JPH1165654A - Unmanned carrier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure realtime performance, algorithmic simplicity, and functionality extension simplification, with respect to an unmanned carrier traveling along a guide path. SOLUTION: This carrier is provided with a guiding FSM(finite state machine) 28 for performing operation of reducing position deflection with respect to a guide path at the time of detecting the guide path, avoiding an FSM 27 for performing an operation for avoiding an obstacle at the time of detecting the obstacle, a storing action FSM 29 for storing the evading of the obstacle and performing an operation in a direction opposite to the operation performed for avoiding the obstacle, and an attitude correcting FSM 30 for performing an operation for reducing an attitude angular deflection around a vertical shaft against the guide path during guide path withdrawal. The priority order is set in the order of the escaping FSM 27, the guiding FSM 28, the storing action FSM 29, and the attitude correcting FSM 30, and at the time of an operation by an FSM whose priority order is higher, the operation by an FSM whose priority order is lower is suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic guided vehicle that travels along a guideway such as a magnetic guideway.
vehicle).

[0002]

2. Description of the Related Art Conventionally, when a plurality of automatic guided vehicles running along a taxiway such as a magnetic taxiway are operated on a taxiway, a host system that supervises the operation grasps the position of each automatic guided vehicle, By instructing each AGV one by one on an appropriate operation route, collisions between AGVs are prevented.

However, in this operation method, the operation route planning algorithm is complicated, and the load on the host system is large. Whenever the layout of the operation route or the number of automatic guided vehicles is changed, the operation route planning of the host system is performed. There is a problem that it is necessary to change the application program.

Therefore, conventionally, in order to release the host system from the management of the automatic guided vehicle, the automatic guided vehicle is provided with a sensor for detecting an obstacle. There has been proposed an operation method of performing slow driving and stopping using a sensor.

However, in this operation method, unless the obstacle is removed, the automatic guided vehicle remains stopped, and the operation efficiency is reduced. The stopped automatic guided vehicle becomes an obstacle for other automatic guided vehicles and congestion occurs. Cause a problem.

Here, in order to release the host system from the management of the automatic guided vehicle and to perform smooth operation, the automatic guided vehicle autonomously avoids collisions between the automatic guided vehicles and removes obstacles. After avoiding, it is necessary to return to the original taxiway again.

Conventionally, in order to realize this, (1. guidance action) recognition of a position deviation (eccentricity) with respect to a guideway → calculation of a direction change angle and a speed from a position deviation amount → command to a drive system → (2 Recognition of the traveling direction environment by the unmanned guided vehicle → modeling of the traveling direction environment inside the unmanned guided vehicle → calculation of the avoiding direction, etc. → Calculation of the direction change angle and speed based on the action plan → Command to the driving system → (3. Recognition of the traveling direction environment by the automatic guided vehicle (as an action to avoid the left object while leaving the taxiway) → Recognition of left side environment by unmanned guided vehicle → Modeling of traveling direction environment inside unmanned guided vehicle → Modeling of left side environment inside unmanned guided vehicle → Formulation of action plan such as calculation of traveling direction → Based on action plan Direction change angle and speed Calculation → command to the drive train → (4. as an action to return to the taxiway after avoiding the object) recognition of the traveling direction environment by the automatic guided vehicle → recognition of the left environment by the automatic guided vehicle → unmanned of the traveling direction environment Modeling inside the guided vehicle → Modeling the left side environment inside the unmanned guided vehicle → Recognizing the posture by the internal sensor → Formulating an action plan such as calculating the direction to the taxiway → The direction conversion angle based on the action plan A serial process of calculating the speed → instructing the drive system has been performed.

[0008]

However, in this operation method, it is necessary to recognize the taxiway and the environment, model the environment, draft an action plan, and calculate the direction change angle and speed.
There is no real-time capability, it is difficult to avoid obstacles smoothly and return to the taxiway while the automatic guided vehicle is traveling, and the algorithm is complicated, so it is low in reliability and requires only development costs In addition, when expanding functions, it is necessary to make changes to all processing systems.Since serial processing is performed, a problem in a certain processing system leads to a fatal trouble as a whole. there were.

In view of the above, the present invention can autonomously return to the taxiway by leaving the taxiway and avoiding collision with another automatic guided vehicle, and return to the taxiway again. And to improve reliability and reduce development costs through the simplicity of the algorithm, ensure ease of function expansion, and ensure that some processing troubles do not lead to fatal troubles as a whole. It is an object of the present invention to provide an automatic guided vehicle capable of performing such operations.

[0010]

According to a first aspect of the present invention, when a taxiway is detected, a steering operation (direction changing operation) is performed so that a positional deviation from the taxiway is within an allowable range.
Finite state machine (FSM)
ne]), the second FSM that steers to avoid an obstacle when an obstacle is detected, and the operation that avoids the obstacle by memorizing that the obstacle has been avoided, A third FSM for maneuvering in a direction, and a fourth FSM for maneuvering so as to reduce a posture angle deviation about a vertical axis with respect to the taxiway while leaving the taxiway, and the second FSM is given first priority. Priority, first FSM second priority, third FS
M is the third priority, the fourth FSM is the fourth priority,
At the time of maneuvering by the higher priority FSM, the operation is performed so as to suppress the maneuvering by the lower priority FSM.

According to the first aspect of the present invention, the vehicle travels along a taxiway unless an obstacle is detected. When an obstacle is detected, the vehicle leaves the taxiway to avoid the obstacle. After avoiding the obstacle, the vehicle can return to the taxiway autonomously.

According to a second aspect of the present invention, in the first aspect, the first FSM includes, as a state, a right turn which is executed when the positional deviation with respect to the taxiway exceeds an allowable range to the left. The second FSM has a left turn to be executed when the position deviation with respect to the taxiway is outside the allowable range to the right, and a turn stop to be executed when the position deviation with respect to the taxiway is within the allowable range. The state includes a right turn to be performed when an obstacle is detected and a stop to be performed when no obstacle is detected. The third FSM has the following states:
The fourth FSM includes a left turn to be executed when there is an avoidance memory and a turn stop to be executed when there is no avoidance memory.
As the state, a right turn is performed when the attitude angle deviation around the vertical axis with respect to the taxiway is left, a left turn is performed when the attitude angle deviation around the vertical axis with respect to the taxiway is right, and a vertical turn with respect to the taxiway. And a turning stop executed when there is no deviation of the attitude angle around the axis.

According to the second aspect of the present invention, the vehicle travels along the taxiway unless an obstacle is detected. When an obstacle is detected, the vehicle departs from the taxiway to the right to avoid the obstacle. And
After avoiding the obstacle, the vehicle can return to the taxiway autonomously.

According to a third aspect of the present invention, in the first aspect, the first FSM includes, as a state, a right turn to be executed when the positional deviation with respect to the taxiway exceeds an allowable range to the left. The second FSM has a left turn to be executed when the position deviation with respect to the taxiway is outside the allowable range to the right, and a turn stop to be executed when the position deviation with respect to the taxiway is within the allowable range. The state includes a left turn to be performed when an obstacle is detected and a turn stop to be performed when no obstacle is detected.
The fourth FSM has a right turn to be executed when there is an avoidance memory and a stop to be executed when there is no avoidance memory.
As a state, a right turn is performed when the attitude angle deviation around the vertical axis with respect to the taxiway is left, a left turn is performed when the attitude angle deviation around the vertical axis with respect to the taxiway is right, and a vertical turn with respect to the taxiway. And a turning stop executed when there is no deviation of the attitude angle around the axis.

According to the third aspect of the present invention, the vehicle travels along the taxiway unless an obstacle is detected. When an obstacle is detected, the vehicle departs from the taxiway to the left to avoid the obstacle. And
After avoiding the obstacle, the vehicle can return to the taxiway autonomously.

[0016]

FIG. 1 is a conceptual diagram showing one embodiment of the present invention. In FIG. 1, 1 is a vehicle body, 2 is a front part of the vehicle body 1,
3 is a rear part of the vehicle body 1, 4 is a left front wheel made of a free wheel, 5 is a right front wheel made of a free wheel, 6 is a left rear wheel, 7 is a right rear wheel, and 8 is a left rear wheel driving a left rear wheel 6. The motor 9 is a right rear wheel drive motor for driving the right rear wheel 7.

In one embodiment of the present invention, the left rear wheel 6
And the right rear wheel 7 can be driven independently of each other, so that if the rotation speed and the rotation direction of the left rear wheel 6 and the right rear wheel 7 are equal, the vehicle travels straight, and if only one of them rotates, the vehicle turns and rotates. If the direction is reversed, a sharp turn is possible.

Reference numeral 10 denotes a gyro for detecting the attitude of the vehicle body 1 about a vertical axis, and 11 denotes a magnetic guideway 1.
2 is a magnetic sensor for detecting a magnetic guide path for detecting the magnetic field No. 2.

The magnetic guideway detecting magnetic sensor 11 is configured to output a voltage proportional to the positional deviation of the magnetic guideway detecting magnetic sensor 11 with respect to the magnetic guideway 12. For example, if the center of the magnetic guideway detecting magnetic sensor 11 coincides with the center of the magnetic guideway 12, the output voltage becomes 5V, and the output voltage is in the range of 3 to 7V as the position is deviated left and right with a width of ± 100 mm. The voltage is configured to change proportionally.

Reference numeral 13 denotes an infrared sensor for detecting a front object which detects an object located in front of the vehicle body 1 in a non-contact manner;
Is an object detection area of the infrared sensor 13 for detecting a front object.

Reference numeral 15 denotes an infrared sensor for detecting a left front object which detects an object located on the left front of the vehicle body 1 in a non-contact manner.
Reference numeral 16 denotes an object detection area of the left front object detection infrared sensor 15.

An infrared sensor 17 for detecting an object located on the left side of the vehicle body 1 in a non-contact manner,
Reference numeral 18 denotes an object detection area of the left-side object detection infrared sensor 17.

These infrared sensors 13 for detecting front objects,
The infrared sensor 15 for detecting the left front object and the infrared sensor 17 for detecting the left object are configured such that their respective voltage outputs change when an object is detected.

Reference numeral 19 denotes a control unit mounted on the vehicle body 1. Reference numeral 20 denotes a gyro 10 for detecting the posture of the vehicle body, a magnetic sensor 11 for detecting a magnetic guide path, an infrared sensor 13 for detecting a front object, and a left front object detection. This is an A / D converter that converts a detection signal consisting of an analog signal output from the infrared sensor 15 and the left-side object detection infrared sensor 17 into a digital signal.

Reference numeral 21 denotes a vehicle control computer to which a digitalized detection signal output from the A / D converter 20 is input, and reference numeral 22 denotes a memory used by the vehicle control computer 21.

Reference numeral 23 denotes a D / A converter for converting the left rear wheel drive motor control signal, the right rear wheel drive motor control signal, and the gyro control signal, which are digital signals output from the vehicle body control computer 21, into analog signals. is there.

Reference numeral 24 denotes a left rear wheel drive motor control signal S consisting of an analog signal output from the D / A converter 23.
The left rear wheel drive motor control device 25 controls the left rear wheel drive motor 8 based on L. The right rear wheel drive motor control signal SR composed of an analog signal output from the D / A converter 23
Is a right rear wheel drive motor control device that controls the right rear wheel drive motor 9 based on the following.

In one embodiment of the present invention, four FSs
M is provided. The first FSM is an FSM that, when the magnetic guideway 12 is detected, performs steering so as to reduce the amount of positional deviation of the vehicle body 1 with respect to the magnetic guideway 12.
It is called SM. This guidance FSM is realized using a magnetic sensor 11 for detecting a magnetic guidance path.

FIG. 2 is a state transition diagram of the guidance FSM. The guidance FSM has three states of turning stop, left turning, and right turning, and the positional deviation to the left with respect to the magnetic guide path 12 is different. If it is large, a right turn of the vehicle body 1 is executed, and if the positional deviation to the right with respect to the magnetic guide path 12 is large, a left turn of the vehicle body 1 is executed, and the positional deviation with respect to the magnetic guide path 12 is reduced. If it is small, the turning stop is executed.

The second FSM is an FSM that, when an obstacle is detected, steers so as to avoid the obstacle.
It is called avoidance FSM. This avoidance FSM is realized using the front object detection sensor 13, the left front object detection sensor 15, and the left object detection sensor 17.

FIG. 3 is a state transition diagram of the avoidance FSM. The avoidance FSM has two states of turning stop and turning right. When an obstacle is detected, the turning right of the vehicle body 1 is executed. And
When no obstacle is detected, the turning of the vehicle body 1 is stopped.

The third FSM is a FSM that stores information that an obstacle has been avoided and performs a steering operation in a direction opposite to the steering operation for avoiding the obstacle.
This storage behavior FSM is realized using the memory 22 as an avoidance storage unit.

FIG. 4 is a state transition diagram of the memory action FSM. The memory action FSM has two states, a turning stop and a left turn. If there is no avoidance memory, the turning of the vehicle body 1 is stopped.

The fourth FSM is an FSM that performs steering so as to reduce an attitude angle deviation about a vertical axis with respect to the magnetic guide path 12 while leaving the magnetic guide path 12, and is hereinafter referred to as an attitude correction FSM. This attitude correction FSM is realized using a gyro for detecting the attitude of the vehicle body.

FIG. 5 is a state transition diagram of the attitude correction FSM. The attitude correction FSM executes a right turn when the attitude angle deviation around the vertical axis with respect to the magnetic guide path 12 is left.
When the attitude angle deviation around the vertical axis with respect to the magnetic guide path 12 is rightward, the left turn is executed, and when there is no attitude angle deviation around the vertical axis with respect to the magnetic guide path 12, the turn stop is executed.

FIG. 6 is a diagram modeling a method of suppressing the FSM. In FIG. 6, 27 is the avoidance FSM, and 28 is the induced FS.
M, 29 are memory behavior FSM, 30 is posture correction FSM, 3
1, 32, 33, and 34 are suppression nodes, and 35 is a drive system of the vehicle body 1.

When the turning command is not input from the input end B, the suppression nodes 31, 32, 33, and 34 are set to output the command from the input end B, and the turning command is input from the input end A. In such a case, the turning command from the input end A is output with priority.

Therefore, for example, the avoidance FSM 27, the lead F
If none of the SM28, the memory action FSM29, and the posture correction FSM30 output a turning command, the forward command is transmitted to the drive system, and the forward action is performed.

Then, for example, during the forward movement, the posture correction F
When the turning instruction is output from the SM 30, the forward action is suppressed, the turning command output from the attitude correction FSM 30 is transmitted to the drive system 35 via the suppression nodes 33 and 34, and the operation of the vehicle body 1 by the attitude correction FSM 30 is controlled. Will be done.

For example, when a turning command is output from the storing action FSM 29 during the operation of the vehicle body 1 by the attitude correcting FSM 30, the turning command output from the storing action FSM 29 is transmitted to the drive system 35 via the suppression nodes 32, 33, 34. And the steering of the vehicle body 1 by the memory action FSM 29 is performed.

Further, for example, when a turn command is output from the guidance FSM 28 during the operation of the vehicle body 1 by the memory action FSM 29, the turn command output from the guidance FSM 28 is transmitted to the drive system 35 via the suppression nodes 31, 32, 33, 34. And the steering of the vehicle body 1 by the guidance FSM 28 is performed.

For example, when a turn command is output from the avoidance FSM 27 during the operation of the vehicle body 1 by the guidance FSM 28, the turn command output from the avoidance FSM 27 is transmitted to the drive system 35 via the suppression nodes 31, 32, 33, 34. Then, the vehicle body 1 is steered by the avoidance FSM 27.

That is, in one embodiment of the present invention, the avoidance FSM 27 has the first priority, the guidance FSM 28 has the second priority, the memory action FSM 29 has the third priority, and the posture correction FSM 30 has the fourth priority. F with the highest priority
At the time of maneuvering by the SM, it is configured to suppress maneuvering by the FSM having a lower priority.

FIG. 7 is a diagram showing a running example of one embodiment of the present invention. 7, reference numeral 38 denotes an automatic guided vehicle according to one embodiment of the present invention, reference numeral 39 denotes an obstacle on the magnetic guide path 12, and arrows indicate the traveling direction of the automatic guided vehicle 38.

Here, when the automatic guided vehicle 38 is started, it is correctly directed forward, and the magnetic sensor 1 for detecting a magnetic guide path is used.
If the output of 1 is 5V and the obstacle 39 ahead is not detected, the avoidance FSM 27, the guidance FSM 28, the memory action FSM 29, and the posture correction FSM 30 do not appear, and the vehicle moves forward.

Then, the magnetic sensor 11 for detecting the magnetic guide path is provided.
When the output voltage becomes 3 V or more and less than 5 V, the induction FSM
At the same time, the advancement is suppressed, and the automatic guided vehicle 3
8 performs an action of making a right turn and reducing a positional deviation with respect to the magnetic guide path 12.

When the output voltage of the magnetic sensor 11 for detecting a magnetic guidance path exceeds 5 V and becomes less than 7 V, the induction FSM
At the same time, the advancement is suppressed, and the automatic guided vehicle 3
8 performs an action of making a left turn and reducing a positional deviation with respect to the magnetic guide path 12. In addition, the gyro 1 for body posture detection
0 is reset while induced FSM28 is expressed.

Thereafter, the infrared sensor 13 for detecting a front object
Detects the obstacle 39, the avoidance FSM 27 appears, and at the same time, the steering and forward movement by the guidance FSM 28 are suppressed, and the automatic guided vehicle 38 makes a right turn and takes an action to avoid the obstacle 39 on the right. At this time, the avoidance to the right is stored in the memory 22.

Then, the infrared sensor 1 for detecting a front object
3. When the infrared sensor 15 for detecting the left front object and the infrared sensor 17 for detecting the left object no longer detect the obstacle 39, the memory 22 is stored, that is, the memory is turned right to avoid the obstacle 39. As a result, the memory behavior FSM 29 appears, and the posture is controlled in the direction along the obstacle 39.

If the left object detecting infrared sensor 17 detects the obstacle 39 while the automatic guided vehicle 38 is avoiding the obstacle 39 while traveling on the right side, the avoidance FSM 27 appears and the steering by the memory action FSM 29 is suppressed. , Automatic guided vehicle 3
Avoidance of the obstacle 39 on the left side of 8 is ensured.

In this way, the automatic guided vehicle 38 moves the obstacle 39 by the memory action FSM 29 and the avoidance FSM 27.
Is passed on the right side, but when passing the obstacle 39, the automatic guided vehicle 38
3. There is no output from either the left front object detection infrared sensor 15 or the left side object detection infrared sensor 17, and the operation returns to the magnetic guide path 12 by the storage behavior FSM29 stored in the memory 22.

Then, the magnetic sensor 11 for detecting the magnetic guide path is provided.
When the guidance FSM 28 is generated by the detection of the magnetic guide path 12 by the, the automatic guided vehicle 38 travels along the magnetic guide path 12. The storage of the memory 22 is cleared by the detection of the magnetic guide path 12 by the magnetic sensor 11 for magnetic guide path detection.

When the automatic guided vehicle 38 exceeds the magnetic guideway 12 due to the depth of the angle of entry into the magnetic guideway 12, the memory action of the FSM is cleared by clearing the memory 22.
29 disappears, and the posture correction FSM 30 by the vehicle body posture detection gyro 10 appears. That is, the posture correction FSM 30 is expressed by the output angle of the vehicle body posture detecting gyro 10 with respect to the magnetic guide path 12, and the automatic guided vehicle 38 corrects the posture to the direction of the magnetic guide path 12.

Then, the magnetic sensor 11 for detecting the magnetic guide path is provided.
When the guidance FSM 28 is generated by the detection of the magnetic guide path 12, the automatic guided vehicle 38 travels along the magnetic guide path 12 thereafter.

As described above, according to the embodiment of the present invention, the vehicle travels along the magnetic guide path 12 unless the obstacle 39 is detected. To avoid the obstacle 39,
After avoiding, the vehicle can return autonomously to the magnetic guideway 12 to perform autonomously.

Therefore, the host system for managing the operation of the automatic guided vehicle 38 does not need to plan an operation route for avoiding the collision of the automatic guided vehicle 38, and can change the layout of the operation route and the number of the automatic guided vehicles 38. The accompanying program can be easily changed, and it is possible to prevent a decrease in operating efficiency and traffic congestion due to the obstacle 39.

Further, according to one embodiment of the present invention, since the processing required for preventing collision can be performed in a multitasking manner, the conventional automatic guided vehicle requires a processing time. Control processes such as environment recognition and action planning are not required, and it is possible to respond to changes in the environment with a high-speed response, so that real-time properties can be ensured.

According to one embodiment of the present invention, the avoidance FSM 27, the guidance FSM 28, the memory behavior FSM 29, and the attitude correction FSM 30 each determine a detection signal from a corresponding infrared sensor or gyro, and Since it is sufficient to select an action pattern, the algorithm can be simplified, reliability can be improved, and development cost can be reduced.

Further, according to the embodiment of the present invention, when the function is extended, it is only necessary to add the FSM and set the suppression relation, and it is not necessary to change the existing system by the function extension. Easiness can be ensured.

According to one embodiment of the present invention, the avoidance FSM 27, the guidance FSM 28, the memory behavior FSM 29, and the posture correction FSM 30 operate and operate in a multitasking manner, so that some of the FSMs cause abnormal operation. However, a normal operation of another FSM may prevent a catastrophic failure.

In the embodiment of the present invention, the case where the obstacle is avoided on the right-hand side has been described. Alternatively, the obstacle may be avoided on the left-hand side.

[0062]

As described above, according to the present invention, it is possible to autonomously leave the taxiway, avoid collision with another automatic guided vehicle, and return to the taxiway again. Moreover,
Since these can be performed by the FSM, real-time performance, improvement of reliability and simplification of the algorithm due to simplicity of the algorithm, reduction of development cost, easiness of function expansion, and troubles in some processing are fatal as a whole Possibility of not causing trouble can be secured.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing one embodiment of the present invention.

FIG. 2 is a state transition diagram of a guided FSM included in an embodiment of the present invention.

FIG. 3 is a state transition diagram of an avoidance FSM included in an embodiment of the present invention.

FIG. 4 is a state transition diagram of a memory behavior FSM included in an embodiment of the present invention.

FIG. 5 is a state transition diagram of a posture correction FSM provided in an embodiment of the present invention.

FIG. 6 is a diagram modeling a method of suppressing FSM provided in an embodiment of the present invention.

FIG. 7 is a diagram showing a running example of one embodiment of the present invention.

[Explanation of symbols]

 2 Front part of vehicle body 3 Rear part of vehicle body 4 Left front wheel 5 Right front wheel 8 Left rear wheel drive motor 9 Right rear wheel drive motor 10 Gyro for body posture detection 11 Magnetic sensor for magnetic guideway detection 13 Infrared sensor for front object detection 15 Left Infrared sensor for front object detection 17 Infrared sensor for left object detection 20 A / D converter 21 Body control computer 22 Memory 23 D / A converter 24 Left rear wheel drive motor control device 25 Right rear wheel drive motor control device

Claims (3)

[Claims] 1. A first finite state machine for maneuvering when a taxiway is detected so that a positional deviation with respect to the taxiway is within an allowable range, and a maneuvering for avoiding an obstacle when an obstacle is detected. A second finite state machine that performs a steering operation, a third finite state machine that stores information that an obstacle has been avoided, and performs a steering operation in a direction opposite to a steering operation that is performed to avoid an obstacle, and leaves the taxiway. A fourth finite state machine that steers so as to reduce a posture angle deviation around a vertical axis with respect to the taxiway, wherein the second finite state machine has first priority, and the first finite state machine has In the second priority, the third finite state machine in the third priority, and the fourth finite state machine in the fourth priority.
An unmanned guided vehicle, wherein the automatic guided vehicle operates so as to suppress the steering by the finite state machine having the lower priority when the finite state machine having the higher priority is operated. 2. The state machine according to claim 1, wherein the first finite state machine executes a right turn when the positional deviation with respect to the taxiway exceeds an allowable range on the left and a positional deviation with respect to the taxiway on the right. A left turn to be executed when the position exceeds the allowable range, and a turn stop to be executed when the positional deviation with respect to the taxiway is within the allowable range. The second finite state machine has a fault as a state. The third finite state machine has a right turn that is executed when an obstacle is detected and a turn stop that is executed when no obstacle is detected. The fourth finite state machine has a state in which, when the attitude angle deviation about the vertical axis with respect to the taxiway is left, the clockwise rotation is executed. Times and on the taxiway A left turn performed when the posture angle deviation around the vertical axis is rightward, and a rotation stop performed when there is no posture angle deviation around the vertical axis with respect to the taxiway. Item 6. The automatic guided vehicle according to Item 1. 3. The first finite state machine includes, as states, a right turn executed when the position deviation with respect to the taxiway exceeds an allowable range on the left side, and a position turn with respect to the taxiway on the right side. A left turn to be executed when the position exceeds the allowable range, and a turn stop to be executed when the positional deviation with respect to the taxiway is within the allowable range. The second finite state machine has a fault as a state. The third finite state machine has a left turn to execute when an object is detected and a stop to execute when no obstacle is detected, and the third finite state machine executes a right turn when there is an avoidance memory as a state. The fourth finite state machine has a state in which, when the attitude angle deviation about the vertical axis with respect to the taxiway is left, the clockwise rotation is executed. Times and on the taxiway A left turn performed when the posture angle deviation around the vertical axis is rightward, and a rotation stop performed when there is no posture angle deviation around the vertical axis with respect to the taxiway. Item 6. The automatic guided vehicle according to Item 1.