JPH0611005U - Automated guided vehicle - Google Patents

Abstract

(57) [Summary] [Purpose] Operate without any problem even if there is a defect in some of the guide lines. [Structure] The line-type image sensor 5 photographs a guide wire on a road surface and outputs an image signal. Also the encoder 11
Outputs a distance signal according to the traveling of the automatic guided vehicle 1. The processing device 10 performs signal processing on the image signal to detect the position of the guide wire, and when the guide wire is partially defective and cannot detect the guide wire position, the processor 10 continuously processes and guides using the distance signal. Estimate where the line should originally be.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an automated guided vehicle so that even if a part of the guide wire is defective, it can be operated without trouble.

[0002]

[Prior art]

 Automated guided vehicles are devices that transport parts, products, and small items at various factories, warehouses, offices, and so on. There are various methods such as an optical induction type and an electromagnetic induction type as a method for guiding an unmanned guided vehicle along a traveling path to drive the vehicle unmanned.

Here, a conventional technique using an image sensor in the detection unit of the light guide type will be described with reference to FIGS. 6 and 7. The automatic guided vehicle 1 includes a vehicle body 4 having one front wheel 2 and two rear wheels 3 and 3. A line-type image sensor 5 is provided as a detection unit on the front bottom surface of the vehicle body 4 or on the steering shaft. The image sensor 5 is a general-purpose image sensor (one in which photoelectric elements are linearly arranged) used in a copying machine or the like, and one-dimensional image data can be read at a light intensity. Further, a light emitting diode lamp 6 for illuminating the road surface detected by the image sensor 5 with a constant brightness is provided on the bottom surface of the vehicle body 4. On the other hand, a guide line 7 with contrast to the road surface (for example, a white line when the road surface is dark) is drawn along the guide path.

When the image sensor 5 is located above the guide wire 7 and an image signal is taken out from the image sensor 5 and subjected to image processing, the relationship between the amount of light and the arrangement direction of the elements of the image sensor is as shown in FIG. become. Therefore, the position of the guide line on the image sensor can be detected by calculating the center position of the part with a large amount of light. In other words, the position where the amount of light is large corresponds to the guide line position. By performing this processing in real time, steering control is performed so that the guide wire detection position is at the center position of the image sensor 5 (this position matches the center position of the vehicle body 4). It is possible to drive unmanned along the guide line 7.

[0005]

[Problems to be solved by the device]

 When the image sensor 5 reaches the α position when the guide wire 7 is missing or dirty as shown in FIG. 9 (a), the image signal output of the image sensor 5 is as shown in FIG. 9 (b). It becomes flat. In such a case, even if the image signal from the image sensor 5 is subjected to image processing, the position of the guide line cannot be detected.

Further, as shown in FIG. 10A, when bright (white or the like) dust 8 or the like is falling near the guide wire 7, when the image sensor 5 reaches the β position, the image of the image sensor 5 is displayed. The signal output has two peaks as shown in FIG. When the image signal from the image sensor 5 is image-processed at such a time, it cannot be determined which of the two peak positions is the guide line position.

As described above, conventionally, if a part of the guide wire 7 is defective, the guide wire position cannot be detected, and accurate guide travel may not be possible.

In view of the above-mentioned conventional technique, the present invention provides an automatic guided vehicle that can perform a good guide running even if a part of the guide wire is defective.

[0009]

[Means for Solving the Problems]

 The configuration of the present invention that solves the above-mentioned problem is an unmanned guided vehicle that travels while detecting a guide line with a contrast on the road surface, and a line type image sensor that captures the guide line and outputs an image signal. A distance sensor that detects the distance traveled by the automated guided vehicle and outputs a distance signal, and the image signal is captured at fixed sampling intervals and image processing is performed to detect the position of the object on the image sensor. And a processing device that obtains the travel distance from the distance signal, stores the detected position of the object and the travel distance as a pair, and compares the data stored in each sampling period to detect the position of the guide wire. And

[0010]

[Action]

 In the present invention, by continuously processing using the detected position of the object and the traveling distance, it is possible to estimate the position where the guide wire should originally exist and to travel even if a part of the guide wire is cut.

[0011]

【Example】

 Embodiments of the present invention will be described below in detail with reference to the drawings. It should be noted that parts having the same functions as those of the conventional art are designated by the same reference numerals for description.

FIG. 1 shows an automated guided vehicle 1 according to an embodiment of the present invention. In this automatic guided vehicle 1, an image sensor 5 and a light emitting diode lamp 6 are provided on a vehicle body 4 having front wheels 2 and rear wheels 3. Further, a processing device 10 and a traveling control device 12 are mounted on the vehicle body 4, and an encoder 11 is mounted on the rotary shaft of the front wheel 2. The encoder 11 detects the traveling distance, the distance signal is sent to the processing device 10, and the image signal from the image sensor 5 is sent to the processing device 10 at regular sampling intervals.

Here, the operation of the processing apparatus 10 will be described first with reference to the flow charts of FIGS. 2 and 3, and then, concretely when there is a defect in a part of the guide wire 7. The operation to be performed will be described with reference to FIG.

The main operation of the processing device 10 is as shown in FIG. That is, in step 1, an image signal is fetched from the image sensor 5 at a predetermined sampling timing, and in step 2, image processing is performed to obtain a peak output position. In step 3, the distance signal is input from the encoder 11, and in step 4, continuous processing is performed. By continuing the process, it is possible to predict and determine the position of the guide line even if the guide line is partially cut. Then, in step 5, a signal indicating the guide line position and the like is sent to the traveling control device 12. The traveling control device 12 performs steering control so that the detected position of the guide wire is at the center of the vehicle body.

The continuous processing operation of the processing device 10 is as shown in FIG. That is, if the continuous processing starts (step 11) and the object is detected due to the peak output by the image processing (step 12), whether this detected object is connected to the object detected by the previous sampling. Is determined (step 13). When there is a connection, the position and length of the object are saved (step 14), and when there is no connection, the detected object is registered as a new object (step 15). This process is repeated until the image data is exhausted (step 16). When the image data is exhausted, in step 17, the guide line, mark, etc. are judged from the number, position, and length of the objects, and the guide is given if there is a branch. Select a line.

Next, a specific processing operation when traveling in the γ direction from the origin position 0 along the guide wire 7 shown in FIG. 4 will be described.

When the automatic guided vehicle 1 starts from the origin 0, a distance signal is output from the encoder 11, and the processing device 10 detects the traveling distance L from the origin position 0 based on the distance signal. In addition, the image signal from the image sensor 5 is taken into the processing device 10 at every constant sampling period, and the processing device 10 performs image processing to detect an object on the floor.

When the image sensor 5 reaches the position A (see FIG. 4), an image signal as shown in FIG. 5 (a) is output, and by image processing this, the guide wire 7 on the image sensor 5 The detection position P1 (FIG. 4) can be obtained. Then, the detection position P1 and the traveling distance L1 are stored. After that, similar processing is performed for each sampling. For example, at the position B, the detected position P2 and the traveling distance L2 are stored, and since P1 and P2 are almost equal, the objects at the positions P1 and P2 are the same object, that is, the guidance. It is determined to be line 7.

At position C, the detection position P3 and the traveling distance L3 are detected and stored. However, at the D position where the guide wire 7 is partially cut off, the image signal becomes flat as shown in FIG. 5 (b), and the guide wire position cannot be detected. However, judging from the traveling distance L4, there is no guide wire. Therefore, the processor 10 estimates that a guide wire exists around the detection position P3 and outputs the position P4 (this is the position estimated from P3 and the position detected before this).

At the E position, the detection position P5 and the traveling distance L5 are detected. At this time, since the positions of the detection positions P5 and P3 are substantially equal to each other and the distance L35 between P5 and P3 is less than or equal to a predetermined allowable value, the object at the detection position P5 is the same object as that detected at P3, that is, Judge as a guide line.

At the F position where there is a bright (white or the like) dust 8, the image signal has the waveform shown in FIG. 5C, and the positions P6 and Q6 are detected and the traveling distance L6 is detected. The object at the position P6 is determined to be the guide line 7, and the object at the position Q6 is registered as a new object. At this time, since it can be determined that another object is not provided at the position of the traveling distance L6 by referring to the preset traveling state data, it is determined that the object at Q6 is the dust 8.

At the G position where there is a bright (white or the like) marker 9, the image signal has the waveform shown in FIG. 5C, and the positions P7 and Q7 are detected and the traveling distance L7 is detected. The object at the position P7 is determined to be the guide line 7, and the object at the position Q7 is registered as a new object. At this time, since it can be determined that the marker 9 is installed at the position of the traveling distance L7 by referring to the preset traveling state data, it is tentatively determined that the object at Q7 is the marker 9.

Since the length LM of the marker 9 is known in advance, it was used when the guide wire was cut when the marker position could not be detected because the marker 9 was cut or soiled in the middle. Using the same method as above, the marker position is estimated and output.

After passing the H position, the marker 9 cannot be detected. Then, the distance between the positions G and H is detected, and when this distance is LM, it is positively determined that the detected object is a marker, and the determination result is output.

At the I position where the guide wire 7 is branched, the image signal has a waveform shown in FIG. 5D, and the positions P8 and P9 are detected and the traveling distance L8 is detected. The objects at the positions P8 and P9 are registered as new objects. At this time, referring to preset traveling state data, it can be determined that there is a branch at the position of the traveling distance L8, so that the objects at the positions P8 and P9 can be determined to be the branched guide line 7. Then, one guide wire 7 is selected by a preset program.

[0026]

[Effect of device]

 According to the present invention, as described in detail in connection with the above embodiments, the guide line can be accurately detected by performing the continuous processing using the detected position of the object obtained by the image processing and the traveling distance. Even if a part is missing, it is possible to estimate the position of the guide line and run. It also enables advanced detection such as branch selection and marker detection.

[Brief description of drawings]

FIG. 1 is a block diagram showing an automatic guided vehicle of the present invention.

FIG. 2 is a flowchart showing a main flow of a processing device.

FIG. 3 is a flowchart showing continuous processing of the processing device.

FIG. 4 is a plan view showing an example of a guide wire.

FIG. 5 is a characteristic diagram showing the relationship between the amount of light in the image sensor and the arrangement direction of the elements of the image sensor.

FIG. 6 is a configuration diagram showing a conventional automatic guided vehicle.

FIG. 7 is a plan view showing a conventional automatic guided vehicle.

FIG. 8 is a characteristic diagram showing the relationship between the amount of light in the image sensor and the arrangement direction of the elements of the image sensor.

FIG. 9 is an explanatory diagram showing a defect of a guide wire and a signal state at that time.

FIG. 10 is an explanatory diagram showing a defect of a guide wire and a signal state at that time.

[Explanation of symbols]

 1 Automated guided vehicle 2 Front wheel 3 Rear wheel 4 Body 5 Image sensor 6 Light emitting diode lamp 7 Guiding wire 8 Dust 9 Marker 10 Processing device 11 Encoder 12 Running control device

Claims (1)

[Scope of utility model registration request] 1. An unmanned guided vehicle that travels while detecting a guiding line with a contrast to a road surface, a line type image sensor for photographing the guiding line and outputting an image signal, and a travel distance of the unmanned guided vehicle. And a distance sensor that outputs a distance signal to detect the position of an object on the image sensor by performing image processing by capturing the image signal at constant sampling intervals, and measuring the traveling distance from the distance signal. An automatic guided vehicle, comprising: a processing device that finds and stores the detected position of an object and a traveling distance as a pair, and compares the stored data in each sampling period to detect the position of the guide wire.