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

Abstract

The invention relates to the technical field of vehicles, and discloses a vehicle speed estimation method, device and equipment, a storage medium, a program product and a vehicle. The vehicle speed estimation method comprises the following steps: 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; and decomposing a longitudinal vehicle speed and a lateral vehicle speed under the relative coordinate system of the vehicle from the resultant 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 prior art, the accuracy of reference vehicle speed estimation is improved.

Description

Technical Field

[0001] The present invention relates to the field of vehicle technology, and in particular to a vehicle speed estimation method, device, equipment, storage medium, program product and vehicle. Background Art

[0002] For vehicles, obtaining accurate vehicle speed is the basis for precise dynamic control. Taking a four-wheel drive vehicle as an example, each wheel can output power, so all wheels may slip or slide in scenarios such as low-adhesion roads or extreme dynamic driving, especially when the vehicle is working in the in-situ steering function or lateral movement function. At this time, all wheel speed signals cannot reflect the actual movement speed of the vehicle. Obtaining the real-time vehicle speed in such scenarios is crucial for the vehicle's anti-skid control, lateral stability control, vehicle lateral movement speed and motion trajectory control during lateral movement, and vehicle center of mass offset suppression during in-situ steering. Although the relevant technology can directly measure the vehicle speed through sensing devices such as five-wheel instruments or Doppler radars, these sensing devices are expensive and cannot be widely used. Therefore, how to obtain accurate vehicle speed at a low cost has become the focus of research by technicians in this field. Summary of the invention

[0003] In view of this, the present invention provides a vehicle speed estimation method, device, equipment, storage medium, program product and vehicle, so as to obtain accurate vehicle speed at a low cost.

[0004] In a first aspect, the present invention provides a vehicle speed estimation method, the method comprising: 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 a longitudinal vehicle speed and a lateral vehicle speed in the vehicle relative coordinate system from a combined speed of the vehicle in 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.

[0005] The present invention estimates the longitudinal reference vehicle speed in the relative vehicle coordinate system using the longitudinal vehicle speed decomposed from the combined speed in the navigation coordinate system and the second longitudinal acceleration converted from the first longitudinal acceleration in the vehicle body fixed coordinate system, and estimates the lateral reference vehicle speed using the lateral vehicle speed decomposed from the combined speed in the navigation coordinate system and the second lateral acceleration converted from the first lateral acceleration in the vehicle body fixed coordinate system; it can be seen that in the reference vehicle speed estimation process, the present invention integrates the vehicle motion information in the vehicle body fixed coordinate system and the vehicle motion information in the navigation coordinate system, improves the accuracy of the reference vehicle speed estimation, and does not need to use high-cost sensing equipment such as Doppler radar; therefore, the present invention achieves the acquisition of accurate vehicle speed at a low cost. The present invention achieves the function of estimating the longitudinal reference vehicle speed and the lateral reference vehicle speed respectively, so that it can be directly applied to the dynamic control of the vehicle, and has low requirements on the computing power of the vehicle controller, and is easy to be applied in engineering. In addition, the present invention does not rely on wheel speed signals, and thus the present invention can not only estimate the longitudinal reference vehicle speed and the lateral reference vehicle speed in conventional driving scenarios, but can also accurately estimate the reference vehicle speed in strongly nonlinear scenarios such as tires with large sideslip angles and high slip rates, especially the longitudinal reference vehicle speed and the lateral reference vehicle speed of four-wheel drive vehicles in lateral movement and on-the-spot turning scenarios, thereby providing the necessary control basis for controlling the lateral movement speed and direction of the vehicle during lateral movement and suppressing the deviation of the vehicle's center of mass during on-the-spot turning.

[0006] In an optional embodiment, the longitudinal vehicle speed and lateral vehicle speed in the relative coordinate system are decomposed from the total speed of the vehicle in the navigation coordinate system, including: determining the center of mass sideslip angle using the heading angle in the navigation coordinate system and the yaw angle in the vehicle body fixation coordinate system; and decomposing the total speed into the longitudinal vehicle speed and the lateral vehicle speed according to the center of mass sideslip angle.

[0007] The present invention uses the center of mass sideslip angle as the basis for decomposing the resultant speed in the navigation coordinate system, so as to decompose the longitudinal vehicle speed and the lateral vehicle speed from the resultant speed, thereby providing a reliable basis for accurately estimating the reference vehicle speed.

[0008] In an optional embodiment, the resultant speed is decomposed into the longitudinal vehicle speed and the lateral vehicle speed according to the sideslip angle of the center of mass, including: determining the longitudinal vehicle speed by multiplying the cosine value of the sideslip angle of the center of mass with the first product of the resultant speed, and determining the lateral vehicle speed by multiplying the sine value of the sideslip angle of the center of mass with the second product of the resultant speed.

[0009] The above-mentioned method of determining the longitudinal vehicle speed and the lateral vehicle speed of the present invention can accurately obtain the longitudinal vehicle speed and the lateral vehicle speed in the vehicle relative coordinate system, and provide a data basis for the correction of the reference vehicle speed.

[0010] In an optional embodiment, the heading angle in the navigation coordinate system and the yaw angle in the vehicle body fixed coordinate system are used to determine the center of mass sideslip angle, including: obtaining the yaw angle by integrating the yaw angular velocity in the vehicle body fixed coordinate system, and determining a first difference between the heading angle and the yaw angle as the center of mass sideslip angle.

[0011] The present invention accurately measures the mass center sideslip angle based on two kinds of data in the navigation coordinate system and the vehicle body consolidation coordinate system, thereby providing a data basis for the accurate decomposition of the resultant speed.

[0012] In an optional embodiment, the longitudinal reference speed is estimated based on the longitudinal speed and the second longitudinal acceleration, including: if the longitudinal speed at a current moment is different from the longitudinal speed at a previous moment, the sum of the longitudinal speed at the current moment and the second longitudinal acceleration is determined as the longitudinal reference speed; the lateral reference speed is estimated based on the lateral speed and the second lateral acceleration, including: if the lateral speed at a current moment is different from the lateral speed at a previous moment, the sum of the lateral speed at a current moment and the second lateral acceleration is determined as the lateral reference speed; wherein the second difference between the current moment and the previous moment is the vehicle controller scheduling cycle.

[0013] When the data collected by the positioning device of the present invention is updated, the reference vehicle speed is determined using the currently updated data, thereby realizing direct fusion of data collected by different devices. This method avoids the error caused by long-term acceleration integration based on the reference vehicle speed at the previous moment, and improves the accuracy of the reference vehicle speed estimation.

[0014] In an optional embodiment, if the longitudinal vehicle speed at a current moment is different from the longitudinal vehicle speed at a previous moment, the sum of the longitudinal vehicle speed at the current moment and the second longitudinal acceleration is determined as the longitudinal reference vehicle speed, including: determining a third difference between the longitudinal vehicle speed at the current moment and the longitudinal vehicle speed at the previous moment, if the third difference is not 0, setting the first correction flag to 1, and based on the first correction flag being 1, the sum of the longitudinal vehicle speed at the current moment and the second longitudinal acceleration is used 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 based on the second correction flag being 1, the sum of the lateral vehicle speed at the current moment and the second lateral acceleration is used as the lateral reference vehicle speed.

[0015] The present invention uses 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 flag, and then corrects the longitudinal reference vehicle speed when the first correction flag is 1, and corrects the lateral reference vehicle speed when the second correction flag is 1. Based on the above method, the present invention can effectively correct the longitudinal reference vehicle speed and the lateral reference vehicle speed according to the update of the signal collected by the positioning device, thereby improving the accuracy of the reference vehicle speed estimation.

[0016] In an optional embodiment, the method also includes: if the third difference is 0, setting the first correction flag to 0, and based on the first correction flag being 0, using the sum of the longitudinal reference vehicle speed at the previous moment and the second longitudinal acceleration as the longitudinal reference vehicle speed; if the fourth difference is 0, setting the second correction flag to 0, and based on the second correction flag being 0, using the sum of the lateral reference vehicle speed at the previous moment and the second lateral acceleration as the lateral reference vehicle speed.

[0017] The present invention uses the acceleration integration method to determine the reference vehicle speed, and uses the signal measured by the positioning device to periodically correct the reference vehicle speed, which greatly improves the accuracy of vehicle speed estimation. Moreover, the above-mentioned calculation process is not complicated, so the present invention can reduce the computing power requirements for the vehicle controller.

[0018] In an optional embodiment, converting a first longitudinal acceleration in a vehicle body fixed coordinate system into a second longitudinal acceleration in a vehicle relative coordinate system includes: determining a third product of a yaw angular velocity in the vehicle body fixed coordinate system and a lateral reference vehicle speed at a previous moment, and determining a sum of the first longitudinal acceleration and the third product as the second longitudinal acceleration; converting a first lateral acceleration in a vehicle body fixed coordinate system into a second lateral acceleration in a vehicle relative coordinate system includes: determining a fourth product of a yaw angular velocity in the vehicle body fixed coordinate system and a 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.

[0019] The present invention estimates the second longitudinal acceleration and the second lateral acceleration in the relative coordinate system of the vehicle based on a kinematic method, thereby improving the accuracy of estimating the longitudinal and lateral accelerations.

[0020] In an optional embodiment, the method further includes: obtaining the absolute longitudinal acceleration, absolute lateral acceleration and absolute yaw angular velocity in the vehicle body fixed coordinate system measured by the inertial navigation device, and obtaining the resultant velocity and heading angle in the navigation coordinate system measured by the positioning device; performing Kalman filtering on the absolute longitudinal acceleration, absolute lateral acceleration and absolute yaw angular velocity to obtain a first longitudinal acceleration, a first lateral acceleration and a yaw angular velocity.

[0021] The present invention can also provide a reference vehicle speed estimation method that integrates information collected by an inertial navigation device and information collected by a positioning device, and greatly reduces the deviation and noise of the measured value of the inertial navigation device compared to the true value by means of Kalman filtering, thereby further improving the accuracy of the reference vehicle speed estimation of the present invention.

[0022] In an optional embodiment, the method further includes: 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.

[0023] By performing low-pass filtering on the obtained longitudinal and lateral reference vehicle speeds respectively, the present invention can also avoid the problem of possible jumps in the longitudinal and lateral reference vehicle speeds after correction, thereby improving the accuracy of the final estimation results of the longitudinal and lateral reference vehicle speeds.

[0024] In an optional embodiment, the longitudinal reference vehicle speed is low-pass filtered to obtain a final estimation result of the longitudinal reference vehicle speed, including: 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; the lateral reference vehicle speed is low-pass filtered to obtain a final estimation result of the lateral reference vehicle speed, including: determining the ratio of the lateral reference vehicle speed to a second preset value as the final estimation result of the lateral reference vehicle speed; wherein the first preset value is the sum of a first filter time constant and 1, the second preset value is the sum of a second filter time constant and 1, and the first filter time constant is the same as or different from the second filter time constant.

[0025] The calculation process of the low-pass filtering processing means provided by the present invention is simple and easy to implement, and can complete the low-pass filtering of the longitudinal and lateral reference vehicle speeds while occupying less or even negligible computing resources.

[0026] In a second aspect, the present invention provides a vehicle speed estimation device, which includes: a conversion module, used to convert a first longitudinal acceleration in a vehicle body fixed coordinate system into a second longitudinal acceleration in a vehicle relative coordinate system, and used to convert 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 to decompose the longitudinal vehicle speed and lateral vehicle speed in the vehicle relative coordinate system from the vehicle's combined speed in the navigation coordinate system; an estimation module, used to estimate the longitudinal reference vehicle speed based on the longitudinal vehicle speed and the second longitudinal acceleration, and used to estimate the lateral reference vehicle speed based on the lateral vehicle speed and the second lateral acceleration.

[0027] In a third aspect, the present invention provides an electronic device, comprising: a memory and a processor, 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 of the first aspect or any corresponding embodiment thereof by executing the computer instructions.

[0028] In a fourth aspect, the present invention provides a computer-readable storage medium having computer instructions stored thereon, the computer instructions being used to enable a computer to execute the vehicle speed estimation method of the first aspect or any corresponding embodiment thereof.

[0029] In a fifth aspect, the present invention provides a computer program product, comprising computer instructions for causing a computer to execute the vehicle speed estimation method of the first aspect or any corresponding embodiment thereof.

[0030] In a sixth aspect, the present invention provides a vehicle, the vehicle comprising a vehicle controller, the vehicle controller being configured to execute the vehicle speed estimation method of the first aspect or any corresponding embodiment thereof. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the related technologies, the drawings required for use in the specific embodiments or the related technical descriptions will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0032] Figure 1 4 is a flow chart of a vehicle speed estimation method according to an embodiment of the present invention.

[0033] Figure 2 is a schematic diagram of a vehicle speed estimation algorithm architecture according to an embodiment of the present invention.

[0034] Figure 3 4 is a flow chart of another vehicle speed estimation method according to an embodiment of the present invention.

[0035] Figure 4 Schematic diagram of a vehicle body fixed coordinate system, a vehicle relative coordinate system and a navigation coordinate system according to an embodiment of the present invention.

[0036] Figure 5 4 is a flow chart of another vehicle speed estimation method according to an embodiment of the present invention.

[0037] Figure 6 is a schematic diagram of lateral movement of a vehicle according to an embodiment of the present invention.

[0038] Figure 7Schematic diagram of a vehicle turning on the spot according to an embodiment of the present invention.

[0039] Figure 8 4 is a structural block diagram of a vehicle speed estimation device according to an embodiment of the present invention.

[0040] Fig. 9 It is a schematic diagram of the hardware structure of the electronic device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0042] In the related art, the technology of estimating the real-time speed of a vehicle by technical means is generally referred to as reference vehicle speed estimation; wherein the reference vehicle speed specifically refers to the actual moving speed of the center of mass of the vehicle.

[0043] For example, the dynamic slope method based on kinematics: the wheel slip state is judged by the wheel speed and acceleration. When at least one wheel is not slipping, all wheel speeds are selected (low selection or high selection) by the driving or braking state to obtain the reference vehicle speed; when all wheels are slipping, the acceleration is integrated with the reference vehicle speed at the moment before the slipping as the basic vehicle speed to obtain the reference vehicle speed when all wheels are slipping; although this method can estimate the reference vehicle speed, its accuracy is not high and it is difficult to directly use it as a control parameter of the vehicle dynamics control system; moreover, there is a lack of effective means to suppress measurement noise, which can easily lead to error accumulation in the integration process and an increasing deviation in the estimation result. In addition, this method can only estimate the longitudinal reference vehicle speed, but cannot estimate the lateral reference vehicle speed.

[0044] In order to improve the accuracy of reference speed estimation, the relevant technology adopts the modeling method of vehicle dynamics and tire force. However, this method requires high-dimensional matrix operations and often requires online solution of the Jacobian matrix. This places very high demands on the computing power of the on-board controller and is difficult to apply in engineering. It cannot be directly applied to many vehicles with low-computing-power on-board controllers. Moreover, this method can often only estimate the longitudinal reference speed but cannot estimate the lateral reference speed.

[0045] According to an embodiment of the present invention, an embodiment of a vehicle speed estimation method is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0046] The present invention can provide a vehicle speed estimation method which can be used in a vehicle controller, such as a VCU (Vehicle Control Unit). Figure 1 is a flow chart of a vehicle speed estimation method according to an embodiment of the present invention. Figure 1 As shown, the process includes the following steps S101 to S103.

[0047] Step S101 : 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 a vehicle body fixed coordinate system into a second lateral acceleration in a vehicle relative coordinate system.

[0048] The body frame is the coordinate system used by the inertial navigation device to measure the vehicle's yaw rate and absolute acceleration, and the vehicle frame is the coordinate system used to characterize the relative acceleration of the vehicle. Figure 2 As shown, the present invention can estimate the longitudinal acceleration and lateral acceleration of the vehicle in the relative coordinate system based on the kinematic relative acceleration. The first longitudinal acceleration can be expressed as The first lateral acceleration can be expressed as The second longitudinal acceleration can be expressed as The second lateral acceleration can be expressed as The present invention can convert the collected acceleration in the vehicle body fixed coordinate system into the acceleration in the vehicle relative coordinate system based on the kinematic relative acceleration estimation method.

[0049] In some optional embodiments, converting a first longitudinal acceleration in a vehicle body fixed coordinate system into a second longitudinal acceleration in a vehicle relative coordinate system includes: determining a third product of a yaw angular velocity in the vehicle body fixed coordinate system and a lateral reference vehicle speed at a previous moment, and determining a sum of the first longitudinal acceleration and the third product as the second longitudinal acceleration.

[0050] Specifically, the sensor for collecting longitudinal and lateral acceleration and yaw angular velocity according to the present invention can be installed at the center of mass of the vehicle, and the relationship between the measured first longitudinal acceleration and the second longitudinal acceleration is expressed as:

[0051]

[0052] Combination Figure 2 As shown, the second longitudinal acceleration is determined in the following manner (iterative process):

[0053]

[0054] in, represents the second longitudinal acceleration, represents the first longitudinal acceleration (the longitudinal acceleration of the vehicle body in the fixed coordinate system at the current moment), represents the lateral reference speed at the previous moment, represents the yaw angular velocity.

[0055] In some optional embodiments, converting a first lateral acceleration in a vehicle body fixed coordinate system into a second lateral acceleration in a 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.

[0056] Specifically, the sensor for collecting longitudinal and lateral acceleration and yaw angular velocity according to the present invention can be installed at the center of mass of the vehicle, and the relationship between the measured first lateral acceleration and the second lateral acceleration is expressed as:

[0057]

[0058] Combination Figure 2 As shown, the second lateral acceleration is determined as follows (iterative process):

[0059]

[0060] in, represents the second lateral acceleration, represents the first lateral acceleration (the lateral acceleration in the vehicle body fixed coordinate system at the current moment), represents the longitudinal reference speed at the previous moment, represents the yaw angular velocity.

[0061] The present invention converts the longitudinal acceleration and lateral acceleration in the vehicle body fixed coordinate system into the longitudinal acceleration and lateral acceleration in the vehicle relative coordinate system based on a kinematic method, determines the second longitudinal acceleration and the second lateral acceleration in the vehicle relative coordinate system, and improves the accuracy of longitudinal and lateral acceleration estimation.

[0062] In some optional embodiments, before step S101, the vehicle speed estimation method also includes: obtaining the absolute longitudinal acceleration, absolute lateral acceleration and absolute yaw angular velocity in the vehicle body fixed coordinate system measured by the inertial navigation device, and obtaining the resultant velocity and heading angle in the navigation coordinate system measured by the positioning device; performing Kalman filtering on the absolute longitudinal acceleration, absolute lateral acceleration and absolute yaw angular velocity to obtain a first longitudinal acceleration, a first lateral acceleration and a yaw angular velocity.

[0063] Among them, the inertial navigation device is, for example, INS (Inertial Navigation System), and the INS signal update frequency can be 100 times / second. The positioning device is, for example, GPS (Global Position System), and the GPS signal update frequency is generally 1 time / second; of course, the positioning device involved in the present invention can also be a Beidou positioning system, a GLONASS satellite navigation system or a Galileo satellite navigation system, etc., which can directly collect the combined speed and heading angle of the vehicle in the navigation coordinate system.

[0064] The navigation coordinate system may also be referred to as the "east north up frame", such as the GPS measurement coordinate system.

[0065] Specifically, the inertial navigation device includes a longitudinal acceleration sensor, a lateral acceleration sensor and a yaw angular velocity sensor. The longitudinal acceleration sensor is used to collect absolute longitudinal acceleration, the lateral acceleration sensor is used to collect absolute lateral acceleration, and the yaw angular velocity sensor is used to collect absolute yaw angular velocity. Positioning devices such as GPS can provide accurate combined velocity and heading angle information, but there are problems of low sampling frequency and time delay, so the combined velocity and heading angle cannot be directly used as control parameters of the dynamic control system in the relevant technology.

[0066] Combination Figure 4 As shown, the horizontal and vertical coordinates of the navigation coordinate system are represented by X e and Y e The horizontal and vertical coordinates of the vehicle body consolidation coordinate system are represented by X b and Y b The horizontal and vertical coordinates of the vehicle relative coordinate system are represented by X v and Y v .in, represents the absolute yaw rate, ψ represents the yaw angle, V represents the direction of the vehicle speed, represents the heading angle, and β represents the sideslip angle of the center of mass. The INS of the present invention is used to measure the absolute longitudinal acceleration of the vehicle body in the fixed coordinate system. Absolute lateral acceleration and the absolute yaw rate The absolute longitudinal, lateral and velocity of the vehicle are measured while being affected by the translational and rotational motion of the vehicle in the horizontal plane.

[0067] Since the absolute longitudinal acceleration, absolute lateral acceleration and absolute yaw rate measured by INS have deviations and noises compared with the true values, if the reference vehicle speed is estimated directly using the results of INS measurement, the estimation results of the longitudinal reference vehicle speed and the lateral reference vehicle speed obtained by long-term integration will have large errors. In order to reduce the errors of the estimation results of the longitudinal reference vehicle speed and the lateral reference vehicle speed, the present invention filters the results of INS measurement by a Kalman filter (such as a classic Kalman filter), weakens the deviations and noises of the absolute longitudinal acceleration, the absolute lateral acceleration and the absolute yaw rate, and thus improves the accuracy of vehicle speed estimation.

[0068] For example, the absolute longitudinal acceleration input to the Kalman filter is Absolute lateral acceleration and the absolute yaw rate Expressed as Then the first longitudinal acceleration is obtained after Kalman filtering First lateral acceleration and the yaw rate

[0069] Specifically, the selected state quantities and observation quantities are The state equation used by the Kalman filter is: The observation equation is: k =x k +.

[0070] in, represents the prior estimate at time k, A represents the state transfer matrix, represents the posterior estimate at time k-1, B represents the input matrix, u k-1 represents the control input vector, W represents the process noise that follows a normal distribution with a mean of zero and a covariance of Q (i.e., the process noise covariance matrix), and y k represents the observation value at time k, H represents the observation matrix, x k represents the true value at time k, V represents the measurement noise that obeys the normal distribution with mean zero and covariance R (i.e., the observation noise covariance matrix).

[0071] The working principle of the Kalman filter of the present invention can be understood as follows: taking the minimum mean square error as the optimal estimation criterion, adopting the state space model of the signal and noise (including the above-mentioned state equation and observation equation), using the estimated value at the previous moment to infer the current state estimate and the estimated value of the error covariance, and then combining the observed value at the current moment to correct the state and error covariance, and so on iteratively and repeatedly to constitute the above-mentioned classic Kalman filter.

[0072] The present invention provides a reference vehicle speed estimation method that integrates INS information and GPS information, and greatly reduces the deviation and noise of INS measurement values ​​compared to true values ​​by means of Kalman filtering, thereby improving the accuracy of the reference vehicle speed estimation of the present invention.

[0073] In combination with the foregoing embodiments, since the vehicle motion state related information measured by INS and GPS belongs to different coordinate systems respectively, the present invention realizes the effective fusion of INS information and GPS information by converting and unifying the information in different coordinate systems.

[0074] Step S102: 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.

[0075] The total speed includes the longitudinal speed and the lateral speed. Figure 2 As shown, the present invention expresses the combined speed of the vehicle in the navigation coordinate system as v e , and the longitudinal speed of the vehicle in the relative coordinate system is expressed as The lateral speed of the vehicle in the relative coordinate system is expressed as The present invention uses the involution speed v e Decomposition of the longitudinal speed in the vehicle relative coordinate system is obtained in the vehicle relative coordinate system. and lateral speed

[0076] 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.

[0077] The reference vehicle speed of the present invention includes a longitudinal reference vehicle speed and a lateral reference vehicle speed. Vehicles using the vehicle speed estimation method provided by the present invention include but are not limited to four-wheel drive vehicles. Among them, the longitudinal reference vehicle speed and the lateral reference vehicle speed involved in the present invention can both be real-time vehicle speeds. The present invention uses the longitudinal vehicle speed and the second longitudinal acceleration when estimating the longitudinal reference vehicle speed, and uses the lateral vehicle speed and the second lateral acceleration when estimating the lateral reference vehicle speed. It can be seen that the estimation process of the reference vehicle speed of the present invention takes into account the information collected by the positioning device and the information collected by the inertial navigation device.

[0078] In some optional embodiments, after step S103, the vehicle speed estimation method may further include: 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.

[0079] Specifically, the present invention passes the longitudinal reference vehicle speed and the lateral reference vehicle speed through corresponding low-pass filters respectively, so as to obtain the final estimation results of the longitudinal reference vehicle speed and the lateral reference vehicle speed.

[0080] The present invention can perform low-pass filtering on the obtained longitudinal and lateral reference vehicle speeds respectively, thereby avoiding the problem of possible jumps in the longitudinal and lateral reference vehicle speeds after correction, and improving the accuracy of the final estimation results of the longitudinal and lateral reference vehicle speeds.

[0081] Specifically, the longitudinal reference vehicle speed is low-pass filtered to obtain a final estimation result of the longitudinal reference vehicle speed, including: 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; the lateral reference vehicle speed is low-pass filtered to obtain a final estimation result of the lateral reference vehicle speed, including: determining the ratio of the lateral reference vehicle speed to a second preset value as the final estimation result of the lateral reference vehicle speed; wherein the first preset value is the sum of a first filter time constant and 1, the second preset value is the sum of a second filter time constant and 1, and the first filter time constant is the same as or different from the second filter time constant.

[0082] The low-pass filtering process of the present invention is as follows:

[0083] in, represents the final estimation result of the longitudinal reference speed, represents the longitudinal reference speed, T s1 represents the first filter time constant, represents the final estimated result of the lateral reference vehicle speed, Indicates the lateral reference speed, T s2 represents the second filtering time constant; T s1 = s2 ≤0.1.

[0084] Based on the above-mentioned low-pass filtering process, it can be seen that the calculation process of the low-pass filtering means provided by the present invention is simple and easy to implement, and the low-pass filtering of the longitudinal and lateral reference vehicle speeds is completed under the condition of occupying less or even negligible computing resources.

[0085] The vehicle speed estimation method provided by the present invention integrates the vehicle motion information in the vehicle body fixed coordinate system and the vehicle motion information in the navigation coordinate system, improves the accuracy of the reference vehicle speed estimation, and does not need to use high-cost sensing equipment such as Doppler radar. Therefore, the present invention realizes the acquisition of accurate vehicle speed under the premise of low cost. The present invention realizes the function of estimating the longitudinal reference vehicle speed and the lateral reference vehicle speed respectively, so that it can be directly applied to the dynamic control of the vehicle, and has low requirements on the computing power of the vehicle controller, and is easy to be applied in engineering. In addition, the present invention does not rely on the wheel speed signal, so the present invention can not only estimate the longitudinal reference vehicle speed and the lateral reference vehicle speed of the conventional driving scene, but also accurately estimate the reference vehicle speed in the strong nonlinear scene such as the tire with a large side slip angle and a high slip rate, especially the longitudinal reference vehicle speed and the lateral reference vehicle speed of the four-wheel drive vehicle in the lateral movement and in-situ turning scene, which provides the necessary control basis for the lateral movement speed and direction control of the vehicle during lateral movement and the suppression of the center of mass deviation of the vehicle during in-situ turning.

[0086] The present invention can provide a vehicle speed estimation method which can be used in a vehicle controller, such as a VCU (Vehicle Control Unit). Figure 3 is a flow chart of a vehicle speed estimation method according to an embodiment of the present invention. Figure 3 As shown, the process includes the following steps S301 to S303.

[0087] Step S301, converting the first longitudinal acceleration in the vehicle body fixed coordinate system into the second longitudinal acceleration in the vehicle relative coordinate system, and converting the first lateral acceleration in the vehicle body fixed coordinate system into the second lateral acceleration in the vehicle relative coordinate system. Figure 1 Step S101 of the illustrated embodiment will not be described in detail here.

[0088] Step S302: 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.

[0089] Specifically, the above step S302 includes step S3021 and step S3022.

[0090] Step S3021, determining 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.

[0091] Specifically, the center of mass sideslip angle may be the difference between the heading angle and the yaw angle.

[0092] In some optional implementations, the above step S3021 includes step a1 and step a2.

[0093] Step a1, obtaining the yaw angle by integrating the yaw angular velocity in the fixed coordinate system of the vehicle body.

[0094] Combination Figure 2 As shown,

[0095] Where ψ is the yaw angle, represents the yaw angular velocity.

[0096] Step a2: determine the first difference between the heading angle and the yaw angle as the center of mass sideslip angle.

[0097] Combination Figure 2 As shown,

[0098] Where β represents the heading angle.

[0099] The present invention can accurately calculate the sideslip angle of the center of mass based on the heading angle in the navigation coordinate system and the yaw angular velocity in the vehicle body fixed coordinate system, thereby providing a data basis for the accurate decomposition of the resultant velocity.

[0100] Step S3022: Decompose the resultant speed into the longitudinal vehicle speed and the lateral vehicle speed according to the sideslip angle of the center of mass.

[0101] The present invention uses the center of mass sideslip angle as the basis for decomposing the resultant velocity, and separates the longitudinal speed and the lateral speed of the vehicle in a relative coordinate system from the resultant velocity in a navigation coordinate system.

[0102] In some optional embodiments, the above step S3022 includes: determining the longitudinal vehicle speed by multiplying the cosine value of the sideslip angle of the center of mass and the first product of the resultant speed, and determining the lateral vehicle speed by multiplying the sine value of the sideslip angle of the center of mass and the second product of the resultant speed.

[0103] like Figure 2 As shown, and combined with the aforementioned embodiments, in, represents the longitudinal vehicle speed, v e represents the total speed, Indicates lateral vehicle speed.

[0104] Specifically, the combined speed v measured by GPS in the present invention is e The velocity decomposition relationship with the vehicle relative coordinate system can be expressed as follows: The center of mass sideslip angle is the inverse tangent of the ratio of the lateral speed to the longitudinal speed of the vehicle in the relative coordinate system of the vehicle, that is: The present invention can specifically convert the combined speed v measured by GPS into eDecomposition is performed in the vehicle relative coordinate system to obtain the longitudinal speed and lateral speed of the vehicle in the vehicle relative coordinate system, and the sampling period of the decomposed GPS-measured speed can be converted, specifically from the GPS signal update period (for example, 1 second) to the controller's scheduling period (for example, 0.01 second). Within two adjacent update periods of the GPS-measured speed, the decomposed longitudinal speed and lateral speed maintain the values ​​of the previous scheduling period. It can be seen that in the embodiment of the present invention, in the case where the GPS signal update period is greater than the controller's scheduling period, the longitudinal speed and lateral speed within two adjacent update periods of the GPS-measured speed maintain the values ​​of the previous scheduling period, thereby realizing the conversion of the GPS signal update period to the controller's scheduling period. Therefore, the present invention can comprehensively utilize the vehicle motion information in the vehicle body fixed coordinate system and the vehicle motion information in the navigation coordinate system.

[0105] The above-mentioned method of determining the longitudinal vehicle speed and the lateral vehicle speed of the present invention can accurately obtain the longitudinal vehicle speed and the lateral vehicle speed in the vehicle relative coordinate system, provide a data basis for correcting the reference vehicle speed, and further determine the accurate longitudinal reference vehicle speed and the lateral reference vehicle speed.

[0106] In combination with the above-mentioned embodiments, the present invention estimates the centroid slip angle according to the yaw rate after Kalman filtering and the heading angle measured by GPS, and decomposes the vehicle speed measured by GPS to obtain the longitudinal vehicle speed and the lateral vehicle speed, and realizes the conversion of the update cycle and the scheduling cycle of the longitudinal vehicle speed and the lateral vehicle speed. The centroid slip angle is used as the decomposition basis of the combined speed measured by GPS to decompose the longitudinal vehicle speed and the lateral vehicle speed from the combined speed, providing a reliable basis for the accurate estimation of the reference vehicle speed.

[0107] Step S303: Estimate the longitudinal reference vehicle speed based on the longitudinal vehicle speed and the second longitudinal acceleration, and estimate the lateral reference vehicle speed based on the lateral vehicle speed and the second lateral acceleration. Figure 1 Step S103 of the illustrated embodiment will not be described in detail here.

[0108] The present invention can provide a vehicle speed estimation method which can be used in a vehicle controller, such as a VCU (Vehicle Control Unit). Figure 5 is a flow chart of a vehicle speed estimation method according to an embodiment of the present invention. Figure 5 As shown, the process includes the following steps S501 to S503.

[0109] Step S501: convert the first longitudinal acceleration in the vehicle body fixed coordinate system into the second longitudinal acceleration in the vehicle relative coordinate system, and convert the first lateral acceleration in the vehicle body fixed coordinate system into the second lateral acceleration in the vehicle relative coordinate system. Figure 1Step S101 of the embodiment shown or Figure 3 Step S301 of the illustrated embodiment will not be described in detail here.

[0110] Step S502: Decompose 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. Figure 1 Step S102 of the embodiment shown or Figure 3 Step S302 of the illustrated embodiment will not be described in detail here.

[0111] Step S503, if the longitudinal vehicle speed at the current moment is different from the longitudinal vehicle speed at the previous moment, the sum of the longitudinal vehicle speed at the current moment and the second longitudinal acceleration is determined 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; wherein the second difference between the current moment and the previous moment is the vehicle controller scheduling cycle.

[0112] When the longitudinal vehicle speeds at two adjacent moments are different, that is, when the value of the signal collected by the positioning device changes, this 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.

[0113] When the data collected by the positioning device of the present invention (the current longitudinal vehicle speed and / or the current lateral vehicle speed) is updated, the reference vehicle speed is determined using the currently updated data. The present invention can realize the direct fusion of the data collected by INS and the data collected by GPS. Compared with the method of estimating the reference vehicle speed by integrating acceleration based on the reference vehicle speed at the previous moment only, the present invention effectively avoids the cumulative error caused by the method of integrating acceleration for a long time based on the reference vehicle speed at the previous moment, and improves the accuracy of the reference vehicle speed estimation.

[0114] In some optional implementations, if the longitudinal vehicle speed at the current moment is different from the longitudinal vehicle speed at the previous moment, the sum of the longitudinal vehicle speed at the current moment and the second longitudinal acceleration is determined as the longitudinal reference vehicle speed, including: determining a third difference between the longitudinal vehicle speed at the current moment and the longitudinal vehicle speed at the previous moment, if the third difference is not 0, setting the first correction flag to 1, and according to the first correction flag being 1, the sum of the longitudinal vehicle speed at the current moment and the second longitudinal acceleration is used as the longitudinal reference vehicle speed. If the third difference is 0, setting the first correction flag to 0, 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.

[0115] Combination Figure 2 As shown, If: VSE_bool_LgtVehSpdCrctnFlg=1, Else: VSE_bool_LgtVehSpdCrctnFlg=0.

[0116] in, Indicates the longitudinal speed of the vehicle at the current moment, Indicates the longitudinal vehicle speed at the previous moment, VSE_bool_LgtVehSpdCrctnFlg indicates the first correction flag; the first correction flag, that is, the longitudinal reference vehicle speed correction flag.

[0117] In general, the longitudinal acceleration of the vehicle in the relative coordinate system is integrated to obtain the longitudinal reference speed: Since the signal is discrete and the time interval is the scheduling cycle of vehicle control, from the perspective of iteration, the expression of the longitudinal reference speed can be converted into the following form:

[0118] The present invention corrects the longitudinal reference speed according to the longitudinal reference speed correction flag. When correcting, the decomposed GPS longitudinal speed replaces the integrated speed, that is, replaces the longitudinal reference speed at the previous moment. The longitudinal reference speed is obtained in the following way:

[0119]

[0120]

[0121] in, represents the longitudinal reference speed (at the current moment), represents the longitudinal reference speed at the previous moment, Represents the second longitudinal acceleration.

[0122] In some optional embodiments, 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 the 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, the sum of the lateral vehicle speed at the current moment and the second lateral acceleration is used as the lateral reference vehicle speed. If the fourth difference is 0, setting the second correction flag to 0, and 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.

[0123] Combination Figure 2 As shown, If: VSE_bool_LatVehSpdCrctnFlg=1, Else: VSE_bool_LatVehSpdCrctnFlg=0.

[0124] in, Indicates the lateral speed of the vehicle at the current moment. Indicates the lateral vehicle speed at the previous moment, VSE_bool_LatVehSpdCrctnFlg indicates the second correction flag; the second correction flag, that is, the lateral reference vehicle speed correction flag.

[0125] In general, the lateral acceleration of the vehicle in the relative coordinate system is integrated to obtain the lateral reference speed: Since the signal is discrete and the time interval is the scheduling cycle of vehicle control, from the perspective of iteration, the representation of the lateral reference speed can be converted into the following form:

[0126] The present invention corrects the lateral reference vehicle speed according to the lateral reference vehicle speed correction flag. When correcting, the decomposed GPS lateral vehicle speed replaces the integrated vehicle speed and the lateral reference vehicle speed at the previous moment. The lateral reference vehicle speed is obtained in the following manner:

[0127]

[0128]

[0129] in, represents the lateral reference speed (at the current moment), represents the lateral reference speed at the previous moment, represents the second lateral acceleration.

[0130] Although ordinary vehicle-mounted GPS has the problems of low sampling frequency and significant delay, and the related technology cannot directly use the vehicle speed and heading angle information provided by GPS as the control parameters of the dynamic control system, the present invention can periodically correct the estimated longitudinal reference vehicle speed and lateral reference vehicle speed through the signal measured by GPS based on the above method, thereby avoiding the problem of continuous accumulation of vehicle speed errors caused by only using the acceleration integration method, thereby significantly improving the accuracy of vehicle speed estimation. It can be seen that the present invention, on the basis of using the acceleration integration method to determine the longitudinal reference vehicle speed and the lateral reference vehicle speed, also uses the signal measured by GPS to periodically correct the longitudinal reference vehicle speed and the lateral reference vehicle speed, which greatly improves the accuracy of vehicle speed estimation, and the above calculation process is not complicated, so the present invention can significantly reduce the computing power requirements for the vehicle controller, thereby improving the scope of application of the present invention.

[0131] like Figure 6 and Figure 7 As shown, Figure 6 Used to indicate lateral movement of a vehicle. Figure 7 It is used to indicate that the vehicle is turning in place, where Ffl represents the power output of the left front wheel, Ffr represents the power output of the right front wheel, Frl represents the power output of the left rear wheel, Frr represents the power output of the right rear wheel, CoG represents the center of mass of the vehicle, and V represents the lateral movement speed. Represents the yaw angle of counterclockwise turning on the spot. When a vehicle using the vehicle speed estimation method provided by the present invention moves laterally, the lateral movement speed and direction can be well controlled by accurately estimating the longitudinal reference speed and the lateral reference speed; when a vehicle using the vehicle speed estimation method provided by the present invention turns on the spot, the deviation of the vehicle's center of mass can be effectively suppressed by accurately estimating the longitudinal reference speed and the lateral reference speed. It can be seen that the present invention can accurately estimate the reference speed in strong nonlinear scenarios such as tires with large side slip angles and high slip rates, especially the longitudinal reference speed and the lateral reference speed of four-wheel drive vehicles in lateral movement and on-the-spot turning scenarios, which provides the necessary control basis for controlling the lateral movement speed and direction of the vehicle during lateral movement and suppressing the deviation of the vehicle's center of mass during on-the-spot turning.

[0132] In summary, the vehicle speed estimation method provided by the present invention integrates the vehicle motion information in the vehicle body fixed coordinate system and the vehicle motion information in the navigation coordinate system, and does not require the use of high-cost sensing equipment such as Doppler radar, thereby achieving accurate estimation and correction of the vehicle's longitudinal reference speed and lateral reference speed. It effectively solves the problems existing in the related technologies such as insufficient accuracy of the vehicle speed estimation results, noise and error accumulation, reliance on accurate dynamics and tire force models, high requirements on the computing power of the vehicle-mounted controller, inability to estimate the lateral reference speed, and lack of operability, and is easy for engineering application.

[0133] The present invention also provides a vehicle speed estimation device, which is used to implement the above-mentioned embodiments and preferred embodiments, and will not be repeated here. As used below, the term "module" can be a combination of software and / or hardware that implements a predetermined function. Although the device described in the following embodiments is preferably implemented in software, it is also possible and conceivable to implement it in hardware, or a combination of software and hardware.

[0134] The present invention provides a vehicle speed estimation device, such as Figure 8 As shown, it includes a conversion module 801, a decomposition module 802 and an estimation module 803.

[0135] The conversion module 801 is used to convert the first longitudinal acceleration in the vehicle body fixed coordinate system into the second longitudinal acceleration in the vehicle relative coordinate system, and to convert the first lateral acceleration in the vehicle body fixed coordinate system into the second lateral acceleration in the vehicle relative coordinate system.

[0136] The decomposition module 802 is used to decompose 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.

[0137] The estimation module 803 is used to estimate the longitudinal reference vehicle speed based on the longitudinal vehicle speed and the second longitudinal acceleration, and to estimate the lateral reference vehicle speed based on the lateral vehicle speed and the second lateral acceleration.

[0138] In some optional implementations, the decomposition module 802 includes a center of mass sideslip angle determination unit and a combined velocity decomposition unit.

[0139] The center-of-mass sideslip angle determination unit is used to 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.

[0140] The combined speed decomposition unit is used for decomposing the combined speed into the longitudinal vehicle speed and the lateral vehicle speed according to the sideslip angle of the center of mass.

[0141] In some optional embodiments, the resultant velocity decomposition unit is used to determine the longitudinal vehicle velocity by multiplying the cosine value of the sideslip angle of the center of mass by the first product of the resultant velocity, and to determine the lateral vehicle velocity by multiplying the sine value of the sideslip angle of the center of mass by the second product of the resultant velocity.

[0142] In some optional embodiments, the center of mass sideslip angle determination unit is used to obtain the yaw angle by integrating the yaw angular velocity in the vehicle body fixed coordinate system, and to determine the first difference between the heading angle and the yaw angle as the center of mass sideslip angle.

[0143] In some optional implementations, the estimation module 803 includes a first estimation unit and a second estimation unit.

[0144] The first estimation unit is used to determine 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 difference between the longitudinal vehicle speed at the current moment and the longitudinal vehicle speed at the previous moment.

[0145] The second estimation unit is used to determine 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 difference between the lateral vehicle speed at the current moment and the lateral vehicle speed at the previous moment.

[0146] Among them, the second difference between the current moment and the previous moment is the vehicle controller scheduling cycle.

[0147] In some optional implementations, the first estimation unit includes a first calculation subunit, a first setting subunit, and a first correction subunit.

[0148] The first calculation subunit is used to determine a third difference between the longitudinal vehicle speed at a current moment and the longitudinal vehicle speed at a previous moment.

[0149] The first setting subunit is used to set the first correction flag to 1 according to the third difference being not 0.

[0150] 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 flag being 1.

[0151] In some optional implementations, the first setting subunit is further configured to set the first correction flag to 0 according to the third difference being 0. The first correction subunit is further configured to set the sum of the previous longitudinal reference vehicle speed and the second longitudinal acceleration as the longitudinal reference vehicle speed according to the first correction flag being 0.

[0152] In some optional implementations, the second estimation unit includes a second calculation subunit, a second setting subunit, and a second correction subunit.

[0153] The second calculation subunit is used to determine a fourth difference between the lateral vehicle speed at a current moment and the lateral vehicle speed at a previous moment.

[0154] The second setting subunit is used to set the second correction flag to 1 according to the fourth difference being not 0.

[0155] The second correction subunit is used to use 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 flag being 1.

[0156] In some optional implementations, the second setting subunit is further configured to set the second correction flag to 0 according to the fourth difference being 0. The second correction subunit is further configured to set the sum of the lateral reference vehicle speed at the previous moment and the second lateral acceleration as the lateral reference vehicle speed according to the second correction flag being 0.

[0157] In some optional embodiments, the conversion module 801 is specifically used to determine the 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 to determine the sum of the first longitudinal acceleration and the third product as the second longitudinal acceleration.

[0158] In some optional embodiments, the conversion module 801 is specifically used to determine the 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 to determine the difference between the first lateral acceleration and the fourth product as the second lateral acceleration.

[0159] In some optional implementations, the vehicle speed estimation device further includes an acquisition module and a Kalman filter module.

[0160] The acquisition module is used to obtain the absolute longitudinal acceleration, absolute lateral acceleration and absolute yaw angular velocity in the vehicle body fixed coordinate system measured by the inertial navigation device, and to obtain the resultant velocity and heading angle in the navigation coordinate system measured by the positioning device.

[0161] The Kalman filter module is used to perform Kalman filter processing on the absolute longitudinal acceleration, the absolute lateral acceleration and the absolute yaw angular velocity to obtain a first longitudinal acceleration, a first lateral acceleration and a yaw angular velocity.

[0162] In some optional implementations, the vehicle speed estimation device further includes a first low-pass filtering module and a second low-pass filtering module.

[0163] The first low-pass filtering module is used to perform low-pass filtering on the longitudinal reference vehicle speed to obtain a final estimation result of the longitudinal reference vehicle speed.

[0164] The second low-pass filtering module is used to perform low-pass filtering on the lateral reference vehicle speed to obtain a final estimation result of the lateral reference vehicle speed.

[0165] In some optional embodiments, a first low-pass filtering module is specifically used to determine the ratio of the longitudinal reference vehicle speed to a first preset value as the final estimation result of the longitudinal reference vehicle speed; a second low-pass filtering module is specifically used to determine the ratio of the lateral reference vehicle speed to a second preset value as the final estimation result of the lateral reference vehicle speed; wherein the first preset value is the sum of the first filter time constant and 1, the second preset value is the sum of the second filter time constant and 1, and the first filter time constant is the same as or different from the second filter time constant.

[0166] The further functional description of the above modules and units is the same as that of the above corresponding embodiments and will not be repeated here.

[0167] The vehicle speed estimation device in the present invention is presented in the form of a functional unit, where the unit refers to an ASIC (Application Specific Integrated Circuit) circuit, a processor and memory that executes one or more software or fixed programs, and / or other devices that can provide the above functions.

[0168] The embodiment of the present invention further provides a vehicle, the vehicle comprising a vehicle controller, the vehicle controller can be used to execute the vehicle speed estimation method provided in any of the above embodiments. The embodiment of the vehicle controller executing the vehicle speed estimation method is the same as the above corresponding embodiment, and will not be repeated here.

[0169] The vehicle controller may be, for example, a VCU (Vehicle Control Unit). Of course, based on the embodiment of the present invention, the vehicle controller may also be any vehicle-mounted controller that can execute the above-mentioned vehicle speed estimation method.

[0170] The embodiment of the present invention also provides an electronic device having the above Figure 8 The vehicle speed estimation device shown, the electronic device can be any electronic device installed on the vehicle for executing the above-mentioned vehicle speed estimation method.

[0171] See also Fig. 9 , Fig. 9 is a schematic diagram of the structure of an electronic device provided by an optional embodiment of the present invention, such as Fig. 9 As shown, the electronic device includes: one or more processors 10, a memory 20, and interfaces for connecting various components, including high-speed interfaces and low-speed interfaces. The various components are connected to each other using different buses for communication, and can be installed on a common mainboard or installed in other ways as needed. The processor can process instructions executed in the electronic device, including instructions stored in or on the 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 optional embodiments, if necessary, multiple processors and / or multiple buses can be used together with multiple memories and multiple memories. Similarly, multiple electronic devices can be connected, and each device provides some necessary operations (for example, as a server array, a group of blade servers, or a multi-processor system). Fig. 9 A processor 10 is taken as an example.

[0172] The processor 10 may be a central processing unit, a network processor or a combination thereof. The processor 10 may further include a hardware chip. The hardware chip may be a dedicated 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.

[0173] The memory 20 stores instructions to be executed by at least one processor 10, so that the at least one processor 10 executes the method shown in the above embodiment.

[0174] The memory 20 may include a program storage area and a data storage area, wherein the program storage area may store an operating system, an application required for at least one function; the data storage area may store data created according to the use of the electronic device, etc. In addition, the memory 20 may include a high-speed random access memory, and may also include a non-transient memory, such as at least one disk storage device, a flash memory device, or other non-transient solid-state storage device. In some optional embodiments, the memory 20 may optionally include a memory remotely arranged relative to the processor 10, and these remote memories may be connected to the electronic device via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0175] The memory 20 may include a volatile memory, such as a random access memory; the memory may also include a non-volatile memory, such as a flash memory, a hard disk or a solid state drive; the memory 20 may also include a combination of the above types of memory.

[0176] The electronic device further comprises a communication interface 30 for the electronic device to communicate with other devices or a communication network.

[0177] The embodiment of the present invention also provides a computer-readable storage medium. The method according to the embodiment of the present invention can be implemented in hardware, firmware, or can be implemented as a computer code that can be recorded in a storage medium, or can be implemented as a computer code that is originally stored in a remote storage medium or a non-temporary machine-readable storage medium and will be stored in a local storage medium through a network download, so that the method described herein can be stored in such software processing on a storage medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware. Among them, the storage medium can be a magnetic disk, an optical disk, a read-only storage memory, a random access memory, a flash memory, a hard disk or a solid-state hard disk, etc.; further, the storage medium can also include a combination of the above types of memories. It can be understood that a computer, a processor, a microprocessor controller, or programmable hardware includes a storage component that can store or receive software or computer code. When the software or computer code is accessed and executed by a computer, a processor, or hardware, the method shown in the above embodiment is implemented.

[0178] A part of the present invention may be applied as a computer program product, such as a computer program instruction, which, when executed by a computer, can call or provide the method and / or technical solution according to the present invention through the operation of the computer. Those skilled in the art should understand that the existence of the computer program instruction in a computer-readable medium includes, but is not limited to, a source file, an executable file, an installation package file, etc., and accordingly, the way in which the computer program instruction is executed by the computer includes, but is not limited to: the computer directly executes the instruction, or the computer compiles the instruction and then executes the corresponding compiled program, or the computer reads and executes the instruction, or the computer reads and installs the instruction and then executes the corresponding installed program. Here, the computer-readable medium may be any available computer-readable storage medium or communication medium accessible to the computer.

[0179] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope 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: 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 includes: 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 includes: 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 method of determining 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 includes: 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, characterized in that: include: 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: The computer-readable storage medium stores computer instructions, 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, characterized in that The method comprises computer instructions for causing 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 includes a vehicle controller configured to execute the vehicle speed estimation method according to any one of claims 1 to 11.

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