JPH0542689B2 - - Google Patents

Description

[Detailed Description of the Invention] (a) Object of the Invention [Field of Industrial Application] This invention relates to a method for guiding an unmanned mobile object such as a mobile robot.

This type of unmanned mobile body moves within rooms such as hospitals and factories.

[Prior Art] Mobile objects such as robots cannot use a scale to directly read the position, except for those that run on rails, so other means are needed to provide position information to the control device of the moving object. Landmarks are one such means.

A moving object uses a visual sensor to read landmarks attached to the floor or wall along its travel route, obtains position information from the landmarks, and controls its own direction and posture by comparing it with a pre-given map. drive.

Conventionally, most of the landmarks that have been proposed use the floors and walls of hallways. In other words, there are methods in which strip-shaped white lines are continuously pasted on the floor and walls of the hallway, methods in which they are pasted discontinuously, and methods in which geometric figures such as squares and triangles are used.

[Problems to be Solved by the Invention] However, all of the methods of pasting landmarks on the floor have the drawback of staining and damage, and in particular, it takes time and effort to paste the landmarks. The same goes for pasting landmarks on walls; it takes time and effort, and if the height of the visual sensor changes depending on the type of moving object, the landmarks must be pasted according to the height. Must be replaced. Furthermore, it becomes unusable due to staining or damage, and there is also a high possibility that the landmarks on the walls may be hidden by luggage in the hallway or the like.

Because of this, installation does not take much time,
It is desired to develop a landmark method that is less likely to be soiled, damaged, or hidden by luggage.

This invention was made in view of the above circumstances, and it is possible to use existing facilities as they are as landmarks, so there is no need for the effort of installing landmarks, and there is no need to damage the landmarks. It is an object of the present invention to provide a method for controlling an unmanned moving object, which is less likely to be damaged or concealed by luggage, and which can always accurately and easily obtain information to control the moving object.

(B) Structure of the Invention [Means for Solving the Problem] Corresponding to this objective, the method for guiding an unmanned moving object of the present invention is a method for guiding a moving object that moves according to a predetermined map. A photoelectric conversion element that receives light from the fluorescent lamp and converts it into electricity by receiving light from the fluorescent lamp and has a barcode configured by removably fitting an opaque ring into the fluorescent lamp, and output from the photoelectric conversion element. It includes a bandpass filter that filters in a set band, a comparator that compares the output of the bandpass filter with a set threshold, a judgment circuit that makes a judgment based on the output of the comparator, and a barcode reader processing circuit. It is characterized by using an AC light source detection device to detect fluorescent lights installed on the ceiling of the moving passage, and using the fluorescent lights as guide marks.

Hereinafter, details of these inventions will be explained with reference to the drawings showing one embodiment.

In FIGS. 1 and 2, 1 is a moving body, and this moving body 1 is the object of guidance.

The moving body 1 includes a control device 3 and a drive device 4 in a vehicle body 2, and the drive device 4 is controlled by the control device 3 having a built-in computer, drives wheels 5, and moves on a floor surface 6. . The control device 3 has a map of the movement route of the moving body 1 programmed in advance, and inputs and processes signals from the AC light source detection device 7 to control the drive device 4. Although the moving object 1 having such a configuration is known, the present invention is particularly different from the known moving object 1 in that the ceiling AC light source 8 is used as a landmark. For detection, the line of sight of the AC light source detection device 7 is set upward, vertically or diagonally upward.

The ceiling AC light source refers to a light source supported on the ceiling 9 that emits light using AC power, and typical examples of such light sources include fluorescent lamps 12 and incandescent lamps. Fluorescent lamps 12, etc. are installed for illumination, but fluorescent lamps 12, etc. installed in a fixed position from the ceiling have a clear installation position and will not be displaced, so they can be installed on land. It can be used as a mark.

If the fluorescent lamp 12 is provided with another optically readable mark such as a bar code, the mobile object 1 can be attached to the fluorescent lamp 12.
can contain more information needed to control the movement of. When providing a barcode on the fluorescent lamp 12, the barcode may be drawn directly on the fluorescent lamp 12, but in order to be able to cope with changing the content of the information expressed by the barcode,
It is effective to make the barcode removable from the fluorescent lamp 12. For this purpose, as shown in FIG. 3, for example, a large number of black rings 13a and 13b made of synthetic resin with different widths are prepared, and these are fitted onto the fluorescent lamp 12 using the elasticity of the material.
If it is removed, the contents of the barcode can be changed. Furthermore, the width of the bar of the barcode can be changed by making the rings 13a and 13b fitted to the fluorescent lamp 12 adjacent to each other or separating them from each other. In this case, in order to prevent the light of the fluorescent lamp 12 from leaking from the contact surfaces of the rings 13a and 13b, as shown in FIG.
An annular groove 14 and an annular protrusion 15 may be formed on the end surface of 3b so that they can be fitted into each other. Next, the configuration of the AC light source detection device 7 will be explained.

As shown in FIG. 5, the AC light source detection device 7 includes an optical system 17, a photoelectric conversion element 18, an amplifier 21, a bandpass filter 22, and comparators 23a and 23.
b and a judgment circuit 24.

The optical system 17 focuses the light from the fluorescent lamp 12 onto the light receiving surface of the photoelectric conversion element 18 . Photoelectric conversion element 18
For example, a CCD, a photodiode, or a phototransistor is used to output an amount of electricity (for example, current) according to the amount of light received. The output of the photoelectric conversion element 18 is input to an amplifier 21 and amplified, and then input to a bandpass filter 22. The bandpass filter 22 has a function of filtering and extracting only the AC light source component of a specific emission frequency from the input signal. For example, if the fluorescent lamp 12 emits light using a 50-cycle AC power source,
Since its emission frequency is 100Hz, if the band of the bandpass filter 22 is set to 100Hz,
Only the AC component of the fluorescent lamp can be extracted from the input signal. The output of the bandpass filter 22 is input to the comparator 23a,
A square wave is generated at a.

Further, the AC light source detection device 7 includes another comparator 23b in order to remove the influence of external light and ensure the determination of the presence or absence of a fluorescent lamp. That is, the comparator 23b directly inputs the output of the amplifier 21 without passing it through the bandpass filter 22. If the threshold level of the comparator 23b is set to a certain level, the output of the comparator 23b will be "High" if the input light is external light such as sunlight.
However, since no rectangular wave is output from the comparator 23a, it can be determined that the input light is not an AC light source. Furthermore, even if the comparator 23a outputs a 100Hz square wave due to AC induction, the comparator 23b, which determines the absolute value of the input light, outputs "Low", so it is possible to reliably determine the presence or absence of an AC light source. . Therefore, when used in a normal environment where the influence of external light and the like need not be considered, the comparator 23b may not be provided. The output of the comparator 23b is input to the judgment circuit 24 together with the output of the comparator 23a, and the fluorescent lamp 1
2 is detected. As the determination circuit 24, for example, an AND circuit can be used.

[Operation] Next, the operation of the method for guiding an unmanned moving object described above will be explained.

As shown in FIG. 1, it is assumed that the moving object 1 runs on the floor surface 6 of the hallway 26. The computer of the control device 3 of the moving body 1 is programmed with a map of the moving route of the moving body 1 and the relationship between the positions of the fluorescent lamps 12 on the map and stored in advance. Suppose now that the moving body 1 is traveling in the direction indicated by the arrow and reaches the position shown in the figure, the AC light source detection device 7 of the moving body 1 detects the n _i -th fluorescent lamp 12.
is detected, and the signal is input to the control device 3. Based on the input signal, the control device 3 calculates the steering angle according to the program and data, and controls the drive device 4. Turn the corner of the hallway. Next, when the moving object 1 reaches under the n _i+ 1th fluorescent lamp 12, the AC light source detection device 7 similarly detects the n _i+1th fluorescent lamp 12, and the signal is input to the control device 3. Then, the control device 3 controls the drive device 4 so that the steering angle returns to its original value. The detection of the fluorescent lamp 12 is performed by the AC light source detection device 7.

As shown in FIGS. 5 and 6, when the light from the fluorescent lamp 12 enters the optical system 17 of the AC light source detection device 7, the optical system 17 focuses the light onto the light receiving surface of the photoelectric conversion element 18. . The photoelectric conversion element 18 converts into a current according to the amount of incident light (FIG. 6a). This current is input to the amplifier 21 and voltage amplified (sixth
Figure b). On the other hand, the amplified voltage is input to the bandpass filter 22. Bandpass filter 22
By setting the band to, for example, 100 Hz, only the 100 Hz AC component including the emission frequency of the fluorescent lamp is extracted (Figure 6c). The output of the bandpass filter 22 is input to a comparator 23a, which generates a rectangular wave when a voltage exceeding a threshold level corresponding to the amount of light from a fluorescent lamp is input (FIG. 6d). The output of the comparator 23a is input to the judgment circuit 24. On the other hand, the output of the amplifier 21 is input to the comparator 23b. A threshold level corresponding to the amount of light from the fluorescent lamp is set in the comparator 23b, and if there is an input exceeding this threshold level, a high signal is output (FIG. 6e). The output of the comparator 23b is input to the judgment circuit 24. Judgment circuit 24
Then, the output of the comparator 23a is a rectangular wave,
If the output of the comparator 23b is High, it is determined that the photoelectric conversion element 18 is being illuminated by light from the AC light source (fluorescent lamp 12).

The attitude of the moving body 1 can be controlled using the ultrasonic sensor 28 or the like while moving along the wall. However, in the initial state, when the moving body 1 is placed at an arbitrary position with respect to the wall, the fluorescent lamp can be used when it is automatically set parallel to the wall. That is, the seventh
As shown in the figure, assuming that the fluorescent lamp 12 is installed at a certain angle (perpendicular in the case shown) to the wall surface 27, the moving body 1 is configured to be movable in all directions. 1 once passed through the fluorescent lamp 12,
After that, the moving object 1 is moved backward to pass the fluorescent lamp 12 again, and the fluorescent lamp 12 is detected at points a and b,
To calculate the position of the moving body 1, the wall surface 2 of the moving body 1
Since the attitude with respect to 7 is calculated, the control device 3 controls the drive device 4 to steer the wheels 5 and correct the attitude. In addition, when the movable body 1 has a rotatable structure, when the AC light source detection device 7 detects the fluorescent lamp 12 at point a, the movable body 1 is rotated on the spot, and the fluorescent lamp 12 is turned on again at point b. 12 may be detected and the attitude of the moving body 1 may be calculated from the points a and b. To control this posture, another sensor, such as a fixed ultrasonic sensor 28 (FIG. 2), is attached to the moving body 1, and the moving body 1 is moved toward the wall surface 2 by the signal from the AC light source detection device 7. After the posture is controlled to be substantially parallel to the wall surface 27, the ultrasonic sensor 28 may be used to accurately detect the position with respect to the wall surface 27, and accurate posture control may be performed. Further, the ultrasonic sensor 28 is
The height of the ceiling of a hallway may be measured by attaching it to the moving body 1 facing upward.

If a barcode is attached to the fluorescent lamp 12,
In order to ensure that the barcode can be decoded reliably, it is desirable to provide the AC light source detection device 7 with a barcode reader processing circuit and to use an optical system 17 that has an automatic focus adjustment mechanism. In this case, the photoelectric conversion element 18 has both the function of recognizing an AC light source and the function of recognizing a barcode, and after recognizing the AC light source by the method described above, the photoelectric conversion element switches to the function of decoding the barcode.

[Other Embodiments] Other embodiments of the AC light source detection device will be described.

In order to detect the direction of the fluorescent lamp without moving the moving body, the photoelectric conversion element 18 is configured with a light receiving element array in which a large number of light receiving elements are arranged. It is important to avoid possible blind spots. As shown in FIG. 9, the arrangement of elements in the light-receiving element array is a light-receiving element array 31 in which a large number of elements are arranged linearly.
Alternatively, as shown in FIG. 10, it is conceivable to use a light-receiving element array 32 in which a large number of elements are arranged in a matrix. 12), and the matrix-shaped light receiving element array 32 not only requires a large number of elements and is expensive, but also has the problem that signal processing is extremely complicated. Therefore, the first
As shown in FIG. 1, a light receiving element array 33 in which a large number of elements are arranged in an annular shape is suitable. When such a light receiving element array 33 is used, as shown in FIG.
If is the central angle measured from point B, then the angle θ between the linear ceiling AC light source 8 (fluorescent lamp 12) and the moving object 1 can be easily determined as θ=(1/2)(x+y). I can do it.

(c) Effects of the invention In the method for guiding an unmanned moving object of this invention,
A ceiling AC light source, such as a fluorescent light installed on the ceiling, is used as a landmark. Fluorescent lights installed on the ceiling were originally installed for illumination purposes, but can be used as landmarks without the hassle of pasting marks on them. Moreover, it does not get dirty, peel off, or be hidden by luggage, so the judgment circuit and processing circuit necessary for mark detection are simplified, and the control of the moving object is ensured. The equipment required for control can be made inexpensive.

The position of the ceiling AC light source is fixed at the time the building is built, and its positional accuracy is good. The position of a moving object is measured by internal sensors such as encoders and potentiometers, but considerable errors accumulate even when moving several meters due to wheel slippage, calculation errors, and the like. In the present invention, by using an AC light source attached to the ceiling as a reference point for correcting this error, it is possible to accurately control the moving object.

In addition, the attitude control of a moving object can be determined by measuring the distance to a wall using a fixed ultrasonic sensor, but even in this case, when the angle between the wall and the moving object is significantly different, the ultrasonic sensor cannot receive reflected ultrasound waves. However, in the guidance method of the present invention, if the moving object is made approximately parallel to the wall in a mode in which the moving object rotates on the spot or in an equivalent mode, then a fixed ultrasonic sensor can be used and precise distance measurement is possible. This allows the moving body to be accurately parallel to the wall.

Also, if a barcode is attached to a fluorescent lamp,
Unlike regular barcode readers, it does not need to have its own light emitting body, and by using an optical system with an automatic focus adjustment mechanism, it can obtain clear images even when the height of the ceiling changes. It is possible to obtain information such as stopping a moving object, turning right, turning left, changing course, specifying the distance from a wall, etc.

[Brief explanation of drawings]

Figure 1 is a plan view showing the positional relationship between the moving body and the ceiling AC light source, Figure 2 is a side view showing the positional relationship between the moving body and the ceiling AC light source, and Figure 3 is a perspective view of the fluorescent lamp. Fig. 4 is a cross-sectional explanatory diagram showing the ring, Fig. 5 is an explanatory diagram of the configuration of the AC light source detection device, Fig. 6 is an explanatory diagram showing the output waveforms of the components of the AC light source detection device, and Fig. 7 is a movement diagram. FIG. 8 is an explanatory plan view showing a method for detecting the posture of a moving body. FIG. 9 is an explanatory plan view showing an example of a light receiving element array. FIG. 10 is an explanatory view showing an example of a light receiving element array. An explanatory diagram showing another example of the array, FIG. 11 is an explanatory diagram showing another example of the light receiving element array, and FIG. 12 is an explanatory diagram showing a method for calculating the angle of a moving object in the light receiving element array shown in FIG. It is. DESCRIPTION OF SYMBOLS 1... Moving body, 2... Vehicle body, 3... Control device, 4... Drive device, 5... Wheels, 6... Floor surface, 7... AC light source detection device, 8... Ceiling AC light source, 9... Ceiling, 12... Fluorescent lamp, 13a...ring, 13b...ring, 14...annular groove, 15...annular protrusion, 17...optical system, 18...
Photoelectric conversion element, 21... Amplifier, 22... Bandpass filter, 23a... Comparator, 23b... Comparator, 24... Judgment circuit, 26... Corridor, 27...
Wall surface, 28... Ultrasonic sensor, 31... Light receiving element array (linear shape), 32... Light receiving element array (matrix shape), 33... Light receiving element array (circular shape).

Claims (1)

[Claims] 1. A method for guiding a moving object that moves according to a predetermined map, which includes a method for guiding a moving object that moves according to a predetermined map, wherein a light-impermeable ring is removably fitted onto a fluorescent lamp and has a bar code. A photoelectric conversion element that receives light and converts it into electricity; a bandpass filter that filters the output from the photoelectric conversion element in a set band; and a comparator that compares the output of the bandpass filter with a set threshold. Detecting the fluorescent lamp installed on the ceiling of the moving passage using an AC light source detection device including a judgment circuit that makes a judgment based on the output of the comparator and a barcode reader processing circuit, and using the fluorescent lamp as a guide mark. A method for guiding an unmanned moving object.