JPH0792265A - Obstacle detection apparatus - Google Patents

Abstract

PURPOSE:To precisely detect a distance and a direction up to an obstacle existing around a car by a method wherein at least one ultrasonic-wave transmitter and a plurality of ultrasonic-wave receivers are installed on the four sides, the front, rear, right and left sides of the car. CONSTITUTION:Ultrasonic waves at different frequencies are sent from four sides of a car (an own vehicle) 3 from sonar sensors 5, 8, 11, 14, ultrasonic waves reflected by an obstacle (other vehicles or the like) are received by remaining sonar sensors 4, 6, 7, 9, 10, 12, 13, 15, and the transmission time and the reception time of the ultrasonic waves are sent to a microcomputer 18. The microcomputer 18 computes the direction and the distance of the obstacle existing around the own vehicle 3 on the basis of the wave-transmission time and the wave-reception time of the ultrasonic waves. When the obstacle is recognized inside a three-dimensional space, the sensors 5, 8, 11, 14 are changed over for wave-reception after the ultrasonic waves have been transmitted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an obstacle detecting device for determining the distance of an obstacle existing around an automobile from the vehicle body of the obstacle and the direction of the obstacle with respect to the vehicle body.

[0002]

2. Description of the Related Art If there is an obstacle ahead of a moving vehicle, it can be visually confirmed by the driver and appropriate measures can be taken. There are various obstacles such as other cars, guardrails, sound insulation walls, protection walls, street trees, houses, earthen walls, and standing signs. This can easily be done with the driver. When an unmanned vehicle is to be driven, an obstacle detection device is required so that the vehicle can avoid the obstacles when traveling. Further, when it is desired to follow the vehicle ahead of the vehicle and allow the vehicle to travel unmanned, the relative position of the vehicle ahead must be accurately detected.
The preceding vehicle in this case is also included in the concept of an obstacle here. The present invention is not only useful for detecting obstacles in unmanned vehicles, but it can also be used to supplement the driver's vision even when manned.

The present inventor considered that an obstacle could be detected by ultrasonic waves. For example, the ultrasonic receiver is attached to the front bumper of the vehicle body. An ultrasonic wave is transmitted from the ultrasonic receiver at a certain time. At this time, if there is an obstacle in front of the vehicle, the transmitted ultrasonic wave is reflected by the obstacle and returns to the ultrasonic receiver. This is received by the ultrasonic receiver. The time difference between them is calculated from the time when the ultrasonic wave is transmitted and the time when the return wave is received. When the time difference multiplied by the ultrasonic velocity is divided by 2, the distance from the ultrasonic receiver to the obstacle is obtained. With such a simple method, it should be possible to obtain the distance from the vehicle body to the obstacle.

A device in which an ultrasonic wave is used to detect an automobile around the automobile has already been proposed by Japanese Utility Model Application Laid-Open No. 2-73299. The purpose is to enable multiple cars to track automatically. This is for automatically driving a plurality of automobiles A, B, C, D, E ... Equipped with eight ultrasonic oscillators and several ultrasonic receivers around the vehicle body.

FIG. 8 shows a schematic structure of one automobile. This has eight sonar sensors 201 in front of the car,
It is provided on the left, right, and rear. It has a transmission / reception circuit 202, a microcomputer 203, a PWM circuit 205, and the like. This controls the DC motor 204. The DC motor 204 rotates the tire 206 at an appropriate rotation speed. In this system, the car A emits ultrasonic waves for a certain period of time and the other car receives the ultrasonic waves. The time of transmission is known in advance, and the time of reception is known to the car. Thereby, the distance between the car A and the other car is known to the other car.

In the next time, car B emits ultrasonic waves and another car receives the ultrasonic waves. As a result, the distance between car B and the other car is known to the other car. In this way, if there are N vehicles, N (N-1) times of measurement are periodically repeated.
Since the data of each individual vehicle is (N-1), the relative position distance cannot be determined. Therefore, there is a central unit that collects these N (N-1) data and performs calculations. Then, the relative plane positions of all cars can be calculated.

This method receives directly transmitted ultrasonic waves rather than reflected waves. Attenuation is small, received signal strength is large, and false reception is small. Since the transmission time is divided, there is no interference. Further, since there are N (N-1) independent data, there is an advantage that the relative positions of the automobiles can be calculated with high accuracy. This, of course, assumes that the clocks on each car are strictly accurate.

[0008]

The above-described method for finding the mutual directional distances of automobiles requires instantaneously complicated calculations. In addition, the target is other automobiles. These vehicles must also be equipped with ultrasonic transceivers. Cannot detect road walls or general obstacles such as stones.

Further, it is indispensable to use three or more cars and collect the data of each car to the central unit by radio, assuming the existence of the central unit. This is because the purpose is to enable multiple cars to track automatically. However, such a method cannot be used in the case where a single vehicle detects obstacles and enables proper automatic driving. Even with two cars, it is impossible. I don't know the direction because I know only one distance.

It is an object of the invention that a single vehicle can detect the relative position of obstacles. Relative position is the distance and direction from a car to an obstacle.

[0011]

An obstacle detecting apparatus of the present invention is an apparatus for detecting an obstacle existing around a vehicle by ultrasonic waves, and at least on each side of a direction in which the obstacle should be detected. One ultrasonic wave transmitter and two or more wave receivers are installed, and the ultrasonic wave transmitters on each side generate ultrasonic waves of different frequencies at the same time or at different times in a pulse shape, and the ultrasonic waves on one side are transmitted. The ultrasonic waves emitted from the wave detector hit the obstacle in that direction and are reflected and detected by the wave receiver on the same side.The time when the ultrasonic wave is received by the wave receiver and the ultrasonic wave by the wave transmitter are detected. The length of the path connecting the transmitter, the obstacle, and the receiver is calculated from the difference in the time of transmission. Since there are two or more receivers on each side, the distance to the obstacle and the obstacle It is characterized by calculating a certain direction.

[0012]

In the apparatus of the present invention, at least one ultrasonic wave transmitter and two or more wave receivers are provided on the front, rear, left and right sides of the vehicle. Of course, it is provided only on the necessary side, and if it is necessary only on the front side, it may be provided only on the front side. If necessary before and after, it should be provided only before and after. What will be described later is provided on four sides. Sensors can be omitted from unnecessary sides.

One set will be described. It has one or more ultrasonic transmitters. One case will be described. When detecting an obstacle two-dimensionally, two wave receivers are enough. The time at which ultrasonic waves are generated in pulses by the transmitter is fixed. The ultrasonic waves strike an obstacle in that direction and are reflected thereby. Part of the reflected wave returns to the two receivers. The time when the ultrasonic wave is received by the receiver is known. Then, the sum of the distance between the transmitter and the obstacle and the distance between the obstacle and the two receivers becomes equal to the product of the sound velocity of the ultrasonic wave and the delay time of transmission and reception. Since there are two receivers, two equations can be made. Therefore, the exact position of the obstacle can be calculated. If you have one receiver, you can only have one equation,
It is not possible to find both the distance and the bearing to the obstacle.

Since the present invention uses two or more wave receivers, the distance and azimuth of an obstacle can be accurately detected.
When a set of a wave transmitter and a wave receiver is provided on four sides, the frequency is changed to distinguish the signals of the wave transmitter. If the frequencies are different, the received pulses can be distinguished on the receiver side.
The wave transmitters on the respective sides may emit pulses at the same time or may emit pulses at different times. Since the source of the pulse can be distinguished by frequency, it may be transmitted at different times.

When there are three or more wave receivers on the same side, the coordinates of the obstacle can be obtained three-dimensionally. This is because there are three equations related to time and distance. Even if there are three, they can be used for two-dimensional obstacle position determination. In this case, since the expression has redundancy, the accuracy can be improved. When deciding the position of the obstacle three-dimensionally, three wave receivers are required, but one of them may be used by the wave transmitter. A sensor that can be used for both transmission and reception is used, and after transmission, the function is switched to the reception function and used as a receiver. By doing so, the position of the obstacle can be three-dimensionally determined by using two dedicated wave receivers and one wave transmitter / receiver.

[0016]

1 is a schematic configuration diagram of an automobile equipped with an obstacle detection device according to an embodiment of the present invention. This car is an electric car. DC motor 2 powered by battery 1
Driven by. Ultrasonic transducers (also called sonar sensors) 4, 5 for transmitting and receiving ultrasonic waves are provided around the automobile 3.
..., 15 is attached. In order to eliminate blind spots, these sonar sensors are attached to the front, rear, left and right of the vehicle, respectively. Of the three sonar sensors on each side, the central part can transmit ultrasonic waves, and the two on both sides are for reception only. The central sonar sensors 5, 8, 11, 14 can also be used for reception. Among sonar sensors, one that transmits ultrasonic waves is also called a wave transmitter, and one that receives ultrasonic waves is also called a wave receiver. The transmission / reception circuit 17 gives a pulse ultrasonic wave of a predetermined frequency to each wave transmitter and receives a reception signal from each wave receiver.

An ultrasonic transducer 16 is provided to process the signals from each sonar sensor. Ultrasonic transducer 1
6 has the following functions.

(1) The output from the transmission / reception circuit 17 to each of the sonar sensors 4 to 15 is converted to the microcomputer 1
Control is performed by switching to an analog switch according to a command from 8. (2) When the reflected wave is received after transmitting the ultrasonic wave, the difference between the reception time and the transmission time is obtained. From the time difference, the microcomputer 18 calculates the distance and azimuth of obstacles existing around the vehicle 3.

(3) The output corresponding to the calculation result of the microcomputer 18 is displayed on the display plate 21. At the same time, the driver can be notified by voice from the voice generator 24. (4) A control signal relating to running of the vehicle is obtained from the calculation result of the microcomputer 18 and the mode of the mode setting device 25 manually set by the driver. The control output obtained here is reported to the driver by the voice generator 24.
At the same time, the duty ratio control is performed in accordance with the rotation and the like of the tire 20 according to the forward movement, backward movement, left turn, right turn, etc. of the automobile 3.

The present invention basically considers the case of recognizing an obstacle in a two-dimensional plane. In the following description, recognition in a two-dimensional plane is targeted unless otherwise specified. Of course, the present invention is also effective for three-dimensional recognition, so this will also be described.

The sonar sensors 5, 8, 11, 14 are used here for transmitting ultrasonic waves. These transmit ultrasonic waves in different directions. Sonar sensor 5 forward,
The sonar sensor 8 sends ultrasonic waves to the left, the sonar sensor 11 sends backward ultrasonic waves, and the sonar sensor 14 sends ultrasonic waves right. By controlling the transmission timing of the transmission / reception circuit 17, ultrasonic waves of different frequencies are transmitted from the sonar sensors 5, 8, 11, and 14 at the same time. The remaining sonar sensors 4, 6,
7, 9, 10, 12, 13, and 15 are used for receiving ultrasonic waves.

The sonar sensors 4 to 15 know the ultrasonic wave transmission time and ultrasonic wave reception time, and the signals are sent to the microcomputer 18. The microcomputer 18
From the transmission time of ultrasonic waves and the reception time of each ultrasonic receiver,
Calculates the location and distance of obstacles around the vehicle.

When recognizing an obstacle in a three-dimensional space,
The sonar sensors 5, 8, 11, and 14 are switched to receive waves by a command from the microcomputer 18 after transmitting ultrasonic waves. That is, in the case of three-dimensional recognition, some sonar sensors transmit waves and all sonar sensors receive waves.

Next, the operation of this embodiment will be described. Figure 3
Shows the transmission waveform and the reception waveform of each sonar sensor. Figure 3
Vehicle 22 as an obstacle in front of and behind the vehicle,
The case where 23 exists will be described. However, the coordinate axis is own vehicle 3
The two axes X and Y are provided so as to be orthogonal to each other in the horizontal plane of the vehicle from any one point. Set the coordinates of the vehicle 22 in front of (X
₂₂ , Y ₂₂ ), and the coordinates of the rear vehicle 23 are (X ₂₃ ,
Y ₂₃ ). The position of each sonar sensor i (4 ≦ i ≦ 15) is represented by coordinates (X _i , Y _i ). The vehicle 22 ahead,
The distance from each previous sonar sensor i (4 ≦ i ≦ 6) is represented by D _i . The rear vehicle 23 and the rear sonar sensor i (10 ≦
The distance to i ≦ 12) is represented by D _i .

The ultrasonic transmitter 5 transmits ultrasonic waves of 40 kHz,
The ultrasonic wave transmitter 8 transmits an ultrasonic wave of 45 kHz, the ultrasonic wave transmitter 11 transmits an ultrasonic wave of 50 kHz, and the ultrasonic wave transmitter 14 transmits an ultrasonic wave of 55 kHz.
ultrasonic waves of 200 kHz for 200 μs at the same time T ₀
It will be transmitted during the period. Then, every 100 ms from the transmission start time, ultrasonic waves are repeatedly transmitted for 200 μs at the same timing. That is, all the ultrasonic wave transmitters are designed to generate pulses of 200 μs at the same time with repetition of 100 ms. The reason why each ultrasonic transmitter sends a pulse of a different frequency is that when it hits an obstacle and is reflected, it can be distinguished. All of the wave transmitters 5, 8, 11, and 14 emit pulses at the same time in synchronism with each other, but they may not be at the same time. This is because, even at different times, the transmitters can be distinguished by the frequency of the ultrasonic waves, so that it is possible to calculate the time difference between the transmitted and received waves.

As the ultrasonic waves hit the vehicles 22, 23, they are reflected. Ultrasonic waves are sent from the sonar sensor 5 to the vehicle ahead and reflected. The ultrasonic wave receiver 4 receives the reflected wave from the front vehicle 22 at time T ₁ . Subsequently, the ultrasonic wave receiver 6 receives the same reflected wave at time T ₂ .

The ultrasonic waves from the sonar sensor 11 hit the rear vehicle and are reflected there. The reflected wave from the rear vehicle 23 is received by the ultrasonic wave receiver 10 at time T ₄ . Next, the ultrasonic wave receiver 12 receives the reflected wave from the same rear vehicle 23 at time T ₅ . The microcomputer 18 determines the ultrasonic wave transmission time T _{0 of the} vehicle and the ultrasonic wave receivers 4, 6, 10,
From the reception times T ₁ , T ₂ , T ₄ , and T _{5 at} 11, the azimuths of the front vehicle 22 and the rear vehicle 23 with respect to the own vehicle and the distance from the own vehicle are obtained. The sound velocity of ultrasonic waves is V. For the vehicle ahead, the following equation holds:

(X ₄ −X ₂₂ ) ² + (Y ₄ −Y ₂₂ ) ² = D ₄ ² (1) (X ₅ −X ₂₂ ) ² + (Y ₅ −Y ₂₂ ) ² = D ₅ ² (2 )

(X ₆ −X ₂₂ ) ² + (Y ₆ −Y ₂₂ ) ² = D ₆ ² (3) D ₄ + D ₅ = (T ₁ −T ₀ ) V (4) D ₅ + D ₆ = (T _2- T ₀ ) V (5)

Similarly, the following equation holds for the position of the rear vehicle. ^{_{(X 10 -X 23) 2 +}} (Y 10 -Y 23) 2 = D 10 2 (6)

(X ₁₁ -X ₂₃ ) ² + (Y ₁₁ -Y ₂₃ ) ² = D ₁₁ ² (7) (X ₁₂ -X ₂₃ ) ² + (Y ₁₂ -Y ₂₃ ) ² = D ₁₂ ² (8 )

D ₁₀ + D ₁₁ = (T ₄ −T ₀ ) V (9) D ₁₁ + D ₁₂ = (T ₅ −T ₀ ) V (10)

By solving these equations, the position coordinates of the front obstacle and the rear obstacle and the distance to them can be obtained. This is sufficient for calculating obstacles in a two-dimensional plane.

More equations are needed to find obstacles in three-dimensional space. When calculating the position of an obstacle in the XYZ space, the following measures are taken in order to obtain more equations. Although the ultrasonic wave transmitters 5, 8, 11, and 14 are originally wave transmitters, they are used for both purposes. The ultrasonic wave transmitters 5, 8, 11, and 14 are switched to T ₀ immediately after transmitting the ultrasonic waves. Then, the ultrasonic wave reception time is measured by each of the ultrasonic wave receivers 4 to 15. The azimuth and distance of the obstacle in the three-dimensional space can be calculated using the same calculation formula as above. That is, assuming that the coordinates of the front obstacle are (X ₂₂ , Y ₂₂ , Z ₂₂ ), the equation for the front obstacle can be rewritten as follows.

(X ₄ −X ₂₂ ) ² + (Y ₄ −Y ₂₂ ) ² + (Z ₄ −Z ₂₂ ) ² = D ₄ ² (11)

[0036] ^{_{(X 5 -X 22) 2 +}} (Y 5 -Y 22) 2 + (Z 5 -Z 22) 2 = D 5 2 (12)

(X _6- X ₂₂ ) ² + (Y _6- Y ₂₂ ) ² + (Z _6- Z ₂₂ ) ² = D ₆ ² (13)

D ₄ + D ₅ = (T ₁ −T ₀ ) V (14) D ₅ + D ₆ = (T ₂ −T ₀ ) V (15) 2D ₅ = (T ₃ −T ₀ ) V (16)

Here, T ₃ is the time when the sonar sensor 5 receives the wave. Since the transceiver is the same, the round trip distance is 2D
Become ₅ . If the coordinates of the three-dimensional obstacle behind are (X ₂₃ , Y ₂₃ , Z ₂₃ ), the following equation holds similarly.

(X ₁₀ −X ₂₃ ) ² + (Y ₁₀ −Y ₂₃ ) ² + (Z ₁₀ −Z ₂₃ ) ² = D ₁₀ ² (17)

(X ₁₁ −X ₂₃ ) ² + (Y ₁₁ −Y ₂₃ ) ² + (Z ₁₁ −Z ₂₃ ) ² = D ₁₁ ² (18)

(X ₁₂ -X ₂₃ ) ² + (Y ₁₂ -Y ₂₃ ) ² + (Z ₁₂ -Z ₂₃ ) ² = D ₁₂ ² (19)

D ₁₀ + D ₁₁ = (T ₄ −T ₀ ) V (20) D ₁₁ + D ₁₂ = (T ₅ −T ₀ ) V (21) 2D ₁₁ = (T ₆ −T ₀ ) V (22)

Here, T ₆ is the time when the sonar sensor 11 receives the wave. As described above, the distance to the obstacle existing around the vehicle body and each obstacle orientation can be obtained on the two-dimensional plane or in the three-dimensional space.

When the obtained distance from the own vehicle of the obstacle becomes equal to or less than the safety distance defined later, it is necessary to control the running of the vehicle and give a warning to the driver. The safe distance is the minimum distance that can be safely traveled. The driver sets the safety distance and controls the traveling of the vehicle by the mode setting device 25.
It is made different depending on the mode set by. There are the following four types of setting modes.

(1) Forward vehicle following mode (2) Avoidance mode (3) Manual mode (4) Garage entry mode

The safe distance to the obstacle is first divided according to whether the mode of the mode setting device is the garage entry mode. In the case of the garage entry mode, the safety distance for the garage entry mode that is predetermined for each direction is referred to. When not in the garage entry mode, the safety distance ahead is obtained from the current vehicle speed. The safety distances in the remaining three directions (right, left, rear) refer to preset distances.

The distance to the obstacle calculated by the microcomputer 18 is compared with the safety distance set as described above. When the distance to an obstacle such as a front vehicle or a rear vehicle becomes shorter than the safety distance, the sound generating device 24
To warn the driver. Further, the calculation result is displayed on the display board 21. For example, when the vehicle in front approaches the safe distance or less (at a dangerous distance), the display as shown in FIG. 4 can be displayed.

The display plate 21 is incorporated in, for example, an instrumental panel of a vehicle body. The vehicle is shown in the center of the display board. An angle memory representing the direction of 360 degrees is provided around the vehicle every 10 degrees. The rightward direction is 0 degrees, the previous direction is 90 degrees, the left is 180 degrees, and the rear is 270 degrees. The direction of the obstacle can be specified by this angle. 36 elongated light emitting diodes are installed between the center car body and each scale (every 10 degrees). If there is an obstacle in front of or behind, within the safe distance, the light emitting diode closest to that direction emits light. If the vehicle ahead is within the safe distance and is in the azimuth of 72 degrees ahead (18 degrees to the right of the center of the front), the light emitting diode at the position of 70 degrees emits a light to warn. A digital display plate indicating the distance is provided above the angle dial. Here, a display of 20.30 m is made. This means that the distance to the vehicle ahead is 20.30m. In this way, when the obstacle approaches within the safe distance (at a dangerous distance), the distance and direction to the obstacle are displayed.

Further, when the obstacle is within the danger distance,
The microcomputer 18 controls traveling as follows according to the mode value of the mode setting device 25.

(1) When the mode value of the mode setting device is the following vehicle following mode. In this case, a signal for generating a word to enter the following traveling state is sent to the voice generating device. The voice generator informs the driver by voice that he will enter the follow-up run. Also, it sends a control signal to the PWM circuit 19 to follow the vehicle ahead while keeping a safe distance. (2) When the mode value is the avoidance mode. Calculate the direction to avoid the vehicle ahead. A signal for performing the avoidance operation is sent to the PWM circuit 19. The avoidance direction is voiced from the voice generator 24. Tell the driver which way to turn to avoid the vehicle ahead.

(3) When the mode value is the manual traveling mode.
The voice generator 24 audibly informs the driver of the fact that the vehicle ahead is approaching and warns the driver. (4) When the mode value is the garage entry mode. Informs the driver that there is an obstacle ahead by using the sound generator 24,
A signal for performing the backward movement is sent to the PWM circuit 19.

(1) to (4) described above are cases where an obstacle exists within the danger distance. If there are no obstacles within the danger distance, it is sufficient to keep the condition as it is. When the mode is a mode other than the manual traveling, a signal for maintaining the current traveling state is sent to the PWM circuit 19.

As described above, the present invention can be applied to the front, rear,
The presence of the right and left obstacles and the distance and direction are automatically sensed. If the obstacle is within the danger distance, a predetermined operation is performed according to the mode value. The PWM circuit 19 controls the speed and the like of the left and right DC motors 2 of the own vehicle in accordance with the transmitted signal. As a result, the desired traveling state can be maintained at all times.

FIG. 5, FIG. 6 and FIG. 7 show flow charts of operations performed by the microcomputer in the present invention.
That is, a flowchart shows operations such as calculation for obtaining the distance and direction to an obstacle, the vehicle operation control, and the display on the display board according to the ultrasonic wave transmission / reception time of each sonar sensor 4-15. Although it is a continuous flow chart, since it cannot be shown on one sheet due to the limitation of drawing size, it is divided into three sheets. This control program starts running when the power is turned on.

(Step 101) When the power is turned on, the RAM of the microcomputer 18 is cleared. Initially set I / O. (Step 102) It is determined whether or not to send the sonar. If sonar, go to step 103. If not, go to step 104. (Step 103) Each ultrasonic wave transmitter / receiver 5, 8, 11, 1
The ultrasonic waves of the frequencies corresponding to 4 are emitted respectively.

(Step 104) The received signal from each ultrasonic wave receiver is analyzed. (Step 105) Based on the reception frequency received by each ultrasonic receiver, it is determined whether the reception waveform is from the front of the vehicle, the left direction, or the right direction. (Steps 106-117) The position and distance of the obstacle are calculated for each direction.

(Step 118) It is determined whether or not the mode value of the mode setting device 25 is the garage entry mode. If it is the garage entry mode, go to step 119. Otherwise, go to steps 120-123. (Step 119) The safety distance set for garage entry is substituted for each direction. (Step 120) The forward safe distance is calculated from the current vehicle speed.

(Steps 121-123) The preset left and right safety distances are substituted for each direction. (Steps 124-127) It is determined whether or not the safety distance set for each direction or calculated from the current vehicle speed is greater than the actual distance to each vehicle. If the safe distance is greater than the actual distance, go to steps 128-131. Otherwise, go to steps 132-135. (Steps 128-131) A flag indicating whether there is an obstacle such as a vehicle in each direction is set to 0.

(Steps 132-135) A flag indicating whether or not there is an obstacle such as a vehicle in each direction is set to 1. (Step 136) All flags set for each direction are multiplied. If the result is 0, it is determined that there is an obstacle around the vehicle, and the process proceeds to step 137. If not, there is no obstacle and the process goes to step 151. (Step 137) The voice generator 24 is activated to inform the driver of the direction and distance at which an obstacle such as a vehicle is present by voice.

(Step 138) A display corresponding to the calculation result is displayed on the display plate 21. (Step 139) If the set value of the mode setting device 25 is set to follow the vehicle ahead, and there is a vehicle ahead, go to step 140. Otherwise, go to step 142. (Step 140) Notify that the voice generator 24 will enter the follow-up mode.

(Step 141) The maximum duty ratio of speed is calculated according to the distance from the vehicle in front. (Step 142) If the mode setting device 25 is in the avoidance mode, go to step 143, otherwise go to step 146. (Step 143) A route for avoiding an obstacle such as a vehicle is calculated from the surrounding situation.

(Step 144) The driver is informed of the calculated avoidance route by voice using the voice generator 24. (Step 145) The maximum duty ratio of speed is calculated from the avoidance route calculated in step 143. (Step 146) If the mode setting device 25 is in the manual traveling mode, proceed to step 147. Otherwise, go to step 148.

(Step 147) The voice generator 24 is used to inform the driver of the fact that the vehicle is in the manual traveling mode. (Step 148) If the mode setting device 25 is in the garage entry mode, go to step 149, otherwise go to step 151. (Step 149) The voice generator 24 informs the driver by voice that the vehicle is in the garage entry mode.

(Step 150) The maximum duty ratio of the speed obtained from the distance to the obstacle such as the surrounding vehicle is calculated. (Step 151) The duty ratio is set so that the duty ratio does not reach the maximum duty ratio. (Step 152) DC motor 2 duty ratio and DC
The product of the circuit period of the motor 2 sets the time for turning on the DC motor and the rotation direction.

As described above, in the case of this embodiment, the sonar sensors 4 to 15 are attached to the automobile 3, and
Three front sonar sensors are set as one set, three left side sonar sensors are set as one set, three right side sonar sensors are set as one set, and three rear sonar sensors are set as one set. The position and direction of the obstacle around the vehicle can be accurately obtained based on the ultrasonic wave transmission time and ultrasonic wave reception time of each set of sonar sensors. In this embodiment, the drive is D
It is performed by the C motor. However, this can also be driven by the engine.

[0067]

INDUSTRIAL APPLICABILITY The present invention uses a moving body such as an automobile in combination with two or more ultrasonic wave receivers and one wave transmitter,
Two or more wave receivers receive the ultrasonic waves emitted from the wave transmitter, which are reflected by the obstacles and returned. Since there are two or more equations regarding the position of the obstacle, the coordinates of the obstacle can be determined. That is, it is possible to accurately obtain the distance and direction from the automobile to the obstacle. The distance and direction of the obstacle is displayed and transmitted by voice. At the same time, it is possible to control the driving of the vehicle so that it is automatically directed in the proper direction. Since the number of sensors is sufficient, the position of the obstacle can be determined in three dimensions.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an automobile including an obstacle detection device of the present invention.

FIG. 2 is a waveform diagram showing the timing of ultrasonic wave transmission and reception in the obstacle detection device of FIG.

FIG. 3 is an explanatory view showing that ultrasonic waves are transmitted from the sonar sensor of the present invention when there are obstacles in the front and rear, are reflected, are returned to the sonar sensor, and are received.

FIG. 4 is a diagram showing an example of a display plate used in the present invention.

FIG. 5 is the first part of a flowchart for obtaining the direction and distance of an obstacle from the time of transmission and reception of ultrasonic waves in the present invention.

FIG. 6 is an intermediate part of a flowchart for obtaining the azimuth and distance of an obstacle from the time of transmission and reception of ultrasonic waves in the present invention.

FIG. 7 is the last part of the flowchart for obtaining the direction and distance of an obstacle from the time of transmission and reception of ultrasonic waves in the present invention.

FIG. 8 is a schematic diagram of a vehicle for explaining the configuration of a vehicle automatic follow-up operation control device of Utility Model No. 2-73299.

[Explanation of symbols]

 1 Battery 2 DC Motor 3 Car 4-15 Sonar Sensor 16 Ultrasonic Handset 17 Transmitter / Receiver Circuit 18 Microcomputer 19 PWM Circuit 20 Tire 21 Display Board 24 Sound Generator 25 Mode Setting Device

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location G05D 1/02 J 9323-3H G08G 1/16 C 7531-3H

Claims (5)

[Claims] 1. An apparatus for detecting obstacles existing around a vehicle by ultrasonic waves, wherein at least one ultrasonic wave transmitter and two or more receivers are provided on each side of the direction in which the obstacles should be detected. A wave generator is installed, and the transmitters on each side generate ultrasonic waves of different frequencies in pulses at the same time or at different times, and the ultrasonic waves emitted from the transmitter on one side are in that direction. It is assumed that it will be reflected by an object and will be detected by the wave receiver on the same side, and the difference between the time when the ultrasonic wave is received by the wave receiver and the time when the ultrasonic wave is transmitted by the wave transmitter causes The feature is that the distance to the obstacle and the azimuth with the obstacle are calculated because the length of the path connecting the wave receiver and the wave receiver is obtained, and there are two or more wave receivers on each side. Obstacle detection device. 2. An ultrasonic wave transmitter arranged on each side of an automobile can be used as a wave receiver, and immediately after transmitting the ultrasonic wave, the ultrasonic wave transmitter functions as a wave receiver, When an obstacle is originally detected, an ultrasonic pulse of one frequency is received by at least three receivers, and due to the time delay from the ultrasonic wave transmission time to the reception time at each receiver, 3 about distance of obstacle and obstacle and sum of distance of obstacle and transmitter
The obstacle detection device according to claim 1, wherein the distance and the azimuth of the obstacle are three-dimensionally calculated by obtaining the above equation and solving the equation. 3. An ultrasonic wave transmitter and two ultrasonic wave receivers as a set are arranged on each side of an automobile, and the ultrasonic wave transmitter transmits ultrasonic waves at time T _0. The first ultrasonic wave receiver and the second ultrasonic wave receiver oscillate, and this wave is reflected by an obstacle in the direction of the side where the set of these transmitters and receivers is arranged and reflected back. The two-dimensional coordinates of the obstacle are (X ₄ , X ₄ ), the coordinates of the transmitter are (X ₃ , Y ₃ ), and the coordinates of the first receiver are assumed to be measured at the times T ₁ and T _2. (X
₁ , Y ₁ ), the coordinates of the second receiver are (X ₂ , Y ₂ ), the sound velocity of the ultrasonic wave is V, and the coordinates (X ₄ , Y ₄ ) of the obstacle are calculated by the following equation. And {(X ₃ −X ₄ ) ² + (Y ₃ −Y ₄ ) ² } ^1/2 + {(X
^{_{1 -X 4) 2 + (Y}} 1 -Y 4) 2} 1/2 = V (T 1 -T
₀ ) ² {(X ₃ -X ₄ ) ² + (Y ₃ -Y ₄ ) ² } ^1/2 + {(X
^{_{2 -X 4) 2 + (Y}} 2 -Y 4) 2} 1/2 = V (T 2 -T
₀ ) ^Two and different sets of ultrasonic transmitters shall emit ultrasonic waves of different frequencies, the receiver shall be able to distinguish the ultrasonic waves received by the frequency, and the signals from the different sets of transmitters shall be And the ultrasonic waves of the transmitter of the group to which it belongs are distinguished, and the ultrasonic waves of the transmitters of each group emit ultrasonic waves at the same time or at different times. apparatus. 4. The obstacle according to claim 1, further comprising a drive device for detecting an obstacle existing on the front, rear, left and right of the vehicle and controlling driving of the vehicle based on the obstacle. Object detection device. 5. The obstacle detection device according to claim 1, further comprising a display plate for displaying to a driver the calculated azimuth and distance to a vehicle existing around the automobile.