JPH07281740A - Method and device for detecting position of unmanned vehicle - Google Patents

Abstract

PURPOSE:To exactly detect a traveling position. CONSTITUTION:A road surface 4 is irradiated with laser light from a laser oscillator 7, and the pattern of interference stripes caused by unevenness on the road surface is caught by an image sensor 8 and outputted to an arithmetic unit 9. On the other hand, the angular velocity information of a gyro 11 is integrated with time by an integrator 12 and outputted to the arithmetic unit 9 as a traveling azimuth angle. The arithmetic unit 9 detects the moving amount of the pattern of interference stripes, gets the traveling distance information of an unmanned vehicle A and detects the position of the unmanned vehicle A by integrating the traveling azimuth angle with that traveling distance. Since the moving amount of the pattern is not affected by the slip of wheels at all, the traveling position can be exactly detected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automated guided vehicle for carrying out physical distribution and transportation in a production factory, a warehouse, or outdoors, and a self-propelled robot for working in a production factory (hereinafter, unmanned traveling body). The present invention relates to a position detection method and device for detecting the traveling position of a vehicle.

[0002]

2. Description of the Related Art As a traveling system for an unmanned traveling body, there is a traveling system in which an unmanned traveling body is guided by a guidance facility (Japanese Patent Application Laid-Open No. 61-61160).
No. 168024), there is a traveling system in which an unmanned traveling body travels autonomously without the need for induction equipment (Japanese Patent Laid-Open No. 62-62160).
No. 221707).

In the former guide traveling system, an induction wire, an optical reflection tape, a magnetic tape, or the like is installed on a traveling route as an induction facility, and an unmanned traveling body is run along them, and an electromagnetic induction system using a dielectric wire is used. In this case, since it is necessary to bury the dielectric wire in the floor, the burial work is troublesome and it is not easy to change the traveling route. In addition, the tape type is extremely dirty and damaged, so maintenance is difficult.

In the latter autonomous traveling system, a gyro for detecting a traveling azimuth angle and a rotation sensor such as a rotary encoder for detecting a rotational speed of wheels are provided on an unmanned traveling body to rotate the traveling azimuth angle detected by the gyro. As shown in FIG. 9, the traveling distance detected by the sensor is integrated to determine the traveling position, and the unmanned traveling body is autonomously traveled.

In FIG. 9, P is the position of the unmanned traveling body, dL is the traveling distance in a minute section, θ is the attitude angle (running azimuth angle) of the unmanned traveling body, and the following integration is performed to obtain the X coordinate value and the Y coordinate. Determine the value.

[0006]

[Equation 1]

[0007]

However, in the conventional position detecting method in which the traveling distance is detected by calculating the traveling distance from the rotational speed of the wheel, the slip amount of the wheel is not constant. There is a problem that it is difficult to accurately detect the traveling position because the distance traveled by one rotation of the wheel changes depending on the degree of wear of the wheel and the distance changes greatly depending on the condition of the road surface.

An object of the present invention is to provide a method and apparatus for detecting the position of an unmanned traveling body, which can accurately detect the traveling position of the unmanned traveling body.

[0009]

In order to achieve the above object, a method for detecting the position of an unmanned vehicle according to the present invention is directed to irradiating a laser beam onto a road surface to form an interference pattern of interference fringes on an image sensor. Then, the amount of movement of this pattern is detected and used as the traveling distance information of the unmanned traveling body, and the traveling azimuth angle of the unmanned traveling body is detected by the gyro, and the traveling azimuth angle is integrated at the traveling distance to perform unmanned traveling. It is configured to detect the position of the body. When the unmanned traveling body travels to the fixed point, it is preferable to correct the position information of the unmanned traveling body to the position of the fixed point.

Further, the position detecting device for an unmanned traveling body according to the present invention is an unmanned traveling system in which the traveling azimuth detected by the gyro is integrated by the arithmetic device with the traveling distance detected by the traveling distance detecting section to detect the position. In the body, the mileage detection unit, a laser oscillator for irradiating the road surface with laser light,
An image sensor is provided which captures the pattern of the interference fringes of the irradiation laser light due to the unevenness of the road surface and outputs the pattern to the arithmetic unit.

[0011]

The image sensor captures the pattern of interference fringes due to the unevenness of the road surface of the laser light and outputs it to the arithmetic unit. The arithmetic unit receives the output signal of the image sensor and detects the amount of movement of the pattern. The amount of movement of the pattern is not affected by the change in the wheel diameter due to the slip or wear of the wheels, and always matches the travel distance of the unmanned traveling body. Therefore, the traveling position of the unmanned traveling body can be accurately detected.

[0012]

1 and 2 show an embodiment of a position detecting device for an unmanned vehicle according to the present invention. Reference numeral 1 in these figures
Is a vehicle body of the unmanned traveling body A. The vehicle body 1 includes four wheels 2, and each wheel 2 is rotated by a servo motor 3 to travel on a road surface 4. Each wheel 2 has a steering function, and four servo motors 3 (only one is shown in FIG. 1).
The steering system (not shown) and the drive system are the same as those of the known unmanned vehicle, such as the front wheels as the steering wheels and the rear wheels as the driving wheels. Can be The steering system and the drive system (motor 3) are controlled by the traveling control device 5.

Reference numeral 6 is a mileage detector. The travel distance detection unit 6 is composed of a laser oscillator 7 and an image sensor 8 and is provided in the center of the vehicle body 1. Laser oscillator 7
Is for irradiating the road surface 4 with laser light as shown in FIGS.

When a laser beam is applied to a rough surface (a surface for diffuse reflection) such as the road surface 4, light interference occurs, and an interference fringe (speckle pattern) S as shown in FIG. 4 is formed. This is because when the laser light hits the rough surface, there is a slight difference in the distance from the rough surface, which causes a phase difference in the diffused light. This interference fringe is determined by the state of the rough surface. If the rough surface is stationary, the interference fringe is stationary, and if the rough surface moves (relative movement in the case of the road surface 4), the interference fringe also moves.

The image sensor 8 captures the interference fringes S generated by the irradiation of the laser light on the road surface 4 and outputs a signal to the arithmetic unit (microprocessor) 9. The arithmetic unit 9 receives the output signal of the image sensor 8 and measures the amount of movement of the interference fringes S, that is, the traveling distance of the unmanned traveling body A. For example, considering one dimension, if the interference fringe S at a certain time is (a) in FIG. 5 and changes to (b) after 10 msec, the resolution of the image sensor 8 becomes 4
If the distance is 0 μm, the movement amount of the interference fringe S is completely equal to the traveling distance of the unmanned traveling body A, so the arithmetic unit 9 sets the traveling distance of the unmanned traveling body A to 40 μm and the speed thereof to 40 μm / 10.
Measure as msec. The height of the laser oscillator 7 and the image sensor 8 from the road surface 4 is usually 5 to 40 mm, but depending on the case, the height may be 4 mm or less.
It may be larger than 0 mm.

Reference numeral 11 is an optical fiber gyro. When the unmanned traveling body A makes a motion including a rotational motion, the gyro 11 detects an angular velocity about the vertical direction of the vehicle body center and outputs a signal to the integrator 12. The integrator 12 is
The angular velocity information of the gyro 11 is time-integrated, converted into an angle, and output to the arithmetic unit 9 as traveling azimuth angle information of the unmanned traveling body A. The arithmetic unit 9 is configured to detect the traveling position of the unmanned traveling body A by integrating the traveling azimuth information obtained by the integrator 12 with the traveling distance information obtained above. The travel control device 5, the travel distance detection unit 6, the computing device 9, the gyro 11, the integrator 12, and the like are mounted on the vehicle body 1.

The position detecting apparatus for an unmanned vehicle according to the present invention having the above-mentioned structure detects the traveling azimuth angle by the gyro 11 and detects the interference fringe S generated by the irradiation of the laser beam on the road surface 4 with the image sensor. Measure the mileage by catching with 8,
The traveling azimuth angle is integrated with the traveling distance to detect the position of the unmanned traveling body A. Therefore, the traveling position of the unmanned traveling body A can always be detected accurately without being affected by the diameter change due to the slip or wear of the wheels 2.

FIG. 6 shows an example in which the unmanned traveling body A is used in a powder carrier. The unmanned traveling body A is a management computer 2
According to the wireless destination instruction of 1, container storage 2
2. The powder metering device 23 and the automatic compounding device 24 travel between the stations 22a, 23a, 24a and the home station 25 to convey the powder. Reference numeral 26 is a virtual traveling route (orbit) in the memory on the unmanned traveling body A, 27
Is a conveyor.

As described above, the present invention knows the current position by accumulating the trajectory of the unmanned traveling body A moving from a specific origin, and constantly repeats two types of integration. Therefore, no matter how accurate the gyro 11 is, it has a small error, and the error increases as the mileage increases. Therefore, as in the case of FIG. While traveling around, the running track will gradually shift and it will not be possible to return to the original point.

Therefore, every time the unmanned traveling body A stops at a predetermined station 22a, 23a, 24a, 25, the traveling position information of the unmanned traveling body A is corrected to the position of that station.

FIG. 7 shows an example of correction control of traveling azimuth angle (posture). In this case, the laser rangefinders 31, 32 provided on the unmanned traveling body A and the stations 22a, 23a, 24
The reflector sheet 33 provided on a and 25 is used. That is, the distances d1 and d2 to the reflector sheet 33 are measured by the two laser rangefinders 31 and 32, and d1 =
The traveling azimuth angle of the unmanned traveling body A is corrected so as to be d2 (θ = 0). Further, even if the distance d1 = d2, if the unmanned traveling body A is too close to or too far from the station, it will be traversed by four-wheel steering, or will be a predetermined distance due to repeated forward and backward movements. To fix.

When correcting the front-back deviation of the stop position of the unmanned vehicle A, the photoelectric switches 41 and 42 provided in the unmanned vehicle A and the dog 4 provided in the station are corrected.
3 and 44 are used, the photoelectric switches 41 and 42 are dog 4
When 3 and 44 are sensed at the same time, the unmanned traveling body A is stopped. The photoelectric switch and the dog may be a pair.

Since the coordinate value of the correct stop position of the unmanned traveling body A at the station is known in advance, after positioning the unmanned traveling body A at the above correct position by the above operation,
The position information of the unmanned traveling body A is corrected to the coordinate value of the positioning stop position. It should be noted that such correction can be performed at a fixed point other than the station. Laser range finder 31, 32,
The reflector sheet 33, the photoelectric switches 41 and 42, and the dogs 43 and 44 can be replaced with other distance measuring means, reflecting means, switch means, and dog means, respectively.

[0024]

As described above, since the method and apparatus for detecting the position of an unmanned vehicle according to the present invention have the above-mentioned structure, they are not affected by wheel slips or diameter changes, and therefore unmanned. The traveling position of the traveling body can be accurately detected. Further, when the unmanned traveling body travels to the fixed point, if the position information of the unmanned traveling body is corrected to the position of the fixed point, an increase in error can be prevented and the position detection accuracy can be maintained.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a position detecting device for an unmanned traveling body according to the present invention.

FIG. 2 is a plan view showing an arrangement example of wheels, an image sensor, and a gyro.

FIG. 3 is a diagram showing operations of a laser oscillator and an image sensor.

FIG. 4 is a diagram showing an example of interference fringes.

FIG. 5 is a diagram showing movement of interference fringes.

FIG. 6 is a diagram showing an example of use of an unmanned traveling body.

FIG. 7 is an explanatory diagram of a method for correcting the position of the unmanned traveling body.

FIG. 8 is an explanatory diagram of a front-back position correction method.

FIG. 9 is a diagram showing a method of calculating a traveling position.

[Explanation of symbols]

 4 road surface 6 mileage detection unit 7 laser oscillator 8 image sensor 9 arithmetic unit 11 gyro 12 integrator A unmanned traveling body S interference fringes

Claims (3)

[Claims] 1. A road surface is irradiated with laser light to capture a pattern of interference fringes due to unevenness of the road surface with an image sensor, and the amount of movement of this pattern is detected to be used as travel distance information of an unmanned traveling body. A position detecting method for an unmanned traveling body, comprising detecting a traveling azimuth angle of the traveling body and integrating the traveling azimuth angle at the traveling distance to detect a position of the unmanned traveling body. 2. The position detecting method for an unmanned traveling body according to claim 1, wherein when the unmanned traveling body travels to a fixed point, the position information of the unmanned traveling body is corrected to the position of the fixed point. 3. An unmanned vehicle which detects a position by integrating a traveling azimuth detected by a gyro with a traveling distance detected by a traveling distance detecting section by a computing device, wherein the traveling distance detecting section has a laser on a road surface. A position detecting device for an unmanned vehicle, comprising: a laser oscillator that irradiates light; and an image sensor that captures an interference fringe pattern of the irradiating laser light due to unevenness of the road surface and outputs the image to the arithmetic device.