JP6930436B2 - Travel control method for automatic guided vehicles - Google Patents

Description

The present invention relates to a traveling control method for an automatic guided vehicle provided with an elevating table on which a transported object is placed, which is guided and controlled by using a guiding means and self-propelled along a predetermined traveling path without a track.

Automated guided vehicles (AGVs) that run on an untracked vehicle are equipped with free wheels (caster wheels) that receive a load in order to enable traveling on curved travel paths, in addition to the driving wheels that drive the vehicle. For example, the vehicle travels on the traveling path by itself while being guided by an electromagnetic wave generated by an electromagnetic induction line installed along a predetermined traveling path (see, for example, Patent Document 1).

The unmanned carrier (1) of Patent Document 1 supplies a new newspaper winder (P) to the paper feed device (2) of the rotary press, and collects the newspaper winder (P) in use. , By making it possible to change the direction of the drive wheel (8) around the vertical axis by a motor different from the motor that rotates the drive wheel (8), it is possible to move laterally (Patent Document 1 [0024]). ..
Then, when the automatic guided vehicle (1) is returned from the stopped position where the entry and stop are stopped, the automatic guided vehicle (1) rolls so as not to interfere with the cones (4A, 4B) of the paper feed device (2). A travel control method is used to prevent this. That is, the automatic guided vehicle (1) is once entered to the front outside the stop position and then moved backward to the stop position, whereby the direction of the free wheel (7) is reversed, and the automatic guided vehicle (7) is in that state. (1) is moved from the stop position in the backward movement direction to be separated from the stop position.

Japanese Patent No. 3162661

The direction of the free wheel of the automatic guided vehicle follows the traveling direction of the automatic guided vehicle, and the direction at the time of stopping is determined by the traveling direction before the stop.
If the traveling direction of the automatic guided vehicle at the time of starting is different from the traveling direction before the stop, the automatic guided vehicle follows the traveling direction at the time of starting after the automatic guided vehicle starts and changes direction from the direction at the time of stopping. Such a change of direction of the free wheel becomes a resistance when the automatic guided vehicle starts.

Conventionally, a device has been devised to increase the diameter of the free wheel and reduce the resistance applied to the free wheel so that the free wheel can start smoothly without wobbling even if the direction of the free wheel is disturbed.
However, in the case of a low-floor automatic guided vehicle equipped with an elevating table on which the transported object is placed, it is necessary to reduce the diameter of the free wheel by sneaking under the transported object and lifting and moving the transported object. , The above-mentioned device cannot be adopted.
In addition, when the weight of the transported object on the lifting table is large, the resistance due to the change of direction of the free wheel increases, so that the problem of wobbling at the time of starting becomes remarkable, and the automatic guided vehicle meanders or overloads. It becomes a factor that causes.
Furthermore, when the travel route of the automatic guided vehicle includes a route that changes direction in various directions, the deviation of the automatic guided vehicle from the travel route varies when the direction is changed, and the automatic guided vehicle is placed at a predetermined stop position. There is a problem that it cannot be stopped stably and accurately.

Since the automatic guided vehicle (1) in Patent Document 1 requires a dedicated motor for changing the direction of the drive wheels (8) around the vertical axis, the manufacturing cost increases.
Moreover, the traveling control method of the automatic guided vehicle (1) in Patent Document 1 only discloses a method of aligning the free wheels (7) in the reciprocating movement in the one-dimensional linear path as described above.
Furthermore, as in Patent Document 1, in the traveling control in which the automatic guided vehicle (1) is guided by the electromagnetic waves generated by the electromagnetic induction wire installed along the traveling path and self-propelled, the traveling path is changed when the direction is changed. It is not possible to solve the above-mentioned problem that the automatic guided vehicle cannot be stopped stably and accurately at a predetermined stop position due to the deviation of the automatic guided vehicle from the above.

In view of the above background, the present invention is a low-floor automatic guided vehicle equipped with a free wheel, a drive wheel, and an elevating table on which a transported object is placed, and the weight is large even if the direction of the free wheel is disturbed. An automatic guided vehicle that does not wobble when an object is placed on an elevating table and starts, and can stop stably and accurately at a predetermined stop position even if the deviation from the traveling path varies when changing direction. The purpose is to provide a control method.

The traveling control method for an automatic guided vehicle according to the present invention is to solve the above-mentioned problems.
It is a traveling control method for an automatic guided vehicle that is guided and controlled using a guiding means and self-propelled along a predetermined traveling route without a track.
The automatic guided vehicle
Equipped with free wheels, left and right drive wheels, and an elevating table on which the transported object is placed.
It sneaks under the transported object and lifts and moves the transported object.
The traveling route is
Includes a turning path in which the direction is different between the upstream side and the downstream side of the mounting position where the transported object is mounted on the lifting table.
The automatic guided vehicle is once moved from the previously described placement position in the direction opposite to the traveling direction on the downstream side, and then traveled toward the previously described placement position so that the free wheels can be aligned in the traveling direction. Wheel alignment process and
A stop position control step of controlling the automatic guided vehicle to stop at the previously described position based on the position recognition information on the ground.
The free wheels are aligned in the traveling direction through the free wheel alignment step, and the elevating table of the automatic guided vehicle stopped at the above-described placement position through the stop position control step is raised and placed on the elevating table. The transport object loading process for mounting the transported object and
The vehicle transporting step of transporting the automatic guided vehicle on which the transported object is placed on the lifting table to a predetermined position along the traveling path.
Including
In the direction change path, by rotating the left and right drive wheels in opposite directions at a constant speed before performing the universal wheel alignment step, only the automatic guided vehicle is on the spot without changing the direction of the transported object. It is characterized by having a direction changing step of changing direction.

According to such a traveling control method of an automatic guided vehicle, the transported object is placed on a turning path in which the directions are different between the upstream side and the downstream side of the mounting position where the transported object is placed on the lifting table of the automatic guided vehicle. The free wheels of the automatic guided vehicle before being placed are in a state of being aligned in the traveling direction on the downstream side by the free wheel alignment step.
Therefore, when the automatic guided vehicle, which raises the lifting table at the above-mentioned placement position and places the transported object on the lifting table, starts in the traveling direction on the downstream side, the automatic guided vehicle has a low floor and a free wheel. Even if the diameter is small and the weight of the transported object is heavy, it can run smoothly without wobbling.
In addition, the automatic guided vehicle before loading the transported object will be placed in the previously described position even if the deviation from the traveling path varies due to the change of direction based on the position recognition information on the ground by the stop position control process. It can be stopped accurately.
Therefore, the transported object can be placed accurately and stably on the lifting table of the automatic guided vehicle, and even if a plurality of different automatic guided vehicles pass the same route many times, the error of the stop position is large. It becomes difficult to get out.
Furthermore, since only the automatic guided vehicle changes its direction on the spot in the direction change route, the automatic guided vehicle, which is relatively lightweight because the vehicle is not loaded, can be placed in the mounting position more accurately. Since it can be stopped, the error of the stop position does not accumulate even when the direction change is repeated.
Moreover, when the left and right drive wheels are worn, even if the amount of rotation of the drive wheels is insufficient and the angle of the in-situ direction change is less than 90 °, the free wheel performed after the direction change step. In the alignment step, when the automatic guided vehicle is once moved from the previously described mounting position in the direction opposite to the traveling direction on the downstream side and then traveled toward the previously described mounting position, the driving wheels are worn. It is possible to correct the deviation of the angle of field change.

Here, it is a preferable embodiment that the proportional gain of the PID control in the guidance control of the free wheel alignment step is made larger than the proportional gain of the PID control in the guidance control of the conveyed material transporting step.

According to such a configuration, the proportional gain of the PID control in the guidance control of the free wheel alignment step in which the transported object is not mounted on the automatic guided vehicle is set to the proportional gain of the PID control on which the transported object is mounted on the automatic guided vehicle. Since it is larger than the proportional gain of PID control in the process guidance control, the quick response of the guidance control is high. Therefore, even if the posture of the vehicle body is disturbed after the free wheels are aligned, the guidance means can be used in a short time. The posture can be corrected, and the vehicle can be stopped accurately at the mounting position.
Moreover, the proportional gain of the PID control in the guidance control of the transported object transporting process in which the transported object is mounted on the automatic guided vehicle is in the guiding control of the universal wheel alignment process in which the transported object is not mounted on the automatic guided vehicle. Since it is smaller than the proportional gain of the PID control, the stability of the induction control in the transported object transporting process is improved.
Furthermore, in the guidance control in the transported object transport process, the mileage is smaller than that in the free wheel alignment process by making the proportional gain in the PID control smaller than the proportional gain in the PID control in the guidance control in the free wheel alignment process. In the conveyed product transporting process, which has a long length, acceleration / deceleration for changing the rotation speed of the drive wheels can be reduced, so that power consumption can be reduced.
In addition, even in the guidance control in the process in which the automatic guided vehicle travels in a state where the conveyed object is not placed other than the free wheel alignment step, the proportional gain in the PID control is the PID control in the guidance control in the free wheel alignment step. It is a more preferable embodiment that the gain is smaller than the proportional gain. As a result, the number of rotations of the traveling wheels can be changed in the process in which the automatic guided vehicle travels in a state in which the transported object other than the universal wheel alignment process, which has a longer mileage than the universal wheel alignment process, is not placed. Since acceleration / deceleration can be reduced, power consumption can be further reduced.

Further, it is a preferable embodiment that the position recognition information is a coordinate reading type barcode.

According to such a configuration, it is possible to improve the accuracy of the stop position in the traveling direction of the automatic guided vehicle in the stop position control for controlling the automatic guided vehicle to stop at the mounting position on the direction change path.

Further, it is a preferable embodiment that the guiding means is a guiding line installed along the traveling path.

According to such a configuration, the automatic guided vehicle travels while being guided by the guide line installed along the traveling route, so that the position accuracy in the direction orthogonal to the traveling direction of the automatic guided vehicle can be improved and the direction change route can be improved. It is possible to improve the accuracy of the stop position in the direction orthogonal to the traveling direction of the automatic guided vehicle in the stop position control for controlling the automatic guided vehicle to stop at the mounting position.

In addition, the transported object is a trolley and luggage on it.
It is a more preferable embodiment to provide a wheel chock for stopping the wheels of the trolley on the ground at the above-described placement position and on the ground at the position where the trolley is lowered from the automatic guided vehicle.

According to such a configuration, the dolly whose wheels are stopped by the wheel chock is reliably positioned on the ground, so that when the lifting table of the automatic guided vehicle is raised and the dolly is placed on the automatic guided vehicle, Since the positions of the automatic guided vehicle and the trolley do not shift, the trolley can be smoothly transported by the automatic guided vehicle.

Further, the lifting table of the automatic guided vehicle is provided with a positioning pin.
It is an even more preferable embodiment that the transported object is provided with a receiving portion that receives the positioning pin.

According to such a configuration, when the elevating table of the automatic guided vehicle is raised and the transported object is placed on the elevating table in the transported object loading step, the receiving portion of the transported object holds the positioning pin of the elevating table. Since it is received, the transported object does not shift from the lifting table of the automatic guided vehicle, so that the transported object can be stably and reliably transported by the automatic guided vehicle.

As described above, according to the traveling control method for the automatic guided vehicle according to the present invention, the following effects are mainly obtained.
(1) In the direction change path in which the directions are different between the upstream side and the downstream side of the loading position where the transported object is placed on the lifting table of the automatic guided vehicle, the free wheel of the automatic guided vehicle before the transported object is placed is By the free wheel alignment step, the vehicle is aligned in the traveling direction on the downstream side of the mounting position. Therefore, when the automatic guided vehicle, which raises the lifting table at the above-mentioned placement position and places the transported object on the lifting table, starts in the traveling direction on the downstream side, the automatic guided vehicle has a low floor and a free wheel. Even if the diameter is small and the weight of the transported object is heavy, it can run smoothly without wobbling.
(2) The automatic guided vehicle before loading the transported object will be placed in the previously described position even if the deviation from the traveling path varies due to the change of direction based on the position recognition information on the ground by the stop position control process. It can be stopped accurately. Therefore, the transported object can be placed accurately and stably on the lifting table of the automatic guided vehicle, and even if a plurality of different automatic guided vehicles pass the same route many times, the error of the stop position is large. It becomes difficult to get out.

It is a schematic plan view which shows the main part of the automatic guided vehicle which concerns on embodiment of this invention. Similarly, it is a schematic plan view showing a state in which the automatic guided vehicle has made an in-situ change of direction by 90 °. It is a partial vertical cross-sectional front view which shows the automatic guided vehicle (the state which the automatic guided vehicle is in the mounting position P of FIG. 4A or FIG. It is a partial vertical sectional front view which shows the said automatic guided vehicle (the state which the automatic guided vehicle is in the position of FIG. 5A) which raised the elevating table and put the transported object on it. It is a schematic plan view which shows the receiving part which receives the positioning pin of the automatic guided vehicle in the transported object. It is an operation explanatory view of the automatic guided vehicle, and is the schematic plan view which shows the movement from the upstream side of the direction change path of the automatic guided vehicle which does not place a transported object to the loading position. It is also an operation explanatory view, and is a schematic plan view showing a 90 ° in-situ direction change of the automatic guided vehicle at the mounting position. It is also an operation explanatory view, and is a schematic plan view which shows a free wheel alignment process and a stop position control process. Similarly, it is an operation explanatory view, and is a schematic plan view which shows the conveyed material placing process. Similarly, it is an operation explanatory view, and is a schematic plan view which shows the conveyed material transport process. It is an operation explanatory view of the automatic guided vehicle, and is the schematic plan view which shows the movement from the upstream side of the direction change path of the automatic guided vehicle on which the transport object was placed by raising the elevating table to the mounting position. It is also an operation explanatory view, and is a schematic plan view showing a state in which the lifting table of the automatic guided vehicle at the mounting position is lowered to lower the transported object. It is also an operation explanatory view, and is a schematic plan view showing a 90 ° in-situ direction change of the automatic guided vehicle at the mounting position. It is also an operation explanatory view, and is a schematic plan view which shows a free wheel alignment process and a stop position control process. Similarly, it is an operation explanatory view, and is a schematic plan view which shows the conveyed material placing process. Similarly, it is an operation explanatory view, and is a schematic plan view which shows the conveyed material transport process. It is a schematic plan view which shows the example of the wheel chock installed on the ground to stop the wheel of a bogie. Similarly, it is an enlarged front view of the main part. It is a flow chart which shows the example of selection of the proportionality constant of PID control in the traveling control method of the automatic guided vehicle which concerns on embodiment of this invention.

Hereinafter, embodiments according to the present invention will be described with reference to the drawings.
In the following embodiment, a state in which the automatic guided vehicle, which is guided and controlled by using a guiding means and self-propelled along a predetermined traveling path, is directed forward with the traveling direction (direction of the arrow in FIG. 1A) as the front. Define the front, back, left, and right with, and let the view from the right be the front view.

As shown in the schematic plan view of FIG. 1A and the partial vertical sectional front view of FIG. 2A, the automatic guided vehicle 1 according to the embodiment of the present invention has front, rear, left and right free wheels 2, 2, ... The wheels 3 and 3 and the elevating table 4 on which the conveyed object D is placed are provided.
Here, the transported object D is a trolley 6 provided with front, rear, left and right wheels 7, 7, ..., And a luggage W on the trolley 6. The automatic guided vehicle 1 may carry an empty trolley 6 in a state where the cargo W is unloaded.

As shown in the schematic plan view of FIG. 1A, the automatic guided vehicle 1 includes a traveling drive device (not shown) of drive wheels 3 and 3, an elevating drive device (not shown) of an elevating table 4, front and rear magnetic sensors S1 and S1, and front. The bar code sensor S2 of the unit and a control device (not shown) are provided.

The magnetic sensor S1 detects a magnetic tape (for example, the magnetic tape A in FIG. 4A) which is a guiding means installed on the ground (for example, the floor surface FL in FIG. 2A), and determines the amount of deviation in the width direction with respect to the center position. To detect. Based on the detection information, the control device controls traveling so as to change the rotation speeds of the left and right drive wheels 3 and 3 so that the automatic guided vehicle 1 can travel along the center of the magnetic tape.

In the present embodiment, the guiding means used for the guiding control is a magnetic tape which is a guiding wire, that is, a magnetic guiding type. Such an induction wire may be a magnetic induction type such as a wire of a magnetic material, an electromagnetic induction type using an induction current from an electric wire, or an optical induction type using an optical tape or a drawn wire. May be good.
Alternatively, without using a guide line, the shape of the surrounding environment is grasped from the information acquired by various sensors, the self-position of the automatic guided vehicle 1 is estimated based on the shape data, and a map is created while correcting it. It may be an autonomous guidance such as moving SLAM (Simultaneously Localization And Mapping).

However, by using the guided vehicle as the guiding means, the automatic guided vehicle 1 travels while being guided by the guided vehicle installed along the traveling route, so that the position accuracy in the direction orthogonal to the traveling direction of the automatic guided vehicle 1 is improved. can. In addition, it is possible to improve the accuracy of the stop position in the direction orthogonal to the traveling direction of the automatic guided vehicle 1 in the stop position control for controlling the automatic guided vehicle 1 to stop at the mounting position in the direction change path described later.

The barcode sensor S2 recognizes a coordinate reading type barcode (for example, the coordinate reading type barcode E in FIG. 4A), which is position recognition information installed on the ground. Based on the recognition information, the control device controls traveling so as to stop at the target stop position while measuring the distance in the traveling direction from the coordinate reading type barcode.
The position recognition information is not limited to the coordinate reading type barcode. For example, in the case of autonomous guidance such as SLAM, the position recognition information is a mark (for example, a pillar or a wall) originally present on the ground. There may be.

By using a coordinate reading type barcode as the position recognition information, the direction of travel of the automatic guided vehicle 1 in the stop position control for controlling the automatic guided vehicle 1 to stop at the mounting position in the direction change path described later. The stop position accuracy can be improved.

The automatic guided vehicle 1 uses the traveling drive device to rotate the left and right drive wheels 3 and 3 in opposite directions at a constant speed so that the left and right drive wheels 3 and 3 rotate around the center of the left and right drive wheels 3 and 3 in the left-right direction on the rotation axis. You can easily change direction on the spot. For example, the schematic plan view of FIG. 1B shows a state in which the in-situ direction is changed by 90 ° clockwise in a plan view.
It should be noted that such an in-situ change may not be a configuration in which the left and right drive wheels 3 and 3 are rotated in opposite directions at a constant speed, but a configuration in which the drive wheels of the four front, rear, left and right wheels are steered.

The elevating table 4 of the automatic guided vehicle 1 can be elevated from the descending position shown in the front view of the partial vertical section of FIG. 2A to the ascending position shown in the front view of the partial vertical section of FIG. Prepare for the diagonal of the table 4.
Further, as shown in the schematic plan view of FIG. 3, the carriage 6 is provided with receiving portions G, G, ... That receive the positioning pins 5, 5 at four locations, and the receiving portions G, G, ... Are rotationally symmetric by 90 °. (4 rotation symmetry).
Since the positioning pins 5 and 5 raised by raising the elevating table 4 as shown in FIG. 2B are inserted into the receiving portions G and G of the trolley 6, the transported object D (from the elevating table 4 of the automatic guided vehicle 1) Since the dolly 6 and the luggage W) do not shift, the automatic guided vehicle 1 can stably and reliably transport the transported object D.

After transporting the transported object D by the automatic guided vehicle 1 and lowering the elevating table 4 to lower the transported object D, the automatic guided vehicle 1 is turned 90 ° clockwise or counterclockwise in a plan view. Even in this state, the receiving portions G, G, ... Are rotationally symmetric by 90 °. Therefore, if the elevating table 4 is raised, the positioning pins 5 and 5 are inserted into the receiving portions G, G of the carriage 6.
Similarly, the automatic guided vehicle 1 transports the transported object D, lowers the elevating table 4 to lower the transported object D, and then rotates the automatic guided vehicle 1 clockwise or counterclockwise by 180 ° in-situ direction. Since the receiving portions G, G, ... Are rotationally symmetric by 90 ° even in the converted state, if the elevating table 4 is raised, the positioning pins 5 and 5 are inserted into the receiving portions G and G of the trolley 6. NS.

In the following, referring to the schematic plan view for explaining the operation of FIGS. 4A to 4E and the schematic plan view for explaining the operation of FIGS. 5A to 5F, the traveling control method of the automatic guided vehicle 1 according to the embodiment of the present invention. Will be described.
A magnetic tape A is installed on the ground in the traveling path B on which the automatic guided vehicle 1 travels, and the coordinate-reading barcodes E, E, etc. are located on the ground at the mounting position P where the automatic guided vehicle 1 stops. ... is installed.
The traveling path B includes a direction change path C in which the directions are different between the upstream side P1 and the downstream side P2 of the mounting position P on which the conveyed object D is placed on the elevating table 4. Only the automatic guided vehicle 1 changes direction without changing the direction.

In the schematic plan view for explaining the operation of FIGS. 4A to 4E, the automatic guided vehicle 1 on which the transported object D is not mounted is stopped at the loading position P at the upstream side P1 of the mounting position P, and the automatic guided vehicle 1 is transported. An example is shown in which the lifting table 4 of the vehicle 1 is raised, the transported object D is placed on the automatic guided vehicle 1, and the transported object D is transported to the downstream side P2.
The trolley 6, which is the transported object D at the loading position P, may or may not be loaded with cargo.

As shown in the schematic plan view of FIG. 4A, the automatic guided vehicle 1 with no load travels from the upstream side P1 of the mounting position P toward the mounting position P and stops at the mounting position P. The free wheels 2, 2, ... Are facing the traveling direction of the upstream side P1, which is the traveling direction before stopping.
When traveling in this way, as described above, the magnetic sensor S1 of the automatic guided vehicle 1 detects the magnetic tape A on the ground, detects the amount of deviation in the width direction with respect to the central position, and uses the detection information. Based on this, the automatic guided vehicle 1 is controlled to travel along the center of the magnetic tape A.
Further, when the barcode sensor S2 of the automatic guided vehicle 1 recognizes the coordinate reading type barcode E on the ground, the target stop position is measured while measuring the distance in the traveling direction from the coordinate reading type barcode E as described above. The running is controlled so as to stop at.

Next, as shown in the schematic plan view of FIG. 4B, the automatic guided vehicle 1 at the mounting position P is turned clockwise by 90 ° in the plan view (direction changing step). The free wheels 2, 2, ... Are facing the circumferential direction, which is the traveling direction before stopping.
Next, as shown in the schematic plan view of FIG. 4C, the automatic guided vehicle 1 is once moved from the mounting position P in the direction opposite to the traveling direction F of the downstream side P2, and then travels toward the mounting position P. By doing so, the free wheels 2, 2, ... Are aligned in the traveling direction F (flexible wheel alignment step), and at the target stop position while measuring the distance in the traveling direction from the coordinate-reading barcode E on the ground. Travel control is performed so as to stop the vehicle (stop position control process).

Next, as shown in the schematic plan view of FIG. 4D, the elevating table 4 of the automatic guided vehicle 1 moved to the mounting position P is raised, and the transported object D is placed on the elevating table 4 (conveyed object loading step). ).
In this state, as described above, the positioning pins 5 and 5 of the elevating table 4 are inserted into the receiving portions G and G of the carriage 6 which is the conveyed object D.
Next, as shown in the schematic plan view of FIG. 4E, the automatic guided vehicle 1 on which the transported object D is mounted on the elevating table 4 is moved from the mounting position P to the traveling direction F of the downstream side P2 in the traveling path B. It is transported to a predetermined position along the route (conveyed object transport process).

In the schematic plan view for explaining the operation of FIGS. 5A to 5F, the automatic guided vehicle 1 on which the transported object D is mounted is stopped at the loading position P at the upstream side P1 of the mounting position P, and the automatic guided vehicle 1 After lowering the lifting table 4 to lower the transported object D from the automatic guided vehicle 1, the lifting table 4 of the automatic guided vehicle 1 is raised to place the transported object D on the automatic guided vehicle 1 and transport it to the downstream side P2. An example is shown.
At the loading position P, there are cases where the load is unloaded from the trolley 6, which is the transported object D, the load is loaded on the trolley 6, the load is unloaded from the trolley 6, and a new load is loaded.

As shown in the schematic plan view of FIG. 5A, the automatic guided vehicle 1 on which the transported object D is mounted on the upstream side P1 of the mounting position P faces the mounting position P from the upstream side P1 of the mounting position P. And stop at the mounting position P. The free wheels 2, 2, ... Are facing the traveling direction of the upstream side P1, which is the traveling direction before stopping.
When traveling in this way, as described above, the magnetic sensor S1 of the automatic guided vehicle 1 detects the magnetic tape A on the ground, detects the amount of deviation in the width direction with respect to the central position, and uses the detection information. Based on this, the automatic guided vehicle 1 is controlled to travel along the center of the magnetic tape A.
Further, when the barcode sensor S2 of the automatic guided vehicle 1 recognizes the coordinate reading type barcode E on the ground, the target stop position is measured while measuring the distance in the traveling direction from the coordinate reading type barcode E as described above. The running is controlled so as to stop at.

Next, as shown in the schematic plan view of FIG. 5B, the elevating table 4 of the automatic guided vehicle 1 that has moved to the mounting position P is lowered, and the conveyed object D is lowered from the elevating table 4.
Next, as shown in the schematic plan view of FIG. 5C, the automatic guided vehicle 1 at the mounting position P is turned clockwise by 90 ° in the plan view (direction changing step). The free wheels 2, 2, ... Are facing the circumferential direction, which is the traveling direction before stopping.
Next, as shown in the schematic plan view of FIG. 5D, the automatic guided vehicle 1 is once moved from the mounting position P in the direction opposite to the traveling direction F of the downstream side P2, and then travels toward the mounting position P. By doing so, the free wheels 2, 2, ... Are aligned in the traveling direction F (flexible wheel alignment step), and at the target stop position while measuring the distance in the traveling direction from the coordinate-reading barcode E on the ground. Travel control is performed so as to stop the vehicle (stop position control process).

Next, as shown in the schematic plan view of FIG. 5E, the elevating table 4 of the automatic guided vehicle 1 moved to the mounting position P is raised, and the transported object D is placed on the elevating table 4 (conveyed object loading step). ).
In this state, as described above, the positioning pins 5 and 5 of the elevating table 4 are inserted into the receiving portions G and G of the carriage 6 which is the conveyed object D.
Next, as shown in the schematic plan view of FIG. 5F, the automatic guided vehicle 1 on which the transported object D is mounted on the elevating table 4 is moved from the mounting position P to the traveling direction F of the downstream side P2 in the traveling path B. It is transported to a predetermined position along the route (conveyed object transport process).

In the present embodiment, the transported object D is a trolley 6 provided with front, rear, left and right wheels 7, 7, ..., And a luggage W on the trolley 6.
Therefore, for example, a schematic plan view of FIG. 6A can be seen on the mounting position P on which the carriage 6 is placed on the elevating table 4 of the automatic guided vehicle 1 or on the floor FL on the ground at the position where the carriage 6 is lowered from the automatic guided vehicle 1. And, as shown in the enlarged front view of the main part of FIG. 6B, wheel chocks H, H for stopping the rotation of the wheels 7, 7, ... Are provided so that the carriage 6 does not move unexpectedly.
Since the carriage 6 on which the wheels 7, 7, ... Are stopped is reliably positioned on the floor surface FL by such wheel chocks H, H, the lifting table 4 of the automatic guided vehicle 1 is raised to raise the carriage 6. Since the positions of the automatic guided vehicle 1 and the trolley 6 do not shift when the vehicle is mounted on the automatic guided vehicle 1, the trolley 6 can be smoothly transported by the automatic guided vehicle 1.

In the above-mentioned traveling control method of the automatic guided vehicle 1, when the direction is changed by 90 ° in the direction changing step, the pulse of the encoder set to drive the drive wheels 3 and 3 by the required rotation by the traveling drive device. The number is based on the diameter of the drive wheels 3 and 3 in a non-weared state.
Therefore, when the drive wheels 3 and 3 are worn, even if the drive wheels 3 and 3 are driven by the required rotation amount by the traveling drive device, the angle of the field direction change becomes less than 90 °.
However, even if the amount of rotation of the drive wheels 3 and 3 is insufficient and the in-situ direction change angle is less than 90 °, the automatic guided vehicle is used in the universal wheel alignment step performed after the direction change step. When 1 is once moved from the mounting position P in the direction opposite to the traveling direction F of the downstream side P2 and then traveled toward the mounting position P, the in-situ direction is changed due to wear of the drive wheels 3 and 3. It is possible to correct the deviation of the angle of.

In the above-mentioned traveling control method of the automatic guided vehicle 1, the direction changing step is not limited to the in-situ change of direction, and the vehicle travels on a curved route by changing the rotation speeds of the left and right drive wheels 3 and 3. By doing so, the direction may be changed.

According to the traveling control method of the automatic guided vehicle 1 as described above, the directions are different between the upstream side P1 and the downstream side P2 of the mounting position P on which the transported object D is placed on the elevating table 4 of the automatic guided vehicle 1. In the conversion path C, the free wheels 2, 2, ... Of the automatic guided vehicle 1 before mounting the transported object D are aligned in the traveling direction F of the downstream side P2 of the mounting position P by the free wheel alignment step. It becomes a state.
Therefore, when the automatic guided vehicle 1 in which the lifting table 4 is raised at the mounting position P and the transported object D is placed on the lifting table 4 starts in the traveling direction F of the downstream side P2, the automatic guided vehicle 1 moves. Even if the floor is low, the diameters of the free wheels 2, 2, ... Are small, and the weight of the transported object D is large, the vehicle can run smoothly without wobbling.

In addition, the automatic guided vehicle 1 before mounting the transported object D is mounted even if the deviation from the traveling path B varies due to the direction change based on the position recognition information on the ground by the stop position control process. It can be stopped accurately at the position P.
Therefore, the transported object D can be accurately and stably placed on the elevating table 4 of the automatic guided vehicle 1, and when a plurality of different automatic guided vehicles 1, 1, ... Pass the same route many times. Even if there is, it becomes difficult for an error in the stop position to appear.
Furthermore, in the direction change path C, since only the automatic guided vehicle 1 changes direction without changing the direction of the transported object D, the unmanned vehicle D is relatively lightweight because the transported object D is not placed. Since the transport vehicle 1 can be stopped at the mounting position P with higher accuracy, the error of the stop position does not accumulate even when the direction change is repeated.

The flow chart of FIG. 7 shows an example of selecting a proportional constant corresponding to the proportional gain of PID control in the traveling control method of the automatic guided vehicle according to the embodiment of the present invention, and before the automatic guided vehicle starts traveling. In addition, the proportionality constant is selected as shown in the flow chart of FIG. 7, and the vehicle travels using the guidance control.
For the proportionality constant, for example, the magnetic sensor of the unmanned carrier detects the magnetic tape on the ground, detects the amount of deviation in the width direction with respect to the center position, and based on the detection information, the unmanned carrier detects the magnetic tape. It is a ratio to change the number of rotations of the left and right drive wheels when the traveling is controlled so that the vehicle can travel along the center of the.

That is, when the automatic guided vehicle travels with the transported object placed on it, the value of "conveyed object present" (for example, proportional constant: 90) is selected and traveled as the proportional constant.
Further, when the automatic guided vehicle performs the free wheel alignment operation in the free wheel alignment step without mounting the transported object, the value of "universal wheel alignment" (for example, proportional constant: 800) is used as the proportional constant. Select and drive.
Further, when the automatic guided vehicle travels without mounting the transported object and without performing the free wheel alignment operation, the value of "without transported object" (larger than "with transported object", and " A value smaller than "alignment of free wheels", for example, a proportional constant: 200) is selected for traveling.

As described above, before the automatic guided vehicle starts traveling, the proportional gain of the PID control (the proportional constant) is selected and the automatic guided vehicle travels by using the guidance control, thereby achieving the following effects.
(1) The proportional gain (for example, proportionality constant: 800) of PID control in the guidance control of the free wheel alignment process in which the conveyed object is not placed on the unmanned carrier is set on the unmanned carrier. Since it is larger than the proportional gain of PID control (for example, proportionality constant: 90) in the guidance control of the transportation process of the transported object, the quick response of the guidance control is high, so that the posture of the vehicle body changes after the free wheels are aligned. Even if it is disturbed, the posture can be corrected by the guiding means in a short time, and the vehicle can be stopped accurately at the mounting position.
(2) The proportional gain (for example, proportionality constant: 90) of PID control in the guidance control of the transported object transporting process in which the transported object is mounted on the unmanned transport vehicle is the said that the transported object is not mounted on the unmanned transport vehicle. Since it is smaller than the proportional gain (for example, proportionality constant: 800) of the PID control in the induction control of the free wheel alignment process, the stability of the induction control of the conveyed material transfer process is improved.
(3) In the induction control in the conveyed material conveying process, the proportional gain in the PID control (for example, proportional constant: 90) is obtained from the proportional gain in the PID control in the induction control in the free wheel alignment process (for example, proportional constant: 800). By reducing the size, acceleration / deceleration for changing the rotation speed of the drive wheels can be reduced in the transported object transporting step in which the mileage is longer than that in the universal wheel alignment step, so that power consumption can be reduced.
(4) Even in the guidance control in the process in which the unmanned carrier travels in a state where the conveyed object is not placed other than the universal wheel alignment step, the proportional gain (for example, proportional constant: 200) in the PID control is set to the universal wheel. Since it is smaller than the proportional gain of PID control in the induction control of the alignment process (for example, proportional constant: 800), the transported object other than the universal wheel alignment process having a longer mileage than the universal wheel alignment process is loaded. In the process in which the unmanned carrier travels in the unplaced state, acceleration / deceleration for changing the rotation speed of the traveling wheels can be reduced, so that power consumption can be further reduced.

All the descriptions of the above embodiments are examples, and the present invention is not limited thereto. Various improvements and modifications can be made without departing from the scope of the present invention.

1 Automated guided vehicle 2 Free wheel 3 Drive wheel 4 Lifting table 5 Positioning pin 6 Bogie 7 Wheel A Magnetic tape (guidance means)
B Travel route C Direction change route D Conveyed object E Coordinate reading type barcode (position recognition information)
F Downstream direction of travel FL Floor surface (ground)
G Receiving part H Wheel chock P Mounting position P1 Upstream side P2 Downstream side S1 Magnetic sensor S2 Bar code sensor W Luggage

Claims (6)

It is a traveling control method for an automatic guided vehicle that is guided and controlled using a guiding means and self-propelled along a predetermined traveling route without a track.
The automatic guided vehicle
Equipped with free wheels, left and right drive wheels, and an elevating table on which the transported object is placed.
It sneaks under the transported object and lifts and moves the transported object.
The traveling route is
Includes a turning path in which the direction is different between the upstream side and the downstream side of the mounting position where the transported object is mounted on the lifting table.
The automatic guided vehicle is once moved from the previously described placement position in the direction opposite to the traveling direction on the downstream side, and then traveled toward the previously described placement position so that the free wheels can be aligned in the traveling direction. Wheel alignment process and
A stop position control step of controlling the automatic guided vehicle to stop at the previously described position based on the position recognition information on the ground.
The free wheels are aligned in the traveling direction through the free wheel alignment step, and the elevating table of the automatic guided vehicle stopped at the above-described placement position through the stop position control step is raised and placed on the elevating table. The transport object loading process for mounting the transported object and
The vehicle transporting step of transporting the automatic guided vehicle on which the transported object is placed on the lifting table to a predetermined position along the traveling path.
Including
In the direction change path, by rotating the left and right drive wheels in opposite directions at a constant speed before performing the universal wheel alignment step, only the automatic guided vehicle is on the spot without changing the direction of the transported object. A traveling control method for an automatic guided vehicle, which comprises a direction-changing process for changing the direction.
The proportional gain of the PID control in the guidance control of the free wheel alignment step is made larger than the proportional gain of the PID control in the guidance control of the transported object transporting step.
The traveling control method for an automatic guided vehicle according to claim 1. The position recognition information is a coordinate reading type barcode.
The traveling control method for an automatic guided vehicle according to claim 1 or 2. The guiding means is a guiding line installed along the traveling path.
The traveling control method for an automatic guided vehicle according to any one of claims 1 to 3. The transported object is a trolley and luggage on it.
A wheel chock for stopping the wheels of the trolley is provided on the ground at the above-mentioned placement position and on the ground at the position where the trolley is lowered from the automatic guided vehicle.
The traveling control method for an automatic guided vehicle according to any one of claims 1 to 4. The lifting table of the automatic guided vehicle is equipped with a positioning pin.
The transported object includes a receiving portion that receives the positioning pin.
The traveling control method for an automatic guided vehicle according to any one of claims 1 to 5.

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