JP4244839B2 - Vehicle collision determination device - Google Patents

Description

  The present invention relates to a vehicle collision determination device, and more particularly to a device that can more accurately determine the risk of collision by a plurality of impact detection sensors.

  In recent years, an increasing number of vehicles are equipped with airbag devices in order to protect occupants during a vehicle collision from serious accidents. The acceleration applied to the vehicle is detected by an acceleration sensor, and when there is a risk of collision, an airbag is deployed between the occupant and the vehicle body. There are various types of collisions such as frontal collision, offset collision, and side collision. Although the center acceleration sensor, the front acceleration sensor, and the side acceleration sensor may be arranged according to each collision mode, there are many cases in which only the center acceleration sensor is arranged for the reason of suppressing an increase in cost.

In a conventional vehicle collision determination device, only one center acceleration sensor that detects the danger of a collision is disposed (see Patent Document 1). The airbag is deployed when the collision determination unit determines that the change in acceleration detected by the acceleration sensor is greater than a predetermined value, and the airbag is not deployed when it is determined that the change is small (for example, when sudden braking is performed).
JP 11-31493 A

  When a collision is determined by one center acceleration sensor, it is difficult to say that the determination is accurate. The reason is the difficulty of selecting the dynamic range of the acceleration sensor. That is, if the dynamic range is selected to be wide (for example, ± 100 G), a change in acceleration can be detected over a wide range, but there is a possibility that the airbag may be deployed other than at the time of an actual collision, such as when a sudden brake is depressed. In addition, the resolution is lowered and it is difficult to make a fine distinction.

  On the other hand, if the dynamic range is selected to be narrow (for example, ± 20 G), the airbag can be prevented from developing (erroneous explosion) when the brake is depressed suddenly. However, when an actual collision occurs, the airbag may not be deployed (non-explosive), so that it does not function as an airbag device, and the passenger is exposed to danger.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a vehicle collision determination device that can more accurately determine the danger of a vehicle collision by devising the configuration of an impact detection sensor.

The inventor of the present application has come up with the idea of arranging a plurality of impact detection sensors in order to detect the same type of collision (for example, frontal collision), and has completed the present invention.
(1) The collision determination apparatus according to the first invention of the present application is, as described in claim 1, a pre-crash sensor for predicting a collision before a vehicle collision by radio waves or ultrasonic waves; and disposed at a predetermined position of the vehicle; A first impact detection sensor that has a narrow dynamic range and detects an impact at the time of a vehicle collision; and is disposed in the vicinity of the first impact detection sensor and has a wider dynamic range than the first impact detection sensor, and an impact at the time of a vehicle collision A second impact detection sensor for detecting the first impact detection sensor; a switching means for switching to the first impact detection sensor or the second impact detection sensor in accordance with a signal from the pre-crash sensor; a first impact detection sensor selected by the switching means or the second A collision determination unit that determines a risk of collision based on a signal from the impact detection sensor and issues a drive signal to the occupant protection device.

  In this collision determination device, the switching means is switched to the first impact detection sensor or the second impact detection sensor side according to the signal from the pre-crash sensor, and based on the detection result of the selected first or second impact detection sensor. Perform collision detection.

According to a second aspect of the present invention, the switching means normally switches to the first shock detection sensor side, and switches to the second shock detection sensor side when a collision is predicted by the pre-crash sensor.
(2) The collision determination device according to the second invention of the present application is, as described in claim 3, a plurality of impact detection sensors arranged close to each other at a predetermined position of the vehicle; and detection by some impact detection sensors Calculation means for calculating a calculation value for occupant protection device operation with priority given to the detection result of the remaining impact detection sensor when the result is far from the detection result of the remaining shock detection sensor; A collision determination unit that determines the risk of collision and issues a drive signal to the occupant protection device.

  In this collision determination device, the calculation means ignores the detection results of some of the impact detection sensors that are apart from the detection results of the remaining impact detection sensors, and calculates the calculation value based only on the detection results of the remaining impact detection sensors. To the collision determination unit.

  According to a fourth aspect of the present invention, the collision determination device according to the third aspect includes at least a first impact detection sensor, a second impact detection sensor, and a third impact detection sensor; and the detection result of the first impact detection sensor is the second impact detection sensor. When away from the detection result and the detection result of the second impact detection sensor, the calculation means uses the average value of the detection results of the second impact detection sensor and the third impact detection sensor as the calculation value.

(1) According to the vehicle collision determination device according to the first aspect of the present invention, since the impact is detected by the first impact detection sensor having a narrow dynamic range during normal traveling, the airbag may erroneously explode when the brake is depressed suddenly. Is prevented. Moreover, since the impact is detected by the second impact detection sensor having a wide dynamic range at the time of collision danger, the airbag is prevented from being unexploded and the occupant is reliably protected.
(2) According to the vehicle collision determination device of the second aspect of the present invention, since a plurality of impact detection sensors are provided for the same collision mode, redundancy is high. In addition, when the detection results of some of the impact detection sensors are far from each other, the calculation value is calculated based on the detection results of the remaining impact detection sensors, so that the collision determination in the collision determination unit is ensured.

<First invention>
The vehicle collision determination device according to the first aspect of the present invention is basically characterized in that different impact detection sensors are used when the risk of collision is low and high, and a pre-crash sensor, a first impact detection sensor, and a second impact detection sensor are used. It comprises an impact detection sensor, switching means, and a collision determination unit.
(A) The pre-crash sensor predicts the danger of a vehicle collision before the operation of the impact detection sensor. Specifically, it emits radio waves and sound waves forward from an oscillator attached to its own vehicle (own vehicle), and receives reflected waves reflected by other vehicles (other vehicles) traveling ahead and obstacles ahead. It is received by the aircraft and the distance between the vehicle and other vehicles is measured.
(B) The first impact detection sensor and the second impact detection sensor detect an impact (change in acceleration) applied when the vehicle collides, and a semiconductor type or capacitance type acceleration sensor can be adopted. For example, an acceleration signal output from the acceleration sensor is converted into a digital signal by an AD converter via an amplifier or the like, and then input to the collision determination unit.

  The first impact detection sensor and the second impact detection sensor are disposed in close proximity in the vehicle and are used for the same purpose. That is, if the first impact detection sensor is a center acceleration sensor that mainly detects a frontal collision, the second impact detection sensor is also a center acceleration sensor. The same applies to the case where the first impact detection sensor is an offset acceleration sensor and the case of a side acceleration sensor.

The first impact detection sensor and the second impact detection sensor have different dynamic ranges. The first impact detection sensor operates during normal driving of the vehicle, and its dynamic range is narrow, and can be selected within a range of, for example, -20G to 20G. On the other hand, the dynamic range of the second impact detection sensor that operates when the vehicle is in danger of collision is wide, and can be selected, for example, in the range of −100G to 100G.
(C) The switching means switches to the first impact detection sensor or the second impact detection sensor side according to a signal from the pre-crash sensor, and selectively selects one of the impact detection sensors. Specifically, it switches to the first impact detection sensor side during normal driving without a danger of a collision by a signal from the pre-crash sensor, but when the danger of a collision is predicted, the second impact detection sensor side. Switch.
(D) When the signal from the first or second impact detection sensor is input, the collision determination unit determines the risk of collision based on a reference value stored in advance.

<Second invention>
The vehicle collision determination device according to the second aspect of the present invention is basically characterized in that it can cope with the case where the impact detection by the impact detection sensor is impossible or inaccurate, and includes a plurality of impact detection sensors, calculation means, and a collision determination unit. .
(A) It is desirable that there are three or more impact detection sensors. This is because when two impact detection sensors are provided and the detection results of both are separated, it is not appropriate to prioritize which one. As the plurality of hit detection sensors, semiconductor type or capacitance type acceleration sensors can be adopted. The plurality of impact detection sensors are arranged in close proximity in the vehicle and are used to detect the same type of collision (for example, a frontal collision).
(B) The calculation means examines the detection results of the plurality of impact detection sensors, and calculates a calculation value as to whether or not to activate the occupant protection device when there is variation or bias. Variations in detection results occur due to, for example, individual differences at the 0G level during manufacturing. Specifically, when the output of the impact detection sensor is 0 to 5V, 2.5V corresponds to the 0G level in one impact detection sensor, and 2.6V corresponds to the 0G level in another impact detection sensor. When the 0G level fluctuates, the calculated value for the threshold value, which is a criterion for determining whether or not to deploy the airbag, varies, resulting in an error for airbag deployment.

  In addition, when the vehicle enters sandy land or climbs a step, the detection result of the impact detection sensor tends to be inaccurate. Thus, in consideration of the situation, for example, when the detection result of the first impact detection sensor is far from the detection result of the second and third impact detection sensors, the calculation means ignores the detection result of the first impact detection sensor, An average value of the detection results of the second and third impact detection sensors is output as a calculated value to the collision determination unit.

  In addition, when the detection results of the first, second, and third impact detection sensors are separated from each other, for example, an intermediate detection result can be employed. When four or more impact detection sensors are employed, the same calculation principle as in the three cases is followed.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
<First embodiment>
(Constitution)
In the first embodiment shown in FIG. 1, a pre-crash sensor 12 is provided at the front center of the vehicle, and the distance between the host vehicle and another vehicle traveling in front of the host vehicle is measured. The airbag ECU 15 disposed in the center of the vehicle includes a first center acceleration sensor 17, a second center acceleration sensor 18, a switching unit 21, and a collision determination unit 23. The first center acceleration sensor 17 has a narrow dynamic range (-20G to 20G), and the second center acceleration sensor 18 has a wide dynamic range (-100G to 100G).

The switching unit 21 switches to either the first center acceleration sensor 17 or the second center acceleration sensor 18 according to a signal from the pre-crash sensor 12. The collision determination unit 23 compares the selected signal from the first center acceleration sensor 17 or the second center acceleration sensor 18 with a reference value stored in advance, and determines the presence or absence of a collision. A driver airbag 25R is accommodated in the steering wheel in front of the driver seat, and a passenger airbag 25L is accommodated in the instrument panel in front of the passenger seat.
(Function)
The operation of this embodiment is as follows. When the inter-vehicle distance between the subject vehicle being measured and the other vehicle ahead is smaller than a predetermined value, the pre-crash sensor 12 issues a collision prediction signal to the switching unit 21. The switching unit 21 is normally switched to the first center acceleration sensor side 17.

However, when a collision prediction signal is input from the pre-crash sensor 12, the switching unit 21 is switched to the second center acceleration sensor 18 side. The collision determination unit 21 compares the magnitude of the acceleration detected by the second center acceleration sensor 18 with a reference value stored in advance. When the former exceeds the latter, the collision determination unit 21 detects the airbag 25L. And 25R drive command.
(effect)
According to this embodiment, the following effects can be obtained. First, the airbags 25L and 25R will not be deployed even if a sudden brake is applied during normal driving (a false explosion is prevented). At this time, the first center acceleration sensor 17 is operating, its dynamic range is ± 20 G, and the sensitivity is low, and the collision determination unit 21 does not determine the risk of collision when the acceleration changes due to sudden braking.

Secondly, the airbags 25L and 25R are surely deployed at the time of collision danger (no explosion is prevented). This is because the second center acceleration sensor 18 is activated at this time, the dynamic range thereof is ± 100 G, and the sensitivity is high, and the collision determination unit 21 determines the collision based on the change in acceleration accompanying the collision.
<Second embodiment>
(Constitution)
FIG. 2 shows a second embodiment of the present invention. In this embodiment, the pre-crash sensor 12 is not provided, and the airbag ECU 30 includes a first center acceleration sensor 31, a second center acceleration sensor 32, a third center acceleration sensor 33, a calculation unit 35, and a collision determination unit. 23. The first, second, and third center acceleration sensors 31, 32, and 33 have the same dynamic range (for example, ± 50 G), and are all disposed close to each other at the center of the vehicle floor. The computing unit 35 computes a computation value based on the acceleration detected by the first, second and third center acceleration sensors 31, 32 and 33.
(Function)
Since the first, second and third center acceleration sensors 31, 32 and 33 are arranged close to each other, the acceleration applied to them at the time of sudden braking or collision is substantially the same. However, as described above, there may be a difference in the magnitude of acceleration detected by the three center acceleration sensors 31, 32, and 33 due to individual differences of the 0G level.

For example, it is assumed that the acceleration detected by the first center acceleration sensor 31 with the 0G level shifted is 10G, and the accelerations detected by the second and third center acceleration sensors 32 and 33 with the 0G level not shifted are 12G and 13G. To do. At this time, the calculation unit 35 ignores 10G detected by the first center acceleration sensor 31, calculates 12G and 13G detected by the second and third center acceleration sensors 32 and 33, and calculates an average value of 12.5G. Is output to the collision determination unit 23 as a calculated value. The collision determination unit 23 compares the input from the calculation means 35 with a reference value stored in advance, and outputs an airbag deployment signal to the airbags 25L and 25R when the former exceeds the latter.
(effect)
The effects of this embodiment are as follows. First, since the three center acceleration sensors 31, 32, and 33 are provided to increase redundancy, even if any one of the center acceleration sensors fails, the remaining two center acceleration sensors detect the change in acceleration. can do.

  Moreover, the collision determination unit 23 can accurately perform the collision determination. Even if there is a deviation in the 0G level of the first center acceleration sensor 31, the detection result (10G) is not adopted, and the detection result obtained from the second and third center acceleration sensors 32 and 33 without deviation in the 0G level ( This is because only 12G and 13G) are employed to calculate the calculation value 12.5G.

It is a plane explanatory view showing the 1st example of the present invention. It is a plane explanatory view showing the 1st example of the present invention.

Explanation of symbols

12: Pre-crash sensor 15, 30: Airbag ECU
17: 1st center acceleration sensor 18: 2nd center acceleration sensor 21: Switching part 23: Collision determination part 25L, 25R: Airbag 31, 32, 33: Center acceleration sensor 35: Calculation means

Claims (4)

A pre-crash sensor that predicts a collision before a vehicle collision by radio waves or ultrasonic waves,
A first impact detection sensor disposed at a predetermined position of the vehicle and having a narrow dynamic range to detect an impact at the time of a vehicle collision;
A second impact detection sensor which is disposed in the vicinity of the first impact detection sensor and has a wider dynamic range than the first impact detection sensor and detects an impact at the time of a vehicle collision;
Switching means for switching to the first impact detection sensor or the second impact detection sensor in accordance with a signal from the pre-crash sensor;
A collision determination unit that determines a risk of collision based on a signal from the first impact detection sensor or the second impact detection sensor selected by the switching unit and issues a drive signal to an occupant protection device;
A vehicle collision determination device comprising:   2. The collision determination device according to claim 1, wherein the switching unit normally switches to the first impact detection sensor side and switches to the second impact detection sensor side when a collision is predicted by the pre-crash sensor. A plurality of impact detection sensors arranged close to each other at a predetermined position of the vehicle;
When the detection results of some of the impact detection sensors are far from the detection results of the remaining impact detection sensors, the calculation results for occupant protection device operation are calculated with priority given to the detection results of the remaining impact detection sensors. Computing means for
A collision determination unit that determines a danger of a collision based on a signal from the calculation unit and issues a driving signal to an occupant protection device;
A vehicle collision determination device comprising: Including at least a first impact detection sensor, a second impact detection sensor, and a third impact detection sensor;
When the detection result of the first impact detection sensor is far from the detection result of the second impact detection sensor and the detection result of the second impact detection sensor, the calculation means is configured to detect the second impact detection sensor and the second impact detection sensor. The collision determination device according to claim 3, wherein an average value of detection results of the three impact detection sensors is used as a calculation value.

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