Diagnostic equipment and diagnostic method for collision detection device

Abstract

To provide a diagnostic method and diagnostic equipment each enabling the condition of a tube for vehicle collision detection to be accurately diagnosed.SOLUTION: A first aspect of the present invention is diagnostic equipment for a collision detection device that detects collision of a vehicle using a tube having sealed inside, the diagnostic equipment includes: a first end unit that is connected to a first end of the tube; a second end unit that is connected to a second end of the tube; a first transmission portion that is provided in the first end unit and transmits detection sound toward the second end unit through the tube; a first receiving portion that receives the detection sound reflected from the second end unit; and a first diagnosis portion that diagnoses condition of the tube on the basis of the detection sound input to the first receiving portion.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a collision detection device for detecting a collision of a vehicle, and more particularly to a diagnostic method and device capable of diagnosing the operating state of a tube used in collision detection. [Background technology]

[0002] In order to detect a vehicle collision, a technology has been proposed in which a pressure detection tube is placed at the front end or side of the vehicle body, pressure changes inside the tube are detected, and a collision is determined to have occurred when the pressure change exceeds a predetermined standard.

[0003] For example, a tube is placed at the front end of the vehicle, and end units connected to both ends of the tube detect changes in the internal pressure of the tube, and a vehicle collision is detected based on the results. When a vehicle collision (pedestrian collision) is detected, a pedestrian protection device such as a bonnet lifter can be activated by a control unit (ECU).

[0004] Surrounding materials such as urethane foam that transmit force to the tube are installed near the tube, but the hardness of the surrounding materials changes depending on the temperature. Therefore, in order to ensure collision detection performance even when the temperature changes, it is possible to install a separate temperature measuring device and calibrate the measured value. However, it is difficult to appropriately set the points where the temperature should be measured, and to estimate and calibrate the change in characteristics due to temperature change.

[0005] Furthermore, if the tube had a hole or was clogged, or if some other problem occurred with the tube, there was no way to detect this, and there was a risk that a collision could not be detected accurately.

[0006] As described above, there is no diagnostic function for determining the condition of the tube, and it is difficult to accurately calibrate the measurement values ​​based on the surrounding environment such as temperature. Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a diagnostic method and diagnostic device capable of accurately diagnosing the condition of a tube for detecting a vehicle collision. [Means for solving the problem]

[0008] In order to solve the above problems, a first aspect of the present invention is a diagnostic device for a collision detection device that detects a vehicle collision using a tube with a sealed interior, comprising: a first end unit connected to a first end of the tube; a second end unit connected to a second end of the tube; a first transmitting unit provided in the first end unit and transmitting a probe sound toward the second end unit through the tube; a first receiving unit receiving the probe sound reflected and returned by the second end unit; and a first diagnostic unit that diagnoses the condition of the tube based on the probe sound input to the first receiving unit.

[0009] Here, the term "vehicle" is a relatively broad concept that includes automobiles, motorcycles, trucks, buses, etc., and can include vehicles and conveyances that are driven by humans. This is particularly effective for automobiles in which safety devices such as airbags are activated when the tube detects the occurrence of a collision accident.

[0010] "Vehicle collision" can include vehicle-to-pedestrian, vehicle-to-bicycle, and vehicle-to-vehicle collisions. However, due to the nature of detection using a tube, it is preferable to apply it to pedestrians and bicycles. Therefore, it is considered appropriate to place the tube according to the present invention in front of the vehicle. In the case of vehicle-to-vehicle collisions, since a large area of ​​collision occurs, there is a large pressure change and it is difficult to judge, so collision detection using an accelerometer is common.

[0011] The "tube" is, for example, arranged along the width direction on the inside of the front bumper of a vehicle, and detects a collision by utilizing the rise in internal pressure of the tube when a pedestrian or the like collides with the vehicle. The first and second end units connected to the ends of the tube have the same pressure as the inside of the tube, and a small hole can be provided to adjust the internal pressure change due to temperature change to atmospheric pressure.

[0012] The inside of the tube can be filled with gas or liquid, but gas is preferred. If the tube is filled with liquid, its weight may lead to erroneous judgment due to inertia when the door is opened or closed. In addition, it is not easy to prevent the liquid from leaking, and there is a risk of performance degradation due to air bubbles in the tube. On the other hand, in the case of gas, it is relatively easy to maintain atmospheric pressure by adjusting the expansion caused by temperature changes by releasing it through a small hole. It is preferable to use normal air as the gas to be filled in the tube in terms of adjusting the internal pressure.

[0013] The "transmitter" may be a speaker or the like, and the "receiver" may be a microphone or the like.

[0014] The "tube condition" includes the temperature inside the tube, and any abnormalities such as tube breakage or deformation.

[0015] The "diagnostic unit" may be a microcomputer, and may be provided inside the first end unit, or may be provided outside the first end unit.

[0016] The first diagnostic unit measures the time it takes for a signal to reach the first receiving unit after being sent from the first transmitting unit, and can estimate the temperature inside the tube based on that time.

[0017] Since the speed of sound in air changes depending on temperature, by transmitting a sound wave inside a tube of a certain length and detecting the change in the speed of sound from the time it takes for the reflected sound to arrive, it is possible to estimate the change in temperature.

[0018] The first diagnostic unit measures the time it takes for a signal to reach the first receiving unit after being sent from the first transmitting unit, and can detect an abnormality in the tube based on that time.

[0019] The first diagnostic unit can detect an abnormality in the tube based on the attenuation or sound of the probe sound received by the first receiving unit.

[0020] The vehicle further includes a determination unit that determines whether or not a vehicle collision has occurred, and the determination unit can calibrate the determination based on the output of the first diagnosis unit. Here, "calibration of the determination" can include, for example, calibration of a value that is a collision criterion based on the internal pressure of the tube.

[0021] The temperature around the tube can be estimated based on the temperature inside the tube. Since urethane foam or the like is arranged around the tube and the pressure (impact) of the collision reaches the tube through the urethane foam, it is important to understand the hardness change due to temperature of the surrounding materials such as the urethane foam. When the temperature is high, the hardness of the urethane foam decreases (becomes softer), and even with a relatively small impact, the internal pressure of the tube is more likely to reach the specified value (threshold value). On the other hand, when the temperature is low, the hardness of the urethane foam increases, and even with a relatively large impact, the internal pressure of the tube is less likely to reach the specified value (threshold value). Therefore, the collision detection criteria can be calibrated taking these conditions into consideration.

[0022] Furthermore, the determination section can detect an abnormality in the tube and issue a warning based on the degree of attenuation of the probe sound input to the first diagnosis section and on acoustic changes.

[0023] A reflecting member for reflecting the detection sound may be further provided near the connection between the second end unit and the tube.

[0024] By providing a reflecting member, the probe sound can be reliably reflected, enabling accurate measurement.

[0025] The device may further include a second transmitting unit provided in the second end unit, which transmits a probe sound toward the first end unit through the tube; a second receiving unit which receives the probe sound reflected and returned by the first end unit; and a second diagnosing unit which diagnoses the condition of the tube based on the probe sound input to the second receiving unit.

[0026] A final diagnosis can be made based on the diagnostic results from the first diagnostic section and the second diagnostic section.

[0027] By transmitting and receiving probe tones from both ends of the tube and performing a diagnosis, a more accurate diagnosis is possible than a one-way diagnosis.

[0028] A second aspect of the present invention is a diagnostic method for diagnosing the operating condition of a tube in a vehicle collision detection device using a tube having a first end and a second end, with a first end unit and a second end unit respectively connected to the ends, the method including the steps of: transmitting a probe sound from the first end unit through the tube toward the second end unit; receiving the probe sound reflected by the second end unit and returning to the first end unit; and diagnosing the operating condition of the tube based on the received probe sound.

[0029] The method may further include a step of measuring the time it takes for the signal to reach the first receiving unit after being sent from the first transmitting unit; and a step of estimating the temperature inside the tube based on the measured time.

[0030] The method may further include a step of measuring the time it takes for the signal to reach the first receiving unit after being sent from the first transmitting unit; and a step of detecting an abnormality in the tube based on the measured time. [Brief description of the drawings]

[0031] [Figure 1]Fig. 1(A) is a schematic diagram of a vehicle equipped with a collision detection device to which the present invention can be applied, and Fig. 1(B) is a schematic cross-sectional view showing the structure of a main part of the collision detection device to which the present invention can be applied. [Diagram 2] 2A is a conceptual diagram (block diagram) showing the structure of a diagnostic device according to a first embodiment of the present invention, and FIG. 2B is a block diagram showing mainly the configuration of a control system of the diagnostic device according to the first embodiment of the present invention. [Diagram 3] Fig. 3(A) is a conceptual diagram (block diagram) showing a state when the tube of the collision detection device according to the first embodiment of the present invention is normal, and corresponds to Fig. 2(A). Fig. 3(B) is a graph showing a waveform of a detection sound when the tube of the collision detection device according to the first embodiment of the present invention is normal. [Figure 4] 4A is a conceptual diagram (block diagram) showing a state when an abnormality (clogging) occurs in a tube of the collision detection device according to the first embodiment of the present invention, and FIG. 4B is a graph showing a waveform of a detection sound when an abnormality (clogging) occurs in a tube of the collision detection device according to the first embodiment of the present invention. [Diagram 5] 5A is a conceptual diagram (block diagram) showing a state when there is an abnormality (hole) in the tube of the collision detection device according to the first embodiment of the present invention, and FIG. 5B is a graph showing a waveform of a detection sound when there is an abnormality (hole) in the tube of the collision detection device according to the first embodiment of the present invention. [Figure 6] 6A is a conceptual diagram (block diagram) showing a state when an abnormality (deformation) occurs in the tube of the collision detection device according to the first embodiment of the present invention, and FIG. 6B is a graph showing a waveform of a detection sound when an abnormality (deformation) occurs in the tube of the collision detection device according to the first embodiment of the present invention. [Figure 7] FIG. 7 is a flowchart showing the operation of the diagnostic device according to the first embodiment of the present invention. [Figure 8] FIG. 8 is a conceptual diagram (block diagram) showing the structure of a diagnostic device according to a second embodiment of the present invention. [Figure 9] FIG. 9 is a conceptual diagram (block diagram) showing the structure of a diagnostic device according to a third embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0032] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A diagnostic device and a diagnostic method according to embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0033] BACKGROUND OF THE PRESENTINVENTION Fig. 1(A) is a schematic diagram of a vehicle 10 equipped with a collision detection device to which the present invention can be applied, and Fig. 1(B) is a schematic cross-sectional view showing the structure of a main part of the collision detection device to which the present invention can be applied.

[0034] 1(A) and (B), a tube 12 extends generally horizontally in the width direction in front of the vehicle. End units 14L, 14R that mainly detect changes in the internal pressure of the tube 12 are connected to both left and right ends of the tube 12. These end units 14L, 14R are connected to a control unit (ECU) 16. The ECU 16 is connected to safety devices such as bonnet lifters 17L, 17R that are activated in the event of a vehicle collision.

[0035] The tube 12 is disposed in front of the bumper beam 22 so as to be covered with the urethane foam 18. A surface layer 20 is provided on the surface of the urethane foam 18.

[0036] When a pedestrian (bicycle) collides in front of the vehicle 10, pressure is applied to the tube 12 through the urethane foam 18, causing the internal pressure of the tube 12 to rise. This is detected by the end units 14L, 14R and output to the ECU 16. The ECU 16 operates the bonnet lifters 17L, 17R when a collision occurs to lift the windshield side of the bonnet (not shown) and mitigate the impact on the pedestrian. Note that an airbag for protecting the pedestrian can be activated instead of or in addition to the bonnet lifters 17L, 17R.

[0037] (Configuration of the first embodiment) 2A is a conceptual diagram (block diagram) showing the structure of a diagnostic device according to a first embodiment of the present invention, and FIG. 2B is a block diagram showing mainly the configuration of a control system of the diagnostic device according to the first embodiment of the present invention.

[0038] 2(A) and (B), one (left) end unit 14L includes a pressure sensor 24L that detects pressure changes in the tube 12, a speaker 30L that sends out a probe sound toward the opposite end unit 14R via the tube 12, and a microphone 32L that receives the probe sound reflected at the end unit 14R and returned via the tube 12. The end unit 14L also includes a microcomputer 34L connected to the pressure sensor 24L, the speaker 30L, and the microphone 32L, and an interface unit 36L that exchanges signals with the ECU 16.

[0039] The end unit 14R on the opposite side (right side) includes a pressure sensor 24R that detects pressure changes in the tube 12, a microcomputer 34R connected to the pressure sensor 24R, and an interface unit 36R that exchanges signals with the ECU 16.

[0040] The ECU 16 detects the presence or absence of a collision with a pedestrian or a bicycle based on a change in the internal pressure of the tube 12 detected by pressure sensors 24L, 24R provided in the left and right end units 14L, 14R.

[0041] Fig. 3(A) is a conceptual diagram (block diagram) showing the normal state of the tube 12 of the collision detection device according to the first embodiment, and corresponds to Fig. 2(A). Fig. 3(B) is a graph showing the waveform of a probe sound when the tube 12 of the collision detection device according to the first embodiment of the present invention is normal. In Fig. 3(B), "output sound" indicates the probe sound output from the speaker 30L, and "reflected sound" indicates the probe sound (received sound) returned from the end unit 14R via the tube 12.

[0042] When the tube 12 is in a normal state, after the output sound is sent from the speaker 30L, the reflected sound is received by the microphone 32L after a certain time. At this time, the reflected sound is slightly attenuated. The round-trip time of the probe sound can be calculated from the speed of sound and the length of the tube 12.

[0043] 4A is a conceptual diagram (block diagram) showing a state when there is an abnormality (clogging) in the tube 12 of the collision detection device according to the first embodiment of the present invention, and FIG. 4B is a graph showing a waveform of a detection sound when there is an abnormality (clogging) in the tube of the collision detection device according to the first embodiment.

[0044] As shown in FIG. 4(A), when there is a blockage 12a in the tube 12, an abnormality in the tube 12 is detected by a shortened time from the output sound to the reflected sound, as shown in FIG. 4(B).

[0045] 5A is a conceptual diagram (block diagram) showing a state when there is an abnormality (hole) in the tube of the collision detection device according to the first embodiment of the present invention, and FIG. 5B is a graph showing a waveform of a detection sound when there is an abnormality (hole) in the tube of the collision detection device according to the first embodiment of the present invention.

[0046] As shown in FIG. 5(A), if there is a hole 12b or a tear in the tube 12, the volume of the reflected sound decreases as shown in FIG. 5(B), and thus an abnormality in the tube 12 can be detected.

[0047] 6A is a conceptual diagram (block diagram) showing a state when an abnormality (deformation) occurs in the tube of the collision detection device according to the first embodiment of the present invention, and FIG. 6B is a graph showing a waveform of a detection sound when an abnormality (deformation) occurs in the tube of the collision detection device according to the first embodiment of the present invention.

[0048] As shown in Figure 6(A), when there is a deformed portion 12c in the middle of the tube 12, an abnormality in the tube 12 is detected, for example, when multiple reflected sounds are received within a certain period of time, as shown in Figure 6(B).

[0049] (Operation of the first embodiment) FIG. 7 is a flowchart showing the operation (diagnosis method) of the diagnosis device according to the first embodiment of the present invention.

[0050] In this embodiment, the ECU 16 periodically sends a signal instructing the end unit 14L to perform diagnosis. Although the measurement of the probe sound itself is performed by the end unit 14L, the ECU 16 manages the timing of the diagnosis and the recording of the results.

[0051] When the ECU 16 issues a diagnostic command to the end unit 14L, a probe sound is transmitted from the speaker 30L of the end unit 14L to the end unit 14R via the tube 12. The probe sound propagates through the tube 12 at the speed of sound, is reflected by the end unit 14R, returns to the end unit 14L, and is received by the microphone 32L. Note that a pattern such as PWM (pulse width modulation) can be used so that the sound used in one measurement contains multiple vibrations.

[0052] When the microphone 32L of the end unit 14L receives the probe sound, the microcomputer 34L measures the travel time of the probe sound (the time from transmission to reception: reflection time) and outputs the result to the ECU 16. At the same time, the waveform (volume) of the received sound is transmitted to the ECU 16.

[0053] In the ECU 16, when there is an abnormality in the waveform of the received sound, for example, as shown in Figures 4(B), 5(B), and 6(B), the abnormal value counter is incremented by "1." After that, when the abnormal value counter value reaches "10," the ECU 16 issues an alarm, judging that there is an abnormality in the tube 12, such as clogging, breakage, or deformation.

[0054] The ECU 16 can be configured to record the sound under normal conditions and issue an alarm if the sound changes by a certain amount or more. This can be used in combination with abnormalities in the waveform, reflection timing, attenuation, etc.

[0055] If there is no abnormality in the waveform of the received sound, it is determined whether the travel time (reflection time) of the detection sound is within a predetermined range of expected values, and if it is outside the range of expected values, the temperature of the tube 12 is estimated based on the difference with the normal time.

[0056] The ECU 16 calculates an estimated temperature value of the tube 12 using the travel time (reflection time) and the length L of the tube 12. When calculating the estimated temperature value, for example, an average value of the last five measured values ​​at short intervals (about 10 seconds) at the beginning and at longer intervals (about 1 to 5 minutes) thereafter is used, thereby making it possible to reduce disturbances.

[0057] If the reflection time is outside the expected range, the ECU 16 increments the abnormal value counter by "1." When the abnormal value counter value reaches "10," the ECU 16 determines that there is an abnormality in the tube 12 and issues an alarm.

[0058] If the reflection time is outside the range of expected values, the temperature of the tube 12 is estimated based on the temperature dependence of the sound speed using the following formula: Estimated temperature = ((2×L / reflection time)-331.5) / 0.61 The estimated temperature is in degrees Celsius.

[0059] If the room temperature is 23°C, the speed of sound at room temperature is 331.5 + 0.61 x 23 = 345.53 m / s. If the length of the tube is 1.5m, the time it takes for sound to travel 3m round trip is: 3÷345.53 = 8.68231412612508 ms. When the temperature rises by 5 degrees, The result is 3 / (331.5+0.61*28) = 8.60634574559642ms. The difference between the two is 0.075968380528665 ms. Therefore, to measure with an accuracy of 1°C, it is necessary to measure time with a resolution of about 0.01 ms. The "tube length" referred to here is the entire tube length, but the total reflection path length may include the reflection paths inside the end units 14L and 14R.

[0060] When the estimated temperature difference is equal to or greater than a certain level, the ECU 16 calibrates the criterion for determining a collision based on the internal pressure of the tube 12. When the temperature around the tube 12 is high, the urethane foam 18 adjacent to the tube 12 becomes soft, and the internal pressure of the tube 12 is likely to increase even if the impact applied to the tube 12 is weak. Conversely, when the temperature around the tube 12 is low, the urethane foam 18 adjacent to the tube 12 becomes hard, and the internal pressure of the tube 12 is unlikely to increase if the impact applied to the tube 12 is weak. Therefore, the ECU 16 can calibrate the criterion for determining a collision based on the internal pressure of the tube 12 based on the estimated temperature of the tube 12.

[0061] (Second Example) 8 is a conceptual diagram (block diagram) showing the structure of a diagnostic device according to a second embodiment of the present invention. In this embodiment, a reflector 140 that reflects a detection sound is disposed in the right-side end unit 14R. The position of the reflector 140 is a position in the end unit 14R close to the end of the tube 12. Also, the reflector 140 does not necessarily have to be plate-shaped, and can be replaced by a member such as a simple protrusion.

[0062] Since the configuration other than the reflector 140 is similar to that of the first embodiment described above, the same reference numerals are used for corresponding components, and duplicated explanations will be omitted.

[0063] By providing the reflector 140, the probe sound can be reliably reflected, making it possible to measure the travel time accurately.

[0064] (Third Example) 9 is a conceptual diagram (block diagram) showing the structure of a diagnostic device according to a third embodiment of the present invention. In the first embodiment described above, the probe sound is outputted and received only from the left end unit 14L, but in this embodiment, the probe sound is outputted and received also from the right end unit 114R. The left and right end units 14L and 114R have a structure that is exactly reversed left and right.

[0065] 9, the end unit 114R includes a pressure sensor 124R for detecting pressure changes in the tube 12, a speaker 130R for sending out a probe sound through the tube 12 toward the end unit 14L on the opposite side, and a microphone 132R for receiving the probe sound reflected by the end unit 14L and returning through the tube 12. The end unit 114R also includes a microcomputer 134R connected to the pressure sensor 124R, the speaker 130R, and the microphone 132R, and an interface unit 136R for exchanging signals with the ECU 16.

[0066] In this embodiment, after one end unit (e.g., 14L) outputs and receives a probe tone, the other end unit (114R) outputs and receives a probe tone after an interval of about one second. The interval is set by the ECU 16 so that it is long enough for the echo to converge.

[0067] Then, the left and right end units 14L, 114R alternately measure travel time (reflection time), and the ECU 16 estimates the temperature of the tube 12 and detects abnormalities. Other operations are similar to those of the first embodiment described above.

[0068] (Interpretation of the technical scope of the present invention) Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and can be modified as appropriate within the scope of the technical ideas expressed in the claims.

Claims

1. A diagnostic device for a collision detection device that detects a vehicle collision using a tube, comprising: a first end unit coupled to a first end of the tube; a second end unit coupled to a second end of the tube; a first transmitting unit provided in the first end unit and configured to transmit a probe tone toward the second end unit through the tube; a first receiving section for receiving a probe sound reflected back from the second end unit; a first diagnosis unit that diagnoses a condition of the tube based on the probe tone input to the first receiving unit.

2. The diagnostic device according to claim 1, characterized in that the first diagnostic unit measures the time it takes for a signal to reach the first receiving unit after being sent from the first transmitting unit, and estimates the temperature inside the tube based on that time.

3. The diagnostic device according to claim 1, characterized in that the first diagnostic unit measures the time it takes for a signal to reach the first receiving unit after being sent from the first transmitting unit, and detects an abnormality in the tube based on that time.

4. 2. The diagnostic device according to claim 1, wherein the first diagnostic unit detects an abnormality in the tube based on an attenuation or sound of the probe sound received by the first receiving unit.

5. A determination unit that determines whether or not a vehicle collision has occurred, 5. The diagnostic device according to claim 1, wherein the determining section calibrates the determination based on an output of the first diagnostic section.

6. 5. The diagnostic device according to claim 1, further comprising a reflecting member for reflecting the probe sound, the reflecting member being disposed near the second end of the tube.

7. a second transmitting unit provided in the second end unit and configured to transmit a probe tone toward the first end unit through the tube; a second receiving section for receiving a probe tone reflected back from the first end unit; 5. The diagnostic device according to claim 1, further comprising: a second diagnostic unit that diagnoses a condition of the tube based on the probe tone input to the second receiving unit.

8. 8. The diagnostic device according to claim 7, further comprising: a final diagnosis section based on the results of the diagnoses in the first diagnostic section and the second diagnostic section.

9. A method for diagnosing an operating condition of a tube in a vehicle collision detection device using the tube having a first end and a second end connected to a first end unit and a second end unit, the method comprising: sending a probe tone from the first end unit through the tube toward the second end unit; receiving a probe tone reflected at the second end unit and returned to the first end unit; and diagnosing an operating condition of the tube based on the received probe tone.

10. measuring the time it takes for a signal to reach the first receiving unit after being sent from the first transmitting unit; 10. The method of claim 9, further comprising: estimating a temperature within the tube based on the measured time.

11. measuring the time it takes for a signal to reach the first receiving unit after being sent from the first transmitting unit; The diagnostic method according to claim 9, further comprising: detecting an abnormality in the tube based on the measured time.

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