JPH0410645B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention captures an image of a mark pasted on a driving road surface using an imaging device, processes the image to determine the amount of deviation from the planned driving path, and calculates the amount of deviation from the planned driving path. The present invention relates to a guiding device for a moving body that guides the moving body so as to eliminate the problem.

[Background of the invention]

One of the typical moving objects is an automatic guided vehicle, and in order to move this automatic guided vehicle along a designated travel route, a traveling detection device is required to detect the traveling situation.

Conventionally, electromagnetic induction type, tape optical type, capacitance type, ultrasonic type, visual guidance type, etc. are known as this running detection device. Among these, the visual guidance type attaches marks at equal intervals in the center of the travel route, and an imaging device attached to the moving object captures images of the marks, which are then image-processed to determine the route from the planned route. This detects the amount of deviation. Therefore, a guidance device using a visual guidance system guides a mobile object onto a planned travel route by utilizing the state quantity detected in this manner.

However, conventionally known guidance devices of this type detect the running situation in front of the moving object, that is, the trajectory deviation, inclination, and amount of movement of the moving object in front of the moving object, and use this as predictive information to drive the running lines on both the left and right sides. 2
Steering is performed by controlling the speed difference between the two motors. Alternatively, a steering mechanism is attached to the wheels, and the aforementioned predictive information is used to control the steering.

Therefore, with only such control, the moving object will be steered significantly left and right on the travel road, making it difficult to run stably.

On the other hand, in conventional guidance devices of this type, the mark is provided in the center of the travel path of the moving object, and as the wheels of the moving object move over the mark, the mark may become dirty or scratched. The reliability of the marks has become a problem because of the occurrence of defects and missing parts.

[Purpose of the invention]

An object of the present invention is to provide a guiding device for a moving body that can perform highly accurate steering.

[Summary of the invention]

The present invention provides front and rear imaging devices that image marks on the running path in front and rear of a moving body, and a predictive running state quantity that processes image signals from the front imaging device to obtain a front track deviation amount and an attitude angle. and an image processing unit that processes the image signal of the image signal of the rear imaging device to obtain a historical running state quantity having a rear track deviation amount and an attitude angle, and the predicted running state quantity and a control amount calculation unit that calculates a steering amount for controlling the front and rear steering mechanisms from the historical running state quantity and outputs the respective steering amounts to the front and rear steering mechanisms, the control amount calculation unit , a straight running section, a high speed running section, and a low speed running section, a steering amount for controlling the front steering mechanism is determined from the predicted running state quantity, and a steering amount for controlling the front steering mechanism is determined from the historical running state quantity. A steering amount for control is determined, and on the other hand, in a steady turning section between high speed and low speed, the front and rear steering amounts are made to be the same.

[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 to 3. FIG. 1 is an overall perspective view of the automatic guided vehicle, FIG. 2 is a side view thereof, and FIG. 3 is a diagram showing the traveling device portion including the steering mechanism. Reference numeral 1 denotes an automatic guided vehicle, which travels on a running path 2. 3 is a line for forming a running route. In other words, line 3
The inside of the area is the route for the automatic guided vehicle. 4a, 4b
is a road mark pasted on the line 3, and the automatic guided vehicle 1 runs using this mark. 6a,
6b is an imaging device attached to the front and rear of the automatic guided vehicle 1, which images the marks 4a and 4b, respectively. 5a and 5b indicate the imaging area (field of view) of each imaging device. 7a and 7b are steering mechanisms attached to the front and rear running wheels. 8 is a running device for running the carrier. 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. Note that 9a and 9b are driving wheels, and 10a and 10b are dependent wheels. 1
Reference numeral 1 denotes a control panel, which includes a control section that inputs a steering signal and a running signal and controls a steering mechanism and a running device. 12 is a processing unit that processes data;
It includes an image processing unit that calculates a running state quantity from the captured information, and a control amount calculation unit that calculates control signals (steering signals and running signals) from the running state quantity. 1
3 is a battery device that supplies power to each device; 1
4 is a loading platform, and 15 is a wireless device for receiving travel command signals from the ground communication section. Figures 1 and 2
Steering mechanism 7a, traveling device 8, and traveling wheels 9 in the figure
FIG. 3 shows the part a in detail.
In FIG. 3, the traveling device 8 includes a traveling motor 16
, a shaft 17b coupled to the motor shaft 17a, spur gears 18 and 19, and the spur gear 1.
Bevel gears 20a and 20b that convert the rotational direction of power transmission of 8 and 19 to the right angle direction, the main shaft 21a of the bevel gears, both end bearings 22a and 22b, and a member that connects the running wheel 9a and the main shaft 21 with a boss. 21b. The casing 23 integrates the spur gear trains 18 and 19, the bevel gear trains 20a and 20b, the main shaft 21a, both end bearings 22a and 22b, and the like. The steering mechanism 7a is fixed to the vehicle body and includes a steering motor 25, a spur gear 24a that decelerates the rotational movement of this motor via a shaft, and a main shaft 24b.
and a member 26 for fixing it to the casing 23. The casing 2 is rotated by the rotation of the steering motor 25.
The structure is such that steering is performed by swinging the wheel 3. Although not shown, the steering mechanism 7b has a similar configuration and is configured to swing the running wheels 9b.

Next, a configuration for controlling the automatic guided vehicle shown in FIGS. 1 to 3 will be explained using FIG. 4. In FIG. 4, 6a and 6b are imaging devices, and only 6a is disclosed in detail. 12 is a processing section, which includes an image processing section 34 and a control amount calculation section 35.
It consists of The control unit 11 includes a control amount calculation unit 3
5, and controls each steering mechanism 7a, 7b and traveling device 8 accordingly. Now, the imaging device 6a (same as 6b)
A camera 2 consisting of a filter 27 and a lens 28
An image is input through 9a. That is, the optical image input through the camera is transmitted to the solid-state image sensor 30.
By exciting the photodiodes 31 arranged in a matrix, a current is generated in the circuit, which is converted into a voltage via a load resistor 32, and then amplified by a preamplifier 33 to generate an electrical image signal. Input the image as . This input image signal is supplied to an analog/digital converter 37 in the image processing section 34 via a switch 36, and is converted into a digital signal. The image signal converted into a digital signal is stored in the image memory 38. The control signal input by the imaging device 6b is similarly supplied to the analog/digital converter 37 via the switch 36 and stored in the converter image memory 38 as a digital signal. Switcher 3
6 is performed at high speed, the image memory 38 stores the latest image signals inputted by the respective imaging devices 6a and 6b. Since the imaging devices 6a and 6b are provided at the front and rear of the transport vehicle, the image memory 38 stores an image signal from the front in the traveling direction of the transport vehicle and an image signal from the rear. The image processor 40 is
According to the image processing algorithm stored in the program memory 39, the running state quantity is calculated using the image signals stored in the image memory 38. Note that the load resistor 32 is adjusted when there is a change in illuminance in the viewing area due to disturbance light or a change in contrast due to dirt on the line 3 or road markings. The control amount calculation section 35 stores the running state amount calculated by the image processing section 34 in the data memory 42,
According to the steering/cruising control algorithm stored in the program memory 43, the control processor 4
1 to calculate control signals (steering signals and running signals). These control signals are supplied to the control section 11, and the control section 11 controls the steering mechanisms 7a, 7b and the traveling device 8 using these as command signals. 44
a and 44b are control amplifiers.

Next, a method of calculating the steering signal will be explained with reference to FIG. Now, assuming that the images input by the imaging devices 6a and 6b are 45 and 46 in FIG. 5, the data on the fixed lines at three locations are a ₁ , a ₂ , b ₁ ,
b ₂ , c ₁ , c ₂ and a ₁ ′, a ₂ ′, b ₁ ′, b ₂ ′, c ₁ ′, c ₂ ′
The position coordinates of Therefore, images 46 and 45 of the posture of the transport vehicle determined in advance by the imaging device.
Let the deviations of the respective marks in images 45 and 46 from the center position (one-point line in the vertical direction on the drawing, called y ₀ ) be the orbital deviation amounts y ₁ and y ₂ , and the inclinations thereof be ₁ and ₂ , and these The calculation unit 47 calculates each running state quantity using the position coordinates. The predicted running state quantity, that is, the running state (y ₁ , ₁ , x ₁ ) obtained from the imaging device in front, is obtained as follows.

The amount of orbital deviation y ₁ is y ₁ = 1/2 (b ₁ + b ₂ ) − _{y 0} = 1/4 (a ₁ + a ₂ + c ₁ + c ₂ )...(1) The attitude angle ₁ is ₁ = tan ^{- 1} 1/2 (c ₁ +c ₂ −a ₁ −a ₂ )/l (2) The position x ₁ is obtained from the mark count value. Further, the historical running state quantity, that is, the running state quantity (y ₂ , ₂ , x ₂ ) obtained from the rear imaging device is determined as follows.

The amount of orbital deviation y ₂ is y ₂ = 1/2 (b' ₁ + b' ₂ ) - y ₀ = 1/4 (a' ₁ + a' ₂ + c' ₁ + c' ₂ )... (3) The attitude angle ₂ is , ₂ = tan ^-1 1/2 (c′ ₁ +c′ ₂ −a′ ₁ −a′ ₂ )/l…
...(4) The position x ₂ is obtained from the mark count value.

Further, the running state quantity at the center position of the transport vehicle, that is, the current running state quantity (y ₃ , ₃ , x ₃ ) is obtained as follows using the predicted running state quantity and the historical running state quantity.

The amount of trajectory deviation y ₃ is y ₃ = 1/2 (y ₁ + y ₂ ) ...(5) The attitude angle is ₃ = 1/2 ( ₁ + ₂ ) ... (6) The traveling position x ₃ is x ₃ = 1 /2 (x ₁ + x ₂ ) ...(7) Using these running state quantities, the steering amounts δ ₁ , δ ₂ are applied to the front and rear steering mechanisms so that the running state quantity becomes small. is determined as follows.

a) In high-speed straight sections and acceleration sections, δ ₁ = G ₁ {y ₁ + (+d) ₁ } ...(8) δ ₂ = -G ₂ {y ₂ + (+d) ₂ } ...(9) However, δ ₁ : Steering amount of front wheels (running wheels 9a) δ ₂ : Steering amounts of rear wheels (running wheels 9b) G ₁ , G ₂ : Operation gain constant l: Length d of automatic guided vehicle 1: Imaging device 6a b) In the low-speed straight section and deceleration section, δ ₁ = -G ₁ {y ₁ + (+d) ₁ } ...(10) δ ₂ = -G ₂ {y ₂ - (+d) ₂ ...(11) c) In the steady cycle section, δ ₁ = δ ₂ = -G ₃ y ₃ (12) where G ₃ is the operation gain constant. In addition, y ₃ is obtained by equation (5).

In this way, the amount of steering changes depending on the driving mode of the automatic guided vehicle.

Next, the flow of each processing operation of the image processing section 34 and the control amount calculation section 35 in FIG. 4 will be explained using FIGS. 6a and 6b.

First, the processing operation flow of the image processing section 34 will be explained using FIG. 6a. First, when the power is turned on, initial settings are performed in step (a), and steps (b) to (p) are executed as follows.

Step (b): Adjust the gains of the imaging devices 6a and 6b regarding the binarization threshold level, which will be described later, so that images of white lines or road markings can be reliably recognized.

Steps (c), (c)', and (d): After confirming that the imaging devices 6a and 6b operate normally, the information on the two surfaces of the traveling path is converted into images by the imaging devices 6a and 6b, and the automated guided vehicle At the same time as confirming the presence or absence of obstacles in front of the driving route No. 1, the image of the white line 3 or each mark 4a, 4b is input.

Step (e): The analog voltage amplified by the preamplifier 33 is sequentially input to the A/D converter 37 to convert the image signal into a digital signal.

Step (f): Transfer the digital signal to the image memory 38 connected to the image processor 40 and store it sequentially.

Steps (g) to (i): Binarization processing of the digital signal stored in the image memory 38, that is, by setting a digital threshold level, signals above that level value are set to "1", and signals below that level are set to "1". After performing conversion processing to set the signal to "0" and specifying a storage address, the data is stored again in the image memory 38. At this time, the total area showing the "1" signal is output to determine whether a white line or road mark is detected, and if it is not normal, the threshold value is lowered in steps.

Step (i): Extract the features of the edge signals in the "1" and "0" signals of the binarized white line 3 or road markings 4a and 4b, and extract the respective two-dimensional addresses (a ₁ , a ₂ ) (c ₁ , c ₂ ) and (a′ ₁ , a′ ₂ )
Calculate (c′ ₁ , c′ ₂ ).

Steps (k), (l): From the address calculated in (j),
Center address (1/2 (a ₁ + a ₂ ), 1/2 (c ₁ + c ₂ ))
, (1/2 (a' ₁ + a' ₂ ), 1/2 (c' ₁ , c' ₂ )).

Step (l): Captured image of white line 3 and mark 4
The image of a is identified. Note that the determination of whether the course is a straight course or a turning course is made by identifying the shape of the mark, and the movement position and movement course of the automatic guided vehicle 1 are ascertained.

Steps (m), (n): Among the center address values obtained in step (k), as shown in FIG. 5, the forward state quantities y ₁ , ₁ and the backward state quantities y ₂ , ₂
Calculate.

Steps (o), (p): count number r of mark images calculated in steps (l) to (m), amount of trajectory deviation
Traveling state quantities such as y ₁ , y ₂ , attitude angles ₁ and ₂ , and mark shape identification are sequentially transferred to the control amount calculation section. Then jump to step (e) again, and step (e) ~
Repeat (p).

Next, the processing operation flow of the control amount calculating section 35 will be explained using FIG. 6b.

Step (A): Initial settings are performed when the power is turned on.

Step (B): Movement address No. of the position to be moved to
J setting and drive the steering mechanism and traveling device.

Step (C): The presence or absence of the driving state quantity signal transferred from the image processing section 34 is checked.

Step (D): Based on the transferred running state quantity, it is determined whether the vehicle is going straight or turning, and if it is a turning motion, it jumps to step (L).

Step (E): Compare the moving address J and the count number r, and jump to step (H) if J≦r+1.

Steps (F) and (G): This step is performed when the vehicle is traveling steadily in a straight line. That is, using the predicted driving state quantities y ₁ and ₁ , the above (8),
By calculating equation (9), the respective steering amounts δ ₁ and δ ₂ are obtained. These δ ₁ and δ ₂ are output to the control unit 11,
The husband's steering mechanism is controlled.

Steps (H) to (K): In order to decelerate the traveling device 8, a deceleration command (a kind of traveling signal) is output to the control section 11. Then, the steering amounts δ ₁ and δ ₂ are calculated using y ₁ , y ₂ , ₁ and ₂ of the predicted driving state amount and the historical driving state amount. The calculation formulas are the above-mentioned formulas (10) and (11). These δ ₁ and δ ₂ are output to the control unit 11,
Each steering mechanism is controlled. Then, the automatic guided vehicle 1 is driven at a slow speed by a timer operation, and then stops at the target position.

Steps (L) to (N): In the case of a deceleration region where the front imaging device 6a detects a turning mark image on the road and the other imaging device 6b detects a mark image on the straight road, δ ₁ , δ ₂ are calculated according to equations (10) and (11). Further, in the case of a steady turning section in which the imaging devices 6a and 6b respectively detect turning mark images on the road, δ ₁ and δ ₂ are calculated according to equation (12). Also,
In the case of an acceleration section in which the front imaging device 6a detects a mark image on a straight road and the rear imaging device 6b detects a mark on a turning road, the above-mentioned equations (8) and (9) are used. δ ₁ and δ ₂ are calculated according to. The steering amount calculated in this way is supplied to the control unit 11 as a steering signal, and each steering mechanism 7a, 7b is controlled.

In this way, according to the present embodiment, road marks are provided on the lines indicating the driving road area, and the front and rear imaging devices capture images of the road marks, so that the predicted driving state quantity of the front and the historical driving state quantity of the rear can be calculated. These driving state quantities are used to perform detailed steering control. Therefore, the automatic guided vehicle can travel on the road with high precision. Of course, the road marks are provided on both sides of the road where they will not be damaged by the running wheels of the conveyance vehicle, and the marks are highly reliable.

〔Effect of the invention〕

As explained above, the present invention provides imaging devices that take images of the traveling path before and after a moving body, uses the front imaging device to obtain a predicted driving state quantity, and uses a rear imaging device to obtain a historical driving state quantity. Then, the straight running section, high speed running section, and low speed running section are as follows.
A steering amount for controlling the front steering mechanism is determined from the predicted driving state amount, and a steering amount for controlling the rear steering mechanism is determined from the historical driving state amount and steering is performed. In a steady turning section between high and low speeds, the front and rear steering amounts are made the same, allowing for highly accurate steering. That is, since the steering amount is adjusted depending on the driving mode, the accuracy is improved.

[Brief explanation of drawings]

Fig. 1 is an overall perspective view of the automated guided vehicle, Fig. 2 is a side view of the automated guided vehicle, Fig. 3 is a diagram showing a traveling device including a steering mechanism, and Fig. 4 shows an embodiment of the present invention. 5 and 5 are diagrams for explaining the calculation method of the steering signal, and FIGS. 6a and 6b are diagrams showing the operation of the embodiment shown in FIG. 4. 1...Automated guided vehicle, 2...Travel path, 3...Line,
4a, 4b... road mark, 6a, 6b... imaging device, 7a, 7b... steering mechanism, 8... traveling device, 9a, 9b... running wheel, 11... control unit, 1
2...processing section, 34...image processing section, 35...control amount calculation section.

Claims (1)

[Scope of Claims] 1. A guiding device for a moving body that includes an imaging device in a moving body, processes an image signal captured by the imaging device, and guides the moving body using the output of a processing unit that calculates a control amount. front and rear imaging devices that capture images of marks on the running path in front and behind the moving object; steering mechanisms installed on the front and rear running wheels of the moving object; A predicted traveling state quantity having a trajectory deviation amount and an attitude angle of is calculated, and the image signal of the image signal of the rear side imaging device is processed to obtain a historical driving state having a rear side trajectory deviation amount and an attitude angle. an image processing unit that calculates a steering amount, and calculates a steering amount for controlling the front and rear steering mechanisms from the predicted driving state amount and the historical driving state amount, and outputs the respective steering amounts to the front and rear steering mechanisms. a control amount calculation section, the control amount calculation section determines a steering amount for controlling the front steering mechanism from the predicted driving state quantity in a straight running section, a high speed running section, and a low speed running section; Further, a steering amount for controlling the rear steering mechanism is determined from the historical traveling state amount,
On the other hand, a guidance device for a moving object, characterized in that in a steady turning section between high speed and low speed, the amount of front and rear steering is made the same.