JP2005082042A - Automatic braking device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an automatic braking device for a vehicle which is controlled so that the automatic brake control is disengaged when the vehicle is stopped while a collision mitigating system is in operation. <P>SOLUTION: The automatic braking device for the vehicle is to exert a braking force without resorting to a braking operation on the basis of the relation between the vehicle concerned and any obstacle ahead of the vehicle, wherein the timing of stopping the brake application after the automatic braking is actuated is selected on the basis of the relation as described above. If in particular, the collision mitigating system is actuated, the automatic brake control is disengaged automatically before collision. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a vehicle automatic brake device that exerts a braking force regardless of a brake operation based on a relationship between the host vehicle and an obstacle existing in front of the host vehicle, and in particular, the vehicle stops under the operation of a collision mitigation system. The present invention relates to an automatic brake device for a vehicle that is controlled such that automatic brake control is released when

  Usually, operations necessary for traveling such as steering, acceleration, or braking while the vehicle is traveling are appropriately performed based on the judgment of the driver. However, under unforeseen circumstances such as driver's carelessness or sudden stop of the preceding vehicle, from the viewpoint of safety, control such as braking control is not performed without waiting for the driver's judgment or in addition to the driver's judgment. Preferably it is done automatically.

  2. Description of the Related Art Conventionally, a so-called automatic brake device that automatically executes braking control under a predetermined condition without performing a brake operation by a driver is known (see, for example, Patent Documents 1 and 2).

These conventional automatic brake devices prevent the collision with the preceding vehicle (collision avoidance system) or when the risk of colliding with the preceding vehicle existing in front of the host vehicle increases. In order to reduce the impact of a collision as much as possible (collision mitigation system), the host vehicle is automatically braked with a relatively large deceleration. Therefore, in a vehicle equipped with such an automatic brake device, the brake is automatically activated even if the driver does not perform a brake operation in order to avoid or mitigate the collision.
JP 2001-114081 A JP 2003-48524 A

  For example, in an ASV (advanced safety vehicle) or a vehicle described in Patent Document 1 that has been proposed as a vehicle equipped with an automatic brake device, the automatic brake control that has once been operated is designed to be released when the vehicle is stopped.・ It is set.

  Further, in the vehicle described in Patent Document 2, when the accelerator operation by the driver is detected after the automatic brake is activated, the automatic brake is set to be released.

  However, such a conventional automatic brake release control may cause a problem at the time of a collision. Specifically, when a fatal damage occurs to the brake system or the power supply due to a collision, there is a possibility that the vehicle may stop without being released.

  If the automatic brake is released when the vehicle is stopped, even if there is a collision, the automatic brake may or may not be released depending on the presence / absence or degree of the collision. Whether or not the automatic braking is working when a third party) tries to resume driving, or whether or not an operation for releasing the automatic braking (for example, “pressing the release button”) is necessary. It is impossible to make an instant determination, and there is a risk of delaying rapid resumption of operation.

  In order to avoid such a situation, the hardware should be secured so that the automatic brake can be released regardless of the degree of the collision in the event of a collision. It is difficult to realize such an arrangement, and causes an increase in the cost, weight, and size of the vehicle.

  The present invention is to solve such a problem, and to provide an automatic brake device for a vehicle that is controlled such that the automatic brake control is released when the vehicle stops under the operation of the collision mitigation system. Main purpose.

  An aspect of the present invention for achieving the above object is an automatic brake device for a vehicle that exhibits a braking force regardless of a brake operation based on a relationship between the host vehicle and an obstacle ahead of the host vehicle. This is an automatic brake device for a vehicle in which the timing for stopping the operation after the operation of the brake is selected based on the above relationship.

  In this aspect, “the relationship between the host vehicle and the obstacle ahead of the host vehicle” means whether there is a relationship in which the host vehicle collides with the obstacle if the vehicle continues to run as it is, and the collision is Indicates whether it can be avoided by automatic brake control.

  In addition, in this aspect, the “front of the host vehicle” is an area that exists in the traveling direction of the host vehicle, and refers to all areas in which the host vehicle may pass in the future due to road shape or steering of the host vehicle. The “obstacle” typically refers to any other animal object that is moving or stopped or is originally stationary on the traveling line of the host vehicle, although the other vehicle is typically traveling.

  According to this aspect, since the timing at which the automatic brake control once activated is released is selected based on the relationship between the host vehicle and the front obstacle, for example, when it is determined that a collision can be avoided. Shall be released when the vehicle stops or when the driver performs a predetermined operation, and when it is judged that collision avoidance is impossible, it shall be released before the collision. The automatic brake release timing is unified, and in the latter case, the automatic brake can be released before the collision.

  Therefore, in this aspect, it is preferable that the automatic brake control is automatically canceled when a collision between the host vehicle and the obstacle is predicted after the automatic brake control is activated. In order to ensure that the automatic brake is released when the host vehicle stops due to a collision, it is particularly preferable to release it before the predicted collision occurrence time. From the viewpoint of maximizing the performance, it is more preferable to cancel immediately before the predicted occurrence time. Such a prediction of the collision and the time of occurrence thereof may be performed within the host vehicle, or may be performed outside the host vehicle and transmitted to the host vehicle through inter-vehicle communication or road-to-vehicle communication.

  As another method, instead of the above-described process of predicting the collision and the time point at which it occurred, the contact between the vehicle and the obstacle is detected, and the automatic brake is immediately released when a slight contact is detected. By doing so, the automatic brake control can be released when the vehicle stops after the collision regardless of the degree of the collision (or the degree of damage due to the collision).

  ADVANTAGE OF THE INVENTION According to this invention, the automatic brake device for vehicles controlled so that automatic brake control was canceled when the vehicle stopped under the collision mitigation system operation can be provided.

  The best mode for carrying out the present invention will be described below with reference to the accompanying drawings. It should be noted that the hardware configuration, operation principle, basic control method, and the like of the vehicle automatic brake device itself are known to those skilled in the art and will not be described in detail.

  FIG. 1 is a system schematic diagram of a vehicle automatic brake device according to an embodiment of the present invention. The automatic brake device according to the present embodiment includes an electronic control unit (ECU) 101 and is controlled by the ECU 101.

  The ECU 101 is connected to a laser radar sensor 102 disposed on, for example, a front grill of the host vehicle. The laser radar sensor 102 irradiates a laser beam toward a predetermined area in front of the host vehicle, and receives a reflected wave of the laser beam irradiated in front of the host vehicle.

  The laser radar sensor 102 is configured to scan a predetermined area in front of the host vehicle at a predetermined cycle. The laser radar sensor 102 reflects a signal and a reflected wave according to time until the irradiated laser light is reflected by an obstacle existing in front of the host vehicle (hereinafter simply referred to as “front obstacle”) and received. A signal corresponding to the incident angle is output to the ECU 101.

  The ECU 101 detects a distance L to a front obstacle existing in a predetermined area in front of the host vehicle based on an output signal of the laser radar sensor 102, and differentiates the detected distance L to thereby detect the front obstacle. The relative speed V1 of the own vehicle is calculated.

  In addition, a vehicle speed sensor 103 is connected to the ECU 101. The vehicle speed sensor 103 outputs a pulse signal to the ECU 101 at a cycle corresponding to the traveling speed of the vehicle. The ECU 101 detects the host vehicle speed V <b> 2 based on the output signal of the vehicle speed sensor 103.

  In addition, a collision sensor 104 is connected to the ECU 101. The collision sensor 104 is an electronic deceleration sensor that outputs a signal corresponding to the magnitude of an impact acting on a portion where the collision sensor 104 is disposed.

  The automatic brake device according to the present embodiment is a hydraulic or electric brake device, and includes a brake actuator 105 that generates a braking force on each wheel. The brake actuator 105 is electrically connected to the ECU 101 and causes each wheel to generate a braking force according to a command signal output from the ECU 101.

  The automatic brake device according to the present embodiment has a brake pedal (not shown) that can be operated by the driver. A brake pedal switch 106 is disposed in the vicinity of the brake pedal. The brake pedal switch 106 is turned on when the brake pedal is depressed, and is turned off when the brake pedal is not depressed. The brake pedal switch 106 is connected to the ECU 101 and outputs a signal corresponding to the state to the ECU 101. The ECU 101 determines whether or not the brake pedal is operated based on the state of the brake pedal switch 106.

  Next, the operation of the automatic brake device according to this embodiment will be described. In this embodiment, the ECU 101 outputs a command signal to the brake actuator 105 so that a deceleration according to the brake operation is generated in the vehicle while the brake pedal is operated. In this case, the vehicle is decelerated according to the brake operation by the driver.

  On the other hand, in the situation where the brake pedal is not operated, when there is an obstacle in front of the vehicle that may impede travel, the ECU 101 reduces the vehicle speed to a predetermined level even if the brake pedal is not operated. A command signal is output to the brake actuator 105 so that the speed is generated.

  In this case, the host vehicle is decelerated without a brake operation by the driver. The process of decelerating the host vehicle without depending on the driver's brake operation is so-called automatic brake control. According to this automatic brake control, the vehicle can be decelerated regardless of the driver's brake pedal operation when the risk of collision with a front obstacle increases while the vehicle is traveling.

  As known to those skilled in the art, there are two situations where the automatic brake is operated: a case where it is determined that a collision cannot be avoided and a case where it is determined that a collision can be avoided. In other words, the automatic brake control may be executed as a collision mitigation system that attempts to reduce the impact caused by the collision as much as possible, or may be executed as a collision avoidance system that avoids the collision.

  In the present invention, the automatic brake control is released before the collision when the collision mitigation system is operated, so that the automatic brake control is released when the vehicle is stopped under the collision mitigation system operation. It is necessary to determine whether it is a system or a collision avoidance system.

  For this determination, the relationship between the distance L to the obstacle and the host vehicle speed V2 is used. An example is shown in FIG. FIG. 2 is a graph in which the horizontal axis represents the distance L [m] and the vertical axis represents the speed V2 [m / s]. The line a represents the collision avoidance limit (so-called braking distance) by the braking control, and the line b represents The collision avoidance limit by steering control is shown.

  That is, an area I below the line a is an area where collision can be avoided by braking control (hereinafter referred to as “collision avoidance area”), and if the relationship between the distance L and the speed V2 is in this area, the collision avoidance system. As a result, automatic brake control is executed. On the other hand, regions II and III above line a are regions where collision avoidance is impossible by braking control (hereinafter referred to as “collision mitigation region”), and if the relationship between distance L and speed V2 is in these regions Automatic brake control is executed as a collision mitigation system.

  As will be apparent to those skilled in the art, FIG. 2 shows an example in which the front obstacle is a stationary object. When the front obstacle is a traveling vehicle, the horizontal axis represents the relative distance, The vertical axis represents the relative speed (V1).

  Next, the flow of execution and release of the automatic brake control by the automatic brake device according to the present embodiment will be described with reference to FIG.

  First, based on the output signal of the laser radar sensor 102, the ECU 101 determines whether there is an obstacle ahead of the host vehicle, and if so, whether the host vehicle may collide with the front obstacle. It is determined whether or not (S301). When there is no possibility of a collision with a front obstacle (“NO” in S301), automatic brake control is not executed.

  When there is a possibility of collision with a front obstacle (“YES” in S301), automatic brake control is executed (S302).

  Next, in order to select the timing for releasing the activated automatic brake from among predetermined options, the ECU 101 uses the region shown in FIG. 2 for the distance L and the speed V2 calculated based on the output signal of the laser radar sensor 102. Region determination is performed using I to III (S303).

  When the distance L and the speed V2 correspond to any one of the areas II and III, which are the collision mitigation areas, it is determined that the collision with the front obstacle is inevitable (therefore, the brake system and the power supply may be damaged). Then, the ECU 101 automatically releases the automatic brake immediately before the collision (that is, regardless of the driver's operation) (S304).

  The timing at which the automatic brake is automatically released in the process of S304 may be basically arbitrary including immediately after the collision, but is preferably “before the collision” in order to ensure the release. From the viewpoint of executing as long as possible, it is more preferable to be “immediately before the collision” as in this embodiment.

  Further, in the process of S304, the determination that it is before or just before the collision may be made by, for example, a) monitoring the distance L in real time and determining that the value has become a predetermined value or less, or A) It may be a predetermined time before the collision occurrence point calculated and predicted from the distance L and the relative speed V1, or c) Information measured and / or calculated outside the host vehicle is transmitted through inter-vehicle communication or road-to-vehicle communication. It may be transmitted to the own vehicle, or d) it may be judged that the output of the collision sensor 104 is monitored in real time, and that the output indicates that the own vehicle has made slight contact with the front obstacle.

  On the other hand, in the area determination of S303, when the distance L and the speed V2 correspond to the area I that is the collision avoidance area, it is determined that the collision with the front obstacle is avoided by executing the automatic brake control. In this case, since a collision does not occur, the conventional problem of being released or not released at any time does not occur.

  In the present embodiment, as an example, the collision is avoided by the automatic brake control, and is released when a predetermined operation is performed by the driver after the vehicle stops (S305). Here, the “predetermined operation” may be a depression of a predetermined button (for example, a “release button”) or a depression of an accelerator pedal.

  As is clear from FIG. 2, in the low vehicle speed range, the automatic brake control is executed as the collision mitigation system, but as a result, a collision may be avoided. In this case, in order to unify the release timing when the collision mitigation system is activated, it is preferable to automatically release the automatic brake control immediately after the vehicle stops.

  Thus, according to this embodiment, when automatic brake control is executed by the collision mitigation system, the automatic brake is automatically released while it can be released. The automatic brake is always released when the person tries to resume driving. Therefore, those who want to resume driving do not have to think about whether or not the automatic brake is released or how to release the automatic brake, and resume driving quickly. it can.

  The present invention can be used for an automatic brake device for vehicles. The appearance, weight, size, running performance, etc. of the vehicle are not limited.

1 is a system schematic diagram of a vehicle brake device according to an embodiment of the present invention. It is a figure which shows the area | region used for the area | region determination which concerns on one Example of this invention based on the relationship between the distance L to an obstruction, and the own vehicle speed V2. It is a flowchart which shows the flow of execution and cancellation | release of automatic brake control by the automatic brake apparatus which concerns on one Example of this invention.

Explanation of symbols

101 Electronic control unit (ECU)
102 Laser radar sensor 103 Vehicle speed sensor 104 Collision sensor 105 Brake actuator 106 Brake switch

Claims (5)

An automatic brake device for a vehicle that exerts a braking force regardless of a brake operation based on a relationship between the host vehicle and an obstacle ahead of the host vehicle,
An automatic brake device for a vehicle, wherein a timing for releasing the control after the operation of the automatic brake control is selected based on the relationship. The automatic brake device for a vehicle according to claim 1,
An automatic brake device for a vehicle, wherein automatic brake control is canceled when a collision between the host vehicle and the obstacle is predicted. The automatic brake device for a vehicle according to claim 2,
An automatic brake device for a vehicle, wherein when a collision between the host vehicle and the obstacle is predicted, the automatic brake control is canceled before the time when the prediction of the collision occurs. The vehicle automatic brake device according to claim 3,
An automatic brake device for a vehicle, wherein when a collision between the host vehicle and the obstacle is predicted, the automatic brake control is released immediately before the prediction occurrence time point. The automatic brake device for a vehicle according to claim 1,
An automatic brake device for a vehicle, wherein automatic brake control is canceled when contact between the host vehicle and the obstacle is detected.

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