JPH04278866A - Tilt sensor for preventing theft for vehicle - Google Patents

Abstract

PURPOSE:To correctly estimate the possibility of the theft for a vehicle due to jack up by discriminating the theft (1) in which a characteristic vibration is generated in a pendulum part by jolting the vehicle and the vehicle is jacked up or the theft (2) due to the tilt of the vehicle due to the getting on of a person and jack up. CONSTITUTION:A pendulum part 5 performs pendulum operation as shown by L1 according to the tilt of a vehicle. On the basis of the deflection points theta1, theta2,... of the pendulum part 5, the augular evaluation data L2 as the data useful for the theft judgement in case (1), and two data as the data useful for the theft judgement in case (2), together with the data L2, i.e., the vibration evaluation data (number of deflection points exceeding a prescribed value L3) and the tilt speed evaluation data (max value of the difference per time of the angular evaluation data) are calculated, and the possibility of the theft for the vehicle is estimated from these data.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle theft prevention inclination sensor having a pendulum portion.

0002

2. Description of the Related Art A vehicle theft prevention system using such an inclination sensor is constructed by attaching a pendulum to a vehicle and defining that the inclination angle of the pendulum is equal to the inclination angle of the vehicle. Some vehicles are designed to determine that the vehicle has been stolen if the inclination angle of the pendulum exceeds a predetermined value for a predetermined period of time or more.

0003

[Problems to be Solved by the Invention] By the way, the following problems have been pointed out in the above judgment.

[0004] When the vehicle is slowly jacked up, the pendulum section itself tilts with almost no vibration, so the relationship between the tilt angle of the pendulum section and the tilt angle of the vehicle can be determined relatively accurately. Since this holds true, it is possible to determine whether the vehicle is stolen. On the other hand, when jacking up a vehicle, which applies a shock to lift the vehicle quickly, the pendulum itself causes its own natural vibration.
The change in the inclination angle of the pendulum part no longer matches the change in the actual inclination angle of the vehicle, making it impossible to determine whether the vehicle is stolen. If this natural vibration converges, the inclination angle of the pendulum =
The relationship between the vehicle inclination angles now holds true, and it becomes possible to determine whether the vehicle is stolen.

Therefore, from the thief's perspective, it is impossible to determine whether the vehicle has been stolen by simply shaking the vehicle to cause natural vibration in the pendulum. If the vehicle is jacked up while the vehicle is being woken up, the vehicle could be stolen, which is inconvenient.

[0006] In the case where the vehicle is jacked up so that it is slightly tilted and the vehicle is raised slightly to steal tires, etc., the above predetermined value is determined as follows: slight tilt angle of the vehicle = slight tilt angle of the pendulum section < If the value is a predetermined value, the theft cannot be determined. Therefore, if the above predetermined value is set to a small value in order to prevent such theft, it is possible to establish the relationship that a small inclination angle of the vehicle = a small inclination angle of the pendulum > the predetermined value, but if a person approaches the vehicle. This relationship holds true even if the vehicle tilts a little while the vehicle is being jacked up, making it difficult to distinguish it from a case where the vehicle tilts due to jacking up, and it can be mistaken for the vehicle to be stolen even though a person has simply climbed into the vehicle. There is a possibility of judgment.

[0007] In the present invention, the vehicle can be stolen by shaking the vehicle to cause natural vibration in the pendulum part as described in (2) above, or jacked up so that the vehicle is tilted slightly as in (2) above. In the case of stealing tires, etc., which are part of a vehicle, by suppressing the inclination angle of the pendulum part, the above-mentioned The purpose is to eliminate misjudgments and effectively prevent theft.

[0008]

[Means for Solving the Problems] In order to achieve such an object, the present invention according to claim 1 includes a sensor section, a calculation section, and an inference section, and the sensor section includes: It has a pendulum part and a detection part, the pendulum part is attached to the vehicle so that it can swing, and the detection part outputs an output pulse in response to the pendulum movement of the pendulum part. The section repeatedly calculates the average value of the previous slope inflection point and the current slope inflection point in the pendulum section from this output pulse, and divides the sum of each individual average value by the number of calculations. , the division result is output as angle evaluation data, and the inference section is characterized in that it infers the possibility of vehicle theft based on the angle evaluation data.

In the present invention according to claim 2, the calculation section calculates vibration evaluation data (the number of inflection points exceeding a predetermined inclination angle of the pendulum section) in addition to the calculation for calculating the angle evaluation data. The inference unit infers the possibility of vehicle theft based on the respective data. It is characterized by being something.

[0010] In the present invention according to claim 3, the inference unit includes a fuzzy rule in which each of the data is an antecedent variable and the possibility of vehicle theft is a consequent variable, and a fuzzy rule corresponding to each variable. The method is characterized in that it performs fuzzy inference on the possibility of vehicle theft according to the membership function.

[0011]

[Operation] According to claim 1, the calculation section individually and repeatedly calculates the average value of both the previous and current inflection points in the pendulum section in response to the input of the output pulse of the sensor section, and also calculates each average value. The sum is divided by the number of calculations, and the moving average value that is the division result is output as the angle evaluation data. Therefore, this angle evaluation data corresponds to the actual tilt angle of the vehicle, so even if the natural vibration of the pendulum part does not converge, in other words, the vehicle can be rocked to cause natural vibration in the pendulum part. However, the inference unit can infer that the vehicle has been stolen from this angle evaluation data.

In the second aspect, in addition to calculating the angle evaluation data, the calculation section calculates the number of times the inclination inflection point of the pendulum section exceeds a predetermined value as vibration evaluation data, and calculates the inclination speed evaluation data. The inference section infers the possibility of vehicle theft based on the respective data.

Therefore, in inferring theft based only on the actual tilt angle of the vehicle based on the angle evaluation data as in claim 1, the tilt angle of the vehicle when the pendulum part is vibrating naturally is obtained, and from this, while the vehicle is rocking, the inclination angle of the vehicle is determined. However, if the shaking of the vehicle is the same as that caused by a person riding in the vehicle and that caused by a jack-up, there is a possibility of an erroneous determination. In such a case, claim 2
Then, the vibration evaluation data shows the vibration state of the vehicle, and the tilting speed evaluation data shows the vehicle's tilting speed, which differs depending on whether a person is on board or when the vehicle is jacked up. By adding evaluation data of vehicle vibration and tilt speed to the inference of vehicle theft, the above-mentioned erroneous determination can be eliminated and accurate inference of theft can be made.

[0014] In claim 3, the inference unit uses a fuzzy rule in which each of the data is an antecedent variable and the possibility of vehicle theft is a consequent variable, and a membership function corresponding to each variable. Fuzzy inference is made regarding the possibility of vehicle theft according to the following.

[0015]

Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a diagram showing the configuration of a tilt sensor according to an embodiment of the present invention, and FIG. 2 is a diagram showing the configuration of the sensor section of FIG. 1. In the figure, 1 is a sensor section, 2 is a calculation section, 3 is an inference section, and 4 is a determination section.

The front configuration of the sensor section 1 is shown in FIG. 2(a), and the cross-sectional configuration is shown in FIG. 2(b), and includes a pendulum section 5 and a detection section 6. The pendulum part 5 consists of a center body 5a and a fan body 5b, the center body 5a is attached to a vehicle (not shown) so that the pendulum part 5 can swing, and the fan body 5b is It is integrally attached to this central body 5a. A large number of slits 5c are formed on the periphery of this fan body 5b.

The detection unit 6 detects a slit 5 at the periphery of the fan body 5b.
c, and the first and second photocouplers 61
, 62. The first photocoupler 61 includes a light emitting diode 61a and a light receiving transistor 61b, and is arranged on the right side when viewed from the front in FIG. 2(a). Similarly, the second photocoupler 62 is a light emitting diode 62
a and a light-receiving transistor 62b, and is arranged on the left side when viewed from the front in FIG. 2(a).

Each photo coupler 61, 62 and slit 5c
The arrangement is as shown in FIG. In FIG. 3, each slit 5c has a slit width of T/2 in the vibration directions A and B of the fan body 5b,
Moreover, they are spaced apart from each other by T/2. The distance between the photocouplers 61 and 62 in the directions A and B is 3T/4. Here, P1 indicates an output pulse of the light receiving transistor 61b of the photocoupler 61, and P2 indicates an output pulse of the light receiving transistor 62b of the photocoupler 62.

As shown in FIG. 3, when the pendulum portion 5a moves in the direction A in accordance with the inclination of the vehicle, the slit 5c also moves in the direction A, but each photo coupler 61, 6
2, the output pulse P1 from the first photocoupler 61 rises earlier than the output pulse P2 from the second photocoupler 62, as shown in FIG. 4(a). Similarly, when the pendulum portion 5a moves in the B direction in accordance with the inclination of the vehicle, the slit 5c moves in the B direction accordingly, so that the second photocoupler 62 is moved as shown in FIG. 4(b).
The output pulse P2 from the first photocoupler 61 rises earlier than the output pulse P1 from the first photocoupler 61. Therefore, the vehicle tilt direction can be determined depending on which of the output pulses P1 and P2 rises first.

The output pulses P1 and P2 respectively output from the sensor section 1 are given to the calculation section 2. The calculation unit 2 uses the output pulses P1 and P2 to calculate the pendulum unit 5.
, (2) tilt inflection point of the pendulum portion 5, (2) vehicle angle evaluation data, (2) vehicle vibration evaluation data, and (2) vehicle tilt speed evaluation data.

The meaning of each data and this calculation will be explained with reference to FIGS. 5 and 6.

■Inclination angle of pendulum section 5: In calculation section 2,
Each output pulse P1, P2 as shown in FIG. 4 is given from the sensor section 1. The calculation section 2 calculates the inclination angle of the pendulum section 5 by counting the input number of output pulses P1 and P2 from the reference position of the pendulum section 5, and sequentially stores each calculation result. L1 indicated by a solid line in FIG. 6 indicates the transition of the tilt angle of the pendulum section 5 stored in the calculation section 2.

(2) Inclination inflection point of the pendulum portion 5: The inclination inflection point of the pendulum portion 5 is the inclination angle of the pendulum portion 5 when the inclination direction of the pendulum portion 5 changes.

In the sensor section 1, the pendulum section 5 moves from direction A to direction B, as shown in FIG. 2(a), according to the inclination of the vehicle.
Or, the inclination angle changes from direction B to direction A, and accordingly, the detection unit 6 outputs pulses P1 and P2 as shown in FIG.
is output, but the calculation unit 2 determines that when the output pulses P1 and P2 have a relationship as shown, for example, between times t1 and t2 in FIG. Find it as a point. This slope inflection point is θ1 in Figure 6.
, θ2, ..., θ20.

■Angle evaluation data: What is angle evaluation data?
The calculation unit 2 repeatedly calculates the average value (individual average value) of the previous inflection point and the current inflection point of the pendulum unit 5 from each inflection point calculated in This refers to the data of the division value obtained when the sum of .

Specifically, the calculation of this angle evaluation data is shown in FIG.
For example, if the previous inflection point was θ1 and the current inflection point was θ2, the individual average value θ2' would be
)/2, and the previous inflection point is θ2 and the current inflection point is θ3, the individual average value θ3' is (θ2+θ3)/2,..., the previous inflection point is θ19, and the current inflection point is θ3. When the point is θ20, the individual average value θ20' is (θ19+θ20)/2. Since the number of calculations is 19, the angle evaluation data in FIG. 6 is (θ2'+...+θ20')/1
It is given by the arithmetic expression in 9.

If the angle evaluation data calculated in this way is defined as the actual tilt angle of the vehicle at L2 in FIG. Even if the inclination angle of the pendulum part 5 changes as shown in FIG.

■Vibration evaluation data: What is vibration evaluation data?
If the inflection point of the pendulum part 5 in the A direction is assumed to be positive and the inflection point in the B direction is assumed to be negative, it is defined as the number of times in which the absolute value of that inflection point exceeds a predetermined threshold. It is. For example, if FIG. 6 shows an inflection point in the positive direction of the pendulum portion 5, then the inflection point θx exceeding the threshold value L3 (in the example, six inflection points θ5 to θ15) are shown. ) and the number of inflection points θx, which are not shown in the figure, as thresholds in the negative direction, and outputs the calculated number as vibration evaluation data.

■Tilt speed evaluation data: Tilt speed evaluation data is defined as the maximum value of the difference between a plurality of angle evaluation data per unit time, and the calculation unit 2 calculates the angle evaluation data per unit time, for example. The maximum value of the difference between Ai and (Ai-1) is calculated. Here, i is the i-th angle evaluation data among the n angle evaluation data obtained every fixed time T, and i-1 is the angle evaluation data obtained one point earlier. This is angle evaluation data. Then, the difference between both angle evaluation data, that is, the maximum value of the difference between Ai-(Ai-1), is given as the tilt speed evaluation data. In this manner, the calculation unit 2 calculates the above-mentioned items 1 to 2, and outputs each data to the inference unit 3.

The inference unit 3 uses a fuzzy rule in which angle evaluation data, vibration evaluation data, and tilt speed evaluation data are respectively set as antecedent variables x1, x2, and x3, and the possibility of vehicle theft is set as a consequent variable y. , and membership functions corresponding to each variable, from which the possibility of vehicle theft is inferred using fuzzy inference.

[0032] The inference of this possibility will be explained.

The fuzzy rules are as follows.

■ if x1=Z then y=S ■ if x1=S and x2=Z a
nd x3=S then y=B ■ if x1=M and x2=Z a
nd x3=S then y=B ■ if x1=S and x2=Z a
nd x3=B then y=S ■ if x1=S and x2=B a
nd x3=M then y=S ■ if x1=S and x2=B a
nd x3=B then y=S ■ yf x1=B then y=B ■ if x1=M and x2=Bthe
n y=B In the above fuzzy rule, each label name Z, S, M, B of the antecedent variable x1 of the angle evaluation data indicates that the evaluation value is zero, small, medium, large, respectively. The label names Z and B of the antecedent variable x2 of
Each of the label names S, M, and B in 3 has an evaluation value of small, medium, and
The label names S and B of the consequent variable y regarding the probability of theft determination indicate that the probability of theft is small and large, respectively.

[0035] In the case of vehicle theft in which the vehicle is jacked up while shaking the vehicle to cause natural vibration in the pendulum portion 5, the angle evaluation data, that is, the inclination angle of the vehicle after the natural vibration has been filtered becomes large. Therefore, in this fuzzy rule, in terms of linguistic expression, ■ is
Since this angle evaluation data is zero, it indicates that there is no such jack-up and therefore the possibility of theft is small.

[0036] ■ The vehicle is tilted little by little at a small tilting speed to prevent it from vibrating. Therefore, this means that the vehicle is slowly raised using a jack, which is a common method for theft, making it possible for theft to occur. It shows that the quality is extremely high.

[0037] ■ is similar to ■ except that the inclination of the vehicle is slightly greater than ■, and this also indicates that the possibility of theft is extremely high.

[0038] Regarding (■), although the vehicle does not vibrate due to a small inclination, the inclination speed is large, so this is a change in the vehicle posture that does not occur when jacking up. The possibility of theft is small because the change in attitude of the vehicle occurs when the vehicle is ridden.

[0039] In case (2), although the vehicle is tilted slightly, it is moving at a high speed that would be unimaginable when jacked up, and it is also vibrating a lot, so there is a high possibility that the vehicle is simply being shaken. The possibility of this is small.

Item (2) is similar to item (2) except that the tilting speed of the vehicle is faster than item (2), and the possibility of theft is small.

[0041] ■ is because the vehicle is being jacked up while rocking and causing natural vibration in the pendulum portion 5.
It is inferred that the angle of inclination of the vehicle is increased and therefore the possibility of vehicle theft is high.

[0042] ■ is smaller than ■ as the angle of inclination of the vehicle, but since it vibrates to an extent that would be unimaginable with a person riding on it, this may mean that the vehicle is being jacked up while vibrating. high and therefore the possibility of theft is high.

As shown in FIG. 7, the inference unit 3 also has membership functions for the antecedent variables x1, x2, and x3, and a membership function for the consequent variable y.

[0044] Then, this inference unit 3 selects the minimum value of the membership values of each antecedent variable x1, x2, x3 as the antecedent suitability for each fuzzy rule ■ to ■ (MIN operation). . Then, the membership function of the consequent variable y for determining vehicle theft is cut using this antecedent variable fitness, and the cut membership functions are superimposed (MAX calculation), and the center of gravity of the superimposed figure is Fuzzy inference is made regarding the possibility of vehicle theft from the location of the vehicle. Since the MIN calculation, MAX calculation, and the center of gravity position in such fuzzy inference are well known, their explanation will be omitted.

The determination unit 4 determines whether the vehicle is stolen based on the inference result from the inference unit 3, and outputs the determination output to an alarm unit (not shown) or the like. The alarm section performs an alarm operation when the judgment output is that the vehicle has been stolen.

[0046]

According to the present invention according to claim 1, the possibility of vehicle theft is inferred based on angle evaluation data. This angle evaluation data is a value obtained by dividing the plurality of average values of the previous and current inclination inflection points of the pendulum portion by the plurality of average values. Therefore, this data corresponds to the actual tilt angle of the vehicle even if the vehicle is jacked up while rocking and causing natural vibration in the pendulum part, so it is possible to effectively prevent vehicle theft in such a manner. be able to.

In the second aspect of the present invention, in addition to calculating the angle evaluation data, the possibility of vehicle theft is inferred from the vibration evaluation data and the tilt speed evaluation data. Therefore, it can be inferred from these three data that it is possible to accurately distinguish between the tilt of the vehicle when a person gets on the vehicle and the tilt of the vehicle due to jacking up. It becomes possible to accurately infer the possibility of

[0048] In claim 3, since the possibility of vehicle theft is inferred by fuzzy inference using these three data, the actual mode of theft and its Therefore, the possibility of vehicle theft can be accurately inferred with higher precision.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a vehicle theft prevention tilt sensor according to an embodiment of the present invention.

FIG. 2 is a diagram showing the configuration of a sensor section in FIG. 1;

FIG. 3 is a diagram showing a slit formed in a fan of the pendulum section of the sensor section in FIG. 1, and a photocoupler disposed opposite to the slit.

FIG. 4 is a diagram showing output pulses of a photocoupler.

FIG. 5 is a diagram showing output pulses of a photocoupler.

FIG. 6 is a diagram showing the relationship between the tilt angle of the vehicle and time, which is used to explain the calculation operation of the calculation unit.

[Figure 7] Provides an explanation of fuzzy inference in the inference section.
FIG. 7 is a diagram showing membership functions of antecedent part variables and consequent part variables.

[Explanation of symbols]

1 Sensor part 2 Arithmetic unit 3 Inference part 4 Judgment section 5 Pendulum part 6 Photocoupler

Claims (3)

[Claims] Claim 1: A sensor section (1), a calculation section (2), and an inference section (3), the sensor section (1) having a pendulum section (5).
and a detection section (6), and the pendulum section (5) has a
It is attached to the vehicle so that it can swing pendulum, and the detection part (
6) outputs an output pulse in response to the pendulum movement of the pendulum section (5), and the calculation section (2) uses this output pulse to determine the previous inclination inflection point and the current inclination point in the pendulum section (5). It repeatedly calculates the average value with respect to the slope inflection point individually, divides the sum of the individual average values by the number of calculations, and outputs the division result as angle evaluation data. ) is a tilt sensor for vehicle theft prevention, characterized in that it infers the possibility of vehicle theft based on angle evaluation data. 2. In addition to calculating the angle evaluation data, the calculation unit (2) calculates vibration evaluation data [pendulum unit (5)
) and the number of inflection points exceeding a predetermined angle of inclination of the angle (
The inclination sensor for vehicle theft prevention according to claim 1, wherein the inference section (3) infers the possibility of vehicle theft based on each of the data. 3. The inference unit (3) uses a fuzzy rule in which each of the data is an antecedent variable and the possibility of vehicle theft is a consequent variable, and a membership function corresponding to each variable. The vehicle theft prevention tilt sensor according to claim 2, wherein the vehicle theft prevention tilt sensor performs fuzzy inference on the possibility of vehicle theft.