JPH0521121Y2 - - Google Patents

Description

[Detailed description of the invention] Purpose of the invention (industrial application field) This invention relates to an obstacle detection device for an unmanned vehicle.

(Prior Art) Conventionally, as shown in FIG. 4, in an obstacle detection device installed in an unmanned vehicle, an ultrasonic receiver 2 receives reflected waves of ultrasonic waves output from an ultrasonic generator 1, and the received signal is detected by an ultrasonic receiver 2. The distance to the obstacle was determined based on the following. When the obstacle comes within 2 meters in front, the speed of the unmanned vehicle 3 is reduced, and when the obstacle comes within 1 meter, the unmanned vehicle 3 is immediately stopped.

(Problem that the invention aims to solve) However, since this obstacle detection device uses ultrasonic waves, it is extremely vulnerable to air noise.
That is, since ultrasonic components are included in the exhaust sound emitted from tools whose driving sources are impact wrenches and the like used in factories, there has been a problem that the tools malfunction due to the ultrasonic components. Furthermore, in the ultrasonic detection area Z, only unstable detection was possible in the outer edge Zo indicated by the dashed line in FIG. 4, and there were many cases of erroneous detection.

The purpose of this invention is to solve the above problems, to provide accurate and accurate
Another object of the present invention is to provide an obstacle detection device for an unmanned vehicle that can reliably detect obstacles.

Structure of the invention (Means for solving problems) In order to achieve the above object, this invention includes an ultrasonic generator and an ultrasonic receiver for detecting obstacles in front of the unmanned vehicle in the direction of travel. an ultrasonic receiver receives reflected waves of ultrasonic waves output from the ultrasonic generator, and a first detection area located near the unmanned vehicle based on the received signal; an ultrasonic detection means for detecting an obstacle in a second detection area located further forward; and an obstacle in a travelable area in a first detection area of the ultrasonic detection means, which is provided on the traveling direction side of the unmanned vehicle. An obstacle detection device for an unmanned vehicle, comprising an optical sensor that detects an obstacle, and a determination unit that determines the existence of an obstacle when both the ultrasonic detection unit and the optical sensor detect the obstacle. This is a summary.

(Function) With the above means, the determination means detects obstacles in the first and second detection areas using ultrasonic waves, and the optical sensor detects obstacles in the first detection area. When an obstacle is detected in the possible area using light, the presence of the obstacle is determined.

(Example) An example embodying this invention will be described below with reference to the drawings.

As shown in FIG. 1, an ultrasonic detection device 11 as an ultrasonic detection means is provided on the front side (travel direction side) of the unmanned vehicle 10, and an ultrasonic generator 12 of the ultrasonic detection device 11 is provided in the front side. The ultrasonic receiving device 13 outputs ultrasonic waves and receives ultrasonic waves reflected from obstacles in front. The ultrasonic detection device 11 detects obstacles in an area within 1 meter in front of the vehicle (first detection area Z1), and also detects obstacles in an area from 1 meter to 2 meters in front of the vehicle (second detection area Z2). ) to detect obstacles. That is, this first detection area Z1 is located closer to the unmanned vehicle 10, and the second detection area Z1 is located closer to the unmanned vehicle 10.
The detection area Z2 is located in front of the first detection area Z1.

Furthermore, in addition to the ultrasonic wave generating and receiving devices 12 and 13, the unmanned vehicle 10 is provided with optical sensors 14a and 14b at both left and right ends of the front side of the unmanned vehicle 10, respectively. Each optical sensor 14a, 14
b detects obstacles in the travelable area of the unmanned vehicle 10 in the first detection area Z1 of the ultrasonic detection device 11, that is, in the area that is the width of the vehicle in the direction of travel and centered around 1 meter in front. It's becoming like that.

Next, the electrical configuration of an unmanned vehicle equipped with this obstacle detection device will be explained based on FIG.
The ultrasonic detection control circuit 15 is connected to the ultrasonic generator 1
2 outputs a received signal to the ultrasonic generator 12 to generate ultrasonic waves at a predetermined timing, and also inputs a received signal from the ultrasonic receiver 13.
Based on the received signal, the ultrasonic detection control circuit 15 calculates the distance to the obstacle by measuring the time from when the ultrasonic generator 12 outputs the ultrasonic wave to when the reflected wave is received. And the same control circuit 1
5 outputs the distance detection signal SG1 to the AND circuit 16 as a determination means when the distance is within 1 meter (first detection area Z1), and when the distance is between 1 meter and 2 meters (second detection area Z
In case 2), the distance detection signal SG2 is output.

The ultrasonic detection device 11 is composed of this ultrasonic detection control circuit 15 and the ultrasonic generation and reception devices 12 and 13.

The AND circuit 16 inputs the detection signal SGf from each of the optical sensors 14a, 14b, and receives the detection signal SGf from the optical sensors 14a, 14b, respectively, and also receives the detection signal SGf from the ultrasonic detection control circuit 15 to detect the first obstacle. When the distance detection signal SG1 indicating that the vehicle is in the detection area Z1 is input, a stop signal is output.

The central processing unit (hereinafter referred to as
The CPU 17 operates based on a control program stored in a program memory 18 consisting of a read-only memory (ROM). The CPU 17 outputs a signal to a traveling drive device (not shown) to control the speed of the vehicle.

The CPU 17 receives the distance detection signal SG2 from the ultrasonic detection control circuit 15 and the stop signal from the AND circuit 16. and,
When the CPU 17 receives a distance detection signal SG2 indicating that an obstacle is in the second detection area Z2 from the ultrasonic detection control circuit 15, it controls the travel drive device to reduce the travel speed of the vehicle from high to low.
Further, when the CPU 17 receives a stop signal from the AND circuit 16, it controls the traveling drive device to stop the vehicle. This signal processing operation of the CPU 17 is performed based on a control program stored in the program memory 18.

The working memory 19 is a readable and rewritable memory (RAM) that temporarily stores the calculation results of the CPU 17.

Next, the operation of the unmanned vehicle equipped with the obstacle detection device configured as described above will be explained.

Ultrasonic detection device 1 while unmanned vehicle 10 is running
The first ultrasonic generator 12 outputs ultrasonic waves, and when there is an obstacle within the detection area of the ultrasonic detector 11, the ultrasonic receiver 13 receives the reflected wave. The ultrasonic detection control circuit 15 determines the distance to the obstacle based on the received signal, and when the distance reaches the second detection area Z2, the CPU 17 determines the distance to the obstacle.
Outputs distance detection signal SG2 to. That is,
The CPU 17 controls the travel drive device to shift from high speed travel to low speed travel.

Further, when the ultrasonic detection control circuit 15 determines that the distance to the obstacle has entered the first detection area Z1 based on the signal from the ultrasonic receiving device 13,
A distance detection signal SG1 is output to the AND circuit 16.
The CPU 17 outputs a stop signal from the AND circuit 16,
That is, the distance detection signal SG1 (signal indicating that there is an obstacle in the first detection area Z1) is output from the ultrasonic detection control circuit 15, and both optical sensors 14
When a stop signal is input by outputting a detection signal SGf (a signal indicating that there is an obstacle approximately 1 meter in front of the vehicle in terms of vehicle width) from a and 14b, the drive control device is driven to stop the vehicle. .

Therefore, for example, if there is an obstacle in the outer edge Zo, which is an unstable detection area that is out of the path of the unmanned vehicle 10 and is formed on both the left and right sides of the detection area of the ultrasonic detection device 11, the obstacle cannot be detected by ultrasonic detection. Even if it is detected by the device 11, there is no detection by the optical sensors 14a, 14b, so a stop signal is not output from the AND circuit 16 to the CPU 17, and the vehicle is not stopped. Further, even if the ultrasonic detection device 11 makes a false detection even though there is no obstacle on the outer edge Zo, a stop signal is output from the AND circuit 16 to the CPU 17 since there is no detection by the optical sensors 14a and 14b. There is no need to stop the vehicle.

Furthermore, the optical sensor 14 is not affected by air noise even if the ultrasonic detection device 11 mistakenly detects an object even though there is no obstacle due to air noise while driving.
Since the detection signal SGf is not output from a, 14b, the AND circuit 16 does not output a stop signal. Therefore, malfunctions due to air noise can be prevented.

Furthermore, even if there is an object with a high reflectance of light in the distance in front of the unmanned vehicle 10 while driving, the optical sensors 14a and 14b mistakenly detect the same object and output the detection signal SGf to the AND circuit 16. The ultrasonic detection device 11 determines that the object is far away (determined to be more than 1 meter away), and the AND circuit 16
Since the distance detection signal SG1 is not outputted to the AND circuit 16, the stop signal is not outputted from the AND circuit 16. Therefore, the vehicle will not stop due to erroneous detection by the optical sensors 14a, 14b.

In this way, in the obstacle detection device for the unmanned vehicle 10 of this embodiment, the ultrasonic detection device 11 detects an obstacle within the first detection area Z1, and both optical sensors 14a and 14b detect an obstacle within the travelable area. We decided to stop the vehicle only when an obstacle is detected in the vicinity of 1 meter in front of the vehicle with a certain vehicle width, as it is dangerous to continue driving. It is possible to reliably detect obstacles to vehicle travel by preventing problems caused by erroneous detection at the outer edge zone Zo that is outside the vehicle path. In addition, the optical sensors 14a and 14b compensate for the influence of air noise, and the optical sensors 14a and 14b use reflected light from objects other than obstacles.
The ultrasonic detection device 11, which is not affected by reflected light, compensates for the false detection of the object 14b, thereby making it possible to accurately and reliably detect the obstacle.

Note that this invention is not limited to the above embodiment; for example, instead of the AND circuit 16 as the determination means in the above embodiment, as shown in FIG. Switches 21a and 21b that close the circuit are provided, and both switches 21a and 21b are connected in series. The ultrasonic detection control circuit 15 of the ultrasonic detection device 11 is connected to both switches 21a and 21b.
The distance detection signal SG1 in both switches 21
It is configured to output to the CPU 17 via a and 21b. Therefore, the obstacle is located in the first detection area Z.
1, if both optical sensors 20a and 20b do not detect an obstacle, the signal (stop signal) is
It will not be input to the CPU 17.

Furthermore, the number of optical sensors is not limited to two, and may be only one, or three or more.

Effects of the invention As detailed above, this invention uses the combination of an ultrasonic detection means and an optical sensor to prevent false detection in unstable detection areas by the ultrasonic detection means, and to avoid being affected by disturbances such as air noise. Since there are no obstacles, it exhibits an excellent effect of accurately and reliably detecting obstacles.

[Brief explanation of the drawing]

Figure 1 is a plan view schematically showing an unmanned vehicle equipped with an obstacle detection device that embodies this invention, Figure 2 is an electrical circuit diagram of the same vehicle, and Figure 3 is a different example of an unmanned vehicle equipped with an obstacle detection device. FIG. 4 is a plan view schematically showing an unmanned vehicle equipped with a conventional obstacle detection device. Unmanned vehicle...10, Ultrasonic detection device...11, Ultrasonic generator...12, Ultrasonic receiver...1
3. Optical sensor...14a, 14b, Ultrasonic detection control circuit...15, AND circuit...16, Optical sensor...20a, 20b, Switch...21a, 21
b. First detection area...Z1, second detection area...Z2.

Claims (1)

[Scope of claim for utility model registration] An unmanned vehicle has an ultrasonic generator and an ultrasonic receiver for detecting obstacles in front of it in the direction of travel, and the reflection of ultrasonic waves output from the ultrasonic generator. An ultrasonic receiver receives the waves, and based on the received signals, detects obstacles in a first detection area located near the unmanned vehicle and a second detection area located in front of the first detection area. an optical sensor that is provided on the traveling direction side of the unmanned vehicle and detects an obstacle in a travelable area in a first detection area of the ultrasonic detection means; and the ultrasonic detection means and the optical sensor. An obstacle detection device for an unmanned vehicle, comprising: determination means for determining the existence of an obstacle when both detect the obstacle.