JP2004345545A - Collision object identifying device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a collision object identifying device capable of detecting the kind of the collision object. <P>SOLUTION: The collision object identifying device has a light transmitting/receiving module 2 and a calculating section 3. The light transmitting/receiving module 2 has a measuring section 24 of a bending loss amount for transmitting a light signal from an LD 22 to an optical fiber 1 mounted to a bumper 101 of a vehicle, converts it to an electric signal with an O/E converter 23, and measures the bending loss amount of the optical fiber 1 based on the signal output. The calculating section 3 measures a duration taken for the amount of the bending loss of the optical fiber 1 to vary following deformation of the bumper 101 at a collision time of the vehicle with the object and to arrive from a trigger level to a threshold level. The calculating section 3 uses an object identification table 34a on a ROM 34 for previously storing a correlation of this duration and a travel speed of the vehicle while corresponding the correlation to the object to extract and identify the object adapting with the measured travel speed and the duration at the collision time of the vehicle with the object. The calculating section 3 has a CPU 32 for performing a control program for outputting the object name signal. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a collision object identification device, and particularly to a measurement system of a type in which an optical fiber is mounted on a vehicle bumper, and can detect that a collision object is a human at the time of a vehicle collision, and BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a collision object identification device that can be used as a device for absorbing and mitigating an impact when a human head collides with a hood due to (hood for a vehicle) or a part of a bonnet jumping (up).
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a vehicle collision sensor of a type in which an optical fiber is mounted on a vehicle bumper is known (for example, see Patent Document 1). The vehicle collision sensor includes a leaky optical fiber provided at least partially exposed along a vehicle bumper, a light projecting unit provided at one end of the leaky optical fiber to make light incident thereon, A light receiving unit is provided at the other end of the fiber and receives light.When the vehicle collides, the leaked optical fiber is deformed or broken, thereby increasing the amount of light that propagates through the leaked optical fiber, The collision detection of the vehicle is performed by utilizing the decrease in the amount of light received by the light receiving unit.
[0003]
In addition to a vehicle collision detection, a collision detection sensor using an optical fiber is known (for example, see Patent Document 2). This collision detection sensor is configured such that an optical fiber conduit is continuously folded back over a plurality of columns erected on the ground in the monitoring area, a flexible tube portion is provided in the optical fiber conduit between the columns, and the inside of the optical fiber conduit is provided. When the optical fiber conduit is hit, the curvature of the flexible tube and the optical fiber inside it increases, and the leakage or reflection of light propagating through the optical fiber increases. Is used to detect collisions such as falling rocks.
[0004]
[Patent Document 1]
JP-A-7-190732
[Patent Document 2]
JP 2002-267549 A
[Problems to be solved by the invention]
However, the above-described conventional vehicle collision sensor using an optical fiber mainly detects disconnection or excessive leakage of light propagating through the optical fiber, and thus cannot detect the type of collision object. There was a disadvantage that it was not possible to identify The same applies to the collision detection sensor for falling rocks described above other than the vehicle collision detection.
[0007]
The present invention has been made in view of the above, and an object of the present invention is to provide a collision object identification device capable of detecting a type of a collision object.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, a collision object identifying device according to the present invention according to claim 1 includes a speed sensor for detecting a running speed of a vehicle, and an optical fiber mounted on a bumper of the vehicle in parallel with a longitudinal direction thereof. A bending loss amount measuring means for converting the transmission light into an electric signal and measuring a bending loss amount of the optical fiber based on the electric signal, and the bumper at the time of collision between the vehicle and an object. A time measuring means for measuring a time required for the bending loss to reach from the first level to a second level larger than the first level by changing the bending loss of the optical fiber with the deformation; An object identification table in which a correlation between a traveling speed and the required time is stored in advance in association with the object, and a traveling speed detected by the speed sensor at the time of collision between the vehicle and the object. And object identification means for extracting and identifying the object matching the required time measured by the time measurement means from the object identification table, and outputting the object name signal. Is the gist.
[0009]
Further, the collision object identification device according to the present invention according to claim 2, relative speed detection means for detecting a relative speed with respect to the object, and an optical signal transmitted to an optical fiber attached to the surface of the device, A bending loss amount measuring means for converting the transmission light into an electric signal and measuring the bending loss amount of the optical fiber based on the electric signal, and the optical fiber with the deformation of the surface at the time of collision between the device and the object. A time measuring means for measuring a time required for the bending loss to change from the first level to a second level larger than the first level by changing the bending loss; An object identification table in which the correlation of the object is stored in advance in association with the object, the relative speed detected by the relative speed detecting means at the time of collision between the device and the object, and the relative speed detected by the time measuring means. Are compatible objects in the required time to identify and extract from the object identification table was, and gist that a object identification means for outputting the object name signal.
[0010]
According to a third aspect of the present invention, in the collision object identifying apparatus according to the first or second aspect, an initial value of a bending loss amount is set at a predetermined position of the optical fiber, and the initial value is set at the time of the collision. In other respects, the gist is that an optical fiber bent portion for maintaining is provided.
[0011]
According to a fourth aspect of the present invention, in the collision object identification device according to any one of the first to third aspects, the bending loss amount measuring unit includes a light source that emits the optical signal and a light source that emits the optical signal. And a light receiving unit that converts the light into an electric signal and receives the light. The light source and the light receiving unit are connected to one end of the optical fiber, and a reflection end is formed at the other end of the optical fiber. Is the gist.
[0012]
According to a fifth aspect of the present invention, in the collision object identification device according to any one of the first to third aspects, the bending loss measuring means includes: a light source that emits the optical signal; The light source is connected to one end of the optical fiber, and the light receiving unit is connected to the other end of the optical fiber. I do.
[0013]
According to a sixth aspect of the present invention, in the collision object identifying apparatus according to the fourth or fifth aspect, the bending loss measuring means includes a delay circuit for delaying a signal output from the light receiving unit for a predetermined time; The gist of the present invention is to include a calculator for calculating a bending loss amount of the optical fiber based on a signal output from the delay circuit and a signal output from the light receiving unit.
[0014]
According to a seventh aspect of the present invention, in the collision object identification device according to any one of the first to sixth aspects, the object includes at least a human body, and the object identification unit includes the object. The gist is to identify whether the object is a human body or not.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0016]
(First Embodiment)
The collision object identification device of the present invention utilizes the bending loss of the optical fiber, and pays attention to the point that the deformation speed of the bumper when the object having a different hardness such as a person or a utility pole collides with the vehicle differs. The deformation speed of the bumper is calculated from the time when the bending loss of the optical fiber changes, and is applied to a measurement system for identifying a collision object.
[0017]
FIG. 1 is a perspective view showing the overall configuration of the present embodiment, and FIG. 2 is a block diagram showing the detailed configuration thereof.
[0018]
As shown in FIG. 1, the collision object identification device of the present embodiment includes an optical fiber 1 laid along a longitudinal direction (axle direction) on, for example, a back surface or a front surface of a front bumper 101 of a vehicle 100. An optical transmitting / receiving module 2 connected to one end of the optical fiber 1, an arithmetic processing unit 3 connected to the output side of the optical transmitting / receiving module 2, and an active processing unit connected to the output side of the arithmetic processing unit 3. And a hood control unit 4. A reflection end is provided at the other end of the optical fiber 1 for reflecting incident light transmitted from the one end thereof and emitting the reflected light from the one end through the optical fiber 1 through a path opposite to the incident light. R is formed.
[0019]
In the present embodiment, the optical fiber 1 is, for example, an SM (single mode) type, φ (outer diameter) 125 μm clad diameter glass is coated with UV curable resin to 250 μm, and furthermore, φ (outer diameter) is made of thermoplastic plastic such as polyester elastomer. ) Use a structure coated to 0.9 mm.
[0020]
A bumper 101 is provided between the fixed portions 10 and 10 except for a portion that gives a bending loss of the optical fiber 1 (an optical fiber bending portion for setting an initial value of the bending loss amount and maintaining the initial value except for a collision). For the purpose of preventing disconnection of the optical fiber 1 at the time of collision deformation, a pipe (tubular member) 11 made of a material such as SUS (stainless steel) is provided, and the optical fiber 1 is inserted into the pipe 11. .
[0021]
Further, a kink imparting portion 12 is provided as a bent portion of the optical fiber 1 at a portion where the bending loss of the optical fiber 1 is provided, so that the kink shape of the optical fiber 1 is changed by the deformation of the vehicle bumper 101. When it is not pulled, it keeps its shape and does not deform. For example, as shown in FIG. 3, the optical fiber 1 can be inserted into the kink imparting portion 12, and preferably, a solid cylindrical main body 12 a such as a sponge having no hollow inside and strong contact with the optical fiber 1. A slit formed with a slit 12b having a width that does not cause constraint is used. By providing, for example, one ring-shaped constraint point at one point around the kink providing section 12, the initially provided kink shape can be maintained. In the case where the optical fiber 1 as in the present embodiment is used, the initial value of the kink diameter φ that is previously given to the optical fiber 1 by the kink providing unit 12 is, for example, more than φ30 mm where bending loss does not occur.
[0022]
As shown in FIG. 2, the optical transmitting / receiving module 2 is connected to one end of the optical fiber 1 via a coupler 21, and an LD (laser diode) 22 serving as a light source of light incident on the optical fiber 1 and transmitting the light to the LD. An O / E (Optical / Electrical) converter 23 forming a light receiving unit (photodetector) for receiving light via the fiber 1 and a bending loss measuring unit 24 connected to the voltage output side of the O / E 23 And In the optical transmitting / receiving module 2, light of a predetermined frequency that is incident from one end of the optical fiber 1 from the LD 22 via the coupler 21 propagates through the optical fiber 1, is reflected at the reflection end R on the other end, and is reversed. The light returns to one end of the optical fiber 1 via the path, is emitted, and is received by the PD 23 via the coupler 21.
[0023]
The bending loss measuring section 24 converts the voltage output from the O / E 23 from an analog signal to a digital signal into an A / D converter 25, and converts the digital signal of the voltage output from the A / D converter 25 into a predetermined time ( 26, a plurality of delay elements 26... 26 which are delayed and output by a predetermined number of samples, a voltage output P ₀ (a voltage output level that is a predetermined time earlier than the present time) and a voltage output P ₀ after a certain time delay outputted by the delay elements 26. Calculation for calculating the bending loss amount dB (dB = −10 · log ₁₀ P / P ₀ ) of the optical fiber 1 based on the undelayed voltage output P (current voltage output level) from the A / D converter 25. And outputs the calculated bending loss amount dB to the calculation processing unit 3. The bending loss measuring section 24 may be integrally formed in the arithmetic processing section 3.
[0024]
As shown in FIG. 2, the arithmetic processing section 3 includes an input I / F (interface) 31 connected to the bending loss measuring section 24 and a CPU 32 for controlling the entire apparatus according to a preset control program (see below). A RAM 33 for storing control data, a ROM 34 for storing a control program and an object identification table 34a (see below), a timer 35 for measuring a set time, generating an interrupt signal INT and outputting it to the CPU 32, A pulse counter 36 which is connected to a PD (photodiode) 111 of a vehicle speed encoder (rotary encoder) 110 which is a speed sensor mounted on an axle or the like of the vehicle 100 and counts output pulses thereof and outputs it as a vehicle speed v; And an output I / F (interface) 37 connected to the section 4.
[0025]
As shown in FIG. 4, the active hood control unit 4 is electrically connected to a flip-up mechanism (actuator) 121 that flips up a vehicle hood (bonnet) 120 with its front side as a fulcrum SP and opens the rear side. A control signal S1 for controlling the opening / closing state is output to the flip-up mechanism 121. The vehicle hood 120 has a structure in which the flip-up mechanism does not operate during normal times such as inspection of an engine room and the front side is opened with the rear side as a fulcrum.
[0026]
Next, the measurement principle of the present embodiment will be described.
[0027]
First, consider a case where the vehicle 100 collides as shown in FIG. 5B from a state before the vehicle 100 collides with the obstacle (collision target) OB as shown in FIG. In this case, when the obstacle OB collides with the vehicle bumper 101 and the optical fiber 1 is pulled due to the deformation of the bumper 101, the initial kink diameter φ of the optical fiber 1 provided by the kink providing unit 12 becomes smaller than before the collision. Become smaller. As described above, when the radius of curvature given to the optical fiber 1 becomes small, the angle between the interface between the core and the clad of the optical fiber 1 and the propagation direction of light changes, and light is radiated out of the optical fiber 1 and transmitted at that portion. Light leakage occurs. This is called bending loss (or radiation loss due to bending) of the optical fiber 1.
[0028]
Due to the bending loss of the optical fiber 1, the voltage output corresponding to the light intensity converted by the O / E converter 23 forming the light receiving section for receiving the transmitted light is reduced. Thus, the voltage output level of the current is P, a predetermined time before the voltage output level bending resulting in loss measuring unit 24 bend when the P ₀ loss dB (dB = -10 · log amount Fc ₁₀ P / P ₀ ) is input to the processing unit 32, and the bending loss dB is the time required from the first level (trigger level) preset by the processing unit 32 to the second level (threshold). By measuring, the hardness of the collision object can be known based on the time.
[0029]
FIG. 6 compares the rate of increase in the amount of bending loss of the optical fiber 1 between a case where the collision object colliding with the vehicle 100 is relatively hard and a case where the collision object is soft. In FIG. 5, the horizontal axis represents a common logarithmic value of time t (log (t)), and the vertical axis represents a common logarithmic value (log) of the bending loss amount dB (dB = −10 · log ₁₀ P / P ₀ ) of the optical fiber 1. (DB)).
[0030]
In FIG. 5, dB _ref1 is a bending loss amount corresponding to a preset first level (hereinafter, “trigger level”), and dB _ref2 is a preset second level (hereinafter, “threshold” or “threshold”). Hold)), t1 is the time when the bending loss dB goes down and reaches the trigger level dB _ref1 (hereinafter, "trigger time"), and t2 is the bending loss dB goes down further. The time when the threshold V _ref2 is reached (hereinafter, “threshold time”) and Δt indicate the required time (Δt = t2−t1) required from the trigger time t1 to the threshold time t2.
[0031]
As shown in FIG. 6, the value of the required time Δt differs depending on the hardness of the collision object, and the value of Δt decreases as the collision object becomes harder. Therefore, the required time Δt when the bending loss dB reaches a predetermined trigger level dB _ref1 to a threshold dB _{ref2 is} measured by the arithmetic processing unit 3, and the hardness of the collision object is determined based on the time Δt. Can be.
[0032]
Further, the value of Δt decreases as the collision velocity v increases. Therefore, the vehicle traveling speed v at the time of collision measured by the vehicle speed rotary encoder 110 is also taken into the arithmetic processing unit 3 so that Δt set in advance according to the collision speed v can be used as a criterion for determining the hardness of the collision object. Can be used as
[0033]
FIG. 7 shows the results of an example in which the value of the required time Δt was measured while changing the vehicle speed v at the time of collision in the range of 40 to 60 km / h (h).
[0034]
In this embodiment, a human body model, a utility pole 1 and a utility pole 2 were used as collision objects having different hardnesses. The LD 22 (light source) of the optical transmitting / receiving module 2 was an LD (laser diode) having a working wavelength of 1.55 μm, and the light receiving unit was an O / E converter (response frequency of 20 MHz). The optical fiber 1 is a 1.3SM (single mode) type having an operating wavelength of 1.55 μm, an MFD (mode field diameter) of 9.0 μm (at 1.3 μm), and a λc (cutoff wavelength) of 1.20 μm. used.
[0035]
Under the above conditions, the trigger start time (trigger time) t1 is when the bending loss dB is 1.5 dB down, and the threshold time t2 is measured when the bending loss dB is 6 dB down, and Δt is determined (Δt = t2). -T1).
[0036]
As a result, as shown in FIG. 6, when the object is a human body model, Δt = 6.5 ms when the vehicle speed v is 40 km / h, Δt = 5.2 ms when the vehicle speed v is 50 km / h, and Δt = 4 when the vehicle speed v is 60 km / h. 0.3 ms. On the other hand, when the object is the electric pole 1, Δt = 1.19 ms when the vehicle speed v is 40 km / h, Δt = 0.95 ms when the vehicle speed v is 50 km / h, and Δt = 0.79 ms when the vehicle speed v is 60 km / h. Further, when the object is the electric pole 2, Δt = 1.79 ms when the vehicle speed v is 40 km / h, Δt = 1.43 ms when the vehicle speed v is 50 km / h, and Δt = 1.19 ms when the vehicle speed v is 60 km / h.
[0037]
From the above results, when the vehicle speed v is 40 to 60 km / h, Δt is equal to or greater than 4.3 ms in the human body model, and Δt is equal to or less than 1.79 ms in the electric poles 1 and 2. Therefore, the average value of both data is Δt. = 10 ms (for example, (4.3 + 1.79) / 2 = 3 ms, etc.) can be used as a threshold (Δt setting time) as a criterion for determining whether the object is a hard object such as a human body or another electric pole. Was. In the above embodiment, two electric poles having different outer diameters are described as examples of hard objects other than humans as objects. However, the present invention is not limited to this, and the same applies to outer walls and guardrails of concrete structures. is there.
[0038]
Accordingly, the correlation between the required time Δt and the vehicle speed v when the bending loss dB reaches the trigger level dB _ref1 to the threshold dB _ref2 in association with the types of collision objects having different hardnesses is used as the object identification table 34a. If stored and set in advance in the ROM 34 of the arithmetic processing unit 3, the vehicle running speed v and the required time Δt at the time of the collision are measured and taken into the arithmetic processing unit 3 to refer to the object identification table 34a and perform the collision. Things can be identified.
[0039]
Next, the operation of the collision object identification device according to the present embodiment will be described with reference to FIG. FIG. 8 is a control flowchart schematically illustrating a processing procedure of a control program executed by the CPU 32 of the arithmetic processing unit 3. This control program is stored in the ROM 34 of the arithmetic processing unit 3.
[0040]
8, first, the CPU 32 of the arithmetic processing unit 3 executes the control program in the ROM 34 to start the timer 35 (step S10), and inputs the vehicle speed v via the pulse counter 36 (step S20). ). Then, it is determined whether or not the input vehicle speed v satisfies a condition of 40 km / h ≦ v ≦ 60 km / h (step S 30). Is input via the input I / F 31 (step S40).
[0041]
Next, the CPU 32 determines whether or not the input bending loss amount dB satisfies a condition of a trigger level dB _ref1 ≦ dB (step S50). When it is determined that the condition is satisfied, the timer at that time is determined. The time of 35 is input as the trigger time t1 (step S60).
[0042]
Next, the CPU 32 inputs the bending loss amount dB output from the arithmetic unit 27 via the input I / F 31 (step S70), and determines whether or not the input bending loss amount dB satisfies the condition of threshold dB _ref2 ≦ dB. Is determined (step S80), and when it is determined that this condition is satisfied, the time measured by the timer 35 at that time is input as the threshold time t2 (step S90).
[0043]
Next, the CPU 32 calculates the required time Δt = t2−t1 from the input trigger time t1 and threshold time t2 by the timer 35 (step S100), and inputs the vehicle speed v via the pulse counter 36 (step S100). S110). Then, with reference to the object identification table 34a, an object matching the vehicle speed v and the required time Δt is extracted (step S120), and it is determined whether or not the extracted object is a human body (step S130). If it is determined that the current state is “1”, a flip-up signal is output to the active hood control device 4 via the output I / F 37 (step S140). As a result, the vehicle hood 120 jumps up, and it becomes possible to absorb and reduce the impact received by the human head or the like.
[0044]
FIGS. 9 (a) to 9 (d) show that, when a collision object colliding with a vehicle is a human, the hood for a vehicle is flipped up to absorb and reduce a shock when a human head collides with an engine or the like. Is schematically shown. 9A is a state before the collision between the human body as the object OB and the vehicle 100, and FIG. 9B is a state where the vehicle hood 120 is opened and jumped immediately after the collision with the human body as the object OB. FIG. 9C shows a state in which the vehicle hood 120 is closed from an open state, and FIG. 9D shows a state in which the vehicle hood 120 is completely closed.
[0045]
Therefore, according to the present embodiment, by utilizing the fact that the deformation speed of the bumper is different depending on the hardness of the collision object, and detecting the transmission loss increasing speed due to the bending loss due to the deformation of the bumper, the type of the collision object is detected. Can be detected. In particular, it has become possible to detect whether the colliding object is a person or another object having a different hardness. Thus, for example, only when it is detected that the collision object is a human body, the vehicle hood is flipped up, so that the impact when the human head collides with the bonnet can be absorbed and alleviated, thereby protecting the vehicle.
[0046]
(Second embodiment)
FIG. 10 is a diagram illustrating a configuration of a collision object identification device according to the second embodiment of the present invention. In the present embodiment, the overall configuration of the collision object identification device has the same configuration as that of FIG. 2 (optical fiber 1, optical transmission / reception module 2 (LD 22, O / E converter 23, and bending loss measuring unit 24), The reflection of the optical fiber 1 in the arithmetic processing unit 3 (input I / F 31, CPU 32, RAM 33, ROM 34, object identification table 34a, timer 35, pulse counter 36, and output I / F 37) and the active hood control unit 4) The end R and the coupler 21 of the optical transceiver module 2 are omitted, the LD 22 of the optical transceiver module 2 is connected to one end of the optical fiber 1, and the PD 23 of the optical transceiver module 2 is connected to the other end of the optical fiber. Only different things.
[0047]
According to this, in addition to the same effects as described above, the reflection end R of the optical fiber 1 and the coupler 21 of the optical transmission / reception module 2 are not required, so that there is an advantage that the device configuration can be further simplified.
[0048]
(Third embodiment)
FIG. 11 is a diagram showing a configuration of a collision object identification device according to the third embodiment of the present invention. In the present embodiment, the overall configuration of the collision object identification device has the same configuration as that of FIG. 2 (optical fiber 1, optical transmission / reception module 2 (LD 22, O / E converter 23, and bending loss measuring unit 24), The arithmetic processing unit 3 (input I / F 31, CPU 32, RAM 33, ROM 34, object identification table 34a, timer 35, pulse counter 36, and output I / F 37) and the active hood control unit 4) The optical fiber 1 is connected to the coupler 21, and a kink providing portion 12 is provided as a bent portion of the optical fiber at a portion where the bending loss of the optical fiber 1 is provided, and a reflection is provided between the kink providing portion 12 and the pipe 11. A connector 53 having an end R is provided. Further, this connector 53 is connected to a wire 51 made of metal, aramid fiber, or FRP having a very low linear expansion coefficient, and the wire 51 laid in the pipe 11 is fixed to a fixed end K provided at the other end. I have.
According to this, in addition to the same effects as described above, the optical fiber 1 does not need to be affected by damage due to the deformation of the bumper 101.
[0049]
In the above embodiment, the case where the speed sensor for detecting the traveling speed of the vehicle is used has been described. However, the present invention is not limited to such a speed sensor, and a laser radar or an ultra Similar effects can be obtained when using a relative velocity detecting means such as an acoustic radar. In particular, when the relative velocity detecting means is used, the collision velocity can be detected more accurately even when the target is moving, so that the collision object identification accuracy can be further improved.
[0050]
Further, in the above-described embodiment, a case has been described in which an apparatus for identifying an object that collides with a vehicle using an optical fiber provided in a bumper of the vehicle is used. However, the present invention is limited to such vehicle collision detection. Instead, any measurement sensor can be applied as long as it is a device that needs to identify whether a collision object is a person or something else.
[0051]
In the above embodiment, the optical fiber is inserted into the pipe 11, but the present invention is not limited to this, and the pipe 11 may not be provided. Further, in the above-described embodiment, the kink providing unit 12 is provided at a portion that gives a bending loss to the optical fiber 1, but the present invention is not limited to this, and the kink providing unit 12 may not be provided. .
[0052]
It should be noted that the present invention is not limited to the exemplary embodiment described above as a representative, and those skilled in the art may use various modes based on the description in the claims without departing from the spirit of the invention. Can be modified and changed. These modifications and variations also belong to the scope of the present invention.
[0053]
【The invention's effect】
According to the first aspect of the present invention, the amount of bending loss of the optical fiber due to the deformation of the bumper at the time of collision between the object and the vehicle is measured, and the amount of bending loss reaches from the first level to the second level. Since an object matching the required time and the traveling speed of the vehicle is identified based on the object identification table, the object colliding with the vehicle can be identified.
[0054]
According to the present invention, since the collision speed can be detected more accurately even when the target object is moving by measuring the relative speed at the time of collision with the target object, The identification accuracy can be further improved.
[0055]
According to the third aspect of the present invention, since the bent portion of the optical fiber is provided so that the initial value of the bending loss of the optical fiber is maintained except at the time of collision, the bending loss can be measured with higher accuracy. It becomes possible.
[0056]
According to the present invention, the optical signal from the light source is reflected by the reflection end of the optical fiber and returned, and the transmitted light is received by the light receiving portion. , The bending loss amount becomes large, whereby the measurement accuracy of the bending loss amount can be further improved. Further, since the light source and the light receiving section can be arranged at one end of the optical fiber, the layout of the device is improved.
[0057]
According to the fifth aspect of the present invention, an optical signal from a light source is made incident from one end of an optical fiber, and transmission light emitted from the other end is received by a light receiving section. Since an optical component such as a coupler for optically coupling the light source and the light receiving unit on the side is not required, the device configuration can be further simplified.
[0058]
According to the present invention, the bending loss amount of the optical fiber is measured by the arithmetic unit from the signal output before the delay with respect to the signal output after the predetermined time delay via the delay circuit. The bending loss amount can be measured with high accuracy and with a simpler configuration without being substantially affected by the drift of the voltage output.
[0059]
According to the present invention, it is possible to identify whether or not the target object is a human body, so that in the case of a human body, for example, it is possible to control the vehicle hood to jump up, The impact when the part collides with the hood can be absorbed and reduced.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an overall configuration of a collision object identification device according to a first embodiment of the present invention.
FIG. 2 is a block diagram illustrating a detailed configuration of a collision object identification device.
FIG. 3 is a perspective view showing a schematic configuration of a kink providing section (bent section of an optical fiber).
FIG. 4 is a side view illustrating a vehicle hood and a flip-up mechanism thereof.
5A and 5B are diagrams illustrating deformation of a bumper and expansion strain of an optical fiber before and after a collision, where FIG. 5A is a top view showing a state before the collision, and FIG. 5B is a top view showing a state after the collision. .
FIG. 6 is a graph showing the relationship between the amount of bending loss and time when a collision object is hard and soft.
FIG. 7 is a diagram illustrating a correspondence relationship between an object, a collision speed, and Δt based on experimental results of the example.
FIG. 8 is a schematic flowchart illustrating the overall operation of the collision object identification device.
FIGS. 9A to 9D are diagrams illustrating a state in which a vehicle hood is flipped up when a collision object is a human body.
FIG. 10 is a block diagram illustrating a configuration of a collision object identification device according to a second embodiment of the present invention.
FIG. 11 is a block diagram illustrating a configuration of a collision object identification device according to a third embodiment of the present invention.
[Explanation of symbols]
1 Optical fiber 1a Kink
2 Optical transmitting / receiving module 3 Arithmetic processing unit 4 Active hood control unit 11 Pipe 12 Kink imparting unit (bending optical fiber)
12a body 12b slit 21 coupler 22 LD (laser diode)
23 PD (photodiode)
24 Bending loss measuring unit 25 A / D converter 26 Delay element 27 Operation unit 31 Input I / F
32 CPU
33 RAM
34 ROM
34a Object identification table 35 Timer 36 Pulse counter 37 Output I / F (interface)
100 vehicle 101 bumper 110 vehicle speed encoder 111 PD (photodiode)
120 Vehicle hood 121 Bouncing mechanism OB Object

Claims (7)

A speed sensor for detecting a running speed of the vehicle,
An optical signal is transmitted through an optical fiber attached to the bumper of the vehicle in parallel with its longitudinal direction, the transmitted light is converted into an electric signal, and a bending loss amount of the optical fiber is measured based on the electric signal. Measuring means;
When the bending loss of the optical fiber changes due to the deformation of the bumper at the time of collision between the vehicle and the object, the bending loss reaches the second level larger than the first level from the first level. A time measuring means for measuring a required time,
An object identification table that stores a correlation between the traveling speed and the required time in advance in association with the object,
At the time of collision between the vehicle and the object, the traveling speed detected by the speed sensor and the object that matches the required time measured by the time measuring unit are extracted from the object identification table. And a target identifying means for identifying and outputting the target name signal. A relative speed detecting means for detecting a relative speed with respect to the object,
Bending loss measuring means for transmitting an optical signal into an optical fiber attached to the surface of the device, converting the transmitted light into an electric signal and measuring the bending loss of the optical fiber based on the electric signal,
When the bending loss of the optical fiber changes due to the deformation of the surface at the time of collision between the device and the object, the bending loss reaches the second level larger than the first level from the first level. A time measuring means for measuring a required time,
An object identification table that stores a correlation between the relative speed and the required time in advance in association with the object,
At the time of collision between the device and the object, the relative speed detected by the relative speed detecting means, and an object that matches the required time measured by the time measuring means is extracted from the object identification table. And a target identifying means for identifying and outputting the target name signal. 3. The collision according to claim 1, further comprising an optical fiber bending portion for setting an initial value of the bending loss amount at a predetermined position of the optical fiber and maintaining the initial value except at the time of the collision. Object identification device. The bending loss measuring means has a light source that emits the optical signal, and a light receiving unit that receives the light signal after converting the optical signal into an electric signal, and the light source and the light receiving unit are provided at one end of the optical fiber. 4. The collision object identification device according to claim 1, wherein a reflection end is formed on the other end of the optical fiber. The bending loss measuring means has a light source that emits the optical signal, and a light receiving unit that receives the optical signal after converting the optical signal into an electric signal, the light source is connected to one end of the optical fiber, The collision object identification device according to any one of claims 1 to 3, wherein the light receiving unit is connected to the other end of the optical fiber. The bending loss amount measuring means includes a delay circuit for delaying a signal output from the light receiving unit for a predetermined time, and a bending loss amount of the optical fiber based on a signal output from the delay circuit and a signal output from the light receiving unit. The collision object identification device according to claim 4, further comprising a computing unit that performs a computation. The collision object identification according to any one of claims 1 to 6, wherein the object includes at least a human body, and the object identification unit identifies whether the object is a human body. apparatus.

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