JPH0924795A - Side collision discrimation device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To quickly and accurately discriminate side collision to a vehicle by making a domain where both quantity of energy and speed variation are great, a collision judging domain out of two dimensional domain of which are formed by axes of coordinates of the quantity of energy and speed variation. SOLUTION: An acceleration signal from an acceleration sensor 1 is permitted to pass through intermittently for every definite period only for a definite period of time while being synchronized with a timing signal of an input timing generating circuit 2, restricted in band by a low pass filter 3, and integrated by an integration circuit thereafter, so that it is transformed into speed variation data for the definite period of time. Meanwhile, high frequency band constituents extracted by a band pass filter 6 is transformed into a quantity of energy by an energy quantity detection means 7. The speed variation and the quantity of energy are compared with each set value equivalent to respective safety limits by compactors 5 and 8, a domain where both the quantity of energy and the speed variation are large, is made a collision judging domain out of two dimensional domains which are formed by axes of coordinates of the quantity of energy and the speed variation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a side collision detection device for a vehicle, which detects a collision of a side vehicle with a side surface of the vehicle and outputs a collision detection signal for activating an airbag device for protecting an occupant.

[0002]

2. Description of the Related Art In recent years, airbag devices have been rapidly spread for the purpose of protecting a driver and a passenger from a shock when a vehicle collision occurs to reduce injuries and fatal accidents. This airbag device detects, with a collision sensor, that a vehicle has received an impact exceeding a certain limit, that is, a safety limit due to the occurrence of a collision, and energizes a squib (electric detonator) with a collision detection signal output from the collision sensor. , The squib is ignited to burn a gas generating agent to generate gas, and an airbag that expands rapidly due to the inflow of this gas is interposed between the occupant and the opposite location in the vehicle to provide a cushioning function. Has become.

There are driver seats and passenger seats as the above-mentioned airbag devices. However, all of the airbag devices that have been put into practical use at the present time expand the airbag by detecting a frontal collision of the vehicle with a collision sensor. Most of them do.
However, in addition to the above-mentioned frontal collision, there are side collisions and rear-end collisions in the vehicle.In particular, when a side collision occurs, a relatively thin and weak door or pillar part on the side surface of the vehicle It often deforms immediately and seriously damages the occupants. Therefore, there is a demand for practical use of an airbag device that detects and operates a side collision of a vehicle.

[0004]

However, the existing airbag apparatus for frontal collision cannot be used as it is for side collision. That is, in the case of a head-on collision, the occupant is impacted after the bumper, chassis, and engine of the vehicle are roughly destroyed in this order. Therefore, the collision sensor is activated 10 to 15 msec after the front surface of the vehicle collides with an object. While it can protect the occupant when activated,
In the case of a side collision, a relatively thin and weak door or pillar portion is deformed at the moment of collision with an opponent vehicle and causes damage to an occupant. For example, a collision occurs while traveling at a speed of 50 km / h. In this case, it is necessary to operate the collision sensor within about 5 msec.

If the detection sensitivity of the collision sensor is set higher than that in the case of a head-on collision, there is a risk of malfunction due to a shock when the door is opened or closed. Therefore, it has been proposed to use a mechanical collision sensor having a damping effect called a flapper type and having a quick response, but there is a problem that this collision sensor cannot exhibit sufficient performance depending on the vehicle type.

Therefore, in order to discriminate a collision more accurately, an acceleration signal output from an electric collision sensor using a piezoelectric element is integrated over time to calculate a speed change amount, and the speed change amount reaches a safety limit. It is conceivable to apply a frontal collision discriminating apparatus that determines that a collision has occurred when the vehicle crosses over to a side collision. However, if you try to distinguish side impact from door impact etc. only by the amount of speed change, it is necessary to set the threshold of the safety limit to a relatively large value. It takes time to get. On the other hand, in the case of a side collision, the expansion of the airbag is delayed and the desired cushioning effect cannot be obtained unless the occurrence of a collision is determined instantaneously. Therefore, it is impossible to accurately distinguish between a side collision and an impact due to door opening / closing only by the integrated value of the acceleration signal within an extremely short period of time required to make a collision determination.

Further, in the field of a collision determination device for a head-on collision, an impact force obtained by calculation based on a speed change amount obtained from an acceleration signal and a specific frequency band component which is included in the acceleration and which appears remarkably at the time of a vehicle collision. Thus, a collision determination curve that divides the collision area and the non-collision area on a plane having two axes of the velocity change amount and the impact force is experimentally obtained in advance, and the collision determination curve output from the collision sensor during traveling is used. An apparatus has been proposed in which the obtained speed change amount and the impact force are functionally calculated, and the collision determination is made based on which side of the collision determination curve, the inside or outside of the collision determination curve, is present (Japanese Patent Laid-Open No. HEI 6-96).
-99787). However, when this device is applied to a side collision as it is, the setting of the collision judgment curve and the comparison judgment of the calculation result with respect to the curve are completely different from those in the case of a frontal collision. It cannot be accurately determined.

The present invention has been made in view of such problems of the prior art, and an object of the present invention is to be able to quickly and accurately determine a side collision with a vehicle. It is to provide a side collision detection device for a vehicle.

[0009]

In order to solve the above-mentioned problems, a vehicle side collision discrimination device according to the present invention converts an acceleration applied laterally to the vehicle into an electric signal which is attached to a side surface portion of the vehicle. An acceleration sensor for detecting the acceleration signal, an integration unit for integrating the output electric signal of the acceleration sensor for a certain period of time to calculate a speed change amount, and a vibration component extraction for extracting only a specific high frequency band component from the output electric signal of the acceleration sensor. Means, an energy amount calculating means for calculating an energy amount from an output signal of the vibration component extracting means, and a two-dimensional region formed with the energy amount and the velocity change amount as coordinate axes, even if the energy amount is large. A region where the amount of change is small, a region where the amount of energy is small even if the amount of speed change is large, and a region where both the amount of energy and the amount of speed change are small are determined as non-collision regions. And, in which a collision judging means for energy amount and speed variation is to both large remaining area collision determination area.

The above-mentioned collision determining means has a first comparing means for outputting a signal when it is determined that the speed change amount calculated by the integrating means is equal to or more than a set value, and the energy amount of the energy amount calculating means is a set value. It is constituted by a second comparing means which outputs a signal when it is determined that the above is true, and a collision determining section which outputs a collision detection signal when signals are simultaneously output from both the first and second comparing means. be able to.

Further, the above-mentioned collision discriminating means functionally calculates the respective outputs of the integrating means and the energy amount calculating means to form a velocity change amount and an energy amount on a two-dimensional area having coordinate axes. A function calculation means for obtaining coordinate values, and a coordinate value of a calculation result of the function calculation means with respect to a collision determination curve dividing a two-dimensional area having a velocity change amount and energy amount as coordinate axes into a collision area and a non-collision area It is also possible to employ a third comparison means for outputting a collision detection signal when it is determined that

Further, the high frequency band component extracted by the vibration component extracting means is 800 Hz or more, preferably 100
The frequency can be set to 0 Hz or higher, more preferably 1100 Hz or higher.

According to the above configuration, the electric signal obtained by converting the lateral acceleration applied to the vehicle is integrated for a certain period of time to calculate the speed change amount, and only the specific high frequency band component is extracted from the electric signal obtained by converting the acceleration. Then, the energy amount of the extracted signal is calculated. Here, if the frequency band component corresponding to the vibration component that remarkably occurs when a shock is directly applied to the acceleration sensor is extracted as the high frequency band component, the energy amount calculated from the extracted signal is the impact force on the acceleration sensor. That is, it corresponds to the impact force on the side surface of the vehicle. Then, when both the speed change amount and the energy amount exceed the set values of the respective safety limits, it is determined to be the collision determination region in the two-dimensional region formed with the speed change amount and the energy amount as the coordinate axes. And outputs a collision detection signal for operating the airbag device.

Therefore, when the door is hit by mistake, for example, when it comes into contact with the wall surface of the building when the door is opened,
Although the amount of change in speed becomes large and exceeds the set value, since the impact is not directly applied to the acceleration sensor, the output electric signal of the acceleration sensor contains almost no high-frequency component energy. Therefore, the amount of energy of the high frequency component included in the acceleration signal does not exceed the set value, and the collision detection signal is not erroneously output.

By the way, in the above-mentioned configuration, since the amount of energy of the high frequency component contained in the output electric signal of the acceleration sensor is calculated, so-called hammering such as hitting the door by a mischief with some object occurs. In such a case, vibration may occur in the acceleration sensor and the energy amount of the high frequency component may exceed the set value. However, since the speed change amount does not exceed the set value, the collision detection signal is not erroneously output. That is, since the speed change amount and the energy amount of the high frequency component both exceed the respective set values only when the opposite vehicle collides with the side surface of the vehicle, the side collision can be accurately discriminated from the door striking and the hammering.

Further, since it is not judged that a side collision occurs unless the speed change amount and the energy amount exceed the respective set values at the same time, each set value for setting the safety limit of the calculated speed change amount and the energy amount. Can be set to a low level that does not occur when hammering or hitting the door. As a result, when a side collision occurs, both the calculated speed change amount and the energy amount show a change exceeding the set value at an early point from the time of the collision occurrence. A collision detection signal can be output, and the airbag can be effectively expanded.

The collision determining means includes a first comparing means for comparing the calculated speed change amount with a set value, a second comparing means for comparing the calculated energy amount with the set value, and a signal output from these comparing means at the same time. When configured as a collision determination unit such as an AND gate that determines whether or not a side collision has occurred, the configuration is extremely simple and a side collision can be determined with high accuracy and speed.
On the other hand, in the collision determination means, a collision determination curve that divides a two-dimensional area having a velocity change amount and an energy amount as coordinate axes into a collision region and a non-collision region is experimentally obtained in advance, and the velocity change amount and the energy amount are determined. If the configuration is such that a collision detection signal is output when it is determined that the coordinate value on the two-dimensional region obtained by functionally calculating is larger than the collision determination curve, Since it is calculated comprehensively together with the impact force, when a side collision occurs, both the speed change amount and the impact force change beyond a certain limit at an early stage from the time of the collision, Since the calculation result has a value existing in the collision determination area of the collision determination curve, it is possible to accurately determine the occurrence of a side collision in an extremely short time.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. First, a first embodiment will be described with reference to FIGS. FIG. 1 is a block diagram showing a side collision determination device for a vehicle according to a first embodiment of the present invention, FIG. 2 is a diagram showing a side collision determination map in FIG. 1, and FIG. 3 is a frequency when a side collision occurs. FIG. 4 is a spectrum diagram showing an energy distribution with respect to FIG. 4, and FIG. 4 is a schematic perspective view of an automobile showing installation positions of acceleration sensors.

In FIG. 1, an acceleration sensor 1 converts an acceleration applied laterally to a vehicle into an electric signal and detects the electric signal, and a piezoelectric element for converting mechanical energy into electric energy by utilizing a piezoelectric effect. It is configured using. As shown in FIG. 4, the acceleration sensor 1 includes a central portion D1 or a lower end portion D1 of a door D on a side surface of an automobile AM.
2, embedded in any one of the sill portion C and the pillar portion P so as to receive the acceleration from the side. The acceleration signal output from the acceleration sensor 1 is converted into digital data by an A / D converter (not shown), and then processed by software with a configuration surrounded by a broken line in FIG. . The side collision airbag is the door D.
Or installed on the side of the seat. Further, although the right side of the automobile AM is shown in the same figure, it goes without saying that the acceleration sensor 1 and the airbag are similarly provided on the left side as well.

The acceleration signal from the acceleration sensor 1 is allowed to pass intermittently at fixed intervals and for a fixed time in synchronization with the timing signal generated by the counting operation of the input timing generation circuit 2. The acceleration signal that has passed through the input timing generation circuit 2 is passed through the low-pass filter 3
Is band-limited by and then integrated by the integrator circuit 4,
It is converted into speed change amount data in a fixed time set by the timing signal. By inputting the above acceleration signal after band-limiting with the low-pass filter 3,
Only the component corresponding to the acceleration applied laterally to the vehicle, which is included in the acceleration signal, is extracted.

On the other hand, a part of the acceleration signal that has passed through the input timing generation circuit 2 is extracted by the bandpass filter 6 only in a predetermined high frequency band component. The extracted high frequency band component will be described with reference to FIG.
In FIG. 3, the solid line curve indicates a side collision, the dashed-dotted line curve indicates a hammering, and the broken line curve indicates a door hitting characteristic curve.
Differences in respective characteristics remarkably appear in high frequency components of z or higher. That is, when a direct impact is applied to the acceleration sensor 1 as in the case of a side collision or hammering, a vibration component around 1 kHz is generated, and thus the bandpass filter 6 includes the vibration component in the acceleration signal. 80
High frequency band component of 0 Hz or more, preferably 1000 Hz
Above, more preferably if set to 1100Hz or more,
In other words, the vibration component corresponding to the impact force is extracted.
As a result, a door impact, in which a shock is indirectly applied to the acceleration sensor 1 and a vibration is not transmitted to the acceleration sensor 1, is excluded, and an impact force that cannot be detected only by the speed change amount is detected.

The high frequency band component extracted by the band pass filter 6 is converted into an energy amount by the energy amount detecting means 7. As the energy amount calculation means 7, for example, a square calculator is used, and by square-calculating the band component that changes between positive and negative, it corresponds to the magnitude of the impact force regardless of whether the acceleration is positive or negative. It is converted into the amount of energy to

The speed change amount and the energy amount respectively calculated by the integrating circuit 4 and the energy amount calculating means 7 are compared with the set values corresponding to the safety limits by the first and second comparators 5 and 8, respectively. This set value will be described with reference to the side collision determination map in which a two-dimensional region is formed with the energy amount E and the velocity change amount V in FIG. 2 as coordinate axes. Figure 2 shows high-speed side impacts and low speeds (20km / h).
In addition to the relationship between the energy amount E of the high frequency component and the velocity change amount V in the frontal collision in the vehicle, the energy amount E of the high frequency component and the velocity change amount V of the door striking and hammering as well.
The regions with the deepest correlation with are surrounded by broken lines. As is clear from the figure, the set value V _R of the first comparator 5 is set to a value slightly larger than the maximum speed change amount V at the time of occurrence of hammering and low-speed side collision. On the other hand, the set value E _R of the second comparator 7 is set to a value slightly larger than the maximum energy amount E when the door is hit.

The both comparators 4, 7 and the AND gate 9 constitute a collision determination means 15. The collision determination means 15 is a two-dimensional area formed with the energy amount E and the speed change amount V in FIG. 2 as coordinate axes, and a region where the speed change amount V is small even if the energy amount E is large, and a speed change amount V. Area where the energy amount E is small even if is large, and an area where both the energy amount E and the velocity change amount V are small are determined as non-collision regions, and the remaining regions where both the energy amount E and the velocity change amount V are large are subjected to collision determination. The area.

Therefore, when the door is hit, the signal V is output from the first comparator 5 because the speed change amount V exceeds the set value V _{R. In} this case, the impact is directly applied to the acceleration sensor 1. Since the acceleration signal of the acceleration sensor 1 contains almost no high-frequency component energy, the output signal level of the energy amount calculation means 7 may exceed the set value E _R of the second comparator 8. Therefore, the AND gate 9 as the collision determination unit does not output the collision detection signal to the trigger circuit 13 by mistake, and the airbag 1
4 does not expand.

On the other hand, when hammering occurs, the acceleration sensor 1 vibrates and the energy amount E of the high frequency component E
May exceed the set value E _R of the second comparator 8, but in this case, the speed change amount V does not exceed the set value V _R of the first comparator 5, so the AND gate 9 still detects the collision detection. The signal is not output incorrectly. Even when the other vehicle collides with the vehicle at a low speed, the collision detection signal is not output as determined in the same manner as when the hammering occurred. This is because, if the airbag 14 is expanded when a low-speed side collision occurs, it is dangerous to the occupant.

On the other hand, when the opposite vehicle collides with the side surface of the vehicle at high speed, both the speed change amount V and the energy amount E of the high frequency component are both set values V _R and E _{R of} both comparators 5 and 8.
Therefore, it is possible to accurately distinguish the side collision from the door striking and the hammering. Moreover, the set values V _R and E _R for setting the safety limits of the calculated speed change amount V and the calculated energy amount E are set to low levels that do not occur in hammering and door striking as described above. Therefore, if a side collision occurs,
Since the calculated speed change amount V and the calculated energy amount E show changes that exceed the set values at an early point in time after the occurrence of a collision, it is possible to determine a side collision in an extremely short time and output a collision detection signal. The thick line portion of the side collision characteristic curve in FIG. 3 indicates the time zone required to output the collision detection signal, but indicates that the collision detection signal can be output immediately after the side collision occurs.

Since the acceleration signal of the acceleration sensor 1 is taken in at every constant period set in the input timing generation circuit 2, the calculated values of the integration circuit 4 and the energy amount calculation means 7 when the side collision does not occur. Need to be cleared each time. Therefore, in the normal state detection circuit 10, a predetermined offset value is subtracted from the acceleration signal from the low pass filter 3, and the subtracted value is integrated in the fixed time set in the input timing generation circuit 2. The integrated value is compared with the reference offset value V ₀ of the third comparator 11, and when the integrated value is smaller than the reference offset value V ₀ , the fourth comparator 11 outputs a signal. Each time the fourth comparator 11 outputs a signal and determines that the vehicle is traveling normally, the reset circuit 12 clears the calculated values of the integrating circuit 4 and the energy amount calculating means 7 each time.

FIG. 5 is a block diagram showing a side collision judgment device for a vehicle according to the second embodiment of the present invention, and FIG. 6 is a view showing a side collision judgment map in FIG. 5, parts that are the same as or equivalent to those in FIG. 1 are assigned the same reference numerals and explanations thereof are omitted, and only configurations that differ from FIG. 1 will be described below.

That is, only the collision determination means 18 is different from FIG. The collision determination means 18 includes the integration circuit 4 and the energy amount calculation means 7.
Coordinate values on a two-dimensional area having the velocity change amount and the energy amount as coordinate axes as shown in FIG. 6 by performing a functional calculation such that each output is multiplied by a predetermined constant and then added. And a third comparator 17 that compares the calculation result of the function calculation means 16 with the value f _X of the collision determination curve in FIG. 6 and outputs a collision detection signal when the calculation result is large. It is composed of and.

As shown in FIG. 6, the value f _x of the collision determination curve is obtained comprehensively by combining the velocity change amount V and the energy amount E corresponding to the impact force with respect to the installed vehicle. It is calculated experimentally in advance. When a side collision at a high speed occurs, both the speed change amount V and the energy amount E change beyond a certain limit at an early stage from the time of the collision occurrence, and the value of the collision judgment curve f _x of the collision judgment region Since the value becomes a value, it is possible to accurately determine the occurrence of a side collision in a very short time, as in the first embodiment.

[0032]

As described above, the vehicle side collision determination device of the present invention determines that a side collision occurs only when the speed change amount and the energy amount simultaneously exceed the respective set values, and therefore, the side impact of the door is not detected. When it occurs, the energy amount does not exceed the set value, while when hammering occurs, the speed change amount does not exceed the set value. Therefore, only when the opposite vehicle collides with the side surface of the vehicle, both the amount of change in speed and the amount of energy of the high frequency component exceed the respective set values,
It is possible to accurately distinguish a side impact from a door hit or hammering.

Further, since the respective set values for setting the safety limits of the speed change amount and the energy amount can be set to low levels which do not occur by hammering or door striking, when a side collision occurs. Has
Since the calculated speed change amount and energy amount show a change that exceeds the set value at an early point after the occurrence of a collision, it is possible to distinguish a side collision in an extremely short time and output a collision detection signal, which is effective for the airbag. Can be expanded dynamically.

Further, when it is determined that the calculation result obtained by functionally calculating the energy amount of the high frequency component and the velocity change amount is present in the collision determination area defined by the collision determination curve previously experimentally determined. If the collision detection signal is output, the collision determination curve is obtained comprehensively by combining the amount of change in speed and the impact force, and is calculated in advance experimentally. When occurs, both the speed change amount and the impact force show a change exceeding a certain limit at an early stage from the time of collision, and the calculation result becomes a value existing in the collision determination area of the collision determination curve. It is possible to accurately determine the occurrence of a side collision in an extremely short time.

[Brief description of drawings]

FIG. 1 is a block configuration diagram showing a side collision determination device for a vehicle according to a first exemplary embodiment of the present invention.

FIG. 2 is a diagram showing a side collision determination map in FIG.

FIG. 3 is a spectrum diagram showing energy distribution with respect to frequency when a side collision or the like occurs.

FIG. 4 is a schematic perspective view of an automobile showing an installation position of an acceleration sensor.

FIG. 5 is a block diagram showing a side collision detection device for a vehicle according to a second embodiment of the present invention.

6 is a diagram showing a side collision determination map in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Acceleration sensor 4 Integration circuit (integration means) 5 1st comparator (1st comparison means) 6 Band pass filter (vibration component extraction means) 7 Energy amount calculation means 8 2nd comparator (2nd comparison means) ) 9 AND gate (collision determination means) 15 collision determination means 16 function calculation means 17 third comparator (third comparison means) 18 collision determination means AM automobile (vehicle)

Claims (4)

[Claims] 1. An acceleration sensor (1) which is attached to a side surface portion of a vehicle (AM) and which detects an acceleration applied laterally to the vehicle by converting it into an electric signal and an output electric signal of the acceleration sensor (1). An integrating means (4) for calculating a speed change amount (V) by integrating a certain period of time, and a vibration component extracting means (6) for extracting only a specific high frequency band component from the output electric signal of the acceleration sensor (1). An energy amount calculation means (7) for calculating an energy amount (E) from an output signal of the vibration component extraction means (6), and the energy amount (E) and the speed change amount (V) are formed as coordinate axes. Energy amount (E) in the two-dimensional area
Is large, the speed change amount (V) is small, the speed change amount (V) is large, the energy amount (E) is small, and the energy amount (E) and the speed change amount (V) are both small. The area is determined to be a non-collision area, and collision determination means (15) and (18) are provided that use the remaining area where both the energy amount (E) and the velocity change amount (V) are large as the collision determination area. Characteristic collision determination device. 2. A first comparing means (5) for outputting a signal when the collision judging means (15) judges that the speed change amount (V) calculated by the integrating means (4) is equal to or more than a set value. A second comparing means (8) which outputs a signal when it is determined that the energy amount (E) of the energy amount calculating means (7) is equal to or more than a set value, and both the first and second comparing means ( 5. The side collision determination device for a vehicle according to claim 1, further comprising a collision determination unit (9) that outputs a collision detection signal when signals are simultaneously output from (5) and (8). 3. A velocity change amount (V) and an energy amount are calculated by the collision determination means (18) functionally calculating the outputs of the integration means (4) and the energy amount calculation means (7). (E) is a function calculating means (16) for obtaining a coordinate value on a two-dimensional area having a coordinate axis, and a two-dimensional area having the velocity change amount (V) and the energy amount (E) as a coordinate area is a collision area. The third comparison means (17) outputs a collision detection signal when it is determined that the coordinate value of the calculation result of the function calculation means (16) is large with respect to the collision determination curve that divides into the non-collision region. The side collision determination device for a vehicle according to claim 1, wherein: 4. The high frequency band component extracted by the vibration component extraction means (6) is 800 Hz or higher.
A side collision determination device for any of the described vehicles. Detailed Description of the Invention]