Vehicle control system

Abstract

The present invention provides a vehicle control device that enables correct AEB warning and braking earlier by improving the response and an accuracy of own vehicle travel path estimation. The present invention can prevent overestimation by, for example, responsively estimating a future steering angle from the yaw angle during a turn in consideration of a change in steering speed at a beginning / a return of steering and by limiting the estimated steering angle so as not to exceed a steady-state steering angle (≈ maximum steering angle) at the time of a right / left turn at an intersection obtained from a vehicle behavior at an early stage of the turn.

Description

Technical Field

[0001] The present 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 change amount of the current steering wheel angle and estimates the traveling trajectory of a vehicle turning at an intersection in a collision determination during intersection turning (right or left turn).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the prior art described in Patent Document 1, the traveling path of a vehicle turning at an intersection is estimated in consideration of the change amount of the steering wheel angle and a limit value, but there are the following problems. That is, since there is no correction for the change amount of the steering wheel angle, the responsiveness of the steering angle estimation when starting and returning the turn is poor. The limit value of the steering wheel angle cannot be uniquely determined only by the intersection angle of the road, and the method for deriving the limit value is not mentioned. Therefore, it is difficult to accurately estimate the traveling path of the host vehicle, and a delay in response and a decrease in accuracy are likely to occur, and there is a risk that an AEB (Autonomous Emergency Braking) warning or braking cannot be performed until immediately before a collision.

[0005] The present invention has been made in view of the above points, and an object thereof is to provide a vehicle control device that enables an AEB warning and braking earlier and correctly by improving the response and accuracy of host vehicle traveling path estimation.

Means for Solving the Problems

[0006] The present invention, which solves the above problems, is a vehicle control device that controls a vehicle that is turning and moving through an intersection, and is characterized by comprising: an object sensor that detects objects around the vehicle; an object path estimation unit that estimates the path of the object detected by the object sensor; a steering angle sensor that detects the steering angle of the moving vehicle; and a vehicle position estimation unit that calculates the steering speed from the steering angle detected by the steering angle sensor, estimates the future steering angle based on the steering speed and a predetermined correction gain, estimates the maximum value of the steady steering angle at the future steering angle based on the rate of change of the steering angle, and estimates the future position of the vehicle based on the future steering angle and the maximum value of the steady steering angle.

[0007] For example, this invention can accurately estimate the future steering angle by considering the change in steering speed during initial and reverse steering based on the yaw angle during a turn, and prevents overestimation by limiting the estimated steering angle so that it does not exceed the steady-state steering angle (≒maximum steering angle) during right or left turns at intersections, which is determined from the vehicle behavior at the beginning of the turn. [Effects of the Invention]

[0008] According to the present invention, by improving the response and accuracy of self-vehicle path estimation, it is possible to reduce malfunctions in AEB and enable early activation for targets that should be activated.

[0009] Further features related to the present invention will become apparent from the description herein and the accompanying drawings. Problems, configurations, and effects not described above will be revealed by the following description of embodiments. [Brief explanation of the drawing]

[0010] [Figure 1] Block diagram of the AEB system in the first embodiment. [Figure 2] A flowchart illustrating the operation of the AEB control processing unit in the first embodiment. [Figure 3A] A diagram illustrating an example of deriving a correction gain for steering speed used to estimate rudder angle (based on yaw angle). [Figure 3B]This diagram illustrates an example of deriving a correction gain for steering speed used to estimate steering angle (based on distance traveled). [Figure 3C] A diagram illustrating the effect of the correction gain for steering speed used to estimate rudder angle. [Figure 4A] A diagram illustrating an example of deriving a steady-state rudder angle for rudder angle estimation (based on distance traveled). [Figure 4B] A diagram illustrating an example of deriving a steady-state rudder angle for rudder angle estimation (based on yaw angle). [Figure 5A] A diagram illustrating the problems that arise when predictions are delayed, and the effects of the present invention. [Figure 5B] A diagram illustrating the problems that arise when predictions are too skewed, and the effects of the present invention. [Figure 6] Block diagram of the AEB system in the second embodiment. [Figure 7] A flowchart illustrating the operation of the AEB control processing unit in the second embodiment. [Modes for carrying out the invention]

[0011] Embodiments of the present invention will be described in detail below with reference to the drawings. In each embodiment, components having the same function will be denoted by the same reference numerals, and redundant explanations may be omitted.

[0012] [First Embodiment] Figure 1 shows a block diagram of the AEB system in the first embodiment.

[0013] As shown in FIG. 1, 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 constituted by in-vehicle ECUs having a CPU and a memory. The VMC 200 has, as its internal function, an actuator control unit 201 that performs engine control, steering control, and brake control of the host vehicle. When the actuator control unit 201 receives a braking G command from the AEB control processing unit 100, it outputs a control signal to the brake actuator 300. The brake actuator 300 has a brake control device 301 that receives a control signal from the actuator control unit 201 and performs brake control based on the control signal.

[0014] The AEB control processing unit 100 performs braking assistance control of the host vehicle according to the possibility of collision between the host vehicle and an obstacle (a target around the host vehicle). The AEB control processing unit 100 of the present embodiment constitutes a vehicle control device that controls (braking assistance control) a host vehicle that turns (turns right or left) and proceeds within 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 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 operation state of the direction indicator by the driver. The yaw rate sensor 502 detects the yaw rate of the host vehicle. The steering angle sensor 503 detects the steering angle of the steering wheel of the host vehicle (sometimes simply referred to as the steering angle). The vehicle speed sensor 504 detects the vehicle speed from the rotation speed of the wheels of the host vehicle or the like. The target sensor 505 is a sensor that detects targets around the host 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 implemented in an in-vehicle ECU (Electronic Control Unit) that is an ADAS controller or an AD controller, and performs AEB control. The AEB control processing unit 100 has, as internal functions, a yaw angle estimation unit 101, a travel distance estimation unit 102, a host vehicle travel path estimation unit (vehicle position estimation unit) 103, a target travel path estimation unit 104, a collision determination unit 105, and a braking control unit 106. In the AEB control processing unit 100, detection of an obstacle and calculation of a predicted travel path of the host vehicle are performed, a determination is made on the possibility of collision between the host vehicle and the obstacle, and when it is determined that the host vehicle will collide with the obstacle, a determination of the start of braking is made using the time to collision TTC or the like, and when it is determined that the start of braking is to be performed, a braking G command necessary for collision avoidance is calculated and output to the VMC 200.

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

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

[0019] The host vehicle travel path estimation unit 103 estimates the future steering angle in good response considering the change in the steering speed (change amount of the steering angle per unit time) of start / return of steering from the yaw angle during turning, limits so that the estimated steering angle does not exceed the steady steering angle (≈ maximum steering angle) in intersection right or left turn obtained from the vehicle behavior at the initial stage of turning, and further derives the estimated travel path (future position or travel path) of the host vehicle using the estimated steering angle and vehicle speed (details will be described later).

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

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

[0022] When the collision determination unit 105 determines the possibility of a collision, the braking control unit 106 uses the time until collision (collision time TTC), etc., to determine when to start automatic braking and calculates the braking G command necessary to avoid the collision.

[0023] This embodiment describes an example where a vehicle is traveling in the right lane towards an intersection on a relatively busy main road and needs to make a right turn at the next intersection. Figure 2 shows the processing of the AEB control processing unit 100 in this embodiment. This processing is performed once at a predetermined interval (e.g., 50ms) within the on-board ECU, which is an on-board ADAS controller or AD controller.

[0024] First, the S101 reads information about the vehicle's speed, steering angle, yaw rate, and turn signal status.

[0025] In S102, the yaw angle from the start of the right or left turn is calculated using the steering angle, yaw rate, and turn signal information read in S101 (yaw angle estimation unit 101). The conditions for starting the calculation of the yaw angle are, for example, when the turn signal is ON and the steering angle is turned 15 degrees or more in the same direction as the turn signal.

[0026] In S103, the vehicle speed (vehicle speed) read in S101 is used to calculate the distance traveled since the start of the right or left turn (distance estimation unit 102). The conditions for starting the distance calculation are, for example, when the turn signal is ON and the steering angle is turned 15 degrees or more in the same direction as the turn signal.

[0027] In S104, the correction gain for the steering speed used to estimate the rudder angle is derived.

[0028] In deriving the correction gain, for example, as shown in Figure 3A, the correction gain λ is set according to the yaw angle from the start of the right or left turn of the vehicle, calculated in S102. Alternatively, as shown in Figure 3B, the correction gain λ is set according to the distance traveled from the start of the right or left turn of the vehicle, calculated in S103. To improve the tracking performance at the start of a turn and during the return to the turn, for example, the correction gain λ is set to be larger at the start of a turn and during the return to the turn (corresponding to the yaw angle and distance traveled). This improves the responsiveness (tracking performance) to the prediction delay, as shown in Figure 3C.

[0029] In S105, the steady-state rudder angle for rudder angle estimation is derived.

[0030] In deriving the steady-state steering angle for steering angle estimation, for example, as shown in Figure 4A, assuming that the driving trajectory for right and left turns at intersections is the same regardless of vehicle speed, the steady-state steering angle is derived based on the correlation between the rate of change of steering angle with respect to driving distance [deg / m] and the steady-state steering angle. Assuming a correlation, the steady-state steering angle [deg] can be obtained from the rate of change of steering angle [deg / m] × kx. The formula for calculating the steady-state steering angle using the rate of change of steering angle (especially its coefficient kx) is identified from experimental data. However, as shown in Figure 4B, the steady-state steering angle can also be derived in a similar manner when using the vehicle's yaw angle at the time of entering the intersection (i.e., the rate of change of steering angle with respect to the vehicle's yaw angle at the time of entering the intersection [deg / deg]) instead of the driving distance.

[0031] In S106, the estimated steering angle is calculated. The estimated steering angle is calculated based on the steering speed of the driver, which is determined from the steering angle detected by the steering angle sensor 503, and the correction gain λ obtained in S104. The estimated steering angle is calculated using, for example, the following equation (1). (Math 1) TIFF0007833556000001.tif33105

[0032] However, the estimated steering angle is limited so as not to exceed the steady-state steering angle (≒maximum steering angle) during right or left turns at intersections, which is determined from the vehicle behavior at the initial stage of turning in S105.

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

[0034] In S108, the predicted path of the target is derived (target path estimation unit 104). The predicted path of the target is calculated by determining the target's ground velocity vector from the relative velocity vector of the detected target, taking into account the translational and rotational motion of the vehicle, and then integrating it.

[0035] In S109, the collision determination unit 105 uses the predicted path of the vehicle obtained in S107 and the predicted path of the target obtained in S108 to determine whether the vehicle will collide with the obstacle (target). If a collision is determined, the process proceeds to S110. Otherwise, the process ends. Here, by improving the response and accuracy of the predicted path of the vehicle in S107, malfunctions in AEB are reduced and early activation is enabled for targets that should be activated.

[0036] In S110, the collision time TTC [s] is calculated. TTC can be calculated, for example, using the following equation (2). (Math 2) TIFF0007833556000002.tif21105

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

[0038] In S112, the necessary braking G command Gcmd[m / s] is used to avoid a collision. 2 Calculate ]. Gcmd can be calculated, for example, using the following formula (3). (Math 3) TIFF0007833556000003.tif20105

[0039] Here, if future accuracy is high, Tth is set to a lower value. This results in early action, which increases the value of d, so Gcmd can be set to a smaller value, i.e., abrupt braking can be avoided.

[0040] In S113, the braking G command calculated in S112 is transmitted to the brake actuator 300 via the VMC200 in order to activate the automatic brake. The processes from S110 to S113 are executed by the braking control unit 106.

[0041] Furthermore, a warning may be issued to the driver of the vehicle based on the collision determination result of the collision determination unit 105, either at the same time as the automatic braking system is activated (braked) as described above, or before the automatic braking system is activated (braked) as described above.

[0042] As shown in Figure 5A, if the prediction is delayed, the system may mistakenly determine that the target is on the vehicle's path, potentially leading to a malfunction. However, this can be resolved by the correction gain of the present invention. Also, as shown in Figure 5B, if the prediction is too curved, the system may mistakenly determine that the target is not on the vehicle's path, potentially leading to a malfunction. However, this can be resolved by the steady-state steering angle (≒maximum steering angle) of the present invention.

[0043] As described above, by considering the change in steering speed during the initial steering input / retraction from the yaw angle during a turn, the future steering angle is estimated with good responsiveness, and the estimated steering angle is limited so as not to exceed the steady steering angle (≒maximum steering angle) for right or left turns at intersections, which is determined from the vehicle behavior at the beginning of the turn. By improving the response and accuracy of the vehicle's predicted path in S107, malfunctions of the AEB are reduced and early activation is possible for targets that should be properly activated.

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

[0045] Figure 6 shows a block diagram of the AEB system in the second embodiment.

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

[0047] The function mask determination unit 110, based on the yaw angle, determines that the intersection has a special shape that differs significantly from a predetermined shape (e.g., 90 degrees), and if so, it masks the AEB function to avoid it not functioning correctly.

[0048] This embodiment, like the first embodiment, is an example of a situation on a relatively busy main road where the vehicle is traveling in the right lane towards an intersection and needs to make a right turn at the next intersection. Figure 7 shows the processing of the AEB control processing unit 100 in this embodiment. Compared to the first embodiment, this embodiment includes a process to mask the driver assistance function in order to avoid the driver assistance function not operating correctly when the system determines, based on the yaw angle from the start of the right or left turn, that the intersection has a special shape that differs significantly from a predetermined shape (for example, 90 degrees).

[0049] The processes from S201 to S208 and from S210 to S214 are the same as the processes from S101 to S113 in the first embodiment, so their explanation will be omitted.

[0050] In S209, it is determined whether the shape of the intersection is a special shape that deviates significantly from orthogonal (90 degrees) by a predetermined amount. If it is determined to be a special shape, the process ends; otherwise, it proceeds to S210. The determination of whether an intersection is a special shape that deviates significantly from orthogonal (90 degrees) is made using one or more of the following conditions, for example. (1) At the start of turning, when the yaw angle of the vehicle from the start of the right or left turn is 1 or more, the steering angle is 1 or less. (2) In the case of a counter-turn, when the yaw angle from the start of the right or left turn of the vehicle reaches a predetermined value of 2 or more, the steering angle is set to a predetermined value of 2 or more. (The terms "greater than" and "less than" refer to the magnitude of the value, taking into account the left and right directions.)

[0051] Based on the above, in this second embodiment, compared to the first embodiment, if the vehicle determines that the intersection has a special shape that differs significantly from a predetermined shape (90 degrees) based on the yaw angle from the start of the right or left turn of the vehicle, the driver assistance function (a function for collision avoidance control) is masked to prevent the driver assistance function from not operating correctly.

[0052] [Summary of the First and Second Embodiments] As described above, the vehicle control device (AEB control processing unit 100) of this embodiment is a vehicle control device that controls the vehicle as it turns and moves through an intersection, and includes an object sensor 505 that detects objects around the vehicle, an object path estimation unit 104 that estimates the path of the object detected by the object sensor 505, a steering angle sensor 503 that detects the steering angle of the moving vehicle, and a steering speed (unit time) from the steering angle detected by the steering angle sensor 503. The system includes a vehicle position estimation unit (vehicle path estimation unit 103) that calculates the amount of change in steering angle per unit, estimates the future steering angle based on the steering speed and a predetermined correction gain, estimates the maximum value of the steady steering angle (≒ maximum steering angle) at the future steering angle based on the rate of change of the steering angle (amount of change in steering angle with respect to yaw angle or travel distance), and estimates the future position (path) of the vehicle based on the future steering angle and the maximum value of the steady steering angle (≒ maximum steering angle).

[0053] Furthermore, the system includes a yaw angle estimation unit 101 that estimates the yaw angle from the start of a right or left turn of the vehicle, and the predetermined correction gain is determined based on the yaw angle estimated by the yaw angle estimation unit 101. Alternatively, the system includes a distance estimation unit 102 that estimates the distance traveled from the start of a right or left turn of the vehicle, and the predetermined correction gain is determined based on the distance traveled estimated by the distance estimation unit 102.

[0054] Furthermore, the maximum value of the steady-state steering angle (≒ maximum steering angle) is determined based on the yaw angle estimated by the yaw angle estimation unit 101. Alternatively, the maximum value of the steady-state steering angle (≒ maximum steering angle) is determined based on the travel distance estimated by the travel distance estimation unit 102.

[0055] Furthermore, the system includes a yaw angle estimation unit 101 that estimates the yaw angle from the start of the vehicle's right or left turn, and a function mask determination unit 110 that masks the collision avoidance control function based on the yaw angle estimated by the yaw angle estimation unit 101, in order to avoid malfunctions in special road shapes where the shape of the intersection differs from a predetermined shape (e.g., 90 degrees).

[0056] This embodiment, for example, can responsively estimate the future steering angle by considering the change in steering speed during initial and reverse steering based on the yaw angle during a turn, and prevents overestimation by limiting the estimated steering angle so that it does not exceed the steady-state steering angle (≒maximum steering angle) for right and left turns at intersections, which is determined from the vehicle behavior at the beginning of the turn.

[0057] According to this embodiment, by improving the response and accuracy of self-vehicle path estimation, malfunctions in AEB are reduced and early activation is enabled for targets that should be activated.

[0058] Although embodiments of the present invention have been described in detail above, the present invention is not limited to the embodiments described above, and various design modifications can be made without departing from the spirit of the invention as described in the claims. For example, the embodiments described above are described in detail in order to explain the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the configurations described. Furthermore, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Moreover, it is possible to add, delete, or replace parts of the configuration of each embodiment with other configurations.

[0059] Furthermore, each of the above configurations, functions, processing units, and processing means may be implemented in hardware, either partially or entirely, by designing them as integrated circuits, for example. Alternatively, each of the above configurations and functions may be implemented in software by having the processor interpret and execute programs that implement each function. Information such as programs, tables, and files that implement each function can be stored in memory, storage devices such as hard disks and SSDs (Solid State Drives), or recording media such as IC cards, SD cards, and DVDs.

[0060] Furthermore, the control lines and information lines shown are those deemed necessary for explanatory purposes, and not all control lines and information lines are necessarily shown in the actual product. In reality, it is safe to assume that almost all components are interconnected. [Explanation of Symbols]

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

Claims

1. A vehicle control device that controls the vehicle as it moves in a circle within an intersection, A target sensor for detecting targets around the vehicle, A target path estimation unit that estimates the path of the target detected by the target sensor, A steering angle sensor that detects the steering angle of the vehicle while it is moving, A vehicle control device comprising: a vehicle position estimation unit that calculates steering speed from the steering angle detected by the steering angle sensor, estimates a future steering angle based on the steering speed and a predetermined correction gain, estimates the maximum value of the steady steering angle at the future steering angle based on the rate of change of the steering angle, and estimates the future position of the vehicle based on the future steering angle and the maximum value of the steady steering angle.

2. In the vehicle control device according to claim 1, The system further includes a yaw angle estimation unit that estimates the yaw angle from the start of a right or left turn of the vehicle. A vehicle control device characterized in that the predetermined correction gain is determined based on the yaw angle estimated by the yaw angle estimation unit.

3. In the vehicle control device according to claim 1, The vehicle further comprises a distance estimation unit that estimates the distance traveled from the start of a right or left turn. A vehicle control device characterized in that the predetermined correction gain is determined based on the mileage estimated by the mileage estimation unit.

4. In the vehicle control device according to claim 1, The system further includes a yaw angle estimation unit that estimates the yaw angle from the start of a right or left turn of the vehicle. A vehicle control device characterized in that the maximum value of the steady-state steering angle is determined based on the yaw angle estimated by the yaw angle estimation unit.

5. In the vehicle control device according to claim 1, The vehicle further comprises a distance estimation unit that estimates the distance traveled from the start of a right or left turn. A vehicle control device characterized in that the maximum value of the steady-state steering angle is determined based on the mileage estimated by the mileage estimation unit.

6. In the vehicle control device according to claim 1, The system further includes a collision determination unit that determines whether or not the vehicle will collide with the target based on the estimated future position of the vehicle and the estimated path of the target. The vehicle control device is characterized in that, based on the judgment result of the collision determination unit, it issues a warning to the driver of the vehicle or applies the brakes to the vehicle.

7. In the vehicle control device according to claim 1, A yaw angle estimation unit that estimates the yaw angle from the start of a right or left turn of the vehicle, In the event that the shape of the intersection differs from a predetermined shape due to a special road shape, the vehicle control device further comprises a function mask determination unit that masks the function for collision avoidance control based on the yaw angle estimated by the yaw angle estimation unit, in order to avoid malfunction.

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