JPS61229646A - Car jack-up detector - Google Patents

Abstract

PURPOSE:To prevent tires from being stolen via jack-up by performing the jack-up detection of a car body with a shock sensor and a ultrasonic sensor and correctly identifying cases when the car body is hit and when it is jacked up. CONSTITUTION:A shock sensor 1 detecting shocks applied to a car body and an ultrasonic sensor 2 detecting the movement of personnel in a car room are provided. The first and second level comparing means 3, 4 comparing detection signals of individual sensors 1, 2 with reference values respectively are provided, the continuous time in which the shock sensor detection signal exceeds the reference value is measured by a measuring means 5, and whether this continuous time exceeds the predetermined reference time or not is detected by a time comparing means 6. If the shock sensor detection signal exceeds the reference value and the ultrasonic sensor detection signal is the reference value or lower and the continuous time exceeds the reference time, an output is generated from a judging means 7, a warning means 8 is operated, thus the theft of tires via jack-up is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a jack-up detection device for an automobile. The jack-up detection device of the present invention is used, for example, to detect jack-up of a vehicle body when a car tire is stolen, issue an alarm, and prevent tire theft.

[Conventional technology]

Conventionally, ultrasonic sensors, impact sensors,
Vehicle body tilt sensors are known.

The ultrasonic sensor is composed of, for example, an ultrasonic Doppler radar, and is installed inside the vehicle interior to detect a thief entering the vehicle interior or a window glass being smashed, and emit an alarm. Shock sensors are made up of, for example, acceleration sensors, and are attached to the car body to detect large impacts applied to the car body. It detects an attempt to break into a part of the vehicle and enter the vehicle interior, and emits a glH signal. The tilt sensor detects the tilt of the vehicle body,
Thereby, for example, when the vehicle body jerks up when a tire is stolen, it is detected and an alarm is issued.

[Problem that the invention seeks to solve]

For example, when using each of the above-mentioned 4° sensors as a sensor to detect jacking up of the car body for the purpose of preventing tire theft, when using an impact sensor, it is necessary to detect the slight shaking when the car body jacks up. Although it outputs a low detection signal, it is difficult to distinguish this borrowed money from the detection signal output when you hit the window glass or the car body. On the other hand, when using an ultrasonic sensor,
When the vehicle body is jacked up, the entire vehicle body moves and there is almost no movement within the vehicle interior, and the detection signal level is extremely low and cannot be used. Another problem is that the tilt sensor is expensive.

[Means for solving problems]

A functional block diagram of the vehicle jack-up detection device of the present invention for solving the above-mentioned problems is shown in FIG. The jack-up detection device of the present invention includes an impact sensor 1 that is attached to a vehicle body and detects an impact applied to the vehicle body, an ultrasonic sensor 2 that is attached to a vehicle interior and detects movement of a person in the vehicle interior, and the impact sensor. a first level comparing means 3 for comparing the detection signal of the ultrasonic sensor with a predetermined reference value and detecting whether or not the detection signal exceeds the reference value; a second level comparing means 4 for detecting whether or not the impact sensor detection signal exceeds the reference value; a time measuring means 5 for measuring the duration of the impact sensor detection signal exceeding the reference value detected by the first level comparing means; time comparison means 6 for detecting whether or not the duration exceeds a predetermined reference time; the first level comparison means detects that the shock sensor detection signal exceeds the reference value; A determination that determines that the ultrasonic sensor detection signal is detected to be less than a reference value by the level comparison means, and that the time comparison means detects that the duration of the impact sensor detection signal exceeds the reference time. means 7, and alarm means 8 which issues an alarm when the determination means determines that the condition is satisfied.

[For production]

First, the basic operating principle of the present invention will be explained below with reference to FIGS. 2 and 3.

Figure 2 shows the detection signal levels of the impact sensor 1 and ultrasonic sensor 2 when a car window or body is hit.
In the figure, the abscissa indicates the striking intensity, and the ordinate indicates the detection signal level. Figure 3 shows the detection signal levels of the impact sensor and ultrasonic sensor when the car body is jacked up.
In the figure, the abscissa indicates the jacking speed, and the ordinate indicates the detection signal level. In both FIGS. 2 and 3, the solid line represents the detection signal of the impact sensor, and the broken line represents the detection signal of the ultrasonic sensor.

As can be seen from Figures 2 and 3, the impact sensor 1 outputs a detection signal whose signal level increases rapidly as the strength of the hit increases when the car body is hit, and also when the car body is jacked up. It detects slight shaking and outputs a relatively low detection signal whose signal level gradually increases according to the jack-up speed. on the other hand,
The ultrasonic sensor 2 also outputs a detection signal with the same tendency as the impact sensor 1, but the detection signal when jacked up is different from the impact sensor 1 because there is no movement of an object inside the vehicle. The signal level is very small compared to

Here, an appropriate threshold voltage v (th) is set as a reference value, and in the 20th step, the regions before and after the detection signal of the ultrasonic sensor 2 exceeds this threshold voltage V (th) are designated as I and H, similarly. In FIG. 3, the regions before and after the detection signal of the shock sensor 1-1 exceeds this threshold voltage V (th) are divided into 1 and 2.

As is clear from Figs. 2 and 3, when the detection signal level of both the impact sensor 1 and the ultrasonic sensor 2 exceeds the threshold voltage V (th), it is determined that there has been a strong impact on the window or vehicle body. However, only the detection signal of the impact sensor 1 has a threshold voltage V (
th) is determined to be the time of jack-up, it is possible to distinguish between a strong hit on the window or the vehicle body and jack-up in areas 6j and 6j.

Regarding region (■) in FIG.
) or less, the same conditions apply as in area (■), so it is not possible to distinguish between hitting the vehicle body and jacking up the vehicle by just looking at the signal level. However, when focusing on the duration of the detection signal of the impact sensor 1, as shown in FIG. The level of is low, and the duration of the signal exceeding the threshold voltage V (th) is intermittent and is much shorter than the duration of the detection signal at the time of jack-up. For example, the duration of a weak tap is about 0.5 seconds, while the duration of a jack-up is about 2 seconds or more.

Therefore, in this region I, the vehicle body is maintained by measuring the duration of the detection signal of the impact sensor 1 that exceeds the threshold voltage V (th) and making a time judgment as to whether or not the value is greater than, for example, 2 seconds. It is possible to distinguish between when it is hit and when it is jacked up.

Regarding region (3), it is not possible to distinguish between hitting the car body and jacking up, but this region (2) is a region where the speed of jacking up is very slow and does not normally occur, so there is no practical problem.

The operation of the apparatus shown in FIG. 1 based on the above-mentioned operating principle will now be described.

The first level comparison means 3 detects that the detection signal of the shock sensor 1 exceeds a predetermined base tits value, the sub-time means 5 measures the duration of the shock sensor detection signal,
Furthermore, the time comparison means 6 detects whether or not the duration exceeds the reference time. Further, the second level comparing means 4 detects that the detection signal of the ultrasonic sensor 2 exceeds a predetermined reference value.

The determination means 7 determines that the detection signal of the impact sensor 1 exceeds the reference value, the detection signal of the ultrasonic sensor 2 is less than or equal to the reference value, and the duration of the detection signal of the impact sensor 1 exceeds a predetermined reference time. When the vehicle body is judged to be jacked up, the 'WAN means 8 issues an alarm.

〔Example〕

A block diagram of a vehicle jack-up detection device as an embodiment of the present invention is shown in FIG.

In FIG. 4, an impact sensor 11 is attached to the vehicle body, and its detection signal is sent to an amplifier 12 and a low-pass filter 13.
, and is led to one input terminal of a comparator 15 through an integrator 14 in sequence. Compare! A threshold voltage V (th) is applied to the other input terminal of 1i15, and the comparison output signal 5(2) is led to one of the input ports of microcomputer 16.

The ultrasonic sensor 17 is installed inside the vehicle, and its detection signal is sent to an amplifier 18, a low-pass filter 19, and an integrator 20.
The signal is led to one input terminal of the comparator 21 through the . A threshold voltage V (th) is applied to the other input terminal of the comparator 20, and its comparison output signal 5(4) is led to another input port of the microcomputer 16.

The operation of the embodiment device shown in FIG. 4 will be explained below with reference to FIGS. 5 and 6. FIG. 5 is a signal waveform diagram of each part of the apparatus shown in FIG. 4. In FIG. 5, (al is the output signal S (1) of the low-pass filter 13, (bl is the output signal 5 (2) of the comparator 15, and (C) is the output signal 5 of the low-pass filter 19.
(3),! d+ is each signal waveform of the output signal 5(4) of the comparator 21, and shows cases in which the vehicle body is hit strongly from the left side, when it is hit weakly, and when it is jacked up.

FIG. 6 is a flowchart showing the processing procedure for detecting jack-up executed by the microcomputer 16 of FIG.

When the impact sensor 11 detects that an impact has been applied to the vehicle body, a detection signal is sent out, amplified by the amplifier 12, and further input to the low-pass filter 13, where high-frequency noise components are removed. Integrator] 4. Integral R'':, 14 has the function of envelope detection of the detection signal,
The integrated output is input to the comparator 15. When the output signal of the integrator 14 becomes equal to or higher than the threshold voltage V (th), the comparator I5 outputs an output signal 5(2) of H" level. In this case, it is determined whether the vehicle body has been hit or not. Or it can be determined that the jack has been increased.Output signal 5
(2) is input to the microcomputer 16.

Similarly, the detection signal from the ultrasonic sensor 17 is sent to an amplifier 18,
The signal is input to the comparator 21 via the low-pass filter 19 and the integrator 20, and when the output signal of the integrator 20 is higher than the threshold voltage V (th), the output signal 5 ( 4) is output and input to the microcomputer 16.

The microcomputer 16 performs the processing shown in FIG. That is, the program starts by turning on the power of the device (step S1), and first the comparator 15
It is determined based on the output signal 5(2) from the impact sensor 11 whether or not a detection signal is being sent out (step S
2). If the detection signal is not being sent out (that is, if the output signal 5(2) is "L"), the duration counter for measuring the duration of the detection signal of the impact sensor 11 is cleared and the step is repeated. Repeat S2 (step S3). A counter built into the microcomputer is used as a duration counter.

If a detection signal is being sent out, the duration counter is incremented by one to measure its duration (step S4), and then it is checked whether or not a detection signal is being sent out from the ultrasonic sensor 17. Check (step S5
). This is done by detecting whether the output signal 5(4) from the comparator 21 is ``I'', and the result is stored in memory 12).

Next, it is determined whether the time counted by the duration counter is 2 seconds or more (step 36). If it is less than 2 seconds, the process returns to step S2. At this time, in step S2, fti%%
If the detection signal of the sensor 11 is "5", it can be determined that the vehicle body has been lightly tapped. If it is longer than 2 seconds, it is determined that the vehicle body has been hit hard or jacked up, and the process moves to the next step S7.

In step S7, it is determined whether or not a detection signal is sent from the ultrasonic sensor 7 at least once within 2 seconds after the detection signal is sent from the impact sensor 11, that is, the output signal 5 (4) of the comparator 21 is "H". It is determined based on the check result in step S5 whether or not. This process of step S7 is necessary because the output timings of the detection signals of the impact sensor 11 and the ultrasonic sensor 17 do not necessarily coincide.

If a detection signal is sent from the ultrasonic sensor 17, it is determined that the vehicle body has been hit strongly, and the process proceeds to step S2.
Return to On the other hand, if no detection signal is sent out, it can be determined that the vehicle body is jacked up, and a warning is issued (step S8).

〔Effect of the invention〕

According to the present invention, when detecting jack up of a car body using an impact sensor and an ultrasonic sensor, it is possible to accurately distinguish between a case where the car body is hit and a case where the car body is jacked up. It is possible to prevent malfunctions in jack-up detection caused by this. As described above, in the present invention, as a security measure for a vehicle, in addition to detecting a strong impact on the vehicle body using an impact sensor, detecting an unauthorized user entering the vehicle interior using an ultrasonic sensor, etc., it is possible to detect a jerk-up of the vehicle body. Thereby, it is possible to prevent tire theft by warning of jack-up when a tire is stolen, and it is possible to further improve security measures for the automobile.

[Brief explanation of drawings]

Fig. 1 is a functional block diagram related to the present invention, Fig. 2 is a characteristic diagram showing the detection signals of the shock sensor and ultrasonic sensor against strong impact on the car body, etc., and Fig. 3 is a characteristic diagram showing the detection signals of the shock sensor and ultrasonic sensor against a strong impact on the car body. 4 is a block diagram of an automobile jack-up detection device as an embodiment of the present invention, and FIG. 5 is a signal waveform diagram of each part of the device in FIG. Fig. 6 is a flowchart showing the processing procedure for jack-up detection in the microcomputer of the apparatus shown in Fig. 4. 11. Shock sensor, 12. 18. Amplifier, 13. 19. Low-pass filter, 14. 20...
Integrator, 15.21... Calibrator, 16... Micro computer, 17... Ultrasonic sensor.

Claims (1)

[Claims] An impact sensor that is attached to a vehicle body to detect an impact applied to the vehicle body; an ultrasonic sensor that is attached to a vehicle interior to detect movement of a person within the vehicle interior; and a detection signal of the impact sensor. a first level comparing means for comparing with a predetermined reference value and detecting whether or not the reference value is exceeded; a first level comparison means for comparing the detection signal of the ultrasonic sensor with a predetermined reference value and detecting whether or not the detection signal exceeds the reference value; a second level comparison means for measuring the duration of the impact sensor detection signal exceeding the reference value detected by the first level comparison means; Time comparison means for detecting whether or not the reference time is exceeded; the first level comparison means detects that the impact sensor detection signal exceeds the reference value; the second level comparison means detects that the ultrasonic sensor determining means for determining that the detection signal is below a reference value and that the time comparing means detects that the impact sensor detection signal duration exceeds the reference time; An automobile jack-up detection device comprising: alarm means that issues an alarm when it is determined that a condition is met.