JPH11327648A - Traveling control method for automated guided carrier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control an automated guided carrier so as to smoothly follow a curved path with a tight turn along a traveling path close to a side barrier with an extremely small clearance. SOLUTION: In this traveling control method, while detecting a guide line 11 by a sensor 9 for detecting a first line on the front side of an advancing direction, the target steering angle θF of a first traveling wheel 7 on the front side of the advancing direction is set to a value for turning a deviation to the guide line 11 to '0'. Then, in a traveling section before a traveling distance from the point of time of detecting a reference marker 41 for a curve warning exceeds a prescribed distance D, the target steering angle θR of a second traveling wheel 8 on the rear side of the advancing direction is set to the almost same angle in the direction of the same side as the target steering angle θF of the first traveling wheel 7 to a center line S along the traveling direction of a car body 2. After the traveling distance exceeds the prescribed distance D, the target steering angle θR of the second traveling wheel 8 is set to the almost same angle in the direction on the opposite side of the target steering angle θF of the first traveling wheel to the center line S.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-dimensional position and route of an automatic guided vehicle that automatically travels along a guide line while detecting a guide line laid on a floor surface with a line detection sensor on the front side in the traveling direction. In particular, the present invention relates to a traveling control method for controlling an automatic guided vehicle traveling on a traveling path set as small as possible with respect to a partition wall such as an indoor wall surface or a storage shelf in a corner section of a traveling route. The present invention relates to a traveling control method of an automatic guided vehicle for smoothly traveling on a curved traveling path of a vehicle.

[0002]

2. Description of the Related Art Conventionally, for traveling control of an automatic guided vehicle used in an automatic guided vehicle system for the purpose of automation and labor saving, a guidance method using a trackless fixed route which is cost-effective and technically advantageous is generally used. Has been adopted. The above fixed path is set by a guidance line with guidance tape etc. stuck on the floor of an unmanned warehouse or factory, and in an unmanned guided vehicle, the line detection sensor detects the guidance line by electromagnetic or optical method It will automatically travel along the guidance line.

FIG. 6 is a plan view schematically showing the automatic guided vehicle 1 which is capable of moving forward and backward along a guide line 11. In the figure, the guide line 11 is a band having a constant width, but only the center line is shown by a one-dot chain line for convenience. First and second steering units 3 and 4 also serving as motor cases for accommodating traveling motors (not shown) are provided at both ends in the traveling direction, that is, the length direction of the vehicle body 2 of the automatic guided vehicle 1.
A pair of first and second running wheels 7 and 8 rotatably mounted on the left and right sides of the first and second steering units 3 and 4, and the steering shafts 12 and 13 about a rotation center. First and second line detection sensors 9, which are connected to the rotatable steering units 3 and 4 so as to rotate integrally about a horizontal plane,
10 are provided. Each pair of the first and second traveling wheels 7 and 8 is individually driven by a traveling motor (not shown) housed and installed in the corresponding steering unit 3 and 4, and is also driven by a steering motor (not shown). Steering shaft 12,
The direction is changed by turning integrally with the steering units 3 and 4 which are turned around a horizontal plane around the turning center 13.

The traveling of the automatic guided vehicle 1 is controlled as follows. That is, the first on the front side in the traveling direction indicated by the arrow
While detecting the guide line 11 with a line detection sensor (hereinafter, referred to as a leading line detection sensor) 9, a center line S along the traveling direction of the vehicle body 2 and a first traveling wheel (hereinafter, referred to as a front traveling direction) in the traveling direction. The leading-side steering angle θ _F formed by the direction of the leading-side wheel 7 is determined by the difference between the midpoint in the width direction of the guide line 11 detected by the leading-side line detection sensor 9 and the middle point of detection by the leading-side line detection sensor 9. Variable control is performed so that the amount is always zero. At this time, the following steering angle θ _R formed by the center line S of the vehicle body 2 and the direction of the rear running wheel (hereinafter referred to as “following wheel”) 8 in the traveling direction is always fixed at 0. Therefore, on a curved road in a corner section of the travel path set by the guide line 11, at least one of a traveling motor (not shown) composed of a DC servo motor for driving the following wheel 8 or at least one of the following wheels 8. The vehicle travels along the guide line 11 while causing slippage. In addition,
The follower-side steering angle θ _R of the automatic guided vehicle 1 shown in the upper part of the figure is not 0, but this will be described later.

[0005]

By the way, the conventional unmanned transfer system is mainly used for unmanned warehouses, mainly for the purpose of automation and labor saving for reducing the burden on workers in a 24-hour production factory. It is used for transferring production materials and products to and from production equipment by automated guided vehicles. On the other hand, in recent years, there is a demand for transporting an object to be transported, such as a liquid crystal glass cassette, in the clean room by the automatic guided vehicle 1.

[0006] Since the clean room is very expensive, it is not possible to provide an extra space for the automatic guided vehicle 1 to travel. In addition, the above-described conveyed objects must be unloaded in a highly accurate positioning state by a lifter that advances and retreats to the side from the automatic guided vehicle, for example. It must be stopped as close to the unloading station as possible. This is because if the AGV stops at a large distance from the station, the length of the lifter that protrudes from the AGV must be increased by a large distance, and the lifter in the AGV This is because a slight positional deviation in the direction of advance of the head is enlarged to a large error on the distal end side.
Therefore, it is necessary for the automatic guided vehicle 1 to travel along a traveling path in which the distance d between the vehicle body 2 and the partition wall 14 such as the indoor wall surface or the storage shelf shown in FIG. 6 is set as small as possible. . The distance d is limited to about 50 mm from the viewpoint of cost and positioning accuracy of the lifter.

[0007] Apart from the above, in the clean room, it is necessary to drive the automatic guided vehicle 1 along the center of the guide line 11 in the width direction with high precision. For this purpose, the traveling wheels 7 and 8 are driven to rotate. Conventional DC as a running motor
Instead of the servomotor, it is necessary to use an AC servomotor having high horsepower and gain and capable of controlling rotation with high fidelity. In this case, in order to cause the leading wheel 7 and the following wheel 8 to rotate at the same rotational speed and to run on the traveling path along the guide line 11 faithfully, the steering angle of the following wheel is fixedly set to 0 on a straight traveling path. However, on a curved road, the occurrence of slippage such that the automatic guided vehicle 1 runs smoothly on the following wheels or the steering motor for which the steering angle is set to 0 cannot be expected. Must be set to an appropriate value corresponding to the steering angle of the leading wheel.

In order to allow the automatic guided vehicle 1 to travel while turning along a curved road, the steering angle θ _R of the following wheel 8 is changed to the leading wheel as shown in the automatic guided vehicle 1 shown in FIG. 7 and at the same angle as the steering angle θ _F and in the opposite phase, that is, in the direction opposite to the leading side with respect to the center line S, so as to make the vehicle body 2 turn along a curved road. Can be considered. However, the partition 14
It is necessary to set the distance d between the vehicle and the automatic guided vehicle 1 as extremely small as about 50 mm as described above. 14 comes into contact with each other.

The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to provide an automatic guided vehicle that moves a traveling path as close as possible to an extremely small distance from a side wall. It is an object of the present invention to provide a traveling control method for an automatic guided vehicle, which can perform traveling control so that the vehicle travels along a curved traveling road smoothly in a small turning state while traveling along a road.

[0010]

In order to achieve the above object, a first aspect of the present invention is to detect a guide line by a first line detecting sensor on a front side in a traveling direction, and to detect a first line on a front side in a traveling direction. Setting the target steering angle of the traveling wheel of the vehicle to a value such that the amount of deviation from the guidance line detected by the first line detection sensor becomes zero, whereby the unmanned guided vehicle travels along the guidance line. In the traveling control method for a transport vehicle, the first line detection sensor is provided with a curve notice reference marker provided near the guide line and for notifying that the guide line becomes a curved road after traveling a reference distance. At the time of detection, in a traveling section in which the traveling distance from the detection time of the reference marker exceeds a predetermined distance that is greater than the reference distance, the eye of the second traveling wheel on the rear side in the traveling direction is detected. The steering angle is set to be substantially the same as the target steering angle of the first traveling wheel on the same side with respect to the center line along the traveling direction of the vehicle body, and the traveling distance from the detection time of the reference marker is reduced. After the predetermined distance is exceeded, the target steering angle of the second traveling wheel is set to substantially the same angle as the direction opposite to the target steering angle of the first traveling wheel with respect to the center line, and the unmanned The traveling of the carrier is controlled.

In the traveling control method for an automatic guided vehicle, the target steering angle of the second traveling wheel on the rear side in the traveling direction is determined by the vehicle body in a traveling section from the time point when the reference marker for curve announcement is detected to a point beyond a predetermined distance. With respect to the center line along the traveling direction of the vehicle, the first steering wheel is set at substantially the same angle as the target steering angle of the first traveling wheel on the front side in the traveling direction, so that the first line detection sensor performs curve traveling. When the guide line of the road is detected and the first traveling wheel is set to the direction of the curved traveling road, the automatic guided vehicle keeps its body parallel to the partition walls such as walls and storage shelves. The front side travels along the curved traveling path of the guidance line while being separated from the partition wall. Next, after exceeding the predetermined distance, the target steering angle of the second traveling wheel is set to be substantially the same as the target steering angle of the first traveling wheel with respect to the center line in a direction opposite to the target steering angle. The automatic guided vehicle continues traveling with the rear side of the traveling direction of the vehicle body turning toward the guide line, and the posture is corrected to the state where the second line detection sensor is located on the guide line.

Therefore, when the traveling control of the unmanned vehicle in the clean room or the like is performed, even when the distance between the vehicle body traveling along the guide line and the partition wall is set as small as possible, the vehicle body may be mounted on the partition wall. On the other hand, while moving in the direction in which the distance from the partition wall increases while maintaining the parallel state, it turns along the guidance line and corrects the posture,
The rear corner portion of the vehicle body in the traveling direction does not contact the partition wall. Therefore, it is not necessary to secure an extra space for traveling of the automatic guided vehicle in a clean room where running costs are high.

[0013] In the above invention, the section of the reference distance from the reference marker for curve announcement to the start of the curve road is the second section.
Setting the target steering angle of the traveling wheel of the vehicle to approximately 0, and setting the position at a predetermined distance from the reference marker within a section from the end of the reference distance to the first end of the curve traveling road from the beginning. Is preferred.

Thus, on a straight running path from the detection of the reference marker to the start of the curved running path, the target steering angle of the second traveling wheel on the rear side in the traveling direction is set to almost 0, and the unmanned The carrier can be run without any trouble so that the center line of the vehicle body is substantially along the center line with the guide line. After that, the vehicle body of the automatic guided vehicle separates while keeping a state parallel to the partition wall on the curved road, and the separation distance is such that the rear end corner does not contact the partition wall when turning the vehicle. At this point, the vehicle body can be quickly corrected to the direction along the guidance line. As described above, since the AGV is caused to travel in a small turn around the curved road, it is not necessary to secure an extra space around the curved road only for the traveling of the AGV.

In the above invention, the first and second traveling wheels on the front and rear sides in the traveling direction can be individually driven by the first and second traveling motors, both of which are AC servomotors. .

Thus, in particular, the AC servo motor as the rear second traveling motor is capable of driving the automatic guided vehicle on a curved road when the steering angle of the second traveling wheel driven thereby is set to zero. Although it is not possible to expect occurrence of slippage such that the vehicle can travel smoothly on the road, in the present invention, the target steering angle of the second traveling wheel is set to an appropriate value corresponding to the target steering angle of the first traveling wheel. AC as a second traveling motor
The rotation of the servomotor can be controlled without any trouble when traveling on a curved road. Therefore, an AC servomotor having high horsepower and gain and capable of controlling the rotation with high fidelity can be used not only for driving the front running wheels but also the rear running wheels, which is more suitable for a clean room.

According to a second aspect of the present invention, the target steering angle of the first traveling wheel on the front side in the traveling direction corresponds to the first steering wheel corresponding to traveling on a straight traveling road.
Is greater than or equal to the second angle and less than or equal to the second angle, the target steering angle of the second traveling wheel on the rear side in the traveling direction is substantially the same angle as the target steering angle of the first traveling wheel on the same side. When the target steering angle of the first traveling wheel is equal to or greater than the second angle, the target steering angle of the second traveling wheel is set to the target steering angle of the first traveling wheel. The opposite directions are set at almost the same angle.

In this traveling control method for an automatic guided vehicle, the first
It can be determined that the automatic guided vehicle has entered the curved traveling path from the straight traveling path by the fact that the target steering angle of the traveling wheel of the traveling wheel is equal to or greater than the first angle, and accordingly, the rearward traveling direction of the unmanned guided vehicle is determined. The target steering angle of the second traveling wheel is set to be substantially the same as the target steering angle of the first traveling wheel on the front side in the traveling direction with respect to the center line along the traveling direction of the vehicle body. On the other hand, the automatic guided vehicle moves away from the partition while keeping its body parallel to the partition, such as a wall surface or a storage shelf, and the front side travels along the curved traveling path of the guide line.

Next, since the target steering angle of the first traveling wheel has become equal to or larger than the second angle, it can be determined that the vehicle has reached a position with a predetermined curvature or more on the curved traveling road. By setting the target steering angle at substantially the same angle as the direction opposite to the target steering angle of the first traveling wheel with respect to the center line, the automatic guided vehicle moves the rear side of the traveling direction in the vehicle body toward the guidance line. The vehicle continues to run while turning, and the posture is corrected so that the rear side of the vehicle body is positioned on the guidance line. Therefore, in this traveling control method,
The effect similar to that of the first invention can be obtained while eliminating the need to detect the reference marker for curve notice in the first invention and measure the traveling distance from the time of detection of the reference marker.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing an entire configuration of an automatic guided vehicle 1 controlled by a traveling control method according to an embodiment of the present invention. In FIG. 1, the same or equivalent components as those in FIG. The description is omitted. The automatic guided vehicle 1 is used in a clean room, and accordingly, a resin cover forming an outer body of the vehicle body 1 is provided with an antistatic coating for preventing dust generation, so that a transferred object is removed. A storage chamber 17 inside the vehicle body 1 to be taken in and out by the lifter 18 is opened and closed by a shutter 19 having a dust prevention structure, and is provided with an airflow control fan 20 and the like capable of switching the air volume, but is not directly related to the present invention. Therefore, detailed description is omitted.

FIG. 2 is a schematic plan view showing a drive system for traveling and steering in the automatic guided vehicle 1. In FIG. 1, first and second steering units 3 and 4 serving also as motor cases for accommodating first and second traveling motors 21 and 22 are provided at first and second end portions in both ends of the vehicle body 2 in the traveling direction. And the second steering shafts 12 and 13 are provided so as to be rotatable about the center of rotation. Both ends of each of the steering units 3 and 4 are individually driven to rotate by first and second traveling motors 21 and 22. A pair of first and second traveling wheels 7, 8 are provided. First and second traveling motors 21, 22
In this embodiment, since the automatic guided vehicle 1 is used for a clean room, an AC servomotor having high horsepower and gain and controllable with high fidelity is used.

Each of the steering units 3 and 4 has first and second line detection sensors 9 for detecting the guidance line 11,
10 are continuously provided so as to rotate integrally around a horizontal plane.
The first and second steered wheels 23, 24, which change the direction of the traveling wheels 7, 8 by rotating the corresponding steering units 3, 4 via the respective steering shafts 12, 13, include first and second steered wheels. The rotation of the steering motors 27, 28 is controlled by individual belts 29, 3
0 and the rotation is controlled. Each steered wheel 23, 2
The steering shafts 12 and 13 serving as the rotation support shafts 4 are provided so that their respective rotation centers are located on the center line S of the vehicle body 2. The rotation of each of the traveling motors 21 and 22 is controlled by a first and second traveling distance detecting rotation amount sensors 3 comprising encoders.
The rotation of the first and second steering motors 27 and 28 is detected by the first and second steering motors 27 and 28.
And the second steering angle detecting rotation amount sensors 33 and 34 (see FIG. 3).

FIG. 3 shows a block diagram of a drive system of the above. In the figure, traveling wheels 7 and 8 are individually and rotationally driven at the same rotational speed by corresponding traveling motors 21 and 22, whereby the vehicle body 2 which is the main body of the automatic guided vehicle 1 travels. In the traveling direction of the traveling wheels 7, 8, the rotation of the first and second steering motors 27, 28 is transmitted to the steering units 3, 4 via the belts 29, 30 and the steering wheels 23, 24, and the steering is performed. The parts 3 and 4 are controlled by individually rotating around a horizontal plane. The rotations of the first and second steering motors 27 and 28 are individually detected by first and second steering angle detecting rotation amount sensors 33 and 34, respectively, and the first and second traveling motors 21 and 28 are respectively detected. 22
Are individually detected by the first and second distance detecting rotation amount sensors 31, 32, respectively.

The control device 37 mounted on the vehicle body 2 includes the first and second line detection sensors 9 and 10 and the first and second line detection sensors 9 and 10.
And the second rotation angle sensors 33 and 34 for detecting the steering angle and the first and second rotation amount sensors 31 for detecting the traveling distance,
The detection signals from the control unit 32 are input, and the detection signals are calculated to control the two-dimensional position and the course of the vehicle body 2.

That is, the central processing unit 38 of the control device 37 inputs the above detection signals to the ROM 3
9, a required program is read out from the RAM 40 to perform required calculations, and the steering motors 27 and 28 and, if necessary, the running motor are used based on the calculated data. Motor 21,
22 is rotationally controlled.

Further, on the floor of the clean room, a guide line for guiding the automatic guided vehicle 1 which is optically or electromagnetically detected by the line detection sensors 9 and 10 and which is attached with a guide tape, for example. 11, a traveling path is set. The line detection sensors 9 and 10 detect the amount of deviation between each detection midpoint and the midpoint in the width direction of the guide line 11. The control device 37 includes the leading-side line detection sensor 9.
Alternatively, the steering target steering angle on the leading side at which the deviation detected by 10 becomes 0 is calculated by calculation, and the steering motor 27 or the steering motor 27 or 8 is adjusted so that the leading traveling wheel 7 or 8 matches the calculated target steering angle. 28 is controlled.

Next, a traveling control method of the automatic guided vehicle 1 according to the present invention will be described with reference to a flowchart of FIG. 4 and an explanatory diagram of FIG. In FIG. 5, in this embodiment, when the traveling path of the automatic guided vehicle 1 set by the guidance line 11 includes a curved traveling path 11b in addition to the straight traveling path 11a, the starting point of the curved traveling path 11b is At a position on the near side by a reference distance R (for example, 600 mm in this embodiment), a curve notice reference marker 41 is provided close to both sides of the guide line 11. The distance d between the automatic guided vehicle 1 traveling along the guide line 11 and the partition 14 is set as small as possible, for example, 50 mm. It is assumed that each automatic guided vehicle 1 is traveling in the direction of the arrow.

In FIG. 4, the control device 37 constantly monitors whether or not the leading line detection sensor (in this case, the first line detection sensor) 9 has detected the curve advance reference marker 41 (see FIG. 4). In step S1), when the detection signal of the marker 41 is input from the leading-side line detection sensor 9, the detection data of the guide line 11 is sequentially input from the leading-side line detection sensor 9 (step S2). Based on the data, the amount of deviation between the midpoint of the detection of the line detection sensor 9 and the midpoint of the guide line 11 is calculated by calculation (step S3).

After that, the control device 37 controls the leading wheel (the first traveling wheel in this case) to set the deviation amount to zero.
7, the target steering angle θ _F is calculated by calculation, and based on this data, the detection signal from the lead-side steering angle detection rotation amount sensor (in this case, the first steering angle detection rotation amount sensor) 33 is referred to. while leading side steering motor by (in this case, the first steering motor) controls the rotation of the 27, and controls so that the steering angle of the leading wheels 7 to the target steering angle theta _F (step S4). Thereby, the automatic guided vehicle 1 travels along the guide line 11 while being controlled so that the detection midpoint of the leading-side line detection sensor 9 matches the midpoint of the guide line 11.

As shown in FIG. 5, the RAM 40 of the control device 37 travels a predetermined distance D from the curve notice reference marker 41,
Control data for running conversion when the vehicle reaches the predetermined position in b is stored. This control data is set in advance according to the curvature of the curved road 11b,
The above-mentioned predetermined distance D is set to a distance of about 1/3 from the end of the reference distance R, that is, the start of the curved road 11b. The control device 37 starts the leading-side traveling distance detection rotation amount sensor (in this case, the first traveling-distance detection rotation amount sensor) from the time when the detection signal of the notice reference marker 41 is input from the leading side line detection sensor 9. 3.) The distance data from 31 is taken in, and the running distance is counted, and it is determined whether or not the calculated running distance exceeds the reference distance R and reaches the predetermined distance D (step S6). If it is determined that the traveling distance has exceeded the reference distance R but has not reached the predetermined distance D, that is, if it is determined that the vehicle is traveling on the curved road 11b but has not reached the predetermined distance D, FIG. As in the unmanned traveling vehicle 1 shown in the middle of FIG. 5, the steering angle θ _R of the following wheel (in this case, the second traveling wheel) 8 is
On the same side as the steering angle θ _F of the leading wheel 7 with respect to the center line S, the setting is made to be the same as the steering angle θ _F of the leading wheel 7 (step S7).

By the above traveling control, the automatic guided vehicle 1
The leading wheel 7 travels along the curved road 11b of the guide line 11 while moving the vehicle body 2 from the start end of the curved road 11b in a direction away from the partition 14 while maintaining a state parallel to the partition 14. I will do it. Therefore, the vehicle body 2
The rear end corner does not abut against the partition 14. In the section of the reference distance R from the time point when the curve notification reference marker 41 is detected to the start end of the curve running path 11b, the vehicle travels with the steering angle θ _R of the following wheel 8 set to 0. It will be described later.

When the control device 37 determines that the travel distance has reached the predetermined distance D, the control device 37 sets the steering angle θ _R of the following wheel 8 to the center as in the unmanned vehicle 1 shown in the upper part of FIG. On the side opposite to the steering angle θ _F of the leading wheel 7 with respect to the line S, the setting is made to be the same as the steering angle θ _F of the leading wheel 7 (step S8). As a result, the unmanned transport vehicle 1 in which the follow-up line detection sensor 10 is in a position largely deviated from the guide line 11 when the predetermined distance D is reached, the rear side of the traveling direction of the vehicle body 2 faces the guide line 11. Then, the traveling is continued in a state where the vehicle turns, and the posture is corrected such that the following line detection sensor 10 is positioned on the guide line 11 as in the automatic guided vehicle 1 shown in the upper part of FIG.

Accordingly, the automatic guided vehicle 1 once moves in a direction away from the partition 14 while keeping the vehicle body 2 parallel to the partition 14, and then turns along the guide line 11 to take a posture. Since the vehicle body 2 has traveled on the straight running path 11a having an extremely small distance d from the partition wall portion 14, the vehicle body 2 travels along the guide line 11 while making a small turn within a range in which the rear end corner does not contact the partition wall portion 14. Will do. Accordingly, it is not necessary to secure an extra space for traveling of the automatic guided vehicle 1 in a clean room where running costs are high. Although not shown in FIG. 4, when the automatic guided vehicle 1 reaches the straight traveling path after traveling on the curved traveling path 11b, the steering angle θ _{R of the} following wheels 8 is adjusted.
Of course, the well-known traveling control for setting the vehicle speed to 0 again is performed.

If it is determined that the reference marker 41 for curve announcement has not been detected (step S1), a detection signal from a conveyed object detection sensor (not shown) disposed in the storage chamber 17 is provided. With reference to, it is determined whether or not the traveling is before the transfer of the transported object (step S9). Now
In the case of traveling before the transfer to the loading station, the control device 37 causes the detection data of the guidance line 11 to be sequentially input from the leading-side line detection sensor 9 (step S10), and based on the detection data. Then, the amount of deviation between the detection midpoint of the line detection sensor 9 and the midpoint of the guide line 11 is calculated by calculation (step S11).

After that, the control device 37 calculates a target steering angle θ _F of the leading wheel 7 for setting the deviation amount to 0, and from the rotation amount sensor 33 for detecting the leading steering angle based on this data. by controlling the leading-side steering motor 27 with reference to the detection signal of the rotation, the steering angle of the leading wheels 7 is controlled to be the target steering angle theta _F (step S1
2). Thereby, the automatic guided vehicle 1 travels along the guide line 11 while being controlled so that the detection midpoint of the leading-side line detection sensor 9 matches the midpoint of the guide line 11.

Subsequently, the control device 37 causes the detection data of the guide line 11 to be sequentially input from the tracking-side line detection sensor 10 (step S14), and based on the detection data, the detection midpoint of the line detection sensor 10. And guidance line 1
1 is calculated by calculation (step S
15). After that, the control device 37 sets the deviation amount to 0.
The target steering angle θ _R of the following wheel 8 is calculated to obtain the following.
The following-side steering motor 28 while referring to the detection signal from the
The by controlling the rotation, and controls so that the steering angle of the follower wheel 8 reaches the target steering angle theta _F (step S16).

As a result, the automatic guided vehicle 1 not only makes the detection midpoint of the leading line detection sensor 9 coincide with the midpoint of the guide line 11 but also makes the following line detection sensor 10
When the vehicle is stopped at the loading station, the center line S of the vehicle body 2 coincides with the center line of the guiding line 11, and the loading station is controlled. Oppose in a precise positioning state. Therefore, the lifter 18 that is advanced in the correct direction from the storage room 17 of the automatic guided vehicle 1 can reliably receive the transported object from the storage shelf or the like.

On the other hand, when it is determined that the traveling is in a state where the transported object is transferred by inputting the detection signal of the transported object from the transported object detection sensor (step S9).
The control device 37 causes the detection data of the guidance line 11 to be sequentially input from the leading-side line detection sensor 9 (Step S).
18) Based on the detection data, the amount of deviation between the midpoint of detection by the line detection sensor 9 and the midpoint of the guide line 11 is calculated by calculation (step S19).

After that, the control device 37 calculates a target steering angle θ _F of the leading wheel 7 to make the deviation amount zero, and, based on the data, calculates a target steering angle θ _F from the rotation amount sensor 33 for detecting the leading steering angle. by controlling the leading-side steering motor 27 with reference to the detection signal of the rotation, the steering angle of the leading wheels 7 is controlled to be the target steering angle theta _F (step S2
0). Next, the control device 37 sets the target steering angle θ _R of the following wheel 8 to be fixed to 0 (step S22).
Thereby, the automatic guided vehicle 1 is controlled so that the detection midpoint of the leading-side line detection sensor 9 coincides with the midpoint of the guidance line 11, and travels substantially along the guidance line 11. Next, when the vehicle stops at the unloading station, the center line S of the vehicle body 2 is slightly shifted on the rear side with respect to the center line of the guide line 11, but the transported object in the storage chamber 17 is supplied by the lifter 18. There is no problem. The reference distance R from the detection of the above-described curve notice reference marker 41
The interval until the vehicle travels is the same as that in steps S18 to S2 described above.
The travel is controlled by the same processing as in step 2.

In the above embodiment, the reference marker 4
1 is detected, the target steering angle θ _R of the following wheel 8 is set to the same angle as the target steering angle θ _F of the leading wheel 7, but the target steering angle θ _R of the following wheel 8 is changed to the target steering angle θ _R of the leading wheel 7. it may be set to a fraction of the steering angle theta _F. In this case, the vehicle body 1 is not moved parallel to the partition wall portion 14, but is slightly swiveled toward the partition wall portion 14 at the rear portion.
The vehicle 1
Can be further driven in a small turning state along the curved road 11b, so that extra space can be further reduced.

As another traveling control method, when the target steering angle θ _F of the first traveling wheel 7 becomes equal to or larger than a small first angle corresponding to traveling on the straight traveling road 11a, the vehicle is moved from the straight traveling road 11a. It is determined that the vehicle has entered the curved road 11b, and accordingly, the target steering angle θ _R of the second traveling wheel 8 on the rear side in the traveling direction is set to the first target steering angle θ _F and the traveling of the vehicle body 2 For a center line S along the direction,
If the same angle is set on the same side as the target steering angle θ _F of the first traveling wheels 7, the automatic guided vehicle 1
While keeping the state parallel to the partition 14.
Away from the vehicle and the front side is the curved road 1 of the guidance line 11
The vehicle can travel in a state along 1b.

Further, the target steering angle θ of the first traveling wheel 7
Curve road 1 due to _F becoming greater than or equal to the second angle
1b, the target steering angle θ _R of the second traveling wheel 8 is set opposite to the target steering angle θ _{F of} the first traveling wheel 7 with respect to the center line S. By setting the sides at almost the same angle, the automatic guided vehicle 1
Is a guide line 11 on the rear side of the vehicle body 2 in the traveling direction.
The traveling is continued in a state of turning toward, and the posture is corrected so that the rear side of the vehicle body 2 is located on the guide line 11.
Therefore, in this traveling control method, it is possible to obtain the same effects as those of the above-described invention, while eliminating the need to detect the reference marker 41 for curve notice and measure the traveling distance from the time of detection of the reference marker 41 in the above-described invention. Can be.

[0043]

As described above, according to the traveling control method for an automatic guided vehicle according to the first aspect of the present invention, when the automatic guided vehicle travels along a curved traveling path from a straight traveling path, the vehicle body of the automatic guided vehicle is controlled. Is moved parallel to the bulkhead while moving in the direction that increases the distance from the bulkhead, and then turns along the guidance line to correct the posture, so travel along the guidance line Even when the distance between the car body and the partition wall is set as small as possible, the vehicle should be driven so that the rear end corner in the traveling direction of the car body makes a small turn along the curved road without contacting the partition wall. Since it can be applied, in particular, it is applied to the traveling control of the automatic guided vehicle in a clean room or the like having a high running cost, and there is no need to provide an extra space for the traveling of the automatic guided vehicle in the clean room.
It is possible to control the automatic guided vehicle to travel so that the narrow traveling space can be efficiently used.

According to the traveling control method of the automatic guided vehicle of the second invention, when the target steering angle of the first traveling wheel becomes equal to or larger than the first angle, the automatic guided vehicle is moved from the straight traveling road to the curved traveling road. Is determined, and the target steering angle of the second traveling wheel on the rear side is set to the same side as the target steering angle of the first traveling wheel with respect to the center line along the traveling direction of the vehicle body. Are set at substantially the same angle, and it is determined that the target steering angle of the first traveling wheel has reached the position with a predetermined curvature or more on the curved traveling road because the target steering angle has reached the second angle or more. Since the target steering angle of the wheel is set to be substantially the same as the direction opposite to the target steering angle of the first traveling wheel with respect to the center line, the detection of the curve advance reference marker in the first invention is performed. And measurement of the mileage from the detection of this reference marker. While not necessary to be obtained the same effect as in the first invention.

[Brief description of the drawings]

FIG. 1 is an overall perspective view of an automatic guided vehicle controlled by a traveling control method according to an embodiment of the present invention.

FIG. 2 is a schematic plan view of a drive system for traveling and steering in the automatic guided vehicle 1 according to the first embodiment.

FIG. 3 is a block diagram of a driving system according to the first embodiment;

FIG. 4 is a flowchart showing a travel control method according to the first embodiment;

FIG. 5 is an explanatory diagram of a travel control method according to the embodiment.

FIG. 6 is an explanatory diagram of a conventional traveling control method for an automatic guided vehicle.

[Description of Signs] 1 Automatic guided vehicle 2 Body 7 First traveling wheel 8 Second traveling wheel 9 First line detection sensor 11 Guidance line 11b Curved traveling path 21 First traveling motor 22 Second traveling Motor 41 Curve notice reference marker D Predetermined distance R Reference distance θ _F Target steering angle of first traveling wheel θ _R Target steering angle of second traveling wheel S Centerline of vehicle body

Claims (4)

[Claims] 1. A target steering angle of a first traveling wheel on a front side in a traveling direction is detected by a first line detection sensor while detecting a guidance line by a first line detection sensor on a front side in a traveling direction. In a traveling control method for an automatic guided vehicle that causes an automatic guided vehicle to travel along the guidance line by setting the detected deviation amount from the guidance line to be zero, a reference provided near the guidance line When the first line detection sensor detects a curve notice reference marker for notifying that the guidance line will become a curved road after traveling a distance, the travel distance from the detection time of the reference marker is the reference distance. In a traveling section up to a predetermined distance that is greater than the distance, the target steering angle of the second traveling wheel on the rear side in the traveling direction is set to the second steering wheel with respect to the center line along the traveling direction of the vehicle body. After the traveling distance from the detection time of the reference marker exceeds a predetermined distance, the target steering angle of the second traveling wheel is set to be substantially the same as the direction of the target steering angle of the traveling wheel. A traveling control method for an automatic guided vehicle, wherein the traveling direction is set at substantially the same angle as the direction opposite to the target steering angle of the first traveling wheel with respect to the center line. 2. A section of a reference distance from a reference marker for curve notice to a start end of a curve traveling road sets a target steering angle of a second traveling wheel to substantially 0, and a position at a predetermined distance from the reference marker is: The travel control method for an automatic guided vehicle according to claim 1, wherein the travel distance is set within a section from an end of the reference distance to a first third from a start end side of the curved road. 3. The vehicle according to claim 1, wherein the first and second traveling wheels on the front side and the rear side in the traveling direction are formed of an AC servomotor.
3. The traveling control method for an automatic guided vehicle according to claim 1, wherein the traveling control unit is individually driven by a second traveling motor. 4. When the target steering angle of the first traveling wheel on the front side in the traveling direction is equal to or more than the first angle corresponding to the traveling on the straight traveling path and is equal to or less than the second angle, the target steering angle on the rear side in the traveling direction. Second
The target steering angle of the traveling wheel is set to substantially the same angle as the direction of the target steering angle of the first traveling wheel on the same side, and the target steering angle of the first traveling wheel is greater than or equal to the second angle. In such a case, the target steering angle of the second traveling wheel is set to substantially the same angle in the direction opposite to the target steering angle of the first traveling wheel. Travel control method.