JPH0370804B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a guiding device for a moving object, such as an automatic guided vehicle, for causing the moving object to travel along a scheduled travel route.

[Background of the invention]

2. Description of the Related Art Various types of guiding devices for a moving object that cause the moving object to travel along a planned travel route are known. In this process, a mark is placed on the road, this mark is input as an image using an imaging device (for example, an ITV camera), and this image signal is processed to calculate the running state quantity (planned) of the moving object. There is a vehicle that guides a moving body by determining the amount of positional deviation from the traveling path and the attitude angle, and then determining the amount of steering using this traveling state. The technology for guiding moving objects by inputting images of marks on the road is, for example,
It is disclosed in Publication No. 10445.

Now, in this type of guidance device that is conventionally known,
The image input by the imaging device is easily affected by ambient light, dirt on the mark, etc., and there are cases where it is impossible to input the image normally, leaving the problem that stable guidance cannot be achieved. In particular, if there is a significant change in the amount of light when a moving object moves from indoors to outdoors, or conversely when it moves from outdoors to indoors, normal image input may not be obtained and the control may become virtually uncontrollable. Become.

[Purpose of the invention]

An object of the present invention is to provide a moving body guiding device that can stably guide a moving body along a planned travel route.

[Summary of the invention]

The present invention provides an imaging device that captures an image of a mark attached to a running path, an image processing unit that inputs the captured image signal and calculates a running state quantity of a moving object based on the image signal, and A control amount calculation unit that inputs a state quantity and calculates a control amount, and is installed in front of the imaging device and configured to transmit incident light. an electro-optical device whose amount of light can be adjusted by an electrical signal; a power supply unit which supplies power to the electro-optical device with an electrical signal that determines the amount of time and amount of light that is transmitted when the electro-optical device is turned on; an aperture that is installed and can adjust the amount of incident light passing through; an aperture adjustment unit that adjusts the aperture by comparing a target value from the image processing unit with an input image signal; and detects the speed of the moving object. a speed detector, the image processing unit transmits a time ratio adjustment signal to the power supply unit that increases the ON time of the optical device as the speed increases according to the signal from the speed detector. a first means for outputting the input image signal;
If the number is not between the upper limit value and the lower limit value, a second voltage adjustment signal is output to the power supply unit to adjust the amount of transmission so that the number is between the upper limit value and the lower limit value. It is characterized by having means.

[Embodiments of the invention]

Hereinafter, the present invention will be explained in detail based on specific examples.

First, the overall configuration of an automatic guided vehicle, which is a type of moving object, will be explained with reference to FIGS. 1 and 2. FIG. 1 is an overall perspective view, and FIG. 2 is a side view thereof. In these figures, 1 is an automatic guided vehicle that travels on a travel path 2. 3 is a line drawn on both sides of the driving path. 4a and 4b are marks attached to the travel path, and the transport vehicle travels using these marks. 6a and 6b are imaging devices attached to the front and rear of the transport vehicle 1, which allow the mark 4 to be
Images a and 4b are taken respectively. 5a and 5b indicate imaging areas of the imaging device. 7a and 7b are steering mechanisms attached to the front and rear running wheels. 8 is a running device for running the transport vehicle, and a running motor 1
6.Includes running wheels 9a. 9a and 9b are running wheels provided on the front and rear, and 10a and 10b are running wheels provided on the left and right sides. Reference numeral 11 denotes a control panel, which includes a control section for inputting a steering signal and a running signal and controlling a steering mechanism and a running device. 12 is a data processing unit that processes data; an image processing unit that calculates a driving state quantity from captured information (image information);
and a control calculation unit that calculates a control signal from the driving state quantity. 13 is a battery device that supplies power to each device; 14 is a loading platform; and 15 is a wireless device for receiving travel command signals from a ground communication station.

Next, an embodiment of the present invention for guiding such an automatic guided vehicle will be described. FIG. 3 is a diagram showing an embodiment of the present invention. In addition, in FIG. 3, in order to simplify the explanation, only the imaging device 6a is shown, and the disclosure of the imaging device 6b is omitted. 12 is a data processing section, which includes the image processing section 30 and the control amount calculation section 20 as described above. Controlled amount calculation unit 20
is a processor 21 and a program memory 22.
and a data memory 23. The control amount calculation section 20 has a function of calculating a control amount based on input driving state quantities and the like, and outputting it to the control section 11. The image processing unit 30 includes an A/D converter 31 that converts analog signals into digital signals.
, an image memory 33 for storing image signals, a program memory 34 for storing programs, and image signal processing, running state quantity calculation, determination of appropriateness of image signals, and appropriate image input according to the processing procedures of the program memory 34. and an image processor 32 that performs processing such as outputting adjustment signals for the image processing. The imaging device 6a includes a lens 52 and a solid-state imaging device 53.
, a load resistor 55, a preamplifier 56, and the like. Reference numeral 40 denotes an aperture adjustment section that adjusts the aperture of the lens 52, and is composed of a high impedance circuit 41, a comparison circuit 42, an amplifier 43, and a servo motor 44. 50 is an electro-optical device whose amount of transmitted light can be adjusted by the amount of electrical signal. As this device, a relatively high-response optical shutter or the like can be used. 51 is a bandpass filter that allows only light in a specific wavelength range to pass through. 60
is a power supply unit, which supplies an electrical signal adjusted to the electro-optical device 50 based on an adjustment signal from the image processing unit 30. This power supply section 60 includes a voltage adjustment section 62 and a drive section 61 that adjusts the on/off duty ratio. 70 is a lighting lamp;
A sodium lamp is used here. Therefore, the bandpass filter 51 is selected to allow only light in the wavelength range of the light emitted by this lamp to pass through. 71 turns on the lamp 70;
A power switch 72 for turning off is a lamp power source that supplies power to the lamp 70.

The guiding operation in this embodiment is basically as follows. First, when a travel command is given from the outside, the control amount calculation section 20 causes the moving body to start traveling toward the commanded position. That is, the control amount calculation section 20 outputs a speed command to the control section 11,
The control unit 11 controls the travel motor 1 according to this speed command.
Drive 6. By driving the motor 16, rotational driving force is transmitted to the running wheels 9a, thereby causing the moving body to run. The image processing unit 30 also inputs an image signal from the imaging device 6a, converts it into a digital signal (binarized signal) with an A/D converter 31, and performs preprocessing such as noise removal. It is later stored in the image memory 33. The image processor 32
According to the procedure of the program stored in the program memory 34, the image signal is read out, the traveling state quantity of the moving body is calculated, and the result is output to the control amount calculating section 20. The control amount calculation section 20 calculates a steering command or a steering amount based on the input driving state amount (positional deviation from the planned travel route, attitude angle), and outputs the steering command or the steering amount to the control section 11 . Based on this signal, the control unit 11 controls the steering mechanism 7.
a and 7b to control the moving body to follow the planned travel route. With these, the mobile object can
You can drive to your destination along the planned route. A detection signal from the speed detector 17 is given to the control section 11 and used for speed feedback control of the motor 16. Further, this detection signal is transmitted to the control calculation section 20.
is given to and used for calculating the control amount. Furthermore,
This speed detection signal is also given to the image processing section 30 and is used for adjusting the amount of light, which will be described later.

Now, in order to perform the above-mentioned guiding operation in FIG. 3 stably, it is necessary to accurately determine the traveling state quantity. In order to calculate accurate driving state quantities, it is a major premise that the image signal input to the image processing section 30 is normal. However, during actual driving, it is difficult to input a normal image signal due to external factors such as large fluctuations in the brightness of reflected light input to the imaging device and dirt on the mark itself to be imaged. Therefore, in this embodiment, the following functions are added. First, it is a function that identifies the type of light that enters the imaging device and reduces the adverse effects of other disturbance light. This is the illumination lamp 70 that emits monochromatic light in FIG.
This can be realized by a power supply section (71 and 72 in FIG. 3) for supplying power to the illumination lamp, and a bandpass filter 51. Next, it is a function to reduce the ill effects of the light from the above-mentioned illumination lamp, ambient light that cannot be removed even by the filter that passes the light area, and marks, stains, and the like. This is based on the judgment of the input image signal by the image processing unit 30, the calculation output of the transmitted light amount adjustment amount, the power supply unit 60 which adjusts the amount of electricity to be supplied based on the transmitted light amount adjustment amount, and the application of the amount of electricity. This can be realized using an electro-optical device 50 that adjusts the amount of transmitted light. Additionally, a function is added to maintain the intensity of light incident on the imaging device at an appropriate value. This function can be achieved within a certain range by adjusting the electro-optical device described above and the amount of electricity applied to it, but if you try to widen the adjustment range, this alone is insufficient, so the aperture adjustment section 40 We decided to implement this by establishing a

Next, the input of image signals controlled by such a configuration will be described in detail. First, the illumination lamp 70 uses a sodium lamp here, and irradiates monochromatic light with a wavelength of 589 mm onto the range surface. In order to fix the input image signal, the switch 71 is controlled by a command from the image processing section 30 to turn the lamp 70 on and off. An electro-optical device 50 and a bandpass filter 51 are installed in front of the imaging device 6a, and light reflected from the road surface and marks is input to the imaging device via 50 and 51. Bandpass filter 51
is from the light passing through the electro-optic device 50
It is an interference filter that passes light with a wavelength of 589mm±20mm. The light that has passed through this filter 51 passes through a lens 52 and is projected onto a solid-state image sensor 53. As a result, the photodiode 54 arranged on a two-dimensional plane constituting the solid-state image sensor 53
A current corresponding to the amount of light flows through the circuit, is converted into voltage by a variable load resistor 55, and is amplified by a preamplifier 56 to form an image signal. The two-dimensional signal is scanned to become a serial signal, which is supplied to the image processing section 30. The output of the preamplifier 56, that is, the image signal, is also supplied to the aperture adjustment section 40. The high impedance circuit 41 converts this image signal into a light amount equivalent signal and outputs it to the comparison circuit 42. In the comparison circuit 42 , it is compared with the target light amount output from the image processing section 30 , and the difference is input to the amplifier 43 . The amplifier 43 operates the servo motor 44 in response to this input to adjust the aperture mechanism of the lens 52. The response of the light amount adjustment of the diaphragm adjustment section 40 is about several hundred milliseconds, which is slower than the adjustment using an electro-optical device. However, it is possible to adjust over a wide range even with large fluctuations in ambient light. The image processing section 30 stores the input image signal in the image memory 33, then reads the image signal to the image processor 32, and determines whether the image signal is normal. This determination method will be described later. If the result of the determination is that it is not normal, an adjustment signal for adjusting the light amount is output to the power supply unit 60. This adjustment signal is
They are a voltage adjustment signal e ₁ and a time ratio adjustment signal P ₁ that adjusts the energization time. The configuration example of the power supply unit 60 is shown in the fourth example.
As shown in the figure. In this FIG. 4, the drive section 61 is
Inverter 611, resistor 612, switch 61
3. Consists of a resistor 614. The switch 613 is turned on and off in accordance with _P1 , and the voltage applied to the electro-optical device 50 is turned on and off.
The light amount adjustment of the electro-optical device 50 is performed with extremely high response, so that it can respond to sudden changes in ambient light. You can quickly respond to the case where the input light decreases due to dirt on the mark. Aperture adjustment section 4
FIG. 5 shows the relationship between the adjustment by 0 and the adjustment by the electro-optic device 50. The electro-optical device 50 has better responsiveness to time. Although the response of the adjustment by the aperture adjustment section 40 is poor, the adjustment range is wide. The moving image capturing time when the moving body 1 is running at high speed is shortened to prevent image blurring, and the electro-optical device 50 can sufficiently cope with this. Further, in a range where a high response is not required, such as when running at low speed or at the start of running, the adjustment by the aperture adjustment section 40 functions effectively in addition to the adjustment by the electro-optic device 50. Note that in FIG. 3, the optical sensor 73 detects changes in the illuminance of the sodium lamp 70. This sensor 73 is
As the specific configuration is shown in FIG. 6A, a proportional voltage signal as shown in FIG. 6B is generated in response to flicker-like illuminance changes of the sodium lamp 70. 731 is an amorphous silicon photodiode, 732 is a voltage conversion resistor, and 733 is an amplifier. Although not disclosed in detail, the output of this sensor 73 is used to adjust the illuminance of the lamp 70.
In FIG. 3, the output of the speed detector 17 is input to the image processing section 30, and this signal is used to obtain the duty adjustment signal _P1 of the electro-optical device 50. That is, as shown in FIG. 7, the ON time of the electro-optical device is adjusted depending on the traveling speed.

Next, an example of a method for determining whether an image signal necessary for automatic light amount adjustment using the electro-optical device 50 is properly inputted and an automatic light amount adjustment method will be described in detail.
First, a method for determining whether an image signal is normal will be explained with reference to FIG. Now, consider a case where an image as shown in FIG. 8 is captured. 80 is a binarized image for one frame captured by the image device 6a. Reference numeral 81 indicates an area where the reflected light is large (an area where the value is "1" in the binary image), and 82 is an area where the reflected light is small (an area where the value is "0" in the binary image).
Such an image is temporarily stored in the image memory 33 after being subjected to pre-processing such as noise removal. Then, the binarized image signals are read out for the three scanning portions 83 to 85 of the upper, middle, and lower portions of the image signal, and the number of pixels _B seek. The determination can be made based on whether the number of _BX is within a predetermined range. In other words, the lower limit
If B _L and the upper limit value are B _U , then it is normal when B _L B _X B _U , and abnormal at other times. Next, we will explain how to make adjustments when it is determined that something is not normal. Now, B _X <
In the case of B _L , the number of "1"s is small, which means that the amount of light is insufficient. It is considered that the smaller this number _X is, the greater the shortage of light quantity is, so the electro-optical device 50 may be adjusted in a direction that increases the light quantity. Furthermore, if B _X >B _U , the amount of light is excessive, so the electro-optical device 50 may be adjusted to reduce _the amount of transmission. To adjust the electro-optical device, it is sufficient to adjust the amount of electricity supplied by the power supply section 60, and therefore the image processing section 30 outputs an adjustment signal for the adjustment. This adjustment signal is
An adjustment signal that minimizes the difference between the actual _{value B} The adjustment signal may be one that adjusts the voltage, one that holds the voltage constant and adjusts the on/off time ratio within a certain period of time, or one that adjusts both the voltage and the time ratio. An example of a method for calculating this adjustment signal is shown in FIGS. 9A and 9B. In FIGS. 9A and 9B, (t/T) is the time ratio and _VX means the voltage. In the embodiment shown in FIG. 3, both the voltage adjustment amount ΔV _X (adjustment signal e ₁ ) and the time ratio adjustment amount Δ(t/T) (adjustment signal P ₁ ) are adjusted.

Next, the image processing section 30 in the embodiment of FIG.
The operations are summarized as shown in FIG. 10. Although not shown, when an operator or the like instructs startup, initial settings on the circuit are made (step F10). Next, input of image signals from the imaging device is started (step F20). Since the input image signal is an analog signal, it is converted into a digital signal (step F30). After this,
Perform pre-processing such as noise removal and binarization processing,
The preprocessed image signals are sequentially stored in the image memory 33 (step F40). After this storage, it is determined whether the input image signal is normal or not. If it is not normal, a target value for adjusting the amount of light for the aperture adjustment section 40 is calculated, and the calculated value is output to the aperture adjustment section 40. This operation is step F50. The aperture adjustment unit 40 adjusts the amount of light passing through the lens 52 so that the input value becomes the target value. In step F60, it is determined whether the input image signal has become appropriate as a result of this adjustment, and if it is appropriate, the process proceeds to the next step. If it is not appropriate, return to step F20 and repeat the same operation as above. In step F70, the presence or absence of an obstacle is checked using the image signal, and if an obstacle is found, an alarm is sounded and an emergency stop command for the moving body is output. Although the moving object has not normally started moving at this point, an interlock is applied to prevent movement if there is an obstacle. This is step F80. In step F90, it is determined whether the moving object has started moving. This can be determined by monitoring the detected speed since the signal from the speed detector is input. If the movement has started, proceed to the next step F110. Processing so far (steps)
FA) is the procedure up to the start of movement. When movement starts, image signal input (step F110),
An A/D conversion operation (step F120) and an operation of preprocessing and storing the preprocessed image signal in the image memory 33 (step F130) are performed. This is the same operation as steps F20, F30, and F40. Next, in step F140, it is determined whether the input image signal is normal or not, and it is determined whether or not adjustment of the electro-optical device 50 is necessary. If no adjustment is required, step F170 to step F210
It calculates running state quantities as shown in and outputs them to the control quantity calculation section. If adjustment is required, the process proceeds to the next step F150, and an adjustment signal is calculated by a method such as the above-mentioned table reference. This adjustment signal includes a voltage adjustment signal e ₁ and a time ratio adjustment signal P ₁
As mentioned above, there is step
When the calculation at F150 is completed, this adjustment signal is output to the power supply section 60. This is step F160. As a result, the amount of transmitted light in the electro-optical device 50 is adjusted, and this result is reflected in the step.
This becomes clear from the image signal input of F110. Perform steps F110 to F140, and if further adjustments are required, proceed to steps F150 and F140.
F160 processing is repeated. As a result, the adjustment of the electro-optical device 50 is performed sequentially. If the adjustment function works and a normal image signal is obtained, the process advances to step F170. The processing from F110 to F160 becomes the image input and electro-optic device adjustment processing FB. The processing in FIG. 10 can be roughly divided into FA, FB, and FC processing. The FA process is a start-up process that is performed until the moving body starts moving. FB and FC processing is performed during the moving period of the mobile object.
This is a process that is repeated one by one. FB is a process for inputting a normal image signal, and FC is a process for determining a driving state quantity based on the normal image signal.

〔Effect of the invention〕

As explained above, the present invention can eliminate the influence of ambient light such as sunlight, and can also eliminate fluctuations in the amount of incident light due to marks, stains, etc., thereby providing a stable image signal. I'm trying to get it. Furthermore, when adjusting the amount of light, aperture adjustment and transmitted light amount adjustment using an electro-optic device are used together, making it possible to achieve high response and widen the adjustment range.

[Brief explanation of drawings]

1 and 2 are diagrams showing a schematic configuration of an automatic guided vehicle, FIG. 3 is a diagram showing an embodiment of the present invention, and FIG.
The figure shows the specific configuration of the power supply unit, Figure 5 shows the time response characteristics for light intensity adjustment, Figure 6A shows the configuration of the photoelectric sensor, and Figure 6B shows the output of the photoelectric sensor. Characteristic diagram, FIG. 7 is a diagram showing an example of adjusting the on time of the electro-optic device with respect to the running speed,
FIG. 8 is a diagram for explaining a method for determining the quality of an image signal, FIGS. 9A and 9B are diagrams for explaining a method for adjusting an electro-optical device, and FIG. 10 is a diagram for explaining a method for determining the quality of an image signal. FIG. 3 is a diagram showing the operation of an image processing section. 1...Automated guided vehicle, 4a, 4b...Mark, 6
a, 6b...imaging device, 7a, 7b...steering mechanism, 8... traveling device, 9a, 9b, 10a, 10
b... Running wheel, 11... Control unit, 12... Data processing unit, 20... Control amount calculation unit, 30... Image processing unit, 40... Aperture adjustment unit, 50... Electro-optical device, 60... ...Power supply unit, 70...Lighting light, 71
...Power switch, 72...Lamp power supply.

Claims (1)

[Scope of Claims] 1. An imaging device that captures an image of a mark attached to a running path, and an image processing unit that receives the captured image signal and calculates a running state quantity of a moving object based on the image signal. , a control amount calculation unit that calculates a control amount by inputting the traveling state quantity, and a moving object guidance device that guides a moving object using the control amount, the device being installed in front of the imaging device, an electro-optical device capable of adjusting the amount of light transmitted through it using an electrical signal; a power supply section that supplies power to the electro-optical device with an electrical signal that determines the amount of time and amount of time the electro-optical device is turned on to allow light to pass therethrough; and the imaging device. installed in front of the
an aperture that can adjust the amount of incident light passing through; an aperture adjustment unit that adjusts the aperture by comparing a target value from the image processing unit with an input image signal; and a speed detection unit that detects the speed of the moving object. The image processing unit outputs a time ratio adjustment signal to the power supply unit so as to increase the ON time of the optical device as the speed increases according to the signal from the speed detector. determining the number of one of the first means and the binarized signal of a specific area of the input image signal;
If the number is not between the upper limit value and the lower limit value, a second voltage adjustment signal is output to the power supply unit to adjust the amount of transmission so that the number is between the upper limit value and the lower limit value. A guiding device for a moving body, comprising: means.