JPH0147722B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for attaching a ground distance detector to a vehicle;
The present invention relates to a road surface condition detection method for detecting the condition of a road surface.

Conventionally, as a device for implementing this type of method, as shown in ``Vehicle Obstacle Detection Device'' of Utility Model Application Publication No. 55-141085, a ground sensor is attached to an electric wheelchair and distance detection using ultrasonic waves is used. It is designed to detect unevenness on the road surface.

However, since this device only detects irregularities on the road surface, it is difficult to know whether the irregularities are temporary and it is possible to continue driving as they are, or whether it is something like a groove that makes it impossible to continue driving as is. The problem is that it cannot be determined.

The present invention has been made in view of the above-mentioned problem, and includes a ground distance detector provided a first predetermined distance in front of the axle of the front wheel in the running direction, and a first distance detector that first measures an abnormal distance. When the abnormal distance is continuously measured from the time point to a second time point when the vehicle has moved by a second predetermined distance shorter than the first predetermined distance, a state in which the vehicle is unable to continue traveling is detected. It is an object of the present invention to provide a road surface condition detection method that can reliably detect road surface conditions that cannot be overcome.

The present invention will be described below with reference to embodiments shown in the accompanying drawings. In FIG. 1, which shows a block diagram showing the overall configuration of an embodiment of the present invention, 1 is a reference pulse generation circuit that generates an ultrasonic carrier wave, a distance signal, etc., and 2 is a reference pulse generation circuit for transmission from the reference pulse generation circuit 1. An ultrasonic transmitter receives carrier wave pulse signal a and emits ultrasonic waves toward the road surface; 3 is an ultrasonic receiver that receives ultrasonic waves reflected from the road surface; A receiving circuit receives the received wave signal b, performs amplification, signal selection, detection, and level comparison to generate a received pulse c; 5 receives the received pulse from the receiving circuit 4 and the distance comparison signal d from the reference pulse generating circuit 1; 6 is a reception discrimination circuit which determines the distance to the obstacle based on the reception pulse and generates an obstacle signal e; 6 inputs the reception pulse c from the reception circuit 4 and the obstacle signal e from the reception discrimination circuit 5 and outputs the reception pulse. A reset circuit generates a reset signal when the obstacle signal e is “0” when c is “1”; 7 is a distance sensor that generates a distance pulse every time the vehicle travels a unit distance of several cm; 8 is a distance sensor When it receives an obstacle signal e of "1" from the reception discrimination circuit 5, it starts counting the distance pulses from the distance sensor 7, and stops counting and resets the count value to 0 in response to a reset signal from the reset circuit 6. A counter circuit 9 generates an alarm signal when the count value reaches a value corresponding to a second predetermined distance (for example, 40 cm). This is an alarm circuit that cancels the alarm generation with a cancel signal based on the input operation.

The ultrasonic transmitter 2 and the ultrasonic transmitter 3 are located approximately from the axle of the rear wheel as shown in Fig. 3a and b.
It is attached 80cm (first predetermined distance) to the rear side. Further, the above-mentioned components 1 to 10 are activated by receiving power supply through a back switch that operates in conjunction with a reverse gear when the vehicle is reversing. Further, the ultrasonic transmitter 2 and the ultrasonic receiver 3 constitute a distance detector.

Next, the operation of the above configuration will be explained with reference to the signal waveform diagram of each part shown in FIG. This second
Signals a, b, c, shown in Figures 1, 2, 3, 4, 5,
d and e correspond to the signals shown in FIG.

Now, ultrasonic pulse a (second
1) is emitted at time t ₁ , and the reflected wave from the road surface of the automobile ground plane is received by the ultrasonic receiver 3 at time ta, then the received wave b (Fig. 2 2) is transmitted to the receiving circuit 4. The input signal passes through an amplifier and a bandpass filter to remove noise, is detected by a detector, and when the level discriminator determines that the level of the received wave that has just been detected is above a predetermined value, the output changes from "0" to "0". “1”
becomes. As a result, the received wave becomes the received pulse c (second
3) and input to the reception determination circuit 5. Therefore, the input of the distance comparison signal d (FIG. 2, 4) of the reference pulse generation circuit 1 is compared with the input at time ta, that is, the rising pulse due to the received pulse c, and if the time ta is now between t ₁ and t ₂ . Then,
Since the distance comparison signal d is "0", its output, the obstacle signal e (FIG. 2, 5), is "0".
Therefore, the counting operation of the counter circuit 8 is not performed.

From this state, if the reflected wave is not reflected from the road surface but from a groove, etc., the ultrasonic pulse a is emitted from the ultrasonic transmitter 2 at time _t3 , and the reflected wave from the groove far from the car ground contact surface is Time tb to sound wave receiver 3
If the received wave b is received at If it is determined that the value is greater than or equal to the value, the output changes from "0" to "1". Thereby, the received wave is converted into a received pulse c, which is input to the reception discrimination circuit 5. Therefore, the input of the distance comparison signal d of the reference pulse generation circuit 1 and the time tb
The input at , that is, the rising pulse due to the received pulse c, is compared, and if time tb is now between t ₄ and t ₅ , the distance comparison signal d is "1", so its output is "1". . That is, the abnormal distance of the groove etc. is determined and the output becomes "1". Then, in response to this first "1" signal, the counter circuit 8 starts counting operation based on the distance pulse from the distance sensor 7.

Thereafter, when the reception discrimination circuit 5 continues to discriminate the abnormal distance based on the reception pulse c from the reception circuit 4, the counter circuit 8 continues to count the distance pulses from the distance sensor 7. Further, the reset circuit 6 does not perform a reset operation on the counter circuit 8 due to the received pulse c from the reception circuit 4 and the obstacle signal e of "1" from the reception discrimination circuit 5.

Then, when the count value in the counter circuit 8 reaches a value corresponding to a second predetermined distance of approximately 40 cm, an alarm signal is generated. As a result, the alarm device 9 generates an alarm to notify the driver of the impediment condition due to the groove or the like.

When the driver or the like recognizes this condition and turns on the cancel switch 10, the alarm device 9 stops generating the alarm.

In addition, if the groove is narrow and can be crossed, the received pulse c immediately returns to the one corresponding to the normal distance, so the reception discrimination circuit 5 does not generate the obstacle signal e of "1". The reset circuit 6 generates a reset signal to the counter circuit 8 to reset the counting operation. Therefore, no alarm is generated in this case.

Next, FIG. 4 is a block diagram showing the main part of another embodiment, in which 8' receives the obstacle signal e of "1" from the reception discrimination circuit 5 and enters the counting operation state, and the If the back signal (signal when the shift lever is put into the back position) is generated, the distance pulse from the distance sensor 7 is counted up, and if the back signal from the back switch 11 is not generated, the distance pulse from the distance sensor 7 is counted up. This is a counter circuit equipped with an up-down counter that counts down and stops the counting operation in response to a reset signal from the reset circuit 6. Therefore, according to this embodiment, the up-down counting function of the counter circuit 8' ensures that the groove is detected even when the car is moved forward a little from the time when the groove is detected and the alarm is generated, and then moved backward again. This can be done to generate an alarm.

Note that the first and second predetermined distances shown above are approximately 80
cm, approximately 40cm, but this value should be changed as appropriate depending on the vehicle model.

In addition, in the above operation, obstacle detection is performed by detecting reflected waves from grooves, etc. that are farther from the ground surface of the car, but reflected waves from protruding obstacles closer to the ground surface may also be detected, or both may be detected. By doing so, both protruding obstacles and groove obstacles from the road surface on which the vehicle is ground may be detected.

Further, the ultrasonic transducers 2 and 3 may be provided in front of the front wheels of the automobile to detect grooves and the like during forward running.

Furthermore, although the ultrasonic transducers 2 and 3 are shown as being provided on one side of the rear wheels, they may be provided on both sides of the rear wheels to perform road surface detection for each.

Furthermore, a warning sound may be generated when an abnormal distance is detected for the first time, and the brake may be forcibly operated when a groove is detected from this point on.

Furthermore, instead of the alarm device 9, a display device that provides a visual display may be used.

Furthermore, if the received pulse c is detected when the distance comparison signal d from the reference pulse generation circuit 1 is "1", it is considered an abnormal distance, but on the contrary, it is now possible to detect the distance from the point at which the ultrasonic wave is emitted to the road surface that can be crossed. A distance comparison signal of "1" is generated until the time when the distance comparison signal is "1", and if the received pulse c is detected when the distance comparison signal is "1", it is assumed that the road surface is normal, and otherwise it is assumed that the road surface is abnormal such as a groove. Good too.

As described above, in the present invention, a ground distance detector is provided a first predetermined distance in front of the axle of the front wheel in the running direction, and this distance detector Since it is detected that the vehicle is unable to continue driving when the abnormal distance is continuously measured from the time point until the second time point when the vehicle has moved by a second predetermined distance shorter than the first predetermined distance, it is detected that the vehicle is unable to continue driving. This has an excellent effect in that it is possible to reliably detect such road surface conditions that cannot be overcome based on distance measurement by one ground distance detector.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention;
2 is a signal waveform diagram of each part in FIG. 1, FIG. 3 is an explanatory diagram of the installation of the ultrasonic transducer, and FIG. 4 is a block diagram showing the main parts of another embodiment. 1... Reference pulse generation circuit, 2, 3... Ultrasonic transmitter and ultrasonic receiver constituting the distance detector, 4
...Receiving circuit, 5...Reception discrimination circuit, 7...Distance sensor, 8...Counter circuit, 9...Alarm device.

Claims (1)

[Scope of Claims] 1. A road surface condition in which a ground distance detector is attached to the front side of the front wheel with respect to the traveling direction of the vehicle to be detected, and the distance from the vehicle to the road surface is measured to detect the condition of the road surface. In the detection method, the distance detector is placed at a first position from the axle of the front wheel.
an abnormal distance from a first point in time when the distance detector first measures the abnormal distance to a second point in time when the vehicle has moved by a second predetermined distance shorter than the first predetermined distance; A road surface condition detection method that detects a condition in which a vehicle cannot continue to drive when continuously measuring.