JPS62886A - Obstacle detecting device for vehicle - Google Patents

Abstract

PURPOSE:To eliminate a flicker of the discrimination display of a receiving and transmitting means which indicates the minimum time of the reception and transmission of a measured wave when a vehicle approaches an obstacle oppositely by displaying even a measured wave receiving and transmtitting means which indicates a time within a specific range for the minimum time together with the measured wave receiving and transmitting means which indicates the minimum time. CONSTITUTION:A receiving and transmitting circuit 2 sends an exciting signal to ultrasonic transmitter and receivers 1A-1D provided to the rear bumper of the vehicle at proper intervals to transmit ultrasonic waves, and also receives reflected received signals to output a signal 2a whose pulse length is proportional to the time required from the transmission of the ultrasonic wave to the reception. The arithmetic circuit 3 consisting of an input interface 31, a microcomputer 32, and an output interface 33 inputs the signal 2a successively to detect the minimum time and also calculate and display the distance to the obstacle on a display device 4. Further, the circuit 3 displays one of the transmitter and receivers 1A-1D which indicates the minimum time and transmitter and receivers which indicate time within the specific range for the minimum time on the display device 4.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an obstacle/object detection device that is installed in a vehicle and that reliably detects and notifies an obstacle, particularly when the vehicle is reversing.

[Prior Art] As this type of obstacle detection device, for example, Japanese Patent Application Laid-open No. 1986-
As shown in No. 5079, a plurality of ultrasonic transducers are installed in the rear bumper of a vehicle, and the distance to an obstacle is detected and displayed based on the time it takes for the ultrasonic waves to reflect off the obstacle and return. A device is known that identifies and displays the transducer with the shortest distance to an obstacle. Such a detection device is highly reliable and has the advantage of being able to easily determine which part of the rear of the vehicle is approaching an obstacle, especially when the vehicle approaches an obstacle from an inclined direction.

[Problems to be Solved by the Invention] By the way, in the conventional device described above, when the obstacle is something like a wall and the vehicle approaches it directly, the distance measured by each transducer is almost negligible. The same value will be obtained. Naturally, distance measurement involves a certain amount of error, so the transducer/receiver that indicates the shortest distance is randomly replaced, causing the identification display of the transducer to flicker, making it difficult to see.

An object of the present invention is to provide an obstacle detection device that solves these problems.

[Means for Solving the Problems] As shown in FIG. 1, the obstacle detection device of the present invention includes a plurality of measuring wave receiving and transmitting means, a time measuring means, a minimum time detecting means, and a distance measuring means, which are arranged in parallel on a vehicle. It is equipped with a calculation means, a distance display means, and a measurement wave reception/transmission means display means.

The measurement wave receiving and transmitting means transmits a measurement wave and receives a reflected wave of the measurement wave reflected by an obstacle. The time measurement means measures the time required for each measurement wave receiving and transmitting means from the time when the measurement wave is transmitted to the time when it is received. The minimum time detection means detects the minimum time among the measured times. The distance calculation means calculates the distance to the obstacle based on the minimum time, and this is displayed on the distance display means. The measuring wave receiving/transmitting means display means displays the measuring wave receiving/transmitting means indicating the minimum time and the measuring wave receiving/transmitting means indicating a time within a predetermined range with respect to the minimum time.

[Example] In FIG. 2, 1A, 1B, and 1C11D are ultrasonic transducers installed at appropriate intervals on the rear bumper of the vehicle, and these transducers 1A to 1D are connected to the transmitting/receiving circuit 2. . The receiving and transmitting circuit 2 sequentially sends an excitation signal to each of the transducers 1A to 1D to cause them to emit ultrasonic waves, and also inputs reflected wave reception signals from each of the transducers 1A to 1D, and processes the process from transmitting to receiving ultrasonic waves. A pulse signal 2a having a pulse length proportional to the time required for is output. 3 is an arithmetic circuit, which is composed of an input interface 31, a microcomputer 32, and an output interface 33. The arithmetic circuit 3 sequentially inputs the pulse signals 2a, detects the minimum time, and calculates the distance to the obstacle from this.

The calculated distance is displayed on the display 4 connected thereto via the output interface 33.

The display 4 is provided on a tray or the like in the vehicle interior.

The arithmetic circuit 3 also displays, on the display 4, the transducers 1A to 1D that have shown the minimum time and the transducers 1A to 1D that have shown the time within a predetermined range with respect to the minimum time, according to the procedure described below. do.

Here, the configuration of the transmitter/receiver circuit 2 is shown in FIG. In the figure, terminals T1, T2, T3, and T4 each have a transducer 1.
A to 1D are connected, and the terminal T5 is connected to the above-mentioned interface 31. 21 is an oscillation circuit that emits an excitation signal, 22 is a switching circuit that sequentially connects one of the transducers 1A to 1D to the oscillation circuit 21 and the reception amplifier circuit 24, 25 is a detection circuit, and 26 is an amplification/detection circuit. The comparator circuit 27 allows the received signal to pass only if it has a sufficient amplitude, and emits the pulse signal 2a having a pulse length proportional to the time from the sending of the excitation signal until the output of the comparator circuit 26 appears. This is a pulse output circuit. Reference numeral 23 denotes a timing pulse generating circuit that generates pulses that determine the operation timings of the transmitting circuit 21, the switching circuit 22, and the pulse output circuit 27.

FIG. 4 shows the appearance of the display 4. The display 4 is provided with indicator lights 42A, 428, 420, and 42D corresponding to the numeric display section 41 and the transducers 1A to 1D. The numerical display section 41 displays the shortest distance to the obstacle calculated by the arithmetic circuit 3 in units of 0.1 m. □ Hereinafter, the operation of the arithmetic circuit 3 will be explained based on the program flowcharts shown in FIGS. 5 and 6. Each ultrasonic transducer I
For A to 1D, the times t1, t2, t3, and t4 from when the excitation signal is emitted to when the received signal is obtained are detected, and the minimum value of these times t1 to t4 is detected by the procedure shown in FIG. 5 to determine the minimum time t. is stored as. That is, step 1
In 01-106, time 11-. The sizes from t4 to t4 are successively compared, and the time from 11 to t4 when the minimum value is shown is step 10.
7 to 110 are stored as the minimum time t. Step 1
In step 11, distance 1 is calculated from the above time t using the following equation.

j! (m)=--340-t Here, 340 (m/s) is the speed of sound.

In step 112, the calculated distance 1 is displayed on the display 4 in units of 0.1 m.

In the program shown in FIG. 6, each of the detected times t1 to
For t4, these are within a predetermined range α for the minimum time t.
If it is within a predetermined range α, the indicator lights 42A to 42D corresponding to the transducers 1A to 1D indicating the time t1 to t4 are turned on. In this embodiment, the range α is 0.1 m$, which is the display unit of distance 1, and the corresponding time (0°6 m5).

Therefore, when the time 11 to t4 is measured as shown in FIG. 7 (1) to (4), the minimum time t is the time t4.
is stored (FIG. 7 (5)), and the above time t is displayed on the display 4.
The corresponding distance of 1.2 m is displayed. Also, time t
4 and the transducer 1A11B which showed times t1 and t2 within a predetermined range α with respect to the above time t.
In response to this, the indicator lights 42A, 42B, and 42D are turned on. This is shown in FIG.

The arithmetic circuit 3 in the above embodiment may be constructed of hard logic instead of the microcomputer 32.

Furthermore, it goes without saying that radio waves or the like can be used instead of ultrasonic waves as the measurement waves.

Obstacles are not limited to those behind the vehicle; obstacles in front of or to the sides of the vehicle can also be detected.

The predetermined range α does not need to correspond to the minimum unit of distance display, and may be set larger than the minimum resolution of distance measurement.

[Effects] As described above, according to the device of the present invention, the measurement wave reception and transmission means exhibits the minimum time for reception and transmission of the measurement wave, and the measurement wave reception and transmission means exhibits the time within a predetermined range with respect to the minimum time. Since the means is also displayed, there is no problem that the identification display of the receiving and transmitting means indicating the minimum time flickers when the vehicle approaches an obstacle such as a wall directly.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of the present invention, FIG. 2 is a block diagram showing the hardware configuration of the device, FIG. 3 is a block diagram showing the configuration of the receiving and transmitting circuit, and FIG. 4 is a front perspective view of the display. Figure 5,
FIG. 6 is a program flowchart, and FIG. 7 is a diagram comparing the measurement times. 1A, IB, 1C11D... Ultrasonic transducer (
Measurement wave reception/transmission means) 2... Receiving/transmission circuit (time measurement means) 3...
...Arithmetic circuit 32...Microcomputer 4...
Display device (distance display means and measurement wave reception/transmission means display means) 1st Wi Figure 2 6m 7yB

Claims (1)

[Claims] A plurality of measurement wave reception and transmission means are installed in parallel on the vehicle and transmit measurement waves and receive reflected waves of the measurement waves reflected by obstacles, and each of the measurement wave reception and transmission means is configured to transmit measurement waves. means for measuring the time required for reception, means for detecting the minimum time among the measured times, means for calculating the distance to the obstacle based on the minimum time, and means for calculating the distance to the obstacle based on the minimum time. An obstacle detection device for a vehicle, comprising means for displaying, and means for displaying a measurement wave reception/transmission means indicating the minimum time and a measurement wave reception/transmission means indicating a time within a predetermined range with respect to the minimum time.