Vehicle control device

Abstract

The invention provides a vehicle control device which can accurately perform AEB warning and braking earlier by improving response and accuracy of self-vehicle travel path estimation. According to the present invention, for example, a change in a steering speed at which a turn / turn is started is taken into consideration from a yaw angle during turning, so that a future steering angle is estimated in good response, and the estimated steering angle is limited so as not to exceed a stable steering angle (approximate maximum steering angle) during left-right turning at an intersection obtained from vehicle operation at the initial stage of turning, thereby preventing the estimated steering angle from being too large.

Description

Technical Field

[0001] The invention relates to a vehicle control device. Background Art

[0002] Patent Document 1 discloses a system that estimates the steering wheel angle based on the current amount of change in the steering wheel angle in collision determination when turning at an intersection (left or right), and estimates the travel trajectory of the vehicle turning at the intersection. Prior art literature Patent Literature

[0003] Patent Document 1: Japanese Patent Application Publication No. 2018-106589 Summary of the invention Problem that the invention aims to solve

[0004] In the prior art described in the above-mentioned Patent Document 1, the travel path of a vehicle turning at an intersection is estimated by taking into account the change in the steering wheel angle and the limit value, but there are the following problems. That is, since the change in the steering wheel angle is not corrected, the responsiveness of the steering angle estimation when starting to turn the steering wheel and returning the steering wheel is poor. The limit value of the steering wheel angle cannot be uniquely determined by the intersection angle of the road alone, and there is no mention of a method for deriving the limit value. Therefore, it is difficult to estimate the travel path of the own vehicle with high accuracy, and response delays and reduced accuracy are prone to occur, and it may not be possible to perform AEB (Autonomous Emergency Braking: collision damage mitigation brake) alarms or brake action before a collision.

[0005] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a vehicle control device capable of performing AEB warning and braking more accurately at an earlier stage by improving the response and accuracy of own vehicle travel path estimation. Technical means of solving problems

[0006] The vehicle control device of the present invention that solves the above-mentioned problem is a vehicle control device that controls a host vehicle that is turning at an intersection, and comprises: a target object sensor that detects a target object around the host vehicle; a target object travel path estimation unit that estimates the travel path of the target object detected by the target object sensor; a steering angle sensor that detects the steering angle of the host vehicle while it is moving; and a vehicle position estimation unit that calculates a steering speed based on the steering angle detected by the steering angle sensor, estimates a future steering angle based on the steering speed and a prescribed correction gain, estimates a maximum value of a stable steering angle among the future steering angles based on a rate of change associated with the steering angle, and estimates a future position of the host vehicle based on the future steering angle and the maximum value of the stable steering angle.

[0007] The present invention, for example, considers the change in the steering speed at the beginning of steering / returning the steering wheel based on the yaw angle during turning, so as to estimate the future steering angle in a responsive manner. By limiting the estimated steering angle to not exceed the stable steering angle (≈maximum steering angle) in left or right turns at an intersection calculated based on the vehicle's behavior at the beginning of the turn, it is possible to prevent the estimation from being too large. Effects of the Invention

[0008] According to the present invention, by improving the response and accuracy of the own vehicle's travel path estimation, it is possible to reduce erroneous operations in AEB and to perform early operations on the positive operation object.

[0009] Other features related to the present invention will become apparent from the description of this specification and the accompanying drawings. In addition, other problems, structures and effects than those described above will become clear from the description of the following embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 This is a block diagram of the AEB system in the first embodiment. Figure 2 This is a flowchart for explaining the operation contents of the AEB control processing unit according to the first embodiment. Figure 3A It is a diagram for explaining an example of deriving the correction gain of the steering speed for steering angle estimation (based on the yaw angle). Figure 3B This is a diagram for explaining an example of deriving the correction gain of the steering speed for steering angle estimation (based on the travel distance). Figure 3C This is a diagram for explaining the effect of the correction gain of the steering speed for steering angle estimation. Figure 4A This is a diagram for explaining an example of derivation of a stable steering angle for steering angle estimation (based on the travel distance). Figure 4B This is a diagram for explaining an example of deriving a stable steering angle for steering angle estimation (based on the yaw angle). Figure 5A It is a diagram for explaining the problem of prediction delay and the effect of the present invention. Figure 5B It is a diagram for explaining the problem in predicting excessive bending and the effect of the present invention. Figure 6 This is a block diagram of an AEB system according to a second embodiment. Figure 7 This is a flowchart for explaining the operation contents of the AEB control processing unit according to the second embodiment. DETAILED DESCRIPTION

[0011] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In each embodiment, components having the same function are given the same reference numerals, and duplicate descriptions may be omitted.

[0012] [First embodiment] Figure 1 A block diagram showing an AEB system according to the first embodiment.

[0013] like Figure 1 As shown, the AEB system 1 includes an AEB control processing unit 100, a VMC (Vehicle Motion Controller) 200 and a brake actuator 300. The AEB control processing unit 100 and the VMC 200 are composed of an on-board ECU having a CPU and a memory. The VMC 200 has an actuator control unit 201 that performs engine control, steering control, and brake control of the vehicle as its internal function. When a brake G command is received from the AEB control processing unit 100, the actuator control unit 201 outputs a control signal to the brake actuator 300. The brake actuator 300 has a brake control device 301, which receives a control signal from the actuator control unit 201 and performs brake control according to the control signal.

[0014] The AEB control processing unit 100 performs brake assist control of the own vehicle according to the possibility of collision between the own vehicle and an obstacle (target object around the own vehicle). The AEB control processing unit 100 of this embodiment constitutes a vehicle control device, which controls (brake assist control) the own vehicle turning (left or right turn) in an intersection. A direction indicator device 501, a yaw rate sensor 502, a steering angle sensor 503, a vehicle speed sensor 504, and a target object sensor 505 are connected to the input side of the AEB control processing unit 100.

[0015] The direction indicator device 501 detects, for example, the operating state of the direction indicator of the driver. The yaw rate sensor 502 detects the yaw rate of the own vehicle. The steering angle sensor 503 detects the steering angle of the steering wheel of the own vehicle (sometimes simply referred to as the steering angle). The vehicle speed sensor 504 detects the vehicle speed based on the rotation speed of the wheels of the own vehicle. The target sensor 505 is a sensor for detecting targets around the own vehicle, and for example, at least one of a monocular camera, a stereo camera, a sonar, an infrared sensor, a radar, and a LiDAR can be used.

[0016] The AEB control processing unit 100 is installed in an on-vehicle ECU (Electronic Control Unit) as an ADAS controller or an AD controller, and performs AEB control. The AEB control processing unit 100 has a yaw angle estimation unit 101, a travel distance estimation unit 102, a vehicle path estimation unit (vehicle position estimation unit) 103, a target path estimation unit 104, a collision determination unit 105, and a braking control unit 106 as internal functions. The AEB control processing unit 100 detects obstacles and calculates the predicted path of the vehicle, determines the possibility of collision between the vehicle and the obstacle, and determines whether to start braking using the collision time TTC when the vehicle and the obstacle collide. When the vehicle and the obstacle collide, the braking start is determined, and when the braking start is determined, the braking G command required to avoid the collision is calculated and output to the VMC 200.

[0017] The yaw angle estimation unit 101 calculates the yaw angle from the start of the left or right turn of the own vehicle using the steering angle and the yaw rate of the own vehicle.

[0018] The travel distance estimation unit 102 calculates the travel distance from the start of the left or right turn of the own vehicle using the vehicle speed from the start of the left or right turn of the own vehicle.

[0019] The own vehicle's travel path estimation unit 103 considers the change in the steering speed (the change in the steering angle per unit time) at the start of turning / returning the steering wheel based on the yaw angle during the turn, so as to estimate the future steering angle in a good response, and limits the estimated steering angle to not exceed the stable steering angle (≈maximum steering angle) in left or right turns at the intersection calculated based on the vehicle's behavior at the beginning of the turn, and then uses the estimated steering angle and vehicle speed to derive the estimated travel path (future position or travel path) of the own vehicle (details will be described later).

[0020] The object path estimation unit 104 derives an estimated path (future position or path) of the object detected by the object sensor 505 .

[0021] The collision determination unit 105 determines the possibility of a collision using the estimated travel path of the own vehicle and the estimated travel path of the detected target object.

[0022] When the collision determination unit 105 determines the possibility of a collision, the brake control unit 106 determines the start of automatic braking using the time until the collision (collision time TTC) and the like, and calculates a brake G command required to avoid the collision.

[0023] The present embodiment is an example of a case where the vehicle is traveling in the right lane toward an intersection on a main road with heavy traffic and needs to turn right at the next intersection. Figure 2The processing of the AEB control processing unit 100 of the present embodiment is shown. This processing is performed once in a predetermined cycle (for example, 50 ms) in the vehicle-mounted ECU, which is the vehicle-mounted ADAS controller or AD controller.

[0024] First, in S101 , the speed (vehicle speed), steering angle, yaw rate, and direction indicator information of the own vehicle are read.

[0025] In S102, the yaw angle from the start of the left or right turn of the own vehicle is calculated using the steering angle, yaw rate, and direction indicator information read in S101 (yaw angle estimation unit 101). The calculation start condition of the yaw angle is, for example, that the direction indicator is on and the steering angle is turned by 15 degrees or more in the same direction as the direction indicator.

[0026] In S103, the speed of the own vehicle (vehicle speed) read in S101 is used to calculate the travel distance from the start of the left or right turn of the own vehicle (travel distance estimation unit 102). The calculation start condition of the travel distance is, for example, that the direction indicator is on and the steering angle is turned in the same direction as the direction indicator by more than 15 degrees.

[0027] In S104, a correction gain of the steering speed for steering angle estimation is derived.

[0028] For example, Figure 3A As shown in FIG. 1 , in deriving the correction gain, the correction gain λ is set according to the yaw angle calculated in S102 from the start of the left or right turn of the own vehicle. Alternatively, Figure 3B As shown in FIG. 1 , the correction gain λ is set based on the travel distance from the start of the left or right turn of the own vehicle calculated in S103. In order to improve the follow-up performance of the start of turning or turning, for example, the correction gain λ is set to increase the start of turning or turning (equivalent to the yaw angle or travel distance of the start of turning or turning). Figure 3C As shown, the responsiveness (followability) to the predicted delay is improved.

[0029] In S105, a stable steering angle for steering angle estimation is derived.

[0030] For example, Figure 4A As shown, in the derivation of the stable steering angle for steering angle estimation, when the driving trajectory of turning left or right at an intersection is assumed to be the same regardless of the vehicle speed, the stable steering angle is derived based on the correlation between the rate of change of the steering angle with respect to the driving distance [deg / m] and the stable steering angle. Assuming that there is a correlation, the stable steering angle [deg] can be calculated based on the rate of change of the steering angle [deg / m] × kx. The calculation formula for the stable steering angle using the rate of change of the steering angle (especially its coefficient kx) is determined based on experimental data. However, if Figure 4BAs shown, when the yaw angle of the own vehicle when entering the intersection (i.e., the rate of change of the steering angle with respect to the yaw angle of the own vehicle when entering the intersection [deg / deg]) is used instead of the travel distance, the stable steering angle can also be derived.

[0031] In S106, the estimated steering angle is calculated. The estimated steering angle is based on the steering angle detected by the steering angle sensor 503. The steering speed of the driver is calculated based on the steering angle obtained, and the estimated steering angle is calculated based on the steering speed and the correction gain λ obtained in S104. The estimated steering angle is calculated using the following equation (1), for example. (Formula 1) T: estimated future time (initial value = 0) δ -1 : Steering angle sensor value Steering speed (value before prediction) λ: Correction gain Δt: Sampling time for estimation processing (e.g. 0.1s)

[0032] However, the estimated steering angle is limited so as not to exceed the stable steering angle (≈maximum steering angle) in the left or right turn at the intersection obtained from the vehicle behavior at the initial stage of the turn in S105.

[0033] In S107 , the predicted path of the own vehicle is derived. The predicted path of the own vehicle is calculated by using the vehicle speed, wheelbase, steering gear ratio, and estimated steering angle and integrating them. The processing from S104 to S107 is performed by the own vehicle path estimation unit 103 .

[0034] In S108, the predicted path of the target object is derived (target path estimation unit 104). The predicted path of the target object is calculated by integrating the ground velocity vector of the target object based on the relative velocity vector of the detected target object and taking into account the translation and rotation of the own vehicle.

[0035] In S109, the predicted path of the own vehicle obtained in S107 and the predicted path of the target object obtained in S108 are used to determine whether the own vehicle collides with the obstacle (target object) (collision determination unit 105). If it is determined to be a collision, the process proceeds to S110. Otherwise, the process ends. Here, in S107, by improving the response and accuracy of the predicted path of the own vehicle, it is possible to reduce erroneous actions in AEB and to perform early operations on the positive action object.

[0036] In S110, the collision time TTC [s] is calculated. TTC can be calculated, for example, using the following equation (2). (Formula 2) d: Relative distance between the vehicle and the obstacle [m] V rel : Relative speed between the vehicle and the obstacle [m / s]

[0037] In S111, it is determined whether TTC is less than a preset braking start determination threshold value Tth[s]. If TTC is less than the preset braking start determination threshold value Tth[s], the process proceeds to S112. Otherwise, the process ends.

[0038] In S112, the necessary braking G command Gcmd [m / s 2 ]. Gcmd can be calculated using the following formula (3), for example. (Formula 3) V: own vehicle speed [m / s] d: Relative distance between the vehicle and the obstacle [m]

[0039] Here, when the future accuracy is high, Tth is set to a lower value. Then, since the early operation is performed, the value of d becomes larger, so it is possible to avoid Gcmd from becoming a smaller value, that is, to avoid emergency braking.

[0040] In S113, in order to activate the automatic brake, the brake G command calculated in S112 is sent to the brake actuator 300 via the VMC 200. The processes from S110 to S113 are executed by the brake control unit 106.

[0041] In addition, a warning may be given to the driver of the own vehicle based on the determination result of the collision determination unit 105 simultaneously with the operation (braking) of the automatic brake or before the operation (braking) of the automatic brake.

[0042] like Figure 5A As shown in FIG. 1 , in the case of prediction delay, the target object is misjudged as being on the path of the vehicle, which may cause erroneous operation, but this can be solved by the correction gain of the present invention. Figure 5B As shown, in the case of predicted excessive bending, it is misjudged that the target object is not on the path of the own vehicle, and there is a possibility of inaction, but this can be solved by the stable steering angle (≈maximum steering angle) of the present invention.

[0043] Therefore, the steering speed for starting to turn / return the steering wheel is considered based on the yaw angle during the turn, so as to estimate the future steering angle with good response, and limit the estimated steering angle to not exceed the stable steering angle (≈maximum steering angle) in left and right turns at the intersection calculated based on the vehicle's behavior at the beginning of the turn. In S107, the response and accuracy of the predicted forward path of the own vehicle are improved, thereby reducing erroneous operations in AEB and enabling early operations on the object of positive action.

[0044] [Second embodiment] Next, a second embodiment of the present invention will be described.

[0045] Figure 6 A block diagram showing an AEB system according to a second embodiment.

[0046] like Figure 6 As shown, the AEB control processing unit 100 of the AEB system 1 of the present embodiment has a function blocking determination unit 110 as an internal function in addition to the first embodiment.

[0047] When the function blocking determination unit 110 determines based on the yaw angle that the intersection has a special shape that is greatly different from a predetermined shape (eg, 90 degrees), the function blocking determination unit 110 blocks the AEB function to prevent the AEB function from failing to function correctly.

[0048] Similar to the first embodiment, the present embodiment is an example of a case where the vehicle is traveling in the right lane toward an intersection on a main road with heavy traffic and needs to turn right at the next intersection. Figure 7 The figure shows the processing of the AEB control processing unit 100 of the present embodiment. Compared with the first embodiment, in the case where the intersection is judged to be a special intersection shape that is greatly different from the prescribed shape (e.g., 90 degrees) based on the yaw angle from the start of the left or right turn of the own vehicle, in order to avoid the driving assistance function not being able to work normally, the present embodiment is provided with a process of shielding the driving assistance function.

[0049] The processes from S201 to S208 and from S210 to S214 are the same as the processes from S101 to S113 of the first embodiment, and thus description thereof is omitted.

[0050] In S209, it is determined whether the shape of the intersection is a special shape that differs from orthogonal (90 degrees) by a predetermined value or more. If it is a special shape, the process ends, otherwise it proceeds to S210. The determination of whether the intersection is a special shape that differs greatly from orthogonal (90 degrees) is performed using, for example, one or more of the following conditions. (1) When the vehicle starts turning left or right, if the yaw angle is greater than or equal to a predetermined value 1, the steering angle is less than or equal to a predetermined value 1. (2) When the yaw angle from the start of the left or right turn of the own vehicle reaches a predetermined value of 2 or more, the steering angle reaches a predetermined value of 2 or more. (Above / below indicates the size of the value taking the left and right directions into consideration)

[0051] As described above, relative to the first embodiment, in this second embodiment, when it is judged that the intersection is a special intersection shape that is greatly different from the prescribed shape (90 degrees) based on the yaw angle from the start of the left or right turn of the own vehicle, the driving assistance function (function for collision avoidance control) can be shielded to avoid the driving assistance function from not working properly.

[0052] [Summary of the first and second embodiments] As described above, the vehicle control device (AEB control processing unit 100) of the present embodiment is a vehicle control device for controlling a self-vehicle that is turning and traveling at an intersection, and includes: a target object sensor 505 that detects a target object around the self-vehicle; a target object travel path estimation unit 104 that estimates the travel path of the target object detected by the target object sensor 505; a steering angle sensor 503 that detects the steering angle of the self-vehicle that is traveling; and a vehicle position estimation unit (self-vehicle travel path estimation unit 104). 3) which calculates a steering speed (amount of change in the steering angle per unit time) based on the steering angle detected by the steering angle sensor 503, estimates a future steering angle based on the steering speed and a specified correction gain, estimates a maximum value of a stable steering angle in the future steering angle based on a rate of change related to the steering angle (amount of change in the steering angle relative to the yaw angle or the travel distance) (≈maximum steering angle), and estimates a future position (travel path) of the own vehicle based on the future steering angle and the maximum value of the stable steering angle (≈maximum steering angle).

[0053] In addition, a yaw angle estimating unit 101 is further provided for estimating a yaw angle from the start of the left or right turn of the own vehicle, and the predetermined correction gain is determined based on the yaw angle estimated by the yaw angle estimating unit 101. Alternatively, a travel distance estimating unit 102 is further provided for estimating a travel distance from the start of the left or right turn of the own vehicle, and the predetermined correction gain is determined based on the travel distance estimated by the travel distance estimating unit 102.

[0054] Furthermore, the maximum value of the stable steering angle (≈maximum steering angle) is determined based on the yaw angle estimated by the yaw angle estimating unit 101. Alternatively, the maximum value of the stable steering angle (≈maximum steering angle) is determined based on the travel distance estimated by the travel distance estimating unit 102.

[0055] In addition, it is also provided with: a yaw angle estimation unit 101, which estimates the yaw angle starting from the left or right turn of the own vehicle; and a function shielding determination unit 110, which shields the function for collision avoidance control based on the yaw angle estimated by the yaw angle estimation unit 101 in order to avoid malfunction when the shape of the intersection is a special road shape different from the prescribed shape (for example, 90 degrees).

[0056] This embodiment, for example, considers the change in the steering speed at the beginning of turning / returning the steering wheel based on the yaw angle during the turn, so as to estimate the future steering angle in a responsive manner. By limiting the estimated steering angle to not exceed the stable steering angle (≈maximum steering angle) in left or right turns at an intersection calculated based on the vehicle's behavior at the beginning of the turn, it is possible to prevent the estimation from being too large.

[0057] According to the present embodiment, by improving the response and accuracy of the own vehicle's travel path estimation, it is possible to reduce erroneous operations in AEB and to perform early operations on the positive operation object.

[0058] The embodiments of the present invention are described in detail above, but the present invention is not limited to the embodiments described, and various design changes can be made without departing from the spirit of the present invention described in the claims. For example, the embodiments described are embodiments that are described in detail in order to easily explain the present invention, and are not necessarily limited to embodiments having all the described structures. In addition, a part of the structure of some embodiments can be replaced by the structure of other embodiments, and the structure of other embodiments can be added to the structure of some embodiments. Furthermore, for a part of the structure of each embodiment, other structures can be added, deleted, or replaced.

[0059] In addition, the above-mentioned various structures, functions, processing parts, processing units, etc. can also be implemented by hardware, such as designing a part or all of them with integrated circuits. In addition, the above-mentioned various structures, functions, etc. can also be implemented by software by interpreting and executing programs that implement the respective functions by a processor. Information such as programs, tables, files, etc. that implement each function can be placed in a storage device such as a memory, a hard disk, an SSD (Solid State Drive), or a recording medium such as an IC card, an SD card, or a DVD.

[0060] In addition, the control lines and information lines are those that are considered necessary for the purpose of explanation, and not all control lines and information lines are necessarily shown in the product. In reality, it can be considered that almost all components are connected to each other. Explanation of symbols

[0061] 1…AEB system, 100…AEB control processing unit (vehicle control device), 101…Yaw angle estimation unit, 102…Driving distance estimation unit, 103…Own vehicle travel path estimation unit (vehicle position estimation unit), 104…Target object travel path estimation unit, 105…Collision determination unit, 106…Braking control unit, 110…Function shielding determination unit (second embodiment), 501…Direction indicator device, 502…Yaw rate sensor, 503…Steering angle sensor, 504…Vehicle speed sensor, 505…Target object sensor.

Claims

1. A vehicle control device for controlling a vehicle turning at an intersection, the vehicle control device comprising: A target sensor for detecting targets around the own vehicle; a target object travel path estimating unit that estimates a travel path of the target object detected by the target object sensor; A steering angle sensor for detecting a steering angle of the self-vehicle while traveling; as well as a vehicle position estimating unit that calculates a steering speed based on the steering angle detected by the steering angle sensor, estimates a future steering angle based on the steering speed and a prescribed correction gain, estimates a maximum value of a stable steering angle among the future steering angles based on a rate of change associated with the steering angle, and estimates a future position of the own vehicle based on the future steering angle and the maximum value of the stable steering angle.

2. The vehicle control device according to claim 1, characterized in that: further comprising a yaw angle estimating unit for estimating a yaw angle from the start of the left or right turn of the own vehicle, The predetermined correction gain is determined based on the yaw angle estimated by the yaw angle estimating unit.

3. The vehicle control device according to claim 1, characterized in that: The vehicle further comprises a travel distance estimating unit for estimating a travel distance from the start of the left or right turn of the vehicle. The predetermined correction gain is determined based on the travel distance estimated by the travel distance estimating unit.

4. The vehicle control device according to claim 1, characterized in that: further comprising a yaw angle estimating unit for estimating a yaw angle from the start of the left or right turn of the own vehicle, The maximum value of the stable steering angle is determined based on the yaw angle estimated by the yaw angle estimating unit.

5. The vehicle control device according to claim 1, characterized in that: The vehicle further comprises a travel distance estimating unit for estimating a travel distance from the start of the left or right turn of the vehicle. The maximum value of the stable steering angle is determined based on the travel distance estimated by the travel distance estimating unit.

6. The vehicle control device according to claim 1, characterized in that: further comprising a collision determination unit for determining whether the own vehicle and the target object collide based on the estimated future position of the own vehicle and the estimated travel path of the target object, The vehicle control device warns a driver of the own vehicle or brakes the own vehicle based on a determination result of the collision determination unit.

7. The vehicle control device according to claim 1, characterized in that: Also available: a yaw angle estimating unit that estimates the yaw angle from the start of the left or right turn of the own vehicle; and The function blocking determination unit blocks the function for collision avoidance control based on the yaw angle estimated by the yaw angle estimation unit in order to avoid malfunction when the shape of the intersection is a special road shape different from a prescribed shape.

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