JP2008203240A - Electromagnetic impedance sensor and passenger protection system using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electromagnetic impedance sensor which realizes variation reduction of a detection accuracy in each part of direction of surface parallel to an aperture surface of a detection coil. <P>SOLUTION: In the detection coil 4 of the electromagnetic impedance sensor, a plurality of portion coils 5, 6 are adjoined mutually and arranged in an arrangement direction by extending substantially using a single wire 10. Thereby, a magnetic flux density variation can be reduced and the detection accuracy is enhanced. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an improvement in an electromagnetic impedance sensor for detecting a detection target made of a conductive material or a soft magnetic material, and an occupant protection system for a vehicle using the same.

An electromagnetic impedance sensor for detecting a detection target by detecting a change in impedance of a coil (generally also called a search coil) due to the proximity of the detection target made of a conductor or a soft magnetic material is described in, for example, Patent Document 1 below. Has been.
JP 09-175319 A

  However, the conventional electromagnetic impedance sensor has a problem that the detection sensitivity varies greatly depending on the position of the detection target when the detection space (the space that needs to be detected) is relatively large compared to the detection target. I understood.

  This is because the detection sensitivity fluctuates depending on the detection target position with respect to the coil arrangement surface arranged facing the detection space so as to cover the detection space. This is because the magnetic flux density in each part of the detection space facing the coil placement surface varies in the plane direction parallel to the coil placement surface.

  The present invention has been made in view of the above problems, and provides an electromagnetic impedance sensor that realizes a reduction in variation in detection accuracy in each part of the surface direction parallel to the opening surface of the detection coil, and an occupant protection system using the electromagnetic impedance sensor. That is the purpose.

  The present invention that solves the above-described problems includes a detection coil having a coil placement surface facing a detection region where non-contact detection of a conductive or soft magnetic detection target is to be performed, and supplying AC power to the detection coil An electromagnetic impedance sensor comprising: a detection circuit unit configured to detect the detection target by detecting a change in electromagnetic impedance of the detection coil by the detection target; wherein the detection coil is disposed on the coil placement surface and has a predetermined arrangement direction. It comprises substantially one conductor wire constituting a plurality of partial coils arranged in sequence. That is, by forming a plurality of partial coils with substantially one conductor wire (for example, twisting the coils into an 8-shape), it is possible to reduce the above-described variation in magnetic flux density and improve detection accuracy. It becomes possible.

  In the electromagnetic impedance sensor of the present invention, a large number of partial coils are dispersedly arranged in a predetermined arrangement direction facing the detection surface, and these partial coils are connected in series. As a result, the AC current feeding circuit and the coil impedance detection circuit for these partial coils can be shared, and the circuit can be simplified.

  In a preferred aspect, in adjacent partial coils of the plurality of partial coils, adjacent sides that are sides of the partial coils that are adjacent to each other and extend in substantially the same direction are energized in the same direction.

  In the present invention, among the conductor wires of the partial coils that are adjacent to each other in the arrangement direction, the adjacent sides that are arranged in parallel and close to each other are energized in the same direction. In other words, any two partial coils adjacent to each other in the arrangement direction generate magnetic fluxes in opposite directions. In this way, since the magnetic fluxes created by the adjacent partial coils strengthen each other, variations in detection sensitivity of each part in the detection surface parallel to the coil placement surface are detected by one large coil. This can be reduced as compared with the case of doing so.

  Note that the term “substantially parallel” as used above does not require that each adjacent side is arranged in parallel or adjacent to each other in parallel from the start end to the end, for example, partially at a predetermined small crossing angle. The distance between two adjacent sides adjacent to each other may not be constant, and each adjacent side may be a curve.

  In a preferred aspect, the detection coil is configured by successively connecting an arrangement direction side extending substantially parallel to the arrangement direction and a right direction side extending substantially perpendicular to the arrangement direction. A plurality of partial coils are formed by extending in one direction and further connecting the side in the arrangement direction and the side in the right-angle direction in the other direction and extending in the other direction in the arrangement direction. Alternatively, the detection coil includes an incomplete winding turn that is a part of a plurality of partial coils and an incomplete winding turn that is a part of the plurality of partial coils. The plurality of partial coils are configured by a return coil portion that is sequentially connected over the plurality of partial coils. In this way, the manufacturing process of the detection coil can be simplified and the number of connection points can be reduced despite the arrangement of a large number of partial coils on the detection surface, so that the reliability can be improved.

  In a preferred aspect, the detection coil arranges the partial coils in the arrangement direction, and then arranges the partial coils in the arrangement direction at positions adjacent to the arrangement direction at right angles. In this way, since a large number of partial coils can be arranged in a two-dimensional direction by a simple winding operation, a detection coil with a small sensitivity variation can be manufactured with a small work load.

  In other words, according to this aspect, the detection coil formed by two-dimensionally arranging a plurality of partial coils adjacent to each other in the same manner as described above in the arrangement direction and the direction perpendicular thereto is substantially one. Since it is composed of conductor wires and the current directions in all the adjacent sides described above can be made uniform, a detection coil with high sensitivity and small sensitivity variation can be configured.

  By the way, there is US law FMVSS 214 as a regulation regarding a case where an object collides with a vehicle door. This regulation stipulates the pole side collision. Specifically, this regulation stipulates that the diameter of the cylindrical pole is 10 inches (about 255 mm) and the collision speed is 20 mph (about 32 km / h). Further, from the viewpoint of occupant protection, the time from when an object collides with the outer plate of the vehicle door to when the collision is detected is required to be within 10 msec. When 10 msec has elapsed since the pole collided with the outer plate, the width in the horizontal direction of the vehicle in the deformation region of the outer plate, that is, the width of the dent recessed by the pole becomes 240 mm.

  And when the electromagnetic impedance sensor of this invention is applied to the collision sensor of a vehicle, the inventors of this invention are the vehicle horizontal direction width | variety of each partial coil which forms a detection coil, The vehicle door which is a detection object It was confirmed that it should be less than the width in the vehicle horizontal direction of the deformation region of the outer plate. Specifically, by setting the vehicle horizontal width of the partial coil to be equal to or less than the vehicle horizontal width of the deformation region of the outer plate, the sensitivity in a large area of the detection coil is improved compared to the case where the partial coil is larger than the width. It can be stabilized. That is, the impedance change rate can be stabilized. Furthermore, by making the vehicle horizontal width of the partial coil equal to or smaller than the vehicle horizontal width of the deformation region of the outer plate, the detection sensitivity can be increased even when compared with one large coil.

  From the above, in order to detect a collision within 10 msec under the side collision condition defined in the US law, the following is preferable. That is, in a preferred aspect of the present invention, the detection target is an outer plate of a vehicle door, and the detection coil is an inner plate that is spaced apart from the outer plate on the vehicle interior side facing the outer plate. Among these, the vehicle horizontal direction width of each of the partial coils is attached to the surface on the outer plate side, and is 240 mm or less.

  Accordingly, it is possible to detect that the object (the pole) has collided within 10 msec from the collision, satisfying the legal conditions. Furthermore, in order to detect that an object (the pole) has collided within 6 msec from the collision, the width in the vehicle horizontal direction of the partial coil may be within 200 mm.

  Moreover, in the above, the case where it grasped | ascertained as an electromagnetic impedance sensor of this invention was demonstrated. In addition, a vehicle occupant protection system may be configured using the electromagnetic impedance sensor of the present invention.

  That is, the occupant protection system of the present invention includes the above-described electromagnetic impedance sensor, a collision determination unit that determines a collision between the vehicle and an object other than the vehicle based on the output of the electromagnetic impedance sensor, and the determination of the collision determination unit And an occupant protection device that operates based on the above. According to the present invention, it is possible to reliably use the signal as an operation signal of the occupant protection device while exhibiting the effect of the electromagnetic impedance sensor.

  A preferred embodiment of an eddy current type conductor detection sensor using the electromagnetic impedance sensor of the present invention will be described below.

(Embodiment 1)
(overall structure)
The circuit configuration of the electromagnetic impedance sensor of Embodiment 1 is shown in FIG.

  In FIG. 1, 2 is a detection circuit unit, and 4 is a detection coil. The detection circuit unit 2 supplies a high-frequency current of several hundred kHz to several MHz to the detection coil 4 and detects a change in the supply current accompanying the impedance change of the detection coil 4. The coil opening surface of the detection coil 4 is arranged to face a detection space (not shown).

  The change in the feeding current can be detected, for example, by detecting the voltage drop of the current detection resistor. In addition, the Colpitts circuit is utilized by using the inductance of the detection coil 4 and the capacitance of the capacitor connected to the detection coil 4. Such a self-excited oscillation circuit may be configured to detect the frequency change. In addition, a capacitor may be connected in series or in parallel with the detection coil 4 in order to increase the voltage change or current change of the detection coil 4. In addition to the detection coil 4, a drive coil for forming an AC electromagnetic field may be provided in the detection space, and the detection coil 4 may detect an AC voltage electromagnetically induced by the AC electromagnetic field.

  A change in the electromagnetic impedance of the detection coil 4 is detected by detecting and smoothing the detected AC voltage to determine its magnitude or detecting its frequency. When the conductor approaches the detection coil 4, the electromagnetic impedance changes (decreases) due to eddy current loss, and when the soft magnetic material approaches the detection coil 4, the electromagnetic impedance also changes (increases).

  The detection circuit unit 2 itself of this type of electromagnetic impedance sensor can be the same as the conventional one. Since this embodiment does not feature the circuit configuration of the detection circuit unit 2, further description of the detection circuit unit 2 is omitted.

(Detection coil 4)
The configuration of the detection coil will be described with reference to FIG.

  In FIG. 2, reference numeral 1 denotes an insulation-coated conductor wire constituting the detection coil 4, 20 denotes a start end (start point) of the conductor wire 1, and 30 denotes an end point (end point) of the conductor wire 1.

  The conductor wire 1 has a right side 11, 13, 15, 17, 19, 21, 23, 25 extending from the start end 20 in a direction substantially perpendicular to the arrangement direction, and an arrangement direction side extending substantially parallel to the arrangement direction. 12, 14, 16, 18, 20, 22, 24, and 26 are alternately formed. Due to the extension of the conductor wire 1, the terminal end 30 of the conductor wire 1 is returned to substantially the same position as the starting end 20. i indicates the direction of current in a half-wave period.

  As a result, the two-turn partial coils 5 and 6 are arranged adjacent to each other in the arrangement direction. The partial coil 5 is constituted by right-angle direction sides 11, 19, 13, 21 and arrangement direction sides 12, 20, 18, 26, and the partial coil 6 is constituted by right-angle direction sides 15, 23, 17, 25, and arrangement direction. The sides 16, 24, 14 and 22 are configured.

  Since the partial coils 5 and 6 are adjacent to each other, the right-side direction sides 13, 21, 17, and 25 are substantially overlapped or adjacent to each other and arranged substantially in parallel. For this reason, these right-angle direction sides 13, 21, 17, and 25 are also called adjacent sides. In this embodiment, since a substantially rectangular detection coil having a length L and a width W is constituted by a single conductor wire 1, four conductor wires that are parallel to the central portion and have the same current direction can be arranged. It has been a problem in the past. It is possible to suppress a drop in sensitivity at the center of the coil opening surface, that is, on the extension line of the coil axis (also referred to as the coil center).

  In addition, the drop of the sensitivity in the coil central part is because the magnetic flux density at this part is smaller than the peripheral part. More specifically, the electromagnetic field formed by the detection coil 4 is, strictly speaking, the vector sum of the electromagnetic fields formed by each side (each conductor line). The electromagnetic field created around the conductor wire is naturally strong in the vicinity of the conductor wire and becomes smaller as the distance from the conductor wire increases. In addition, since the detection surface assumed that the detection target exists is a predetermined distance away from the coil opening surface in the coil axis direction, the electromagnetic field formed by each side on the detection surface is as much as the coil opening surface on the coil axis. It does not decline. However, as the diameter of the detection coil 4 increases, it is a fact that the sensitivity decrease becomes remarkable. This problem is effectively improved by the configuration of FIG. Further, the figure 8 coil shown in FIG. 2 has an advantage that the winding operation is easy.

(Modification)
Although FIG. 2 shows an example of two turns, it is natural that the number of turns is free.

(Modification)
In FIG. 2, the adjacent sides 13 and 21 and the adjacent sides 17 and 25 intersect at a predetermined angle. In this way, it is possible to suppress an increase in the strength of the electromagnetic field in the vicinity of the adjacent sides 13, 21, 17, 25 having a larger total current amount than other parts.

(Embodiment 2)
Another embodiment of the detection coil 4 will be described with reference to FIG. The detection coil 4 of this embodiment is obtained by adding partial coils 7 to 10 to the detection coil 4 of the first embodiment shown in FIG. The partial coil 7 is added in the arrangement direction following the partial coil 6. The partial coil 8 is disposed adjacent to the partial coil 5 in the second arrangement direction. The partial coil 9 is disposed adjacent to the partial coil 6 in the second arrangement direction. The partial coil 10 is disposed adjacent to the partial coil 5 in the second arrangement direction. The partial coils 8 to 10 are arranged substantially line symmetrically with respect to the partial coils 5 to 8. Each of the partial coils 5 to 10 constituting the detection coil 4 is constituted by one conductor wire 1.

  More specifically, in the detection coil 4, after the three partial coils 5 to 7 are arranged in the arrangement direction, the three partial coils 8 to 10 are arranged in the arrangement direction at positions adjacent to the arrangement direction at right angles. Is. In this way, it is possible to form a substantially rectangular detection coil having a length L and a width 2W by using a single conductor wire 1 to form six partial coils 5 to 10 that are adjacent to each other and that have the same current direction on the adjacent sides. Therefore, the sensitivity drop can be further suppressed.

(Embodiment 3)
Another embodiment of the detection coil 4 will be described with reference to FIG. The detection coil 4 of this embodiment is configured by extending the detection coil 4 shown in the second embodiment shown in FIG. In this arrangement method, the same effect as that of the second embodiment can be obtained.

(Embodiment 4)
Another embodiment of the detection coil 4 will be described with reference to FIG. The detection coil 4 of this embodiment is formed by winding each of the partial coils 5 to 10 arranged in the arrangement direction and the right-angle direction so as to proceed to the next partial coil after winding the conductor wire 1 many times. It is a feature that the conductor wire 1 is bent at a right angle when going from one partial coil to the next partial coil, whereby the current directions of adjacent sides of each partial coil can be matched.

(Embodiment 5)
Another embodiment of the detection coil 4 will be described with reference to FIG. The detection coil 4 of this embodiment has the current direction of each adjacent side matched by a single conductor wire 1 so that each partial coil has a triangular coil opening surface. Can play.

(Modification)
In FIG. 2, the adjacent sides 13, 21, 17, 25 can be widely distributed in the arrangement direction in order to suppress an increase in the electromagnetic field in the vicinity of the adjacent sides 13, 21, 17, 25. The width in the arrangement direction in which the adjacent sides 13, 21, 17, 25 are arranged can be determined as appropriate.

(Modification)
If the traveling direction of the conductor wire 1 is substantially the same as in the above embodiments, the shape of the coil opening surface of each partial coil can be a trapezoid, a polygon, a substantially circle, or the like. In the case of a substantially circular shape or the like, adjacent pieces of two partial coils adjacent to each other do not need to be disposed adjacent to each other or overlapped with each other, and can partially overlap or cross each other.

(Embodiment 6)
The case where the electromagnetic impedance sensor of the present invention is applied to a vehicle side collision detection device will be described. FIG. 7 is a horizontal sectional view showing the inside of the vehicle door 1. As shown in FIG. 7, the vehicle door 100 includes an outer plate 101 located on the outer side of the vehicle and an inner plate 102 that is spaced apart from the outer plate 101 on the vehicle interior side facing the outer plate 101. And the detection coil 4 of this invention is attached to the surface at the side of the outer plate 101 among the inner plates 102.

  Here, as a condition in the pole side collision defined in the US method FMVSS 214, a case where a cylindrical pole having a diameter of 10 inches (about 255 mm) is caused to collide at a collision speed of 20 mph (about 32 km / h), from the collision. The impedance change rate of the detection coil 4 when 10 msec elapsed was analyzed.

  First, when the pole collides at the collision speed, the deformed state of the outer plate 101 when 10 msec has elapsed since the collision is shown by a broken line in FIG. As shown by the broken line in FIG. 7, the outer plate 101 is deformed into an arc shape following the shape of the pole. The recess width W1 in the deformation region of the outer plate 101 is 240 mm.

  Here, there are four types of detection coils 4 to be analyzed as shown in FIG. As shown in FIG. 8A, the first coil 121 has a vehicle horizontal width of 1440 mm and is a single coil having no partial coil. As shown in FIG. 8B, the second coil 122 has a vehicle horizontal width of 1440 mm and has two partial coils 122a and 122b. That is, the second coil 122 corresponds to the coil shown in FIG. 2, and the width in the vehicle horizontal direction of each of the partial coils 122a and 122b is 720 mm. As shown in FIG. 8C, the third coil 123 has a vehicle horizontal width of 1440 mm and has four partial coils 123a to 123d. The width in the vehicle horizontal direction of each of the partial coils 123a to 123d of the third coil 123 is 360 mm. As shown in FIG. 8D, the fourth coil 124 has a vehicle horizontal width of 1440 mm and has six partial coils 124a to 124f. The width in the vehicle horizontal direction of each of the partial coils 124a to 124f of the fourth coil 124 is 360 mm.

  Further, for each of the four types of detection coils 121 to 124, analysis was performed by shifting the collision position of the pole that is the collision object. Specifically, the collision center of the pole was shifted from the center position of the detection coils 121 to 124 to one end of the detection coil 4.

  The analysis results are shown in FIG. In FIG. 9, the analysis result of the first coil 121 is indicated by a two-dot chain line, the analysis result of the second coil 122 is indicated by a one-dot chain line, the analysis result of the third coil 123 is indicated by a broken line, The analysis results of the four coils 124 are indicated by solid lines. The position of the collision center on the horizontal axis is 0 mm. The center position of the pole that is the collision object, that is, the center of curvature at which the outer plate 101 is deformed in an arc shape is located at the center of the detection coils 121 to 124. This is the case.

  As is clear from FIG. 9, in the case of one large coil (first coil) 121 shown in FIG. 8A, the absolute value of the impedance change rate after the collision before the object collision is 0 mm at the collision center. It is about 0.046 from the position of 550 to around 550 mm.

  In the case of the second detection coil 122 shown in FIG. 8B, the absolute value of the impedance change rate is larger than that of the first coil 121 when the position of the collision center is closer to the center of the detection coil 122. It has high sensitivity. However, when the position of the collision center moves away from the center of the second coil 122, the detection sensitivity decreases.

  In the case of the third coil 123 shown in FIG. 8C, the absolute value of the impedance change rate of the third coil 123 changes in a wave shape with respect to the position of the collision center. At a certain position, the absolute value of the impedance change rate is larger than that of the first coil 121, and at another position, the absolute value of the impedance change rate is small. That is, the detection sensitivity varies, and there is a region where the detection sensitivity is lower than that of the first coil 121.

  In the case of the fourth coil 124 shown in FIG. 8D, the absolute value of the impedance change rate of the fourth coil 124 is substantially a constant value near 0.055. That is, the absolute value of the impedance change rate is stable regardless of the position at the center of the collision, and has a higher sensitivity than the first coil 121.

  From the above, by making the vehicle horizontal width of the partial coil of the detection coil 4 equal to or less than the deformation width of the outer plate 101 due to the object collision, the detection sensitivity can be increased and the detection sensitivity varies with respect to the collision position. Can be suppressed.

(Embodiment 7)
A vehicle occupant protection system can be configured using the electromagnetic impedance sensor described above. This occupant protection system will be described with reference to FIG. FIG. 10 is a block diagram showing the occupant protection system of the present embodiment.

  As shown in FIG. 10, the occupant protection system includes an electromagnetic impedance sensor 200, a collision determination unit 300, and an occupant protection device 400. As the electromagnetic impedance sensor 200, any of the embodiments of the electromagnetic impedance sensor described above can be applied. The collision determination unit 300 determines a collision between the vehicle and an object other than the vehicle based on the output of the electromagnetic impedance sensor 200. For example, when the electromagnetic impedance sensor 200 is attached to the vehicle door 1 as in the sixth embodiment, the collision determination unit 300 determines whether or not the vehicle door and an object have collided (side collision). This determination is made by a change in impedance. The occupant protection device 400 is an airbag or the like, for example, and operates based on the determination of the collision determination unit 300.

  The partial coil may be arcuate as shown in FIG. Here, reference numeral 40 shown in FIG. 11 corresponds to a substantially middle point of the coil length of the detection coil 4. From the start point 20 to the intermediate point 40 is the forward coil portion 41, and from the intermediate point 40 to the end point 30 is the return coil portion. That is, the forward coil portion 41 in which incomplete circular turns that are a part of a plurality of partial coils (two in FIG. 11) are sequentially connected across the plurality of partial coils, and the non-turns that are a part of the plurality of partial coils. The detection coil 4 is constituted by a return coil portion 42 in which complete turn is successively connected across the plurality of partial coils.

It is a circuit diagram of the electromagnetic impedance sensor of each embodiment. FIG. 3 is a schematic plan view of a detection coil illustrating the detection coil winding method according to the first embodiment. 6 is a schematic plan view of a detection coil illustrating a detection coil winding method according to Embodiment 2. FIG. 6 is a schematic plan view of a detection coil showing a detection coil winding method according to Embodiment 3. FIG. 6 is a schematic plan view of a detection coil showing a detection coil winding method according to Embodiment 4. FIG. FIG. 10 is a schematic plan view of a detection coil illustrating a detection coil winding method according to a fifth embodiment. FIG. 2 is a horizontal sectional view showing the inside of the vehicle door 1. The detection coils 121 to 124 to be analyzed are shown. An analysis result is shown. It is a block diagram showing an occupant protection system. It is a model top view of a detection coil which shows an example of a detection coil winding method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Conductor wire 2 Detection circuit part 4 Detection coil 5-10 Partial coil 20 Start end 30 Termination 40 Intermediate point 41 Forward coil part 42 Return coil part 100 Vehicle door 101 Outer plate 102 Inner plate 121-124 Detection coil 200 for analysis Electromagnetic impedance Sensor 300 Collision determination unit 400 Crew protection device

Claims (7)

A detection coil having a coil placement surface facing a detection region to be subjected to non-contact detection of a conductive or soft magnetic detection target;
In the electromagnetic impedance sensor comprising: a detection circuit unit that detects the detection target by supplying AC power to the detection coil and detecting a change in electromagnetic impedance of the detection coil by the detection target;
2. The electromagnetic impedance sensor according to claim 1, wherein the detection coil is substantially composed of a single conductor wire constituting a plurality of partial coils arranged on the coil arrangement surface and sequentially arranged in a predetermined arrangement direction. The electromagnetic impedance sensor according to claim 1,
In the adjacent partial coils of the plurality of partial coils, adjacent sides that are sides of the partial coils that are adjacent to each other and extend in substantially the same direction are energized in the same direction. Sensor. The electromagnetic impedance sensor according to claim 1 or 2,
The detection coil is
An arrangement direction side extending substantially parallel to the arrangement direction and a right direction edge extending substantially perpendicular to the arrangement direction are sequentially connected to extend in one direction of the arrangement direction. An electromagnetic impedance sensor in which the plurality of partial coils are configured by sequentially connecting an arrangement direction side and a right-angle direction side and extending in the other direction of the arrangement direction. The electromagnetic impedance sensor according to claim 1 or 2,
The detection coil is
A forward coil portion in which incomplete circular turns that are a part of the plurality of partial coils are sequentially connected across the partial coils, and an incomplete circular turn that is a part of the plurality of partial coils. The electromagnetic impedance sensor which comprises the said some partial coil by the return coil part connected in sequence over the coil. In the electromagnetic impedance sensor according to any one of claims 1 to 4,
The detection coil is
An electromagnetic impedance sensor that, after arranging the partial coils in the arrangement direction, successively arranging the partial coils in the arrangement direction at positions adjacent to the arrangement direction at right angles. In the electromagnetic impedance sensor according to any one of claims 1 to 5,
The detection target is an outer plate of a vehicle door,
The detection coil is attached to a surface of the outer plate on the outer plate side of the inner plate that is spaced apart from the outer plate on the vehicle interior side of the outer plate,
The electromagnetic impedance sensor in which a width in a vehicle horizontal direction of each of the partial coils is 240 mm or less. The electromagnetic impedance sensor according to any one of claims 1 to 6,
A collision determination unit that determines a collision between the vehicle and an object other than the vehicle based on the output of the electromagnetic impedance sensor;
An occupant protection device that operates based on the determination of the collision determination unit;
An occupant protection system characterized by comprising: