JPS61245072A - Obstruction display device which can be utilized for automobile or the like - Google Patents

Abstract

PURPOSE:To grasp concretely a position of an obstruction by forming and placing two pairs or more of ultrasonic wave transmitting sources and receivers, and applying an object reflected wave signal which has been received by the receiver, through a serial/parallel converting circuit, so that the obstruction can be displayed on a display board. CONSTITUTION:When a gate signal is generated from a timing generating circuit block 3, sensor driving circuit blocks 1A, 1B drive an ultrasonic sensor by its gate signal, a receiving wave is detected and shaped, and a serial signal is supplied to a serial/parallel converting circuit 2. Subsequently, in the circuit 2, a concentric circle group centering around a point for showing each ultrasonic wave transmitting source, an ellipse group whose each point is a focus, and a converted parallel signal are made to correspond, and when each parallel signal satisfies an AND condition in an intersection of its curve group, it is displayed as an obstruction on a display board 4. In this way, a position of the obstruction can be grasped concretely.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an obstacle display device J for the purpose of displaying obstacles behind or on the sides of an automatic rickshaw or the like.

Conventionally, cable cameras or simply mirrors have been used for this purpose. However, cameras are expensive, and because they are secret machines, they often break down and have a narrow field of view, making it difficult to see at night if the lights are off. It may be effective only when the driver's head position is within a certain range, or it may be necessary to attach many mirrors to widen the visible range, making checking the position complicated. It is said that the cleaning becomes frequent and the design becomes poor.

The shortcomings were removed.

There are also devices that use ultrasonic waves to display the distance to rear obstacles, but since they only measure distance in one direction, they can only be used when backing up into a garage, and can be used to assist in confirming rear safety. It could not be used to assist in checking safety when turning left.

By using an ultrasonic sensor for two or more days, the present invention realizes an obstacle display device that is sturdy and has no moving parts and can visually grasp the object position to a certain degree, making the operation of automobiles, etc. safer. We have achieved that goal.

Hereinafter, the implementation means and principle of the present invention will be explained with reference to an embodiment in which a pair of ultrasonic sensors are arranged on the left and right sides of the rear of the own φh vehicle.

FIG. 1 is a conceptual block diagram thereof. IA and IB are circuit blocks that drive the ultrasonic sensor using the fB signal, detect and shape the received wave, and send it out as a serial signal. The specific circuit is shown in FIG. 2 in the case where a piezo electrode is used as an ultrasonic sensor. In Figure 2 [1]
, (2), (3), and (4) are AND gated (5)
is a comparator, (6) is a transverse wave circuit, and (η is a line driver).

In FIG. 1, 2 is a serial-parallel conversion circuit block. A specific example of the circuit is shown in FIG. Below, elements in specific circuits are EIA, /JEDE
It uses a CMOS IC standardized by C, and detailed explanations of the functions of the elements are omitted. In Figure 3, a 4051 analog multiplexer is used for serial-to-parallel conversion, and a latch circuit using resistive feedback is constructed using a 4051 analog multiplexer.
This is achieved by making the logic equal to the SA or SR signal only when the signal is selected.

3 in FIG. 1 is a timing generation circuit block. A typical example of the circuit is shown in FIG.

FIG. 5 shows the timing of the eight signals in FIG. 4. Here, it is assumed that the frequency of CLK equally divides the distance between the sensors IA and IB into four at the speed of sound. For example, if the distance between the sensor blocks is 2 meters and the speed of sound is 400 meters per second, the frequency of CLK can be calculated as 400÷2x4-1 → 800 hertz.

4 in FIG. 1 is a display device. FIG. 6 shows an example of wiring for a display panel that is compatible with the timing generation circuit described above. The places marked with circles in the figure are the light points indicating obstacles, a, ab
, b is located at the intersection of the 8 lines. This light spot is a&! ! ,
It is assumed that the wiring is such that the b line and 3&i of ab&I are lit by logical AND. In the case of FIF, in addition to the normally used negative and positive electrodes, it can be easily realized by having a structure that has electrodes that correspond to a grid in a triple-distribution vacuum tube.

For example, the A line is the cathode, the B line is the anode, the AB line is the grid, and the A line and B line are in an active rod state.

However, it is only necessary to control the light so that it does not turn on unless the AB line is active.

FIG. 7 shows an example of means for implementing logical AND in the case of LEDs. 8 when FIP is not cost-effective due to low snow production, etc.
If placed at a light spot, the same performance can be obtained. 1. By replacing the above circuit with a microprocessor, there is no need to implement AND logic through wiring. FIG. 8 is a simple block diagram in that case. IA,
IB is a block for detecting waves from the speaker rl rib and microphone, 4 is a display device, and 5 is a microprocessor block. The display panel in this case has the same arrangement of light spots as shown in Figure 6, but by omitting the AB line and calculating the AND logic inside the microprocessor, lighting control can be performed by dynamic scanning, resulting in wire savings. It can be achieved.

FIG. 9 is a simple flow chart showing the operation of the microprocessor in the configuration shown in FIG. Since the circuit based on the CMO 5 is simply replaced, a detailed explanation will be omitted.

The invention relies on the principle of triangulation. In other words, the location of the obstacle is known from information on the time it takes for the transmitted signal to return to a plurality of receivers. Although this principle is well known, it is effective only when the object to be measured is known to be one point.

The problem is when there are two points or there is a width, and the multi-line AND method, which is a component of the present invention, is missing. For example, if the ab line is omitted in Fig. 6, the number of points that should be two points is Obstacles have 4 points, and if the obstacle is too wide, the entire display will light up, making it impossible to obtain a correct display. For example, if there is information that the distance is 3 from point A4 and the distance is 4 from point B, you can specify one point (1. If the left and right sides of the straight line connecting A and B are specified), it is possible to specify 1 point from point 5A. Given the information of the distance between 3 and 5 and the information that 4 and 6 are distance from point B, (3, 4) (3, 6) (5, 4)
It can be estimated that it is any one of the four points (5, 6), but in reality it is only one of two or more of these points. The reason for this uncertainty is that although n vectors are required to represent n points, only n pairs of scalar weights are obtained.

, Of course, the present invention does not provide a vector contribution, but only increases the number of n scalars to three sets. Therefore, accurate display can be obtained up to two obstacles, but if the obstacles have a wide range, display errors cannot be completely eliminated. A display error occurs to the same extent as a switch matrix without diodes, that is, when three switches are pressed, the fourth switch that is not pressed is also turned on. Fortunately, however, the ultrasonic skin does not go behind obstacles, so theoretically possible display errors are rarely realized in a way that poses a practical problem. At most, the area adjacent to the original obstacle will be illuminated.

As described above, the principle of the present invention is well known, but in order to make it usable as an obstacle display device, the % line AND method, which is a component of the present invention, is essential. Although this seems like an easy idea, it was necessary to make sure that the actual display errors were within an acceptable range.

Although one means for realizing the horizontal slope of the present invention as simply as possible has been shown, in reality, various embodiments are conceivable. For example, in Figure 3, the demultiplexer ■C4051 used for serial-to-parallel conversion converts 8 bits to 16 bits.
The range and accuracy of measurement and display can be changed by changing to a bit type or using a shift buffer instead of a demultiplexer.

For example, increase the number of sensors and change from 4&I& to 5.
If necessary, display errors can be attributed to @ by using the AND in &I. However, the circuit becomes complicated, the number of wiring layers increases, the time required to manufacture the FIP increases, and the required memory capacity becomes extremely large when processing with a microprocessor, so it is not practical at present.

For example, a DAC is attached to the output of the counter IC 4040B shown in Figure 4, and the ultrasonic sensor 5! ! degree to D
It can be controlled so that it increases as A C'dJ increases, and can be improved to be effective against distant objects. Or, create a proper sawtooth wave using the gate signal in Figure 2! ! ! ! lr! The same is true even if l is controlled.

For example, by attaching an IF sensor to a clock supply circuit, it is possible to correct display errors caused by changes in the speed of sound. Alternatively, if a microcomputer is used, it is easy to measure the speed of sound based on the arrival time between the left and right sensors and automatically correct changes in the speed of sound.

The features of the present invention are described below.

1. Not only the distance but also the specific location of obstacles can be grasped.

2. The trowel surface (a surface that does not diffusely reflect ultrasonic waves) is naturally not visible on the display, so guardrails and paved roads are not visible.

3. There are no moving parts and there are few broken parts, so there are fewer failures.

4. Only 3 wires are required between the display part and the sensor: power supply, gate, and serial signal line. If the power supply and gate are shared, 2 wires are sufficient.By time-sharing, the gate and serial wires can be connected.1. It would be easy to share the same number two.

5. The 8 signal lines between the display part and the sensor can pass digital signals of about 1,000 hertz.

6. Since the display screen is refreshed several dozen times per second,
Noise or false indications caused by other traffic vehicles equipped with the same ultrasonic sensor are of no concern in practice.

for example! It is tolerable compared to the malfunction of the system that sounds a warning tone.

Advantages of using ultrasound instead of radio waves.

1.Do not cause radio interference.

2. When it comes to obstacles with speed differences, the reception frequency of sharks differs from the transmission frequency of mosquitoes, so by narrowing the frequency range of the ultrasonic speaker, roadside information and two-way traffic information when driving at high speeds are cut. I can do it. However, care must be taken because if the image is cut too much, nothing will be visible when the image is packed at high speed.

3. There is no problem even at night.

Advantages of using a multi-line AND method for display.

1. As a method to realize two-dimensional display using ultrasound,
Possible methods include arranging directional ultrasonic sensors or oscillating the sensors, but the first method is expensive.
The latter method has moving parts and is prone to failure.

2. It is possible to realize a 3-wire AND on an electronic circuit and use dynamic scanning for display, but this would be expensive.

3. This can be easily achieved using FIP.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention in which a pair of chord sensors are installed on each side of an automobile. IA and IB are sensor-ff1l power circuit blocks, 2 is a serial-to-parallel conversion circuit block, 3 is a timing signal generation block, and 4 is a display device block. FIG. 2 is a circuit example of a sensor drive circuit block. (
1), (2), (3), and (4) are Nant gate elements, (
5) is a Humbalator element, (6) is a detection circuit, and ■ is a line driver. FIG. 3 is a circuit example of a serial-parallel conversion circuit block. 4051B is analog multiplexer CMO
The resistor FJYR is a resistor for forming a latch circuit. FIG. 4 is a circuit example of a timing signal generation block. 4040F is a counter, and 4028B is a CMOS IC that has a decoder function. FIG. 5 is a timing chart of the timing signals generated in FIG. 4. FIG. 6 is an example of wiring for a display device. The circles at the intersections of each wiring indicate the luminous flux. FIG. 7 is an example of a circuit that realizes the AND logic of light spots using LEDs. FIG. 8 is a block diagram when the present invention is implemented using a microprocessor. IA and IB are sensor driving circuit blocks, 4 is a display device block, and 5 is a microprocessor block. FIG. 9 is a simple flow chart showing the processing of the microcomputer with the configuration shown in FIG.

Claims (1)

[Claims] Two or more ultrasonic sources and receivers are arranged in pairs, and each ultrasonic source alternately emits ultrasonic pulses in the form of a circuit, and the object reflected wave signal received by the receiver is serially and parallelly transmitted. It has a converting circuit (or program), and on the display panel, the parallel signal after the above conversion is made to correspond to a group of concentric circles centered on the point representing each ultrasonic oscillation source, and a group of ellipses centered on each point. , an obstacle display device characterized in that an obstacle is displayed when each parallel signal satisfies an AND condition at an intersection point of a group of curves.