JPS58189573A - Obstacle detector of vehicle - Google Patents

Abstract

PURPOSE:To obtain an obstacle detector for a vehicle, which is capable of moving backward the vehicle safely enough, by outputting the information a road surface state behind the vehicle by an ultrasonic distance measurement. CONSTITUTION:A distance D to a road surface 6 is measured by width of a pulse outputted by an RS type FF11 which is set and reset responding to ultrasonic transmitting and receiving signals through ultrasonic transmitter and receiver 5, 7 provided on a rear bumper 19, etc. of a vehicle. When it is detected by the first and the second comparing circuits 15, 16 that the width of the output pulse of the FF11 corresponding to the distance D which is varied in accordance with unevenness of this road surface 6 is below a prescribed value and above other prescribed value, alarms by the first and the second alarming circuits 17, 18 are generated. According to this constitution, it is possible to obtain an obstacle detector for a vehicle, which is capable of moving backward the vehicle safely enough.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vehicle obstacle detection device, and more particularly to a vehicle obstacle detection device NK that uses ultrasonic waves to detect various obstacles behind a vehicle.

Conventionally, a contact prevention device using ultrasonic waves has been used for the purpose of preventing an accident in which a vehicle body contacts an obstacle at the rear when the vehicle is backing up. This vehicle contact prevention device emits ultrasonic waves from an ultrasonic generator installed at the rear of the vehicle toward the rear of the vehicle body, receives the reflected waves from the ultrasonic generator trap, and
It was configured to measure the presence or absence of an obstacle in the rear and the distance to the obstacle, and either give an appropriate warning to the driver or directly display the distance. Therefore, conventional devices of this type are unable to detect relatively low obstacles, grooves, or severe unevenness on the road surface, and are unable to detect obstacles that are relatively low, such as grooves or severe unevenness on the road surface, and cannot detect obstacles that are relatively low. I had the good luck point of not having one.

Therefore, an object of the present invention is to be able to detect relatively low obstacles at the rear of the vehicle width and unevenness of the road surface that may impede the running of the vehicle, and to ensure sufficient safety at the rear of the vehicle. An object of the present invention is to provide an obstacle detection device Il for a vehicle.

The configuration of the present invention for achieving the above object includes a transmitter installed at the rear of a vehicle for intermittently transmitting ultrasonic waves toward the road surface according to a transmission timing signal that is repeatedly output; means for receiving reflected ultrasonic waves from obstacles on the road surface and converting them into electrical signals; means for detecting wave reception timing based on the electrical signals; The present invention is characterized in that it comprises means for outputting a time difference signal indicating the time difference between the corresponding reception timing and output means for outputting information regarding the road surface condition behind the axle based on the time difference signal. are doing. According to such a configuration, when there are severe irregularities on the road surface or when there are low obstacles on the road surface, the time difference indicated by the time difference signal is 7'5'? It is possible to reliably detect that there is an obstacle or groove that is outside the range of the foot and that impedes running on the road surface, and it is possible to sufficiently check the safety of the rear.

The output means may be configured to directly display the distance to the road surface based on the time difference signal, or may be configured to generate a buzzer when the distance to the road surface increases or decreases beyond a predetermined appropriate range. , a lamp or the like may be used to issue an alarm. Historically, the device of the present invention can be configured to share a part of the circuit of a conventional ultrasonic obstacle detection device, and if configured in this way, the circuit scale can be greatly increased. Therefore, it is possible to obtain an extremely reliable low-profile device that can reliably detect the state of obstacles in the entire area behind the axle without causing any interference.

Hereinafter, the present invention will be explained in detail with reference to illustrated embodiments.

FIG. 1 shows an embodiment of the invention.
``This vehicle obstacle detection device [1] has an oscillation circuit 2 that generates a signal Sst- with a frequency of about 40 KHz, and the oscillation circuit 2 has a constant period T output from a pulse generation circuit 3.
It is controlled by the gate pulse signal St (FIG. 2(a)) to output the signal 8s' only when the level of the gate pulse signal S becomes high. The period 'r of the gate signal S is, for example, 20 to 30
m5, and the pulse generating circuit 3 is controlled so that it is at a high level only for a short period of time. Therefore, the signal S is input to the ultrasonic transmitter 5 via the amplifier circuit 4 for a short period of time when the gate pulse: Signal S
Ultrasonic waves of the same frequency as the frequency of l are converted to UK.

The ultrasonic transmitter 5 is fixed downwardly to the rear nozzle 19 of a vehicle (not shown) by appropriate means so that the ultrasonic wave U is transmitted toward the road surface 6. The reflected wave Rt that hit the road surface 6 and was reflected - also directed downward to receive the wave) is converted into an electrical signal.This converted electrical signal is an input signal of 8m (11m).
After being input to the amplifier 8 as (FIG. 2(C)) and amplified there, the amplified output signal Sa (FIG. 2(d)) is subjected to envelope MIIs detection by the detection circuit 9. The envelope detection output signal S, (FIG. 2(e)) obtained by the detection circuit 9 is inputted to the reception pulse generation circuit 1O and waveform-shaped,
As shown in FIG. 2(f) K'', a rectangular wave signal that rises at the reception timing of the reflected wave L and falls at the end of reception is used as a reception wave signal S, which is sent to the flip-flop 11. Applied to one input.

Gate pulse signal S! is (transmission timing) and the rising time t2 (transmission timing) of received pulse 1g signal S6 (
The time difference Δt between the receiving timing and the receiving timing is that the ultrasonic wave output from the transmitting wave a5 hits the path 1fii6 and is reflected, and the receiving wave 57
In this embodiment, it changes according to the distance from the bumper 19 of the vehicle to the road surface 6.

A flip-flop 11 is provided to generate a time difference signal representing this time difference Δtt-, and a gate pulse signal S and a reception pulse signal S6 are applied to a set terminal and a reset terminal, respectively. Therefore, this flip-flop 11 receives the gate pulse signal S! It is set at the rising timing of the received pulse signal S8, and is set at the rising timing of the received pulse signal S8. As a result, a pulse signal S having a pulse width Δt is output as a time difference signal.

Based on the pulse signal S, it is determined whether or not there is any obstacle on the road surface 6 that would impede the running of the vehicle, and if there is an obstacle, the information is output. 12 is input. The fault determination circuit 12 determines whether the distance casing is normal on a flat road surface [Dn
It is determined whether the distance is between a lower limit distance Da that is shorter than Do by a predetermined value and an upper limit distance Db that is longer than Do by a predetermined value, and an output signal indicating whether the cage D is shorter than Dl or longer than Db. This is a circuit that outputs 0*-Ox. Therefore, the fault determination circuit 12 converts the first reference pulse signal P with the pulse width Wa corresponding to the lower limit distance Da into the gate pulse signal S! a first reference pulse generator 13 that outputs an output based on;
A second reference pulse output a14 is provided based on a second reference pulse signal Pvk gate pulse signal S having a pulse width wb corresponding to the upper limit distance 11Db. 1st and 2nd
The reference pulse signal Pt p P* is shown in Figure 2 (hL, (+
)K, one period and rising timing are equal to gate pulse signal S, and each reference pulse signal P, , P
.

is applied to one input of each of the first and wc2 comparison circuits 15 and 16. The first and second comparator circuits 15 and 16 also receive the pulse No. 748 s7, respectively, and each receives two input pulses (No. i S, 748).

The pulse widths of,P,and,S,,,P,are compared.

The a1!1 comparison circuit 15 calculates the pulse width W of the pulse signal S.
This is a pulse width comparison circuit in which the level of the output signal ol becomes high when the distance @D becomes shorter than Dl, that is, when the distance @D becomes shorter than Dl, the second comparison (b) path 1
6 is the output signal 0.6 when the pulse width W of the pulse signal S becomes longer than wb, that is, when the distance #h becomes longer than Db. This is a pulse width comparison circuit in which the level ゛ is a high level.

Output signal 0. ．． 0. is input as the discrimination output signal of the fault discrimination circuit 12 to @l and the second alarm circuit 17.18, and the output signal 01 p O! is configured to issue a pressure alarm in response to the level of becoming high.

According to such a configuration, when the distance changes depending on the unevenness of the road surface 6, the presence or absence of grooves, etc., the pulse width W of the pulse signal S7 changes accordingly, so that the distance is outside the normal distance Dn. When t becomes less than Da or more than Db, the first alarm circuit 17 or the second alarm circuit 18 is activated to notify the driver that the road surface is high or low. In this case, if there is an obstacle such as a relatively large stone on the road surface 6, the alarm circuit 17 will be activated.

Therefore, in addition to road surface irregularities, grooves, etc., obstacles placed on the road surface can also be detected, and the safe state of the road surface behind the vehicle can be ensured.

In the above embodiment, the S piece provided with two alarm circuits t is shown, or the output No. 18 is 0. ．． 0. one alarm circuit responsive to tk
f&ke, output signal 01,0. On the other hand, it became a high level! This alarm circuit may be activated at #a.

Warning circuit (Vrc can be configured as appropriate to give a warning to the driver using a buzzer, lamp, etc.) With the configuration shown in Figure 1, the Vrc can be configured so that each buzzer sound of w@i circuit 17 and 18 is different. The driver can hear the tone of the buzzer, 41k
The height of the road surface behind the vehicle can be known from the vC.

@3 Figure VC shows another example of leprosy according to the present invention. The vehicle obstacle detection device vt2I shown in FIG. Another set of ultrasonic transmitter 22 and receiver 23 is provided at point Par.

The ultrasonic transmitter 22 is installed to emit an ultrasonic wave U' toward the rear of the vehicle in a substantially horizontal direction, and the receiving wave 523 is a reflection of the ultrasonic wave iU' that hits an obstacle in the rear and is reflected. Board'
It is set up so that it can receive all waves. In Fig. 3, in each part where a<Iν1? Corresponding parts are indicated by the same reference numerals and the explanation ψ1 is omitted entirely. Each ultrasonic transmitter 5
, 22 are equipped with the equipment shown in FIG. Just as in the case of tl, the signal S from the launch 1 line 2 is controlled by the gate pulse signal 8.

is applied via amplifier 4 to each ultrasonic transmitter 5.22.
Ultrasonic sounds @U, U' are heard from the road surface 6 and vehicles (not shown).
(Fig. 4(a)
), (b) 8). iMUkJ6 and wall 24
The reflected waves R and R' reflected by the receiver 7.23 are converted into electric signals S, a, S, b (Fig.
) l and input to the amplifier 25. Here, since the receivers 7.23 are arranged at right angles to each other,
Only the reflected waves of the ultrasonic waves from the corresponding transmitters can be detected and converted into corresponding electrical signals.

Reflection corresponding to ultrasonic waves U, U/? E7. Generally, the signal obtained based on R' is 8sapSsbk, and the increase is 1M! Since the switching signal SW output from the switching circuit 26 is alternately amplified in the switching circuit 25, the amplifier VC outputs the switching signal SW output from the switching circuit 26.
is entered. This switching No. 1g SW is a pulse signal generated by the switching circuit 26 based on the gate pulse signal S, and its level is alternately inverted at each rising point of the gate pulse signal S. 41 So 1(e)). The amplifier 25 is configured to amplify the signals S and a when the level of the switching signal SW is high, and amplify the signal S3b when the level of the switching signal 8W is low. Use.

As shown in Figure 4(f), the increased output signal S, / is the signal corresponding to the reflected wave H and the signal corresponding to the reflected wave R'.
It is output in a format that alternately includes the following symbols.

The amplified output signal S,/ is envelope-detected by the detection circuit 9, and its detection output 4'p,@S,' (4th Shil(g
)) is determined by the passive pulse generation circuit IO with waveform shape n,
Square wave pulse signal 8. ' (Figure 4 (h)) as a flip-flop (F/F)
be done. The flip-flop 11 converts the pulse signal 3./ into the time difference (
It occurs as g, but upper λ [: As you can see from the explanation,
This pulse signal d, / is the distance 1Il to the path 1ml]6
A nozzle with a pulse width Wl corresponding to IID and a wall surface 24
Distance to ゛@corresponding to L (Rus IIJ W, of)
(This is a pulse signal in which pulses and pulses are alternately generated (Fig. 4 (1)).

The pulse signal S, / is the same as the first and second reference pulse signal P1. as shown in FIG. Pt is input to the first and second comparison circuits 15 and 16, respectively, and the first and second comparison circuits 1415 and 16 are activated only when the switching signal SW is at the level. The pulse widths of the input signals are compared in two lines, and the result is the output signal, which drives the first and second alarm circuits 17 and 18. This pulse width comparison operation is as follows: 1st
It is similar to that of the device shown in the figure. This device 1j21 is provided with a third reference pulse generator 27 and a third comparator circuit 28 in order to detect all of the distances and output an alarm even when the distance is less than a predetermined distance. Standard) (Russ generator 2
7 is a predetermined pulse @W based on the switching signal SW.
(Third criterion for C) The pulse signal Psk is output, and the pulse width wt and Wc are compared during the period when the switching signal SW is at a low level (S, Wc≧W.

In this case, the output signal O3 of the third comparison circuit 'N128 is configured to be at a high level. Output signal O8
is input to a third alarm circuit 29 provided corresponding to the third comparison circuit 28, and when the level of the output signal 0 becomes high level, the $3 alarm circuit 29 is activated to alert the driver. be able to.

Therefore, if the pulse width Wc is set appropriately, an alarm can be output when the vehicle moves backward and the distance to the wall 24 reaches a desired value.

According to such a configuration, by simply adding a small circuit to the device l shown in FIG. Since it can be detected, the safety behind the vehicle can be confirmed even more reliably.

According to the present invention, as described above, it is possible to reliably detect the unevenness of the road surface behind the vehicle, the presence or absence of grooves, stones, etc.
This provides an excellent effect of allowing the vehicle to move backwards extremely safely.

[Brief explanation of drawings]

Fig. 1 is a block diagram of an embodiment of the present invention, Fig. 2(a)
2 to 2 (I) are time charts showing waveforms of various parts of the device shown in FIG. 1, FIG. 3 is a block diagram of another embodiment of the present invention, and FIG. 4 (a) to 4 ( 1) is a time chart showing the waveforms of each part of the apparatus shown in FIG. 1.21... Obstacle construction device for vehicle, 2... Oscillation circuit, 3... Pulse generation circuit, 5, 22... Ultrasonic wave transmitter, 6... Road surface, 7, 23 ...Receiver, 9...
Detection circuit, 11... clip flop (F/F),
12... Fault determination circuit, 17... First alarm circuit,
18...Second alarm circuit, 19...Third alarm circuit, U
, U/...Ultrasonic wave, R, R'...Reflected wave, 8m.
...Signal, S, ...Gate pulse signal, S, ...Input signal, S, a, S, b ...Electrical signal, S6...
・Reception Hals m number, S-t...pulse signal, SW...
- Switching signal, 0. ．． 0. ．． 0. ...Output signal. Patent applicant: Diesel Kiki Co., Ltd. Agent: Patent attorney Masatoshi Takano Figure 1 447 - Figure 2 112

Claims (1)

[Claims] 1. Means for repeatedly outputting a transmission timing signal;
A transmitter attached to the rear of the vehicle that transmits ultrasonic waves tlLt intermittently toward the road surface in accordance with the transmission timing signal, and a transmitter that receives reflected waves of the ultrasonic waves from the road surface or obstacles on the road surface. means for converting the ultrasonic wave into an electric signal; means for detecting the reception timing based on the WM distribution multiplied signal; and a time difference indicating the time difference between the transmission timing of the ultrasonic wave and the reception timing with respect to the transmission timing. An obstacle detection device for a vehicle, comprising means for outputting a signal, and output means for outputting information regarding a road surface condition behind the vehicle based on the time difference signal. 2. The output means includes a determination means for determining whether or not the time difference sky is within a predetermined range in response to the time difference signal, and means for outputting a warning according to the determination result of the determination means, An obstacle detection device for a vehicle according to claim 1, wherein the vehicle obstacle detection device outputs an S report when the position of the obstacle is outside a predetermined level range.