A method and device for calculating target curvature

Abstract

The present application relates to a method and device for calculating target curvature, and relates to the field of vehicle braking technology. The method comprises the following steps: based on the real-time speed and the sideslip angle of the center of mass of the own vehicle, the longitudinal speed and the lateral speed of the own vehicle are obtained; based on the relative longitudinal speed and the relative lateral speed of the target vehicle relative to the own vehicle, the real-time speed of the target vehicle is obtained in combination with the longitudinal speed and the lateral speed of the own vehicle; based on the relative lateral acceleration of the target vehicle relative to the own vehicle and the lateral acceleration of the own vehicle, the lateral acceleration of the target vehicle is obtained; based on the real-time speed and the lateral acceleration of the target vehicle, the motion curvature of the target vehicle is obtained. The present application obtains relevant information of the target vehicle through the driving condition of the own vehicle and the relative condition of the target vehicle, and obtains the motion curvature of the target vehicle through data processing, so as to provide data basis for the automatic emergency braking system to perform collision prediction and improve driving safety.

Description

Technical Field

[0001] The present application relates to the field of vehicle braking technology, and in particular to a method and device for calculating a target curvature. Background Art

[0002] In the automatic emergency braking system, it is necessary to judge the urgency of the current collision threat with the target, and the estimation of the collision threat requires the calculation of the target's motion trajectory. All target motion trajectories are a combination of speed and curvature, such as the target accelerating to turn left, decelerating to turn right, moving straight at a constant speed, or being stationary. Radar can calculate the relative lateral and longitudinal speeds and accelerations of the target through the Doppler effect, but the curvature cannot be directly obtained.

[0003] At present, there is a lack of relevant technologies to obtain target curvature, which makes it difficult for the automatic emergency braking system to predict collision risks.

[0004] Therefore, in order to meet the corresponding safety requirements, a new target curvature calculation technology is now provided. Summary of the invention

[0005] The present application provides a target curvature calculation method and device, which obtains relevant information of the target vehicle through the driving conditions of the own vehicle and the relative conditions of the target vehicle, and obtains the motion curvature of the target vehicle through data processing, providing data basis for the automatic emergency braking system to predict collisions, thereby improving driving safety.

[0006] To achieve the above objectives, this application provides the following solutions.

[0007] In a first aspect, the present application provides a method for calculating a target curvature, the method comprising the following steps:

[0008] Based on the real-time vehicle speed and the sideslip angle of the center of mass of the own vehicle, the longitudinal speed and the lateral speed of the own vehicle are obtained;

[0009] Based on the relative longitudinal speed and relative lateral speed of the target vehicle relative to the own vehicle, combined with the longitudinal speed and lateral speed of the own vehicle, the real-time speed of the target vehicle is obtained;

[0010] Obtaining a lateral acceleration of the target vehicle based on a relative lateral acceleration of the target vehicle relative to the own vehicle and a lateral acceleration of the own vehicle;

[0011] Based on the real-time vehicle speed and the lateral acceleration of the target vehicle, a motion curvature of the target vehicle is obtained.

[0012] Furthermore, the method further comprises the following steps:

[0013] The center of mass sideslip angle of the own vehicle is obtained based on the distance between the center of mass and the front axle, the distance between the center of mass and the rear axle, the vehicle wheelbase, the front wheel cornering stiffness, the rear wheel cornering stiffness, the vehicle mass, the steering wheel angle, the steering angle coefficient and the real-time vehicle speed.

[0014] Further, the obtaining of the center of mass sideslip angle of the own vehicle based on the distance between the center of mass and the front axle, the distance between the center of mass and the rear axle, the vehicle wheelbase, the front wheel cornering stiffness, the rear wheel cornering stiffness, the vehicle mass, the steering wheel angle, the steering angle coefficient and the real-time vehicle speed comprises the following steps:

[0015] Obtaining a first coefficient of the own vehicle based on the distance between the center of mass of the own vehicle and the front axle, the distance between the center of mass and the rear axle, the vehicle wheelbase, the front wheel cornering stiffness, the rear wheel cornering stiffness, and the vehicle mass;

[0016] Obtaining a front wheel turning angle of the own vehicle based on a steering wheel angle and a steering angle coefficient of the own vehicle;

[0017] Obtaining a motion curvature of the own vehicle based on the front wheel turning angle of the own vehicle, the vehicle wheelbase, the first coefficient, and the real-time vehicle speed;

[0018] Obtaining a rear wheel slip angle of the own vehicle based on the motion curvature of the own vehicle, the vehicle mass, the distance between the center of mass and the front axle, the vehicle wheelbase, the real-time vehicle speed, and the rear wheel slip stiffness;

[0019] The center of mass sideslip angle of the own vehicle is obtained based on the rear wheel sideslip angle of the own vehicle, the vehicle wheelbase, and the motion curvature.

[0020] Further, based on the distance between the center of mass of the own vehicle and the front axle, the distance between the center of mass and the rear axle, the vehicle wheelbase, the front wheel cornering stiffness, the rear wheel cornering stiffness and the vehicle mass, according to the first coefficient calculation formula, the first coefficient of the own vehicle is obtained;

[0021] The first coefficient calculation formula is: in,

[0022] L w =L f +L r ;

[0023] L w is the vehicle wheelbase, L f is the distance between the center of mass and the front axle, L r is the distance between the center of mass and the rear axle, C f is the front wheel cornering stiffness, C r is the rear wheel cornering stiffness, and M is the vehicle mass.

[0024] Further, based on the steering wheel angle and the steering angle coefficient of the own vehicle, the front wheel turning angle of the own vehicle is obtained according to the front wheel turning angle calculation formula;

[0025] The front wheel turning angle calculation formula is δ f =θμ; where

[0026] δ f is the front wheel turning angle, θ is the steering wheel angle, and μ is the steering angle coefficient.

[0027] Further, based on the front wheel turning angle of the own vehicle, the vehicle wheelbase, the first coefficient and the real-time vehicle speed, the motion curvature of the own vehicle is obtained according to a motion curvature calculation formula;

[0028] The motion curvature calculation formula is: in,

[0029] c is the motion curvature, δ f is the front wheel turning angle, L w is the vehicle wheelbase, k is the first coefficient, and v is the real-time vehicle speed.

[0030] Further, based on the motion curvature of the own vehicle, the vehicle mass, the distance between the center of mass and the front axle, the vehicle wheelbase, the real-time vehicle speed, and the rear wheel cornering stiffness, the rear wheel cornering angle of the own vehicle is obtained according to a rear wheel cornering angle calculation formula;

[0031] The rear wheel slip angle calculation formula is: in,

[0032] a r is the rear wheel slip angle, c is the motion curvature, M is the vehicle mass, L f is the distance between the center of mass and the front axle, L w is the vehicle wheelbase, v is the real-time vehicle speed, C r is the rear wheel cornering stiffness.

[0033] Further, based on the rear wheel sideslip angle of the own vehicle, the vehicle wheelbase and the motion curvature, the center of mass sideslip angle of the own vehicle is obtained according to a center of mass sideslip angle calculation formula;

[0034] The calculation formula of the center of mass sideslip angle is: β = cL w -a r ;in,

[0035] The center of mass sideslip angle is the center of mass sideslip angle, a r is the rear wheel slip angle, Lw is the vehicle wheelbase, and c is the motion curvature.

[0036] Further, based on the real-time vehicle speed and the lateral acceleration of the target vehicle, the motion curvature of the target vehicle is obtained according to a target vehicle motion curvature calculation formula;

[0037] The target vehicle motion curvature calculation formula is: in,

[0038] c obj is the motion curvature of the target vehicle, v obj is the real-time speed of the target vehicle, a latobj is the lateral acceleration.

[0039] In a second aspect, the present application provides a target curvature calculation device, the device comprising:

[0040] A first vehicle speed calculation module, which is used to obtain the longitudinal speed and lateral speed of the own vehicle based on the real-time vehicle speed and the center of mass sideslip angle of the own vehicle;

[0041] A second vehicle speed calculation module, which is used to obtain the real-time vehicle speed of the target vehicle based on the relative longitudinal vehicle speed and relative lateral vehicle speed of the target vehicle relative to the own vehicle, combined with the longitudinal vehicle speed and lateral vehicle speed of the own vehicle;

[0042] A first acceleration calculation module, which is used to obtain the lateral acceleration of the target vehicle based on the relative lateral acceleration of the target vehicle with respect to the own vehicle and the lateral acceleration of the own vehicle;

[0043] The first motion curvature calculation module is used to obtain the motion curvature of the target vehicle based on the real-time vehicle speed and the lateral acceleration of the target vehicle.

[0044] Furthermore, the device also includes:

[0045] The center of mass sideslip angle calculation module is used to obtain the center of mass sideslip angle of the own vehicle based on the distance between the center of mass of the own vehicle and the front axle, the distance between the center of mass and the rear axle, the vehicle wheelbase, the front wheel cornering stiffness, the rear wheel cornering stiffness, the vehicle mass, the steering wheel angle, the steering angle coefficient and the real-time vehicle speed.

[0046] Furthermore, the center of mass sideslip angle calculation module is further used to obtain a first coefficient of the own vehicle based on the distance between the center of mass of the own vehicle and the front axle, the distance between the center of mass and the rear axle, the vehicle wheelbase, the front wheel cornering stiffness, the rear wheel cornering stiffness and the vehicle mass;

[0047] The center of mass sideslip angle calculation module is also used to obtain the front wheel turning angle of the own vehicle based on the steering wheel angle and the steering angle coefficient of the own vehicle;

[0048] The center of mass sideslip angle calculation module is further used to obtain the motion curvature of the own vehicle based on the front wheel turning angle of the own vehicle, the vehicle wheelbase, the first coefficient and the real-time vehicle speed;

[0049] The center of mass sideslip angle calculation module is further used to obtain the rear wheel sideslip angle of the own vehicle based on the motion curvature of the own vehicle, the vehicle mass, the distance between the center of mass and the front axle, the vehicle wheelbase, the real-time vehicle speed, and the rear wheel sideslip stiffness;

[0050] The center-of-mass sideslip angle calculation module is also used to obtain the center-of-mass sideslip angle of the own vehicle based on the rear wheel sideslip angle of the own vehicle, the vehicle wheelbase and the motion curvature.

[0051] Further, the center of mass sideslip angle calculation module is further used to obtain the first coefficient of the own vehicle according to the first coefficient calculation formula based on the distance between the center of mass of the own vehicle and the front axle, the distance between the center of mass and the rear axle, the vehicle wheelbase, the front wheel cornering stiffness, the rear wheel cornering stiffness and the vehicle mass;

[0052] The first coefficient calculation formula is: in,

[0053] L w =L f +L r ;

[0054] L w is the vehicle wheelbase, L f is the distance between the center of mass and the front axle, L r is the distance between the center of mass and the rear axle, C f is the front wheel cornering stiffness, C r is the rear wheel cornering stiffness, and M is the vehicle mass.

[0055] Furthermore, the center of mass sideslip angle calculation module is also used to obtain the front wheel turning angle of the own vehicle according to the front wheel turning angle calculation formula based on the steering wheel angle and the steering angle coefficient of the own vehicle;

[0056] The front wheel turning angle calculation formula is δ f =θμ; where

[0057] δ f is the front wheel turning angle, θ is the steering wheel angle, and μ is the steering angle coefficient.

[0058] Furthermore, the center of mass sideslip angle calculation module is further used to obtain the motion curvature of the own vehicle according to the motion curvature calculation formula based on the front wheel turning angle of the own vehicle, the vehicle wheelbase, the first coefficient and the real-time vehicle speed;

[0059] The motion curvature calculation formula is: in,

[0060] c is the motion curvature, δ f is the front wheel turning angle, L w is the vehicle wheelbase, k is the first coefficient, and v is the real-time vehicle speed.

[0061] Furthermore, the center of mass sideslip angle calculation module is further used to obtain the rear wheel sideslip angle of the own vehicle according to the rear wheel sideslip angle calculation formula based on the motion curvature of the own vehicle, the vehicle mass, the distance between the center of mass and the front axle, the vehicle wheelbase, the real-time vehicle speed, and the rear wheel sideslip stiffness;

[0062] The rear wheel slip angle calculation formula is: in,

[0063] a r is the rear wheel slip angle, c is the motion curvature, M is the vehicle mass, L f is the distance between the center of mass and the front axle, L w is the vehicle wheelbase, v is the real-time vehicle speed, and Cr is the rear wheel cornering stiffness.

[0064] Furthermore, the center of mass sideslip angle calculation module is further used to obtain the center of mass sideslip angle of the own vehicle according to a center of mass sideslip angle calculation formula based on the rear wheel sideslip angle of the own vehicle, the vehicle wheelbase and the motion curvature;

[0065] The calculation formula of the center of mass sideslip angle is: β = cL w -a r ;in,

[0066] The center of mass sideslip angle is the center of mass sideslip angle, a r is the rear wheel slip angle, L w is the vehicle wheelbase, and c is the motion curvature.

[0067] Furthermore, the first motion curvature calculation module is further used to obtain the motion curvature of the target vehicle based on the real-time vehicle speed and the lateral acceleration of the target vehicle according to the target vehicle motion curvature calculation formula;

[0068] The target vehicle motion curvature calculation formula is: in,

[0069] c obj is the motion curvature of the target vehicle, v obj is the real-time speed of the target vehicle, a latobj is the lateral acceleration.

[0070] The beneficial effects of the technical solution provided by this application include:

[0071] The present application obtains relevant information of the target vehicle through the driving conditions of the own vehicle and the relative conditions of the target vehicle, and obtains the motion curvature of the target vehicle through data processing, thereby providing data basis for the automatic emergency braking system to predict collisions and improve driving safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0072] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0073] Figure 1 A flowchart of the target curvature calculation method provided in an embodiment of the present application;

[0074] Figure 2 A schematic diagram of the principle of the target curvature calculation method provided in an embodiment of the present application;

[0075] Figure 3 This is a structural block diagram of the target curvature calculation device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0076] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0077] The embodiments of the present application are further described in detail below in conjunction with the accompanying drawings.

[0078] The embodiment of the present application provides a target curvature calculation method and device, which obtains relevant information of the target vehicle through the driving condition of the own vehicle and the relative condition of the target vehicle, and obtains the motion curvature of the target vehicle through data processing, thereby providing data basis for the automatic emergency braking system to predict collision and improve driving safety.

[0079] In order to achieve the above technical effects, the overall idea of ​​this application is as follows:

[0080] A method for calculating target curvature, the method comprising the following steps:

[0081] S1. Based on the real-time speed and the sideslip angle of the center of mass of the own vehicle, obtain the longitudinal speed and the lateral speed of the own vehicle;

[0082] S2, based on the relative longitudinal speed and relative lateral speed of the target vehicle relative to the own vehicle, combined with the longitudinal speed and lateral speed of the own vehicle, obtain the real-time speed of the target vehicle;

[0083] S3, obtaining the lateral acceleration of the target vehicle based on the relative lateral acceleration of the target vehicle with respect to the own vehicle and the lateral acceleration of the own vehicle;

[0084] S4. Obtaining the motion curvature of the target vehicle based on the real-time vehicle speed and lateral acceleration of the target vehicle.

[0085] The embodiments of the present application are further described in detail below in conjunction with the accompanying drawings.

[0086] First, see Figures 1-2 As shown, the embodiment of the present application provides a method for calculating target curvature, the method comprising the following steps:

[0087] S1. Based on the real-time speed and the sideslip angle of the center of mass of the own vehicle, obtain the longitudinal speed and the lateral speed of the own vehicle;

[0088] S2, based on the relative longitudinal speed and relative lateral speed of the target vehicle relative to the own vehicle, combined with the longitudinal speed and lateral speed of the own vehicle, obtain the real-time speed of the target vehicle;

[0089] S3, obtaining the lateral acceleration of the target vehicle based on the relative lateral acceleration of the target vehicle with respect to the own vehicle and the lateral acceleration of the own vehicle;

[0090] S4. Obtaining the motion curvature of the target vehicle based on the real-time vehicle speed and lateral acceleration of the target vehicle.

[0091] The embodiment of the present application obtains relevant information of the target vehicle through the driving condition of the own vehicle and the relative condition of the target vehicle, and obtains the motion curvature of the target vehicle through data processing, thereby providing a data basis for the automatic emergency braking system to predict collisions and improve driving safety.

[0092] Furthermore, the method further comprises the following steps:

[0093] The center of mass sideslip angle of the own vehicle is obtained based on the distance between the center of mass and the front axle, the distance between the center of mass and the rear axle, the vehicle wheelbase, the front wheel cornering stiffness, the rear wheel cornering stiffness, the vehicle mass, the steering wheel angle, the steering angle coefficient and the real-time vehicle speed.

[0094] Further, the obtaining of the center of mass sideslip angle of the own vehicle based on the distance between the center of mass and the front axle, the distance between the center of mass and the rear axle, the vehicle wheelbase, the front wheel cornering stiffness, the rear wheel cornering stiffness, the vehicle mass, the steering wheel angle, the steering angle coefficient and the real-time vehicle speed comprises the following steps:

[0095] Obtaining a first coefficient of the own vehicle based on the distance between the center of mass of the own vehicle and the front axle, the distance between the center of mass and the rear axle, the vehicle wheelbase, the front wheel cornering stiffness, the rear wheel cornering stiffness, and the vehicle mass;

[0096] Obtaining a front wheel turning angle of the own vehicle based on a steering wheel angle and a steering angle coefficient of the own vehicle;

[0097] Obtaining a motion curvature of the own vehicle based on the front wheel turning angle of the own vehicle, the vehicle wheelbase, the first coefficient, and the real-time vehicle speed;

[0098] Obtaining a rear wheel slip angle of the own vehicle based on the motion curvature of the own vehicle, the vehicle mass, the distance between the center of mass and the front axle, the vehicle wheelbase, the real-time vehicle speed, and the rear wheel slip stiffness;

[0099] The center of mass sideslip angle of the own vehicle is obtained based on the rear wheel sideslip angle of the own vehicle, the vehicle wheelbase, and the motion curvature.

[0100] Further, based on the distance between the center of mass of the own vehicle and the front axle, the distance between the center of mass and the rear axle, the vehicle wheelbase, the front wheel cornering stiffness, the rear wheel cornering stiffness and the vehicle mass, according to the first coefficient calculation formula, the first coefficient of the own vehicle is obtained;

[0101] The first coefficient calculation formula is: in,

[0102] L w =L f +L r ;

[0103] L w is the vehicle wheelbase, L f is the distance between the center of mass and the front axle, L r is the distance between the center of mass and the rear axle, C f is the front wheel cornering stiffness, C r is the rear wheel cornering stiffness, and M is the vehicle mass.

[0104] Further, based on the steering wheel angle and the steering angle coefficient of the own vehicle, the front wheel turning angle of the own vehicle is obtained according to the front wheel turning angle calculation formula;

[0105] The front wheel turning angle calculation formula is δ f =θμ; where

[0106] δ f is the front wheel turning angle, θ is the steering wheel angle, and μ is the steering angle coefficient.

[0107] Further, based on the front wheel turning angle of the own vehicle, the vehicle wheelbase, the first coefficient and the real-time vehicle speed, the motion curvature of the own vehicle is obtained according to a motion curvature calculation formula;

[0108] The motion curvature calculation formula is: in,

[0109] c is the motion curvature, δ f is the front wheel turning angle, L w is the vehicle wheelbase, k is the first coefficient, and v is the real-time vehicle speed.

[0110] Further, based on the motion curvature of the own vehicle, the vehicle mass, the distance between the center of mass and the front axle, the vehicle wheelbase, the real-time vehicle speed, and the rear wheel cornering stiffness, the rear wheel cornering angle of the own vehicle is obtained according to a rear wheel cornering angle calculation formula;

[0111] The rear wheel slip angle calculation formula is: in,

[0112] a r is the rear wheel slip angle, c is the motion curvature, M is the vehicle mass, L f is the distance between the center of mass and the front axle, L w is the vehicle wheelbase, v is the real-time vehicle speed, and Cr is the rear wheel cornering stiffness.

[0113] Further, based on the rear wheel sideslip angle of the own vehicle, the vehicle wheelbase and the motion curvature, the center of mass sideslip angle of the own vehicle is obtained according to a center of mass sideslip angle calculation formula;

[0114] The calculation formula of the center of mass sideslip angle is: β = cL w -a r ;in,

[0115] The center of mass sideslip angle is the center of mass sideslip angle, a r is the rear wheel slip angle, L wis the vehicle wheelbase, c is the motion curvature.

[0116] Further, based on the real-time vehicle speed and the lateral acceleration of the target vehicle, the motion curvature of the target vehicle is obtained according to a target vehicle motion curvature calculation formula;

[0117] The target vehicle motion curvature calculation formula is: in,

[0118] c obj is the motion curvature of the target vehicle, v obj is the real-time speed of the target vehicle, a latobj is the lateral acceleration.

[0119] The technical solution of the embodiment of the present application calculates the motion curvature of the target based on the current mainstream linear two-wheeled vehicle model, and the specific situation is as follows:

[0120] First, the sideslip angle and lateral acceleration are calculated based on the vehicle's parameters and motion state. Secondly, the lateral and longitudinal velocities along the vehicle coordinate system are calculated based on the sideslip angle and vehicle speed information. Then, the target's absolute motion speed and absolute lateral acceleration are calculated using the target's relative lateral and longitudinal velocities and relative lateral acceleration given by the millimeter-wave radar. Finally, the target's motion curvature is calculated using the circular motion relationship.

[0121] The specific schematic diagram of the scheme principle is shown in the attached figure of the specification. Figure 2 As shown, based on the corresponding two-wheeled vehicle linear model, the specific situation is as follows:

[0122] First, calculate the vehicle's center of mass sideslip angle β and the vehicle's lateral acceleration A along the Y axis. lat , the calculation steps are as follows:

[0123] Determine the coefficient k, the first coefficient, as follows:

[0124] The first coefficient calculation formula is: in,

[0125] L w =L f +L r ;

[0126] L w is the vehicle wheelbase, L f is the distance between the center of mass and the front axle, L r is the distance between the center of mass and the rear axle, C f is the front wheel cornering stiffness, C r is the rear wheel cornering stiffness, and M is the vehicle mass.

[0127] Then, the front wheel turning angle δ of the vehicle is obtained according to the steering wheel angular velocity. f :

[0128] The front wheel turning angle calculation formula is δ f =θμ; where

[0129] δ f is the front wheel turning angle, θ is the steering wheel angle, and μ is the steering angle coefficient.

[0130] By combining the above formulas, the motion curvature of the vehicle can be obtained:

[0131] The formula for calculating motion curvature is: in,

[0132] c is the motion curvature, δ f is the front wheel turning angle, Lw is the vehicle wheelbase, k is the first coefficient, and v is the real-time vehicle speed.

[0133] Determine the rear slip angle of the ego vehicle:

[0134] The rear wheel slip angle calculation formula is: in,

[0135] a r is the rear wheel slip angle, c is the motion curvature, M is the vehicle mass, L f is the distance between the center of mass and the front axle, L w is the vehicle wheelbase, v is the real-time vehicle speed, C r is the rear wheel cornering stiffness.

[0136] Determine the sideslip angle of the center of mass of the ego vehicle:

[0137] The formula for calculating the center of mass side slip angle is: β = cL w -a r ;in,

[0138] The center of mass sideslip angle is the center of mass sideslip angle, a r is the rear wheel slip angle, L w is the vehicle wheelbase, and c is the motion curvature.

[0139] It should be noted that, as shown in the accompanying drawings of the specification Figure 2 As shown, the real-time speed of the vehicle along the X and Y axes are:

[0140] v x =vcosβ,v y = vsinβ;

[0141] Wherein, v is the real-time vehicle speed, v xis the real-time speed of the vehicle along the X axis, v y is the real-time speed of the vehicle along the Y axis.

[0142] The absolute speed of the target can be calculated based on the relative speed of the millimeter-wave radar, that is, the real-time speed of the target vehicle:

[0143] in,

[0144] v x is the real-time speed of the vehicle along the X axis, v y is the real-time speed of the vehicle along the Y axis, vx rel is the relative speed between the own vehicle and the target vehicle on the X axis, vy rel is the relative speed between the own vehicle and the target vehicle on the Y axis, v obj is the real-time speed of the target vehicle.

[0145] Calculate the target vehicle's lateral acceleration based on the own vehicle's lateral acceleration:

[0146] a latObj =a lat +a rel ;in,

[0147] a lat is the lateral acceleration of the own vehicle, which can be directly obtained from the vehicle sensor or calculated by the yaw angular velocity and the vehicle. rel is the relative lateral acceleration between the own vehicle and the target vehicle, a latObj is the lateral acceleration of the target vehicle.

[0148] Finally, the motion curvature of the target vehicle is calculated:

[0149] The calculation formula of the target vehicle motion curvature is: in,

[0150] c obj is the motion curvature of the target vehicle, v obj is the real-time speed of the target vehicle, a latobj is the lateral acceleration.

[0151] Second, see Figure 3 As shown, based on the same inventive concept as the method embodiment, the embodiment of the present application provides a target curvature calculation device, which includes:

[0152] A first vehicle speed calculation module, which is used to obtain the longitudinal speed and lateral speed of the own vehicle based on the real-time vehicle speed and the center of mass sideslip angle of the own vehicle;

[0153] A second vehicle speed calculation module, which is used to obtain the real-time vehicle speed of the target vehicle based on the relative longitudinal vehicle speed and relative lateral vehicle speed of the target vehicle relative to the own vehicle, combined with the longitudinal vehicle speed and lateral vehicle speed of the own vehicle;

[0154] A first acceleration calculation module, which is used to obtain the lateral acceleration of the target vehicle based on the relative lateral acceleration of the target vehicle with respect to the own vehicle and the lateral acceleration of the own vehicle;

[0155] The first motion curvature calculation module is used to obtain the motion curvature of the target vehicle based on the real-time vehicle speed and the lateral acceleration of the target vehicle.

[0156] The embodiment of the present application obtains relevant information of the target vehicle through the driving condition of the own vehicle and the relative condition of the target vehicle, and obtains the motion curvature of the target vehicle through data processing, thereby providing a data basis for the automatic emergency braking system to predict collisions and improve driving safety.

[0157] Furthermore, the device also includes:

[0158] The center of mass sideslip angle calculation module is used to obtain the center of mass sideslip angle of the own vehicle based on the distance between the center of mass of the own vehicle and the front axle, the distance between the center of mass and the rear axle, the vehicle wheelbase, the front wheel cornering stiffness, the rear wheel cornering stiffness, the vehicle mass, the steering wheel angle, the steering angle coefficient and the real-time vehicle speed.

[0159] Furthermore, the center of mass sideslip angle calculation module is further used to obtain a first coefficient of the own vehicle based on the distance between the center of mass of the own vehicle and the front axle, the distance between the center of mass and the rear axle, the vehicle wheelbase, the front wheel cornering stiffness, the rear wheel cornering stiffness and the vehicle mass;

[0160] The center of mass sideslip angle calculation module is also used to obtain the front wheel turning angle of the own vehicle based on the steering wheel angle and the steering angle coefficient of the own vehicle;

[0161] The center of mass sideslip angle calculation module is further used to obtain the motion curvature of the own vehicle based on the front wheel turning angle of the own vehicle, the vehicle wheelbase, the first coefficient and the real-time vehicle speed;

[0162] The center of mass sideslip angle calculation module is further used to obtain the rear wheel sideslip angle of the own vehicle based on the motion curvature of the own vehicle, the vehicle mass, the distance between the center of mass and the front axle, the vehicle wheelbase, the real-time vehicle speed, and the rear wheel sideslip stiffness;

[0163] The center-of-mass sideslip angle calculation module is also used to obtain the center-of-mass sideslip angle of the own vehicle based on the rear wheel sideslip angle of the own vehicle, the vehicle wheelbase and the motion curvature.

[0164] Further, the center of mass sideslip angle calculation module is further used to obtain the first coefficient of the own vehicle according to the first coefficient calculation formula based on the distance between the center of mass of the own vehicle and the front axle, the distance between the center of mass and the rear axle, the vehicle wheelbase, the front wheel cornering stiffness, the rear wheel cornering stiffness and the vehicle mass;

[0165] The first coefficient calculation formula is: in,

[0166] L w =L f +L r ;

[0167] L w is the vehicle wheelbase, L f is the distance between the center of mass and the front axle, L r is the distance between the center of mass and the rear axle, C f is the front wheel cornering stiffness, C r is the rear wheel cornering stiffness, and M is the vehicle mass.

[0168] Furthermore, the center of mass sideslip angle calculation module is also used to obtain the front wheel turning angle of the own vehicle according to the front wheel turning angle calculation formula based on the steering wheel angle and the steering angle coefficient of the own vehicle;

[0169] The front wheel turning angle calculation formula is δ f =θμ; where

[0170] δ f is the front wheel turning angle, θ is the steering wheel angle, and μ is the steering angle coefficient.

[0171] Furthermore, the center of mass sideslip angle calculation module is further used to obtain the motion curvature of the own vehicle according to the motion curvature calculation formula based on the front wheel turning angle of the own vehicle, the vehicle wheelbase, the first coefficient and the real-time vehicle speed;

[0172] The motion curvature calculation formula is: in,

[0173] c is the motion curvature, δ f is the front wheel turning angle, L w is the vehicle wheelbase, k is the first coefficient, and v is the real-time vehicle speed.

[0174] Furthermore, the center of mass sideslip angle calculation module is further used to obtain the rear wheel sideslip angle of the own vehicle according to the rear wheel sideslip angle calculation formula based on the motion curvature of the own vehicle, the vehicle mass, the distance between the center of mass and the front axle, the vehicle wheelbase, the real-time vehicle speed, and the rear wheel sideslip stiffness;

[0175] The rear wheel slip angle calculation formula is: in,

[0176] a r is the rear wheel slip angle, c is the motion curvature, M is the vehicle mass, L f is the distance between the center of mass and the front axle, L w is the vehicle wheelbase, v is the real-time vehicle speed, and Cr is the rear wheel cornering stiffness.

[0177] Furthermore, the center of mass sideslip angle calculation module is further used to obtain the center of mass sideslip angle of the own vehicle according to a center of mass sideslip angle calculation formula based on the rear wheel sideslip angle of the own vehicle, the vehicle wheelbase and the motion curvature;

[0178] The calculation formula of the center of mass sideslip angle is: β = cL w -a r ;in,

[0179] The center of mass sideslip angle is the center of mass sideslip angle, a r is the rear wheel slip angle, L w is the vehicle wheelbase, and c is the motion curvature.

[0180] Furthermore, the first motion curvature calculation module is further used to obtain the motion curvature of the target vehicle based on the real-time vehicle speed and the lateral acceleration of the target vehicle according to the target vehicle motion curvature calculation formula;

[0181] The target vehicle motion curvature calculation formula is: in,

[0182] c obj is the motion curvature of the target vehicle, v obj is the real-time speed of the target vehicle, a latobj is the lateral acceleration.

[0183] The technical solution of the embodiment of the present application calculates the motion curvature of the target based on the current mainstream linear two-wheeled vehicle model, and the specific situation is as follows:

[0184] First, the sideslip angle and lateral acceleration are calculated based on the vehicle's parameters and motion state. Secondly, the lateral and longitudinal velocities along the vehicle coordinate system are calculated based on the sideslip angle and vehicle speed information. Then, the target's absolute motion speed and absolute lateral acceleration are calculated using the target's relative lateral and longitudinal velocities and relative lateral acceleration given by the millimeter-wave radar. Finally, the target's motion curvature is calculated using the circular motion relationship.

[0185] The specific schematic diagram of the scheme principle is shown in the attached figure of the specification. Figure 2 As shown, based on the corresponding two-wheeled vehicle linear model, the specific situation is as follows:

[0186] First, calculate the vehicle's center of mass sideslip angle β and the vehicle's lateral acceleration A along the Y axis. lat , the calculation steps are as follows:

[0187] Determine the coefficient k, the first coefficient, as follows:

[0188] The first coefficient calculation formula is: in,

[0189] L w =L f +L r ;

[0190] L w is the vehicle wheelbase, L f is the distance between the center of mass and the front axle, L r is the distance between the center of mass and the rear axle, C f is the front wheel cornering stiffness, C r is the rear wheel cornering stiffness, and M is the vehicle mass.

[0191] Then, the front wheel turning angle δ of the vehicle is obtained according to the steering wheel angular velocity. f :

[0192] The front wheel turning angle calculation formula is δ f =θμ; where

[0193] δ f is the front wheel turning angle, θ is the steering wheel angle, and μ is the steering angle coefficient.

[0194] By combining the above formulas, the motion curvature of the vehicle can be obtained:

[0195] The formula for calculating motion curvature is: in,

[0196] c is the motion curvature, δ f is the front wheel turning angle, L w is the vehicle wheelbase, k is the first coefficient, and v is the real-time vehicle speed.

[0197] Determine the rear slip angle of the ego vehicle:

[0198] The rear wheel slip angle calculation formula is: in,

[0199] a r is the rear wheel slip angle, c is the motion curvature, M is the vehicle mass, L f is the distance between the center of mass and the front axle, L w is the vehicle wheelbase, v is the real-time vehicle speed, and Cr is the rear wheel cornering stiffness.

[0200] Determine the sideslip angle of the center of mass of the ego vehicle:

[0201] The formula for calculating the center of mass side slip angle is: β = cL w -a r ;in,

[0202] The center of mass sideslip angle is the center of mass sideslip angle, a r is the rear wheel slip angle, L w is the vehicle wheelbase, and c is the motion curvature.

[0203] It should be noted that, as shown in the accompanying drawings of the specification Figure 2 As shown, the real-time speed of the vehicle along the X and Y axes are:

[0204] v x =vcosβ,v y = vsinβ;

[0205] Wherein, v is the real-time vehicle speed, v x is the real-time speed of the vehicle along the X axis, v y is the real-time speed of the vehicle along the Y axis.

[0206] The absolute speed of the target can be calculated based on the relative speed of the millimeter-wave radar, that is, the real-time speed of the target vehicle:

[0207] in,

[0208] v x is the real-time speed of the vehicle along the X axis, v y is the real-time speed of the vehicle along the Y axis, vx rel is the relative speed between the own vehicle and the target vehicle on the X axis, vy rel is the relative speed between the own vehicle and the target vehicle on the Y axis, v obj is the real-time speed of the target vehicle.

[0209] Calculate the target vehicle's lateral acceleration based on the own vehicle's lateral acceleration:

[0210] a latObj =a lat +a rel ;in,

[0211] a lat is the lateral acceleration of the own vehicle, which can be directly obtained from the vehicle sensor or calculated by the yaw angular velocity and the vehicle. rel is the relative lateral acceleration between the own vehicle and the target vehicle, a latObj is the lateral acceleration of the target vehicle.

[0212] Finally, the motion curvature of the target vehicle is calculated:

[0213] The calculation formula of the target vehicle motion curvature is: in,

[0214] c obj is the motion curvature of the target vehicle, v obj is the real-time speed of the target vehicle, a latobj is the lateral acceleration.

[0215] It should be noted that the target curvature calculation device provided in the embodiment of the present application, and its corresponding technical problems, technical means and technical effects are similar to the principles of the target curvature calculation method in terms of principle.

[0216] It should be noted that, in this application, relational terms such as "compared to" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0217] The above is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A method for calculating target curvature, characterized in that: The method comprises the following steps: Based on the real-time vehicle speed and the sideslip angle of the center of mass of the own vehicle, the longitudinal speed and the lateral speed of the own vehicle are obtained; Based on the relative longitudinal speed and relative lateral speed of the target vehicle relative to the own vehicle, combined with the longitudinal speed and lateral speed of the own vehicle, the real-time speed of the target vehicle is obtained; Obtaining a lateral acceleration of the target vehicle based on a relative lateral acceleration of the target vehicle relative to the own vehicle and a lateral acceleration of the own vehicle; Based on the real-time vehicle speed and the lateral acceleration of the target vehicle, obtaining the motion curvature of the target vehicle; The method further comprises the following steps: Obtaining a first coefficient of the own vehicle based on the distance between the center of mass of the own vehicle and the front axle, the distance between the center of mass and the rear axle, the vehicle wheelbase, the front wheel cornering stiffness, the rear wheel cornering stiffness, and the vehicle mass; Obtaining a front wheel turning angle of the own vehicle based on a steering wheel angle and a steering angle coefficient of the own vehicle; Obtaining a motion curvature of the own vehicle based on the front wheel turning angle of the own vehicle, the vehicle wheelbase, the first coefficient, and the real-time vehicle speed; Obtaining a rear wheel slip angle of the own vehicle based on the motion curvature of the own vehicle, the vehicle mass, the distance between the center of mass and the front axle, the vehicle wheelbase, the real-time vehicle speed, and the rear wheel slip stiffness; The center of mass sideslip angle of the own vehicle is obtained based on the rear wheel sideslip angle of the own vehicle, the vehicle wheelbase, and the motion curvature.

2. The target curvature calculation method according to claim 1, characterized in that: Based on the distance between the center of mass of the own vehicle and the front axle, the distance between the center of mass and the rear axle, the vehicle wheelbase, the front wheel cornering stiffness, the rear wheel cornering stiffness and the vehicle mass, according to the first coefficient calculation formula, a first coefficient of the own vehicle is obtained; The first coefficient calculation formula is: in, L w =L f +L r ; L w is the vehicle wheelbase, L f is the distance between the center of mass and the front axle, L r is the distance between the center of mass and the rear axle, C f is the front wheel cornering stiffness, C r is the rear wheel cornering stiffness, and M is the vehicle mass.

3. The target curvature calculation method according to claim 1, characterized in that: Based on the steering wheel angle and steering angle coefficient of the own vehicle, according to the front wheel angle calculation formula, obtain the front wheel angle of the own vehicle; The front wheel turning angle calculation formula is δ f =θμ; where δ f is the front wheel turning angle, θ is the steering wheel angle, and μ is the steering angle coefficient.

4. The target curvature calculation method according to claim 1, characterized in that: Based on the front wheel turning angle of the own vehicle, the vehicle wheelbase, the first coefficient and the real-time vehicle speed, the motion curvature of the own vehicle is obtained according to a motion curvature calculation formula; The motion curvature calculation formula is: in, c is the motion curvature, δ f is the front wheel turning angle, L w is the vehicle wheelbase, k is the first coefficient, and v is the real-time vehicle speed.

5. The target curvature calculation method according to claim 1, characterized in that: Based on the motion curvature of the own vehicle, the vehicle mass, the distance between the center of mass and the front axle, the vehicle wheelbase, the real-time vehicle speed, and the rear wheel cornering stiffness, the rear wheel cornering angle of the own vehicle is obtained according to a rear wheel cornering angle calculation formula; The rear wheel slip angle calculation formula is: in, a r is the rear wheel slip angle, c is the motion curvature, M is the vehicle mass, L f is the distance between the center of mass and the front axle, L w is the vehicle wheelbase, v is the real-time vehicle speed, C r is the rear wheel cornering stiffness.

6. The target curvature calculation method according to claim 1, characterized in that: Based on the rear wheel sideslip angle of the own vehicle, the vehicle wheelbase and the motion curvature, according to the center of mass sideslip angle calculation formula, the center of mass sideslip angle of the own vehicle is obtained; The calculation formula of the center of mass sideslip angle is: β = cL w -a r ;in, The center of mass sideslip angle is the center of mass sideslip angle, a r is the rear wheel slip angle, L w is the vehicle wheelbase, and c is the motion curvature.

7. The target curvature calculation method according to claim 1, characterized in that: Based on the real-time vehicle speed and the lateral acceleration of the target vehicle, the motion curvature of the target vehicle is obtained according to a target vehicle motion curvature calculation formula; The target vehicle motion curvature calculation formula is: in, c obj is the motion curvature of the target vehicle, v obj is the real-time speed of the target vehicle, a latobj is the lateral acceleration.

8. A target curvature calculation device, characterized in that: The device comprises: A first vehicle speed calculation module, which is used to obtain the longitudinal speed and lateral speed of the own vehicle based on the real-time vehicle speed and the center of mass sideslip angle of the own vehicle; A second vehicle speed calculation module, which is used to obtain the real-time vehicle speed of the target vehicle based on the relative longitudinal vehicle speed and relative lateral vehicle speed of the target vehicle relative to the own vehicle, combined with the longitudinal vehicle speed and lateral vehicle speed of the own vehicle; A first acceleration calculation module, which is used to obtain the lateral acceleration of the target vehicle based on the relative lateral acceleration of the target vehicle with respect to the own vehicle and the lateral acceleration of the own vehicle; A first motion curvature calculation module, which is used to obtain the motion curvature of the target vehicle based on the real-time vehicle speed and the lateral acceleration of the target vehicle; The device also includes: A center of mass sideslip angle calculation module, which is used to obtain a first coefficient of the own vehicle based on the distance between the center of mass of the own vehicle and the front axle, the distance between the center of mass and the rear axle, the vehicle wheelbase, the front wheel cornering stiffness, the rear wheel cornering stiffness and the vehicle mass; The center of mass sideslip angle calculation module is also used to obtain the front wheel turning angle of the own vehicle based on the steering wheel angle and the steering angle coefficient of the own vehicle; The center of mass sideslip angle calculation module is further used to obtain the motion curvature of the own vehicle based on the front wheel turning angle of the own vehicle, the vehicle wheelbase, the first coefficient and the real-time vehicle speed; The center of mass sideslip angle calculation module is further used to obtain the rear wheel sideslip angle of the own vehicle based on the motion curvature of the own vehicle, the vehicle mass, the distance between the center of mass and the front axle, the vehicle wheelbase, the real-time vehicle speed, and the rear wheel sideslip stiffness; The center-of-mass sideslip angle calculation module is also used to obtain the center-of-mass sideslip angle of the own vehicle based on the rear wheel sideslip angle of the own vehicle, the vehicle wheelbase and the motion curvature.

Images