JP2016052868A - Vehicle control apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle control apparatus capable of alleviate discomfort of a driver and appropriately controlling a vehicle.SOLUTION: A vehicle control apparatus includes: collision prediction time calculation means capable of calculating first collision prediction time for predicting time until a vehicle itself collides with an obstacle on the basis of relative distance and relative speed between the vehicle itself and the obstacle, and second collision prediction time for predicting time until the vehicle itself collides with the obstacle on the basis of the relative distance and relative speed between the vehicle itself and the obstacle, and acceleration of the vehicle itself or the relative acceleration between the vehicle itself and the obstacle; determination means for determining either of the first and second collision prediction time to be used to control the vehicle itself, on the basis of the acceleration, the relative acceleration, or the acceleration and the relative acceleration; and control means for controlling the vehicle. Further, the control means controls the vehicle itself using either of the first and second collision prediction time on the basis of the determination of the determination means.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to a vehicle control device.

  Pre-Crash Safety (hereinafter referred to as “PCS”) technology is known that monitors obstacles with a millimeter-wave radar or stereo camera and reduces damage or avoids collision when it is determined that there is a risk of collision. Yes. As an index for determining the possibility of collision with an obstacle (for example, another vehicle), generally, TTC (Time To Collision) obtained by dividing the relative distance between the host vehicle and the other vehicle by the relative speed is known. Yes. In recent years, E-TTC (Enhanced TTC) that takes into account the relative acceleration of the host vehicle with respect to other vehicles has also been proposed (see, for example, Patent Document 1). When the other vehicle suddenly decelerates, the PCS can be appropriately executed at an earlier timing when the E-TTC is used.

JP 2011-121491 A

  Incidentally, peripheral monitoring sensors such as millimeter wave radars and stereo cameras that calculate relative acceleration usually have a response delay. However, in the driving support device disclosed in Patent Document 1, such a response delay is not taken into consideration, and therefore, there is a possibility that the PCS operates at an incorrect timing against the driver's intention. For example, when the road is congested and the host vehicle is traveling following other vehicles while repeatedly accelerating and decelerating, the vehicle is traveling at a low speed, so the possibility of a collision is low. Even in such a case, if the possibility of collision is determined based on the predicted collision time using E-TTC, the PCS may be activated when it is not necessary to activate the PCS. As a result, the driver may feel uncomfortable with respect to the operation timing such as warning by PCS or automatic braking.

  Therefore, an object of the present disclosure is to provide a vehicle control device that can reduce the driver's uncomfortable feeling and appropriately control the vehicle.

  In one aspect of the present disclosure, a first collision prediction time for predicting a time until the host vehicle collides with the obstacle based on a relative distance and a relative speed between the host vehicle and the obstacle, Predicting a time until the host vehicle collides with the obstacle based on a relative distance to the obstacle, a relative speed, and an acceleration of the host vehicle or a relative acceleration between the host vehicle and the obstacle. A collision prediction time calculation unit that can calculate two collision prediction times, and the first collision prediction time and the second collision prediction time based on the acceleration, the relative acceleration, or the acceleration and the relative acceleration. Determining means for determining which of the vehicle is to be controlled, and a control means for controlling the own vehicle, wherein the control means is configured to control the first vehicle based on the determination by the determining means. Collision prediction time and To provide a vehicle control apparatus and controls the vehicle by using either the serial second collision prediction time.

  According to the present disclosure, it is possible to obtain a vehicle control device that can reduce the driver's uncomfortable feeling and appropriately control the vehicle.

1 is a schematic configuration diagram of a vehicle control device according to an embodiment of the present invention. It is a flowchart explaining an example of the calculation flow of the collision prediction time TTC in the control processing of the vehicle control apparatus shown in FIG. It is a flowchart explaining another example of the calculation flow of the collision prediction time TTC in the control processing of the vehicle control apparatus shown in FIG. It is a flowchart explaining another example of the calculation flow of the collision prediction time TTC in the control processing of the vehicle control apparatus shown in FIG. It is a flowchart explaining the determination flow of the collision possibility in the control processing of the vehicle control apparatus shown in FIG. It is an example of TTC calculation MAP.

  Hereinafter, an embodiment will be described in detail with reference to the accompanying drawings.

  A schematic configuration of the vehicle control device 1 according to the present embodiment will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram of a vehicle control device according to an embodiment of the present invention.

  The vehicle control device 1 (hereinafter referred to as “control device”) has a function as vehicle control means for performing predetermined control on the host vehicle. Predetermined control includes, for example, cruise control that keeps the vehicle speed of the host vehicle constant, inter-vehicle control that keeps the distance between the host vehicle and an obstacle (for example, another vehicle), the inter-vehicle time, and the relative speed, and collision prevention Pre-crash safety (pre-crash safety) to reduce damage or avoid collision when it is determined that there is a risk of collision with another vehicle while the host vehicle is driving. Safety (hereinafter referred to as “PCS”) technology (for example, pre-crash brake control in which braking is automatically performed when it is determined that there is a possibility of collision).

  Here, the other vehicle means a preceding vehicle, a stationary object (for example, a stationary vehicle) and an oncoming vehicle that are located in front of the host vehicle. In the following description, the other vehicle is mainly described as a preceding vehicle. .

(Configuration of control device 1)
FIG. 1 shows an example of a schematic configuration diagram of the control device 1. The control device 1 includes a sensor unit 10, a collision determination device 11, a brake control device 12, a meter 13, and a buzzer 14, which are connected via an in-vehicle LAN (Local Area Network) such as a CAN (Controller Area Network). ing.
[Sensor part 10]
The sensor unit 10 includes a wheel speed sensor 15, a millimeter wave radar 16, and a stereo camera 17.

  The wheel speed sensor 15 detects the wheel speed from the wheel pulse that is output when a magnetic body or the like arranged at a predetermined interval in the circumferential direction of the wheel is detected by the magnetic sensor. The vehicle speed is obtained from the wheel speed and the wheel diameter.

The millimeter wave radar 16 is disposed in the center of the front of the host vehicle such as the front grille of the host vehicle, and emits a millimeter wave at a predetermined angle (for example, 10 degrees left and right with the front as the center). The millimeter wave reflected by the preceding vehicle existing in this range is received. The millimeter wave radar 16 is, for example, an FMCW (Frequency Modulated Continuous Wave) radar. The millimeter wave radar 16 may be, for example, an electronic scan type millimeter wave radar. In this case, the relative distance L _r between the host vehicle and the preceding vehicle is detected using the delay time of the reflected wave. These detection data are transmitted to the collision determination device 11 at predetermined intervals.

For example, the stereo camera 17 is arranged on the rearview mirror with the optical axis facing the front of the vehicle. The stereo camera 17 has two CCD cameras or two CMOS cameras that are spaced apart by a predetermined distance. The stereo camera 17 performs pre-processing for removing lens distortion, optical axis deviation, focal length deviation, imaging element distortion, and the like on the frames imaged by each camera using calibration data prepared in advance. Until the distance (relative distance L _r ) is measured.

Although the millimeter wave radar 16 and the stereo camera 17 are illustrated in the present embodiment, it is sufficient that at least one of them is provided. Alternatively, a laser radar, an infrared radar, a sound wave radar (sonar), or the like may be provided instead of the millimeter wave radar 16 or the stereo camera 17.
[Collision determination device 11]
The collision determination device 11 is, for example, a microcomputer in which a ROM (Read Only Memory), a RAM (Random Access Memory), and the like are connected to each other via a bus around a CPU (Central Processing Unit), such as a flash memory. A temporary storage device, an I / O port, a timer, a counter, etc. (not shown) are provided. The ROM stores programs and data executed by the CPU. The collision determination device 11 includes a collision prediction time calculation unit 111, a determination unit 112, and a determination unit 113 as main functional blocks that function when the CPU executes a program stored in the ROM. Note that these functional blocks do not necessarily have to be based on another program, and a part for realizing a plurality of functional blocks may be included in the same program.

The collision prediction time calculation unit 111 calculates a collision prediction time TTC used for determining the possibility of collision. The collision prediction time calculation unit 111 can calculate the first collision prediction time TTC _1st and the second collision prediction time TTC _2nd .

  Then, the possibility of collision is determined based on the predicted collision time TTC calculated by the predicted collision time calculation unit 111. The determination unit 112 determines whether or not to control the vehicle so that each device (brake control device 12, meter 13, and buzzer 14) described later operates.

  The determination unit 113 determines the predicted collision time TTC used for determining the possibility of collision.

The first predicted collision time TTC _1st is calculated based on the relative distance L _r and the relative speed V _r between the host vehicle and the preceding vehicle, for example, as in the following equation (1). TTC _1st is the time required for the host vehicle and the preceding vehicle to collide when the current relative speed V _r continues.

第２の衝突予測時間ＴＴＣ_２ｎｄは、自車両と他車両との相対距離Ｌ_ｒ、相対速度Ｖ_ｒ及びＡ_selectに基づき、例えば、下式（２）のように演算される。

The second predicted collision time TTC _2nd is calculated based on the relative distance L _r between the host vehicle and the other vehicle, the relative speed V _r, and A _select , for example, as in the following expression (2).

相対距離Ｌ_ｒは、ミリ波レーダ１６、ステレオカメラ１７等によって検出される。相対速度Ｖ_ｒは_、相対距離Ｌ_ｒに基づき演算される。Ａ_selectは、ミリ波レーダやステレオカメラ等の周辺監視センサの応答遅れを考慮し、自車両と先行車両の運転状態によって決定されるパラメータである。本実施形態において、Ａ_selectは、自車両と先行車両の運転状態に応じて、自車両の加速度Ａ_０又は自車両と先行車両との相対加速度Ａ_ｒが選択される。このパラメータを変更することにより、適切なタイミングで各デバイスが作動するようにＴＴＣ算出式（２）を補正することができる。詳細は後述する。

The relative distance L _r is detected by the millimeter wave radar 16, the stereo camera 17, and the like. The relative velocity _{V r is} calculated based on the relative distance _{L r.} A _select is a parameter that is determined by the driving conditions of the host vehicle and the preceding vehicle in consideration of response delays of peripheral monitoring sensors such as millimeter wave radars and stereo cameras. In this embodiment, A _{the select,} depending on the operating condition of the preceding vehicle and the subject vehicle, the relative acceleration A _r between the acceleration A ₀ or host vehicle and the preceding vehicle of the own vehicle is selected. By changing this parameter, the TTC calculation formula (2) can be corrected so that each device operates at an appropriate timing. Details will be described later.

Here, when the vehicle approaches the preceding vehicle (will close) is, V _r and A _r are both negative value (-) is defined as the own vehicle moves away with respect to the preceding vehicle (moved away In this case, both V _r and A _r are defined as positive values (+).
[Brake control device 12]
The brake control device 12 includes a brake actuator (not shown) provided corresponding to the front, rear, left and right wheels in the host vehicle, and a brake ECU (Electronic Control Unit).
The brake ECU includes, for example, a CPU, a ROM, a RAM, a data bus connecting them, and an input / output interface, and the CPU performs predetermined processing according to a program stored in the ROM. Based on the braking command output from the collision determination device 11, the brake ECU controls the brake actuator provided on each wheel of the vehicle to brake the vehicle.

  The brake control device 12 performs automatic braking based on the determination result from the collision determination device 11. The brake control device 12 is a device that brakes the host vehicle without the driver depressing the brake pedal. Specifically, the brake ECU controls the opening and closing of the valve of the brake actuator, so that the brake hydraulic pressure generated by the pump is supplied to the wheel cylinder, and the wheels are braked independently for each wheel.

  The brake control device 12 can also perform light braking that is not intended to substantially generate braking force. Light braking is performed by selecting the lowest control hydraulic pressure that can be generated by the brake actuator and operating the brake actuator. This operation is performed by the brake ECU based on the determination result from the collision determination device 11.

Although not shown, when the brake control device 12 performs automatic braking or light braking of the host vehicle, the stop lamp is turned on based on the current command supplied from the brake control device 12, and attention is paid to the driver of the following vehicle. Arouse.
[Meter 13]
The meter 13 includes a meter panel in a front panel (not shown) in front of the vehicle interior and a meter ECU. The meter ECU includes, for example, a CPU, ROM, RAM, a data bus connecting them, and an input / output interface. The meter ECU performs predetermined processing according to a program stored in the ROM, and controls a speedometer and an odometer (not shown) in the meter panel based on the vehicle speed calculated by the collision determination device 11, Based on an alarm command output from the collision determination device 11, control for turning on a warning light of a PCS (not shown) is performed.
[Buzzer 14]
The buzzer 14 is installed adjacent to the meter 13 on the front panel, for example, and alerts the driver by sounding a PCS warning sound or the like based on an alarm command output from the collision determination device 11. It promotes acceleration suppression and deceleration.

(Operation procedure of the control device 1)
Next, the control contents of the control device 1 according to the present embodiment will be described with reference to the drawings. 2 to 4 are flowcharts for explaining an example of a calculation flow of the predicted collision time TTC in the control process of the vehicle control device shown in FIG. FIG. 5 is a flowchart illustrating a collision possibility determination flow in the control process of the vehicle control device shown in FIG. FIG. 6 is an example of a TTC calculation MAP.

In order to determine the possibility of collision, a predicted collision time TTC used to determine the possibility of collision is determined. Based on this determination, the vehicle is controlled in a predetermined case. Specifically, control of each device such as the brake control device 12, the meter 13, and the buzzer 14 is performed. More specifically, it is determined which of the collision prediction times TTC (the first collision prediction time TTC _1st and the second collision prediction time TTC _2nd ) to control the vehicle. This determination is executed by the determination unit 113 provided in the collision determination device 11.

  In the present embodiment, the collision prediction time TTC is determined using the TTC calculation MAP (see FIG. 6). The ROM of the collision determination device 11 stores a TTC calculation MAP for determining the collision prediction time TTC.

  When determining the predicted collision time TTC, a calculation formula (hereinafter referred to as “TTC calculation formula”) of the predicted collision time TTC suitable for the driving state of the host vehicle and the preceding vehicle is determined by using the TTC calculation MAP.

In the present embodiment, the TTC calculation formula can be determined based on the acceleration / deceleration state of the host vehicle. In the present embodiment, defined as when the acceleration A ₀ of the vehicle is greater than or equal to the threshold value α is defined as the vehicle is accelerating, when the acceleration A ₀ is smaller than the threshold α is the vehicle decelerates To do.

First, as shown in FIG. 2, the acceleration _A0 is calculated (step S1). Based on the vehicle speed V ₀ of the host vehicle obtained from the wheel speed sensor 15, the acceleration A ₀ is calculated. For example, A ₀ is calculated by differentiating the vehicle speed V ₀ with respect to time. Incidentally, by the accelerator sensor (not shown), it may be calculated acceleration A ₀ based on the operation amount of the accelerator pedal (accelerator opening). If acceleration _A0 is calculated, it will progress to step S2.

In step S2, (if decelerating, YES in step S2) the acceleration _{A 0} of the vehicle if it is less than the threshold value alpha, using the second estimated collision time _{TTC 2nd} (Step S5). On the other hand, (if accelerated, NO in step S2) the acceleration _{A 0} of the vehicle equal to or larger than the threshold value alpha, using either of the first collision prediction time _{TTC 1st} or second collision prediction time _{TTC 2nd} Good (steps S6 and S7).

Incidentally, in this case, to determine the time-to-collision TTC as each device at a more appropriate timing is controlled, in combination with the acceleration A ₀ on the basis of the approaching state between the host vehicle and the preceding vehicle TTC calculation formula Can be determined. In this case, when the relative acceleration A _r between the subject vehicle and the preceding vehicle is equal to or greater than β is defined as the vehicle moves away with respect to the preceding vehicle (continue to separated), relative acceleration A _r is the threshold β If it is less than that, it is defined that the host vehicle approaches (approaches) the preceding vehicle.

Therefore, when the acceleration A ₀ of the vehicle is greater than or equal to the threshold alpha (NO in step S2), the process proceeds to step S3, performing a calculation of the relative acceleration A _r between the subject vehicle and the preceding vehicle. The relative acceleration _Ar is calculated based on the inter-vehicle distance L _r obtained from the millimeter wave radar 16 and the stereo camera 17. For example, the relative speed V _r is calculated by differentiating the inter-vehicle distance L _r with time, and the relative acceleration _Ar is calculated by differentiating the relative speed V _r with time. When the relative acceleration _Ar is calculated, the process proceeds to step S4.

In step S4, when the relative acceleration _Ar is less than the threshold β (when the host vehicle approaches the preceding vehicle, YES in step S4), the second predicted collision time TTC _2nd is used (step S6). In this case, it is preferable to correct the TTC calculation formula (2) so that the second collision prediction time TTC _2nd is advanced so that each device operates at an early timing. This correction is referred to as “approaching”. Using the relative acceleration A _r between the subject vehicle and the preceding vehicle A _{the select} in formula (2), determining the TTC calculation formula. The TTC calculation formula is defined as the following formula (3) (see FIG. 6). Since the host vehicle is approaching the preceding vehicle ( _Ar is less than the threshold value β) and the host vehicle is in an accelerated state ( _A0 is greater than or _equal to the threshold value α), it is considered that the possibility of a collision is high. This is because it is necessary to operate the device at an early timing.

一方、相対加速度Ａ_ｒが閾値β以上の場合（自車両が先行車両から離反していく場合、ステップＳ４のＮＯ）、第１の衝突予測時間ＴＴＣ_１ｓｔを用いるのが好ましい（ステップＳ７）。自車両が先行車両から離反しており（Ａ_ｒが閾値β以上）、Ｅ−ＴＴＣを用いて早いタイミングで、各デバイスを制御する必要はないからである。

On the other hand, when the relative acceleration _Ar is equal to or greater than the threshold value β (when the host vehicle moves away from the preceding vehicle, NO in step S4), it is preferable to use the _first predicted collision time TTC _1st (step S7). Own vehicle preceding vehicle are separated from the (A _r is greater than or equal to the threshold beta), at an earlier timing by using the E-TTC, because it is not necessary to control each device.

  Then, the collision prediction time TTC is calculated based on the TTC calculation formula determined as described above (step S8). The calculation of the collision prediction time TTC is executed by the CPU of the collision determination device 11.

Thus, based on the operating state of the host vehicle and the preceding vehicle, taking into account also the relative acceleration A _r in combination with acceleration A _0, it is possible to determine the estimated collision time lengths TTC. Thereby, each device can be controlled at a more appropriate timing.

  In the present embodiment, the TTC calculation formula can also be determined from the approaching state of the host vehicle and the preceding vehicle.

That is, in this case, as shown in FIG. 3, first, the relative acceleration _Ar is calculated (step S11). Since the method for calculating the relative acceleration _Ar is the same as described above, the description thereof is omitted. When the relative acceleration _Ar is calculated, the process proceeds to step S12.

In step S12, when the relative acceleration _Ar is less than the threshold β (YES in step S12), the second collision prediction time TTC _2nd is used (step S15). On the other hand, when the relative acceleration _Ar is equal to or greater than the threshold β (NO in step S12), either the first collision prediction time TTC _1st or the second collision prediction time TTC _2nd may be used (steps S16 and S17).

Incidentally, in this case, to determine the TTC calculation formula based on more appropriate for each device at the time determines the time-to-collision TTC to be controlled, the acceleration state of the vehicle in combination with the relative acceleration A _r You can also.

Therefore, when the relative acceleration _{A r} is not less than the threshold value beta (NO in step S12), the process proceeds to step S13, performs a calculation of the acceleration _{A 0.} Description method of calculating the acceleration A ₀ is the same as described above will be omitted. If acceleration _A0 is calculated, it will progress to step S14.

In step S14, when the acceleration _{A 0} is less than the threshold alpha (YES in step S14), and using the _{TTC 2nd} second collision prediction time (step S16). In this case, it is preferable to correct the TTC calculation formula (2) so that the second collision prediction time TTC _2nd is delayed so that each device does not operate at an early timing. This correction is referred to as “separation”. The acceleration _{A 0} used A _{the select} in formula (2), determining the TTC calculation formula. The TTC calculation formula is defined as the following formula (4) (see FIG. 6). Since the host vehicle is far from the preceding vehicle ( _Ar is greater than or _equal to the threshold value β) and the host vehicle is in a deceleration state ( _A0 is less than the threshold value α), the driver may be aware of the danger and decelerate himself / herself This is because it is considered that the possibility of collision is high and it is not necessary to operate each device at an early timing.

一方、加速度Ａ_０が閾値α以上の場合（ステップＳ１４のＮＯ）、第１の衝突予測時間ＴＴＣ_１ｓｔを用いるのが好ましい（ステップＳ１７）。自車両が先行車両から離反しており（Ａ_ｒが閾値β以上）、Ｅ−ＴＴＣを用いて早いタイミングで、各デバイスを制御する必要はないからである。

On the other hand, when the acceleration A ₀ is equal to or greater than the threshold value α (NO in step S14), it is preferable to use the _first collision predicted time TTC _1st (step S17). Own vehicle preceding vehicle are separated from the (A _r is greater than or equal to the threshold beta), at an earlier timing by using the E-TTC, because it is not necessary to control each device.

  Then, the collision prediction time TTC is calculated based on the TTC calculation formula determined as described above (step S18).

Further, when the acceleration A ₀ is less than the threshold value α (YES in step S14) and the relative acceleration _Ar is less than the threshold value β (YES in step S14), the TTC calculation formula corrected to “separation side” It is preferable to obtain a collision prediction time TTC " _2nd of 2 (see FIG. 6). Even if the host vehicle approaches the preceding vehicle, the driver depresses the brake pedal and the host vehicle is in a decelerating state. This is because there is a high possibility of recognizing the danger, so the possibility of collision is considered low, and it is not necessary to operate each device at an early timing.

As described above, according to this embodiment, it is possible to determine the TTC calculation formula based on at least the acceleration A ₀ or relative acceleration A _r, the combined use of acceleration A ₀ and the relative acceleration A _r, The collision prediction time TTC can be calculated so that each device is controlled at a more appropriate timing.

As shown in FIG. 4, after the calculation of the acceleration _{A 0} and the relative acceleration _{A r} (step S21, S22), makes a determination of the acceleration _{A 0} and the relative acceleration _{A r} (S25 from step S23), TTC calculated MAP , The TTC calculation formula is determined so that each device is controlled at a more appropriate timing (steps S26 to S29), and the collision prediction time TTC can be calculated (step S30).

That is, based on the acceleration A ₀ , the relative acceleration A _r , or the acceleration A ₀ and the relative acceleration _Ar , the first collision prediction time TTC _1st and the second collision prediction time TTC _2nd (TTC ′ _2nd, TTC ′ _2nd ) Can be used to determine whether or not to control the host vehicle, and this determination is performed by the determination means 113 provided in the collision determination device 11.

Then, in response to the determination by the determination unit 113, the host vehicle is controlled using either the first collision prediction time TTC _{1st or} the second collision prediction time TTC _2nd calculated by the collision prediction time calculation unit 111. .

At this time, the first collision prediction time TTC _1st and the second collision prediction time TTC _2nd may be calculated by the collision prediction time calculation unit 111.

The collision prediction time (first collision prediction time TTC _1st or second collision prediction time TTC _2nd ) determined by the determination unit 113 is calculated by the collision prediction time calculation unit 111, and the calculated collision prediction time is used. You may control the own vehicle.

The acceleration A _0, taking into account the parameters other than the relative acceleration A _r, may determine the TTC calculation formula.

  For example, the TTC corrected to “approaching side” only when the vehicle is traveling at a certain high speed, such as when the driver steps on the accelerator pedal to overtake the preceding vehicle and approaches the preceding vehicle Calculation formula (3) may be used.

  Further, the formula (1) may be used when the own vehicle repeats acceleration / deceleration and follows the preceding vehicle and travels at a low speed, such as when the road is congested. This is because, particularly when the host vehicle is traveling at a low speed, a response delay is likely to occur in the detection results or calculation results of the millimeter wave radar 16 and the stereo camera 17.

  In this way, the collision prediction time TTC may be determined in consideration of the vehicle speed of the host vehicle. Further, the collision prediction time TTC may be determined according to each traffic situation by judging the road traffic situation from the road traffic information communication system or the like.

  Next, a method for determining the possibility of collision will be described with reference to FIG.

  As described above, after the collision prediction time TTC is calculated, the collision possibility is determined using the collision prediction time TTC. This determination is executed by the determination unit 112 provided in the collision determination device 11.

Specifically, as shown in FIG. 5, it is determined whether or not the predicted collision time TTC is less than the threshold value TTC _th (step S41), and if it is _less than TTC _th (YES in step S41), a collision is possible. It is determined that the device is high, and the devices such as the brake control device 12, the meter 13, and the buzzer 14 are controlled. Specifically, automatic braking is performed by controlling the opening and closing of the valve of the brake actuator based on the braking command output from the collision determination device 11. Then, the meter 13 and the buzzer 14 are controlled so as to output a predetermined alarm. For example, based on an alarm command output from the collision determination device 11, the meter 13 is controlled to turn on a PCS warning light. Alternatively, control is performed so that the buzzer 14 sounds a PCS warning sound.

On the other hand, when the collision prediction time TTC is equal to or greater than the threshold value TTC _th (NO in step S41), the device is not controlled. The process ends. In this case, since the possibility that the own vehicle will collide with the preceding vehicle is low, it is not necessary to control each device and urge the driver to call attention.

Note that the value (V _r ² −2 · A _select · L _r ) inside the square root symbol (second term) of the TTC calculation formula (2) of the second collision prediction time TTC _2nd is a negative value (−). In this case, that is, when the following expression (5) holds, TTC _2nd is an imaginary number. In this case, since it means that the host vehicle and the preceding vehicle do not collide, it is determined that TTC _2nd = ∞ (infinity) and no collision occurs.

以上、本発明を実施するための最良の形態について実施形態を用いて説明したが、本発明はこうした実施例に何等限定されるものではなく、本発明の要旨を逸脱しない範囲内において種々の変形及び置換を加えることができる。

The best mode for carrying out the present invention has been described above with reference to the embodiments. However, the present invention is not limited to these embodiments, and various modifications can be made without departing from the scope of the present invention. And substitutions can be added.

In the case where the obstacle is a stationary object or an oncoming vehicle, when the host vehicle and the preceding vehicle are approaching, in order to prevent each device from operating at an early timing due to erroneous detection of the millimeter wave radar 16, It is preferable to calculate the _first collision prediction time TTC _1st using (1). The reason why each device is controlled every time a detection error occurs is that it causes a sense of incongruity against the driver's intention.

DESCRIPTION OF SYMBOLS 1 Control apparatus 11 Collision determination apparatus 111 Collision prediction time calculation means 112 Determination means 113 Determination means

Claims (1)

A first collision prediction time for predicting a time until the host vehicle collides with the obstacle based on a relative distance and a relative speed between the host vehicle and the obstacle, and a relative distance between the host vehicle and the obstacle. Calculating a second collision prediction time for predicting a time until the host vehicle collides with the obstacle based on the relative speed and the acceleration of the host vehicle or the relative acceleration between the host vehicle and the obstacle. Possible collision prediction time calculation means,
A determination unit that determines which of the first collision prediction time and the second collision prediction time is used to control the host vehicle based on the acceleration, the relative acceleration, or the acceleration and the relative acceleration. When,
Control means for controlling the host vehicle,
The said control means controls the said own vehicle using either the said 1st collision prediction time or the said 2nd collision prediction time based on the determination by the said determination means.

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