example, 0.01 second) of the controller, and maintain the values of the last scheduling period in the two adjacent updating periods of the GPS measured speed; therefore, in the embodiment of the invention, the conversion from the GPS signal updating period to the scheduling period of the controller is realized by keeping the value of the previous scheduling period by the longitudinal speed and the lateral speed measurement in the two adjacent updating periods of the speed measured by the GPS in the case that the GPS signal updating period is larger than the scheduling period of the controller, so that the invention can comprehensively utilize the vehicle motion information under the vehicle body consolidation coordinate system and the vehicle motion information under the navigation coordinate system.

The mode for determining the longitudinal speed and the lateral speed can accurately obtain the longitudinal speed and the lateral speed under the relative coordinate system of the vehicle, and provide data basis for correction of the reference speed, so that the accurate longitudinal reference speed and the accurate lateral reference speed can be determined.

By combining the embodiment, the invention estimates the centroid side deflection angle according to the yaw rate after Kalman filtering and the heading angle measured by the GPS, decomposes the vehicle speed measured by the GPS to obtain the longitudinal vehicle speed and the lateral vehicle speed, and realizes the conversion of the update period and the dispatch period of the longitudinal vehicle speed and the lateral vehicle speed. The centroid side deflection angle is used as a decomposition basis of the GPS measurement on the combined speed, so that the longitudinal vehicle speed and the lateral vehicle speed are decomposed from the combined speed, and a reliable basis is provided for accurate estimation of the reference vehicle speed.

Step S303, estimating a longitudinal reference vehicle speed based on the longitudinal vehicle speed and the second longitudinal acceleration, and estimating a lateral reference vehicle speed based on the lateral vehicle speed and the second lateral acceleration. Please refer to step S103 in the embodiment shown in fig. 1 in detail, which is not described herein.

The invention can provide a vehicle speed estimation method which can be used for a vehicle controller, such as a VCU (Vehicle Control Unit, vehicle controller). Fig. 5 is a flowchart of a vehicle speed estimation method according to an embodiment of the present invention, as shown in fig. 5, including the following steps S501 to S503.

Step S501, converting the first longitudinal acceleration in the vehicle body consolidation coordinate system into the second longitudinal acceleration in the vehicle relative coordinate system, and converting the first lateral acceleration in the vehicle body consolidation coordinate system into the second lateral acceleration in the vehicle relative coordinate system. Please refer to the step S101 of the embodiment shown in fig. 1 or the step S301 of the embodiment shown in fig. 3 in detail, which will not be described herein.

Step S502, the longitudinal speed and the lateral speed of the vehicle in the relative coordinate system are resolved from the combined speed of the vehicle in the navigation coordinate system. Please refer to the step S102 of the embodiment shown in fig. 1 or the step S302 of the embodiment shown in fig. 3 in detail, which will not be described herein.

Step S503, if the longitudinal speed at the current moment is different from the longitudinal speed at the previous moment, determining the sum of the longitudinal speed at the current moment and the second longitudinal acceleration as a longitudinal reference speed, and if the lateral speed at the current moment is different from the lateral speed at the previous moment, determining the sum of the lateral speed at the current moment and the second lateral acceleration as a lateral reference speed, wherein the second difference between the current moment and the previous moment is the scheduling period of the vehicle controller.

In the case that the longitudinal vehicle speeds at two adjacent moments are different, that is, in the case that the value of the signal acquired by the positioning device is changed, the embodiment corrects the longitudinal reference vehicle speed by the longitudinal vehicle speed at the current moment and corrects the lateral reference vehicle speed by the lateral vehicle speed at the current moment.

When the data (the current longitudinal speed and/or the current lateral speed) collected by the positioning equipment are updated, the reference speed is determined by utilizing the current updated data, the invention can realize the direct fusion of the data collected by the INS and the data collected by the GPS, and compared with a mode of estimating the reference speed by using the acceleration integration on the basis of the reference speed at the previous moment, the invention effectively avoids the accumulated error brought by the way of long-time acceleration integration on the basis of the reference speed at the previous moment, and improves the accuracy of the reference speed estimation.

In some alternative embodiments, if the longitudinal speed at the current moment is different from the longitudinal speed at the previous moment, determining the sum of the longitudinal speed at the current moment and the second longitudinal acceleration as the longitudinal reference speed comprises determining a third difference value between the longitudinal speed at the current moment and the longitudinal speed at the previous moment, if the third difference value is not 0, setting the first correction mark position as 1, setting the sum of the longitudinal speed at the current moment and the second longitudinal acceleration as the longitudinal reference speed according to the first correction mark position as 1. And if the third difference value is 0, setting the first correction mark position as 0, and taking the sum of the longitudinal reference vehicle speed and the second longitudinal acceleration at the previous moment as the longitudinal reference vehicle speed according to the first correction mark position as 0.

As shown in connection with fig. 2, if:VSE_bool_LgtVehSpdCrctnFlg=1,Else:VSE_bool_LgtVehSpdCrctnFlg=0。

Wherein, Represents the longitudinal vehicle speed at the current time,The VSE_pool_ LGTVEHSPDCRCTNFLG represents the first correction flag bit, namely the longitudinal reference vehicle speed correction flag bit.

In general, the longitudinal acceleration of the vehicle in the relative coordinate system is integrated to obtain a longitudinal reference vehicle speed: since the signal is discrete, the time interval is the scheduling period of the vehicle control, from an iterative point of view, the representation of the longitudinal reference vehicle speed can be converted into the following form:

The invention corrects the longitudinal reference vehicle speed according to the longitudinal reference vehicle speed correction zone bit, and replaces the integral vehicle speed with the decomposed GPS longitudinal vehicle speed during correction, namely replaces the longitudinal reference vehicle speed at the last moment, and the longitudinal reference vehicle speed is obtained by the following modes:

Wherein, Represents the longitudinal reference vehicle speed (at the current time),A longitudinal reference vehicle speed indicating the previous time,Representing a second longitudinal acceleration.

In some alternative embodiments, if the lateral vehicle speed at the current moment is different from the lateral vehicle speed at the previous moment, determining the sum of the lateral vehicle speed at the current moment and the second lateral acceleration as the lateral reference vehicle speed comprises determining a fourth difference value between the lateral vehicle speed at the current moment and the lateral vehicle speed at the previous moment, if the fourth difference value is not 0, setting the second correction mark position as 1, setting the sum of the lateral vehicle speed at the current moment and the second lateral acceleration as the lateral reference vehicle speed according to the second correction mark position as 1. And if the fourth difference value is 0, setting the second correction mark position as 0, and taking the sum of the lateral reference vehicle speed and the second lateral acceleration at the previous moment as the lateral reference vehicle speed according to the second correction mark position as 0.

As shown in connection with fig. 2, if:VSE_bool_LatVehSpdCrctnFlg=1,Else:VSE_bool_LatVehSpdCrctnFlg=0。

Wherein, Represents the lateral vehicle speed at the current moment,The VSE_pool_ LATVEHSPDCRCTNFLG represents the second correction flag bit, namely the lateral reference vehicle speed correction flag bit.

In general, the lateral acceleration of the vehicle in the relative coordinate system is integrated to obtain a lateral reference vehicle speed: Since the signal is discrete, the time interval is the scheduling period of the vehicle control, from an iterative point of view, the representation of the lateral reference vehicle speed can be converted into the following form:

According to the invention, the mark bit is corrected according to the lateral reference vehicle speed, the lateral reference vehicle speed is corrected, the integrated vehicle speed is replaced by the decomposed GPS lateral vehicle speed during correction, and the lateral reference vehicle speed at the last moment is replaced, and then the lateral reference vehicle speed is obtained by the following modes:

Wherein, Represents the lateral reference vehicle speed (at the current time),Indicating the lateral reference vehicle speed at the previous time,Representing a second lateral acceleration.

Although the common vehicle-mounted GPS has the problems of low sampling frequency and obvious delay, the related technology cannot directly use the information of the vehicle speed and the course angle provided by the GPS as the control parameter of the dynamics control system, the invention can periodically correct the estimated longitudinal reference vehicle speed and the estimated lateral reference vehicle speed through the GPS measured signal based on the mode, thereby avoiding the problem of continuous accumulation of the vehicle speed errors caused by adopting the acceleration integration mode, and obviously improving the accuracy of vehicle speed estimation. On the basis of determining the longitudinal reference vehicle speed and the lateral reference vehicle speed by using an acceleration integration mode, the invention also uses GPS measured signals to periodically correct the longitudinal reference vehicle speed and the lateral reference vehicle speed, greatly improves the accuracy of vehicle speed estimation, and has low complexity in the calculation process, so that the invention can obviously reduce the calculation force requirement on a vehicle controller, thereby improving the application range of the scheme of the invention.

As shown in fig. 6 and 7, fig. 6 is for illustrating lateral movement of the vehicle, fig. 7 is for illustrating in-situ steering of the vehicle, in which Ffl represents power output from the left front wheel, ffr represents power output from the right front wheel, frl represents power output from the left rear wheel, frr represents power output from the right rear wheel, coG represents the vehicle centroid, V represents lateral movement speed,Indicating the yaw angle of the in-situ counter-clockwise steering. The vehicle using the vehicle speed estimation method can well control the transverse moving speed and the transverse moving direction through accurately estimating the longitudinal reference vehicle speed and the lateral reference vehicle speed when the vehicle moves transversely, and can effectively inhibit the deviation of the mass center of the vehicle through accurately estimating the longitudinal reference vehicle speed and the lateral reference vehicle speed when the vehicle uses the vehicle speed estimation method to steer in situ. The invention can accurately estimate the reference vehicle speed of the tire in strong nonlinear scenes such as large slip angle, high slip rate and the like, especially the longitudinal reference vehicle speed and the lateral reference vehicle speed of the four-wheel drive vehicle in the transverse movement and in-situ steering scenes, and provides necessary control basis for controlling the transverse movement speed and the direction of the vehicle in the transverse movement and inhibiting the mass center deviation of the vehicle in the in-situ steering.

In summary, the vehicle speed estimation method provided by the invention fuses the vehicle motion information under the vehicle body consolidation coordinate system and the vehicle motion information under the navigation coordinate system, does not need high-cost sensing equipment such as Doppler radar, realizes accurate estimation and correction of the longitudinal reference vehicle speed and the lateral reference vehicle speed of the vehicle, effectively solves the problems of insufficient precision, accumulated noise and error, dependence on accurate dynamics and tire force models, high calculation force requirement on a vehicle-mounted controller, incapability of estimating the lateral reference vehicle speed, no operability and the like of the vehicle speed estimation result in the related art, and is easy for engineering application.

The present invention also provides a vehicle speed estimating device, which is used for implementing the above embodiments and preferred embodiments, and will not be described in detail. As used below, the term "module" may be a combination of software and/or hardware that implements a predetermined function. While the means described in the following embodiments are preferably implemented in software, implementation in hardware, or a combination of software and hardware, is also possible and contemplated.

The invention provides a vehicle speed estimation device, as shown in fig. 8, comprising a conversion module 801, a decomposition module 802 and an estimation module 803.

The conversion module 801 is configured to convert a first longitudinal acceleration in a vehicle body consolidation coordinate system to a second longitudinal acceleration in a vehicle relative coordinate system, and to convert a first lateral acceleration in the vehicle body consolidation coordinate system to a second lateral acceleration in the vehicle relative coordinate system.

The decomposing module 802 is configured to decompose the longitudinal speed and the lateral speed of the vehicle in the relative coordinate system from the total speed of the vehicle in the navigation coordinate system.

An estimation module 803 for estimating a longitudinal reference vehicle speed based on the longitudinal vehicle speed and the second longitudinal acceleration, and for estimating a lateral reference vehicle speed based on the lateral vehicle speed and the second lateral acceleration.

In some alternative embodiments, the decomposition module 802 includes a centroid slip angle determination unit and a resultant velocity decomposition unit.

And the centroid side deflection angle determining unit is used for determining the centroid side deflection angle by utilizing the course angle under the navigation coordinate system and the yaw angle under the vehicle body consolidation coordinate system.

And the combined speed decomposition unit is used for decomposing the combined speed into a longitudinal vehicle speed and a lateral vehicle speed according to the centroid slip angle.

In some alternative embodiments, the resultant velocity decomposition unit is configured to determine a first product of a cosine value of the centroid slip angle and the resultant velocity as the longitudinal vehicle velocity and to determine a second product of a sine value of the centroid slip angle and the resultant velocity as the lateral vehicle velocity.

In some alternative embodiments, the centroid slip angle determining unit is configured to obtain the yaw angle by performing an integral operation on the yaw rate in the vehicle body consolidation coordinate system, and is configured to determine a first difference between the heading angle and the yaw angle as the centroid slip angle.

In some alternative embodiments, the estimation module 803 includes a first estimation unit and a second estimation unit.

And the first estimation unit is used for determining the sum of the longitudinal vehicle speed at the current moment and the second longitudinal acceleration as a longitudinal reference vehicle speed according to the difference between the longitudinal vehicle speed at the current moment and the longitudinal vehicle speed at the previous moment.

And the second estimation unit is used for determining the sum of the lateral vehicle speed at the current moment and the second lateral acceleration as a lateral reference vehicle speed according to the fact that the lateral vehicle speed at the current moment is different from the lateral vehicle speed at the previous moment.

The second difference between the current time and the previous time is the scheduling period of the vehicle controller.

In some alternative embodiments, the first estimation unit includes a first calculation subunit, a first setting subunit, and a first correction subunit.

And the first calculating subunit is used for determining a third difference value between the longitudinal vehicle speed at the current moment and the longitudinal vehicle speed at the previous moment.

And the first setting subunit is used for setting the first correction mark position to be 1 according to the third difference value not being 0.

And the first correction subunit is used for taking the sum of the longitudinal vehicle speed at the current moment and the second longitudinal acceleration as the longitudinal reference vehicle speed according to the first correction zone bit being 1.

In some alternative embodiments, the first setting subunit is further configured to set the first correction flag position to 0 according to the third difference value being 0. The first correction subunit is further configured to use, according to the first correction flag bit being 0, a sum of the longitudinal reference vehicle speed and the second longitudinal acceleration at a previous time as the longitudinal reference vehicle speed.

In some alternative embodiments, the second estimation unit includes a second calculation subunit, a second setting subunit, and a second correction subunit.

And the second calculating subunit is used for determining a fourth difference value between the lateral vehicle speed at the current moment and the lateral vehicle speed at the previous moment.

And the second setting subunit is used for setting the position of the second correction mark to be 1 according to the fourth difference value not being 0.

And the second correction subunit is used for taking the sum of the lateral vehicle speed at the current moment and the second lateral acceleration as the lateral reference vehicle speed according to the second correction zone bit being 1.

In some alternative embodiments, the second setting subunit is further configured to set the second correction flag position to 0 according to the fourth difference value being 0. And the second correction subunit is further configured to use the sum of the lateral reference vehicle speed and the second lateral acceleration at the previous moment as the lateral reference vehicle speed according to the second correction flag bit being 0.

In some alternative embodiments, the conversion module 801 is specifically configured to determine a third product of the yaw rate in the vehicle body consolidation coordinate system and the lateral reference vehicle speed at a previous time, and to determine a sum of the first longitudinal acceleration and the third product as the second longitudinal acceleration.

In some alternative embodiments, the conversion module 801 is specifically configured to determine a fourth product of the yaw rate in the vehicle body consolidation coordinate system and the longitudinal reference vehicle speed at a previous time, and to determine a difference between the first lateral acceleration and the fourth product as the second lateral acceleration.

In some alternative embodiments, the vehicle speed estimation device further includes an acquisition module and a kalman filter module.

The acquisition module is used for acquiring the absolute longitudinal acceleration, the absolute lateral acceleration and the absolute yaw rate under the vehicle body consolidation coordinate system measured by the inertial navigation equipment, and acquiring the combined speed and the course angle under the navigation coordinate system measured by the positioning equipment.

And the Kalman filtering module is used for carrying out Kalman filtering processing on the absolute longitudinal acceleration, the absolute lateral acceleration and the absolute yaw rate so as to obtain a first longitudinal acceleration, a first lateral acceleration and a yaw rate.

In some alternative embodiments, the vehicle speed estimation device further includes a first low-pass filtering module and a second low-pass filtering module.

The first low-pass filtering module is used for carrying out low-pass filtering processing on the longitudinal reference vehicle speed so as to obtain a final estimation result of the longitudinal reference vehicle speed.

And the second low-pass filtering module is used for carrying out low-pass filtering processing on the lateral reference vehicle speed so as to obtain a final estimation result of the lateral reference vehicle speed.

In some alternative embodiments, the first low-pass filtering module is specifically configured to determine a ratio of the longitudinal reference vehicle speed to a first preset value as a final estimation result of the longitudinal reference vehicle speed, and the second low-pass filtering module is specifically configured to determine a ratio of the lateral reference vehicle speed to a second preset value as a final estimation result of the lateral reference vehicle speed, where the first preset value is a sum of a first filtering time constant and 1, and the second preset value is a sum of a second filtering time constant and 1, and the first filtering time constant is the same as or different from the second filtering time constant.

Further functional descriptions of the above respective modules and respective units are the same as those of the above corresponding embodiments, and are not repeated here.

The vehicle speed estimation device of the present invention is presented in the form of functional units, where the units are ASIC (Application SPECIFIC INTEGRATED Circuit) circuits, processors and memories executing one or more software or firmware programs, and/or other devices that can provide the above-described functions.

The embodiment of the invention also provides a vehicle, which comprises a vehicle controller, wherein the vehicle controller can be used for executing the vehicle speed estimation method provided by any embodiment. The embodiment of the vehicle controller for executing the vehicle speed estimation method is the same as the corresponding embodiment described above, and will not be described here again.

The vehicle controller may be, for example, a VCU (Vehicle Control Unit, whole vehicle controller), and of course, on the basis of the embodiment of the present invention, the vehicle controller may also be any vehicle-mounted controller capable of executing the above vehicle speed estimation method.

The embodiment of the invention also provides an electronic device, which is provided with the vehicle speed estimating device shown in the figure 8, and can be any electronic device which is installed on a vehicle and is used for executing the vehicle speed estimating method.

Referring to fig. 9, fig. 9 is a schematic structural diagram of an electronic device according to an alternative embodiment of the present invention, and as shown in fig. 9, the electronic device includes one or more processors 10, a memory 20, and interfaces for connecting components, including a high-speed interface and a low-speed interface. The various components are communicatively coupled to each other using different buses and may be mounted on a common motherboard or in other manners as desired. The processor may process instructions executing within the electronic device, including instructions stored in or on memory to display graphical information of the GUI on an external input/output device, such as a display device coupled to the interface. In some alternative embodiments, multiple processors and/or multiple buses may be used, if desired, along with multiple memories and multiple memories. Also, multiple electronic devices may be connected, each providing a portion of the necessary operations (e.g., as a server array, a set of blade servers, or a multiprocessor system). One processor 10 is illustrated in fig. 9.

The processor 10 may be a central processor, a network processor, or a combination thereof. The processor 10 may further include a hardware chip, among others. The hardware chip may be an application specific integrated circuit, a programmable logic device, or a combination thereof. The programmable logic device may be a complex programmable logic device, a field programmable gate array, a general-purpose array logic, or any combination thereof.

Wherein the memory 20 stores instructions for execution by the at least one processor 10 to cause the at least one processor 10 to perform the method illustrated by implementing the embodiments described above.

The memory 20 may include a storage program area that may store an operating system, application programs required for at least one function, and a storage data area that may store data created according to the use of the electronic device, etc. In addition, the memory 20 may include high-speed random access memory, and may also include non-transitory memory, such as at least one magnetic disk storage device, flash memory device, or other non-transitory solid-state storage device. In some alternative embodiments, memory 20 may optionally include memory located remotely from processor 10, which may be connected to the electronic device via a network. Examples of such networks include, but are not limited to, the internet, intranets, local area networks, mobile communication networks, and combinations thereof.

The memory 20 may comprise volatile memory, such as random access memory, or nonvolatile memory, such as flash memory, hard disk or solid state disk, or the memory 20 may comprise a combination of the above types of memory.

The electronic device also includes a communication interface 30 for the electronic device to communicate with other devices or communication networks.

The embodiments of the present invention also provide a computer readable storage medium, and the method according to the embodiments of the present invention described above may be implemented in hardware, firmware, or as a computer code which may be recorded on a storage medium, or as original stored in a remote storage medium or a non-transitory machine readable storage medium downloaded through a network and to be stored in a local storage medium, so that the method described herein may be stored on such software process on a storage medium using a general purpose computer, a special purpose processor, or programmable or special purpose hardware. The storage medium may be a magnetic disk, an optical disk, a read-only memory, a random-access memory, a flash memory, a hard disk, a solid state disk, or the like, and further, the storage medium may further include a combination of the above types of memories. It will be appreciated that a computer, processor, microprocessor controller or programmable hardware includes a storage element that can store or receive software or computer code that, when accessed and executed by the computer, processor or hardware, implements the methods illustrated by the above embodiments.

Portions of the present invention may be implemented as a computer program product, such as computer program instructions, which when executed by a computer, may invoke or provide methods and/or aspects in accordance with the present invention by way of operation of the computer. Those skilled in the art will appreciate that the existence of computer program instructions in a computer-readable medium includes, but is not limited to, source files, executable files, installation package files, and the like, and accordingly, the manner in which computer program instructions are executed by a computer includes, but is not limited to, the computer directly executing the instructions, or the computer compiling the instructions and then executing the corresponding compiled programs, or the computer reading and executing the instructions, or the computer reading and installing the instructions and then executing the corresponding installed programs. Herein, a computer-readable medium may be any available computer-readable storage medium or communication medium that can be accessed by a computer.

Although embodiments of the present invention have been described in connection with the accompanying drawings, various modifications and variations may be made by those skilled in the art without departing from the spirit and scope of the invention, and such modifications and variations fall within the scope of the invention as defined by the appended claims.

Claims

1. A vehicle speed estimation method, characterized in that the method comprises:

Converting a first longitudinal acceleration in a vehicle body fixed coordinate system into a second longitudinal acceleration in a vehicle relative coordinate system, and converting a first lateral acceleration in the vehicle body fixed coordinate system into a second lateral acceleration in the vehicle relative coordinate system;

Decomposing the longitudinal speed and lateral speed of the vehicle in the relative coordinate system from the total speed of the vehicle in the navigation coordinate system;

A longitudinal reference vehicle speed is estimated based on the longitudinal vehicle speed and the second longitudinal acceleration, and a lateral reference vehicle speed is estimated based on the lateral vehicle speed and the second lateral acceleration.

2. The method according to claim 1, characterized in that the step of decomposing the longitudinal speed and the lateral speed of the vehicle in the relative coordinate system from the combined speed of the vehicle in the navigation coordinate system comprises:

Determine the center of mass sideslip angle by using the heading angle in the navigation coordinate system and the yaw angle in the vehicle body fixed coordinate system;

The resultant speed is decomposed into the longitudinal vehicle speed and the lateral vehicle speed according to the center of mass sideslip angle.

3. The method according to claim 2, characterized in that the step of decomposing the resultant speed into the longitudinal vehicle speed and the lateral vehicle speed according to the sideslip angle of the center of mass comprises:

A first product of the cosine value of the center-of-mass sideslip angle and the resultant speed is determined as the longitudinal vehicle speed, and a second product of the sine value of the center-of-mass sideslip angle and the resultant speed is determined as the lateral vehicle speed.

4. The method according to claim 2 or 3, characterized in that the determining of the sideslip angle of the center of mass by using the heading angle in the navigation coordinate system and the yaw angle in the vehicle body fixed coordinate system comprises:

The yaw angle is obtained by integrating the yaw angular velocity in the fixed coordinate system of the vehicle body;

A first difference between the heading angle and the yaw angle is determined as the center of mass sideslip angle.

5. The method according to any one of claims 1 to 3, characterized in that

The estimating the longitudinal reference vehicle speed based on the longitudinal vehicle speed and the second longitudinal acceleration comprises: if the longitudinal vehicle speed at a current moment is different from the longitudinal vehicle speed at a previous moment, determining the sum of the longitudinal vehicle speed at the current moment and the second longitudinal acceleration as the longitudinal reference vehicle speed;

The estimating the lateral reference vehicle speed based on the lateral vehicle speed and the second lateral acceleration comprises: if the lateral vehicle speed at a current moment is different from the lateral vehicle speed at a previous moment, determining the sum of the lateral vehicle speed at the current moment and the second lateral acceleration as the lateral reference vehicle speed;

Among them, the second difference between the current moment and the previous moment is the vehicle controller scheduling cycle.

6. The method according to claim 5, characterized in that

If the longitudinal vehicle speed at the current moment is different from the longitudinal vehicle speed at the previous moment, determining the sum of the longitudinal vehicle speed at the current moment and the second longitudinal acceleration as the longitudinal reference vehicle speed, comprising: determining a third difference between the longitudinal vehicle speed at the current moment and the longitudinal vehicle speed at the previous moment, and if the third difference is not 0, setting a first correction flag to 1, and according to the first correction flag being 1, determining the sum of the longitudinal vehicle speed at the current moment and the second longitudinal acceleration as the longitudinal reference vehicle speed;

If the lateral vehicle speed at the current moment is different from the lateral vehicle speed at the previous moment, the sum of the lateral vehicle speed at the current moment and the second lateral acceleration is determined as the lateral reference vehicle speed, including: determining a fourth difference between the lateral vehicle speed at the current moment and the lateral vehicle speed at the previous moment, if the fourth difference is not 0, setting the second correction flag to 1, and according to the second correction flag being 1, using the sum of the lateral vehicle speed at the current moment and the second lateral acceleration as the lateral reference vehicle speed.

7. The method according to claim 6, characterized in that the method further comprises:

If the third difference is 0, the first correction flag is set to 0, and according to the first correction flag being 0, the sum of the longitudinal reference vehicle speed at the previous moment and the second longitudinal acceleration is used as the longitudinal reference vehicle speed;

If the fourth difference is 0, the second correction flag is set to 0. According to the second correction flag being 0, the sum of the lateral reference vehicle speed at the previous moment and the second lateral acceleration is used as the lateral reference vehicle speed.

8. The method according to any one of claims 1 to 3, characterized in that

The converting the first longitudinal acceleration in the vehicle body fixed coordinate system into the second longitudinal acceleration in the vehicle relative coordinate system comprises: determining a third product of the yaw angular velocity in the vehicle body fixed coordinate system and the lateral reference vehicle speed at a previous moment, and determining the sum of the first longitudinal acceleration and the third product as the second longitudinal acceleration;

The converting of the first lateral acceleration in the vehicle body fixed coordinate system into the second lateral acceleration in the vehicle relative coordinate system includes: determining a fourth product of the yaw angular velocity in the vehicle body fixed coordinate system and the longitudinal reference vehicle speed at a previous moment, and determining a difference between the first lateral acceleration and the fourth product as the second lateral acceleration.

9. The method according to claim 4, characterized in that the method further comprises:

Obtaining the absolute longitudinal acceleration, the absolute lateral acceleration and the absolute yaw angular velocity in the vehicle body fixed coordinate system measured by the inertial navigation device, and obtaining the resultant velocity and the heading angle in the navigation coordinate system measured by the positioning device;

Kalman filtering is performed on the absolute longitudinal acceleration, the absolute lateral acceleration, and the absolute yaw angular velocity to obtain the first longitudinal acceleration, the first lateral acceleration, and the yaw angular velocity.

10. The method according to any one of claims 1 to 3, characterized in that the method further comprises:

The longitudinal reference vehicle speed is subjected to low-pass filtering to obtain a final estimation result of the longitudinal reference vehicle speed; and the lateral reference vehicle speed is subjected to low-pass filtering to obtain a final estimation result of the lateral reference vehicle speed.

11. The method according to claim 10, characterized in that

The low-pass filtering of the longitudinal reference vehicle speed to obtain a final estimation result of the longitudinal reference vehicle speed includes: determining a ratio of the longitudinal reference vehicle speed to a first preset value as the final estimation result of the longitudinal reference vehicle speed;

The low-pass filtering of the lateral reference vehicle speed to obtain a final estimation result of the lateral reference vehicle speed includes: determining a ratio of the lateral reference vehicle speed to a second preset value as the final estimation result of the lateral reference vehicle speed;

The first preset value is the sum of the first filtering time constant and 1, the second preset value is the sum of the second filtering time constant and 1, and the first filtering time constant is the same as or different from the second filtering time constant.

12. A vehicle speed estimation device, characterized in that the device comprises:

a conversion module, for converting a first longitudinal acceleration in a vehicle body fixed coordinate system into a second longitudinal acceleration in a vehicle relative coordinate system, and for converting a first lateral acceleration in the vehicle body fixed coordinate system into a second lateral acceleration in the vehicle relative coordinate system;

A decomposition module, used for decomposing the longitudinal speed and lateral speed of the vehicle in the relative coordinate system from the total speed of the vehicle in the navigation coordinate system;

An estimation module is used for estimating a longitudinal reference vehicle speed based on the longitudinal vehicle speed and the second longitudinal acceleration, and for estimating a lateral reference vehicle speed based on the lateral vehicle speed and the second lateral acceleration.

13. An electronic device, comprising:

A memory and a processor, wherein the memory and the processor are communicatively connected to each other, the memory stores computer instructions, and the processor executes the vehicle speed estimation method according to any one of claims 1 to 11 by executing the computer instructions.

14 . A computer-readable storage medium, characterized in that computer instructions are stored on the computer-readable storage medium, and the computer instructions are used to enable a computer to execute the vehicle speed estimation method according to any one of claims 1 to 11.

15 . A computer program product, comprising computer instructions, wherein the computer instructions are used to enable a computer to execute the vehicle speed estimation method according to any one of claims 1 to 11.

16 . A vehicle, characterized in that the vehicle comprises a vehicle controller, wherein the vehicle controller is used to execute the vehicle speed estimation method according to any one of claims 1 to 11.