JP7533234B2 - Automated guided vehicles - Google Patents

Description

Applicable under Article 30, Paragraph 2 of the Patent Act. Published on the Toyota Industries Corporation website on September 24, 2020, and started selling on September 24, 2020.

The present invention relates to an automated guided vehicle.

In the automatic guided vehicle system disclosed in Patent Document 1, as shown in FIG.
An autonomous driving section in which autonomous guided vehicle 200 autonomously drives is provided between the first following section and the second following section in the route of 00. A return pattern 202 is provided as a pattern for returning autonomous guided vehicle 200 in the autonomous driving section to conductor 201 in the second following section, in which outer edges on both outsides in a direction perpendicular to the traveling direction of autonomous guided vehicle 200 fan out toward the autonomous driving section side, and when the outer edge is detected, autonomous driving control is switched to following driving control.

JP 2012-89077 A

Incidentally, an automated guided vehicle travels along a preset route, but may travel through a certain section along the travel route where a guide line cannot be installed. In this case, if a return pattern that spreads out to the left and right in the travel direction is provided to return to the guide line using the technology of Patent Document 1, it is necessary to provide a space on both the left and right sides in which the vehicle can travel so that the vehicle can travel with a width corresponding to the return pattern. If the vehicle travels straight from the source guide line to the destination guide line without providing a return pattern that spreads out to the left and right in the travel direction, it becomes difficult to transfer from the source guide line to the destination guide line if the posture of the vehicle when starting travel in the non-guide line section is deviated from the extension direction of the guide line.

The automated guided vehicle for solving the above problem is an automated guided vehicle that runs along a guide line extending on a floor while detecting the guide line with an on-board guide sensor, the travel route having a non-guide line section in the middle where the guide line is not provided, and a first guide line is detected by the on-board guide sensor.
The gist of the invention is that while traveling in a straight line in a driving direction learning section which begins when a mark on the road surface is detected just before the non-guide line section in which the vehicle travels while detecting the first guide line and before the non-guide line section in which the vehicle travels while detecting the second guide line by the vehicle-mounted guide sensor, the vehicle learns the driving direction from odometry information while detecting the first guide line by the vehicle-mounted guide sensor, and sets a virtual guide line in the non-guide line section, and the vehicle travels along the virtual guide line in the non-guide line section.

According to this, while traveling in a straight line in the traveling direction learning section that starts when a mark on the road surface is detected from the section where the vehicle-mounted guide sensor detects the first guide line to the section where the vehicle-mounted guide sensor detects the second guide line, the vehicle learns the traveling direction using odometry information and sets a virtual guide line in the non-guide line section, and travels along the virtual guide line in the non-guide line section. When traveling simply straight from the first guide line to the second guide line, it is difficult to detect the second guide line if the posture of the machine at the time of starting traveling in the non-guide line section is deviated from the extending direction of the guide line, but by learning the traveling direction during straight traveling in the traveling direction learning section and setting the virtual guide line in the non-guide line section, it becomes easier to detect the second guide line without being affected by the posture of the machine at the time of starting traveling in the non-guide line section. As a result, it is possible to easily move from the first guide line to the second guide line through the non-guide line section where no guide line is provided on the traveling route.

In addition, in an unmanned guided vehicle, when traveling along the virtual guide line in the non-guide line section, if the vehicle-mounted guide sensor cannot detect the second guide line even after traveling a predetermined distance, it is preferable to have the vehicle stop.

In addition, in the automated guided vehicle, it is preferable to set the virtual guide line in accordance with the learned traveling direction and a turning command that continues for a fixed angle and a fixed distance.

According to the present invention, it is possible to easily transfer from the first guide line to the second guide line via a non-guide line section in which no guide line is provided on the travel route.

FIG. 2 is a schematic plan view of an automatic guided vehicle according to the embodiment. FIG. 2 is a block diagram of an automated guided vehicle according to an embodiment. 4 is a flowchart for explaining an operation in the embodiment. 4A, 4B, and 4C are schematic plan views of a traveling automated guided vehicle. FIG. 4A, 4B, and 4C are schematic plan views of a traveling automated guided vehicle. 4A, 4B, and 4C are schematic plan views of a traveling automated guided vehicle. 4A, 4B, and 4C are schematic plan views of a traveling automated guided vehicle. FIG. FIG. 4A and 4B are schematic plan views of a traveling automated guided vehicle. 4A and 4B are schematic plan views of a traveling automated guided vehicle. 4A and 4B are schematic plan views of a traveling automated guided vehicle. FIG. 1 is an explanatory diagram for explaining the background art.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the automated guided vehicle system 10 includes an automated guided vehicle 20.
The automated guided vehicle 20 is, for example, an automated tractor. The automated guided vehicle system 10 detects guide lines extending on a floor with an on-vehicle guide sensor and causes the automated guided vehicle 20 to travel along the guide lines.

The automated guided vehicle 20 includes a machine base 21. The machine base 21 includes a pair of left and right drive wheels 22, 23 and a pair of left and right driven wheels 24, 25. The drive wheels 22, 23 are rear wheels, and the driven wheels 24, 25 are front wheels. The drive wheels 22, 23 are fixed wheels whose direction does not change.

The machine base 21 includes a left driving wheel motor 26 for rotating the left driving wheel 22 and a right driving wheel motor 27 for rotating the right driving wheel 2
A right drive wheel motor 27 is provided to rotate the right drive wheel 3.
The left and right drive wheels 22, 23 are rotated in synchronism with each other by the drive of motor 7. Steering is performed by driving the left and right drive wheels (fixed wheels) 22, 23 with separate motors 26, 27 and utilizing the speed difference between them.

A guide sensor 28 is mounted on the front center of the machine base 21 in the width direction. The guide sensor 28, which is a vehicle-mounted guide sensor, detects a guide line 41 extending on the floor, which is the road surface.
, 42 (see FIG. 4A ). For example, a magnetic tape is used as the guide lines 41, 42, and a magnetic sensor is used as the guide sensor 28. Alternatively, for example, a white line may be used as the guide lines 41, 42, and an optical sensor may be used as the guide sensor 28.

As shown in Fig. 1, a horizontal plane is defined by orthogonal x- and y-axes, with the x-axis direction being the front-rear direction of the vehicle and the y-axis direction being the width direction of the vehicle. The y-axis passes through the center point Pd of the drive wheels 22, 23. The x-axis passes through the center point Pd of the drive wheels 22, 23 and the center point P
Pass through g.

4A, the automated guided vehicle 20 can be made to travel along a preset route using the guide lines 41, 42. The travel route includes a certain section that is a non-guide line section where the guide lines 41, 42 cannot be installed.

A driving direction learning section is provided before the non-guide line section. The driving direction learning section is a straight driving section.
As shown in FIG. 1, a mark sensor 29 is mounted on the right side of the guide sensor 28 at the front of the machine base 21. The mark sensor 29 detects a mark 43 (see FIG. 4(a)) provided on the floor.
), (b), and (c) are detected. The mark 43 is provided next to the end of the first guide line 41. The mark 43 indicates the start point of the traveling direction learning section, that is, the start of the traveling direction learning section before the end of the traveling section defined by the first guide line 41.
The mark 43 may be, for example, a magnetic mark, and the mark sensor 29 may be, for example, a magnetic sensor.

As shown in FIG. 2, the automated guided vehicle 20 includes a controller 30.
is mounted on a machine base 21.
The guide sensor 28 and the mark sensor 29 are connected to the controller 30. The controller 30 receives detection signals from the guide sensor 28 and the mark sensor 29.

The left drive wheel motor 26 and the right drive wheel motor 27 are connected to the controller 30. The controller 30 controls the left drive wheel motor 26 and the right drive wheel motor 27 to perform running and steering. The controller 30 is configured to run the automated guided vehicle 20 along the guide lines 41, 42 extending on the floor while detecting the guide lines 41, 42 with a guide sensor 28. The left drive wheel rotation sensor 31 and the right drive wheel rotation sensor 32 are connected to the controller 30. The controller 30 detects the x-axis coordinate position of the machine base 21, the y ...
In FIG. 4B, the attitude angle θ of the machine base 21 is a positive predetermined value, and in FIG. 4C, the attitude angle θ of the machine base 21 is a negative predetermined value.
In Fig. 4A, the attitude angle θ of the machine base 21 is 0. The attitude angle θ is controlled so as to gradually decrease as the guided traveling using the guide lines continues.

Next, the operation will be described.
The controller 30 executes the process shown in FIG.
4(a), 4(b), and 4(c) show examples of travel routes of the automatic guided vehicle 20. In FIG.

4A, the travel route of the automated guided vehicle 20 is defined by a first guide line 41 extending linearly, and also by a second guide line 42 extending linearly in the same direction as the first guide line 41. The first guide line 41 and the second guide line 42 are formed on a straight line. The travel route of the automated guided vehicle 20 has a non-guide line section in which the guide lines 41, 42 are not provided.

Here, the position of the center point Pd of the left and right drive wheels 22, 23 in FIG. 1 is the position (x, y) in the xy coordinate system, and the attitude angle of the machine base 21 at this position is θ.
The position of the center point Pg of the guide sensor 28 in is taken as the position (x', y') in the xy coordinate system, and the attitude angle of the machine base 21 at this position is taken as θ'.

4A, 4B, and 4C, the non-guide line section is the section from where the automated guided vehicle 20 travels while detecting the first guide line 41 with the guide sensor 28 to where the automated guided vehicle 20 travels while detecting the second guide line 42 with the guide sensor 28. When entering this non-guide line section, the following is carried out.

As shown in FIG. 4(a), (b), and (c), the guide sensor 2 is activated during straight driving in the driving direction learning section that starts when the mark 43 provided on the road surface is detected just before the non-guide line section.
In step 8, the vehicle learns the driving direction from the odometry information while detecting the first guide line 41, and sets a virtual guide line Lvg1 in the non-guide line section. Then, the vehicle drives along the virtual guide line Lvg1 in the non-guide line section.

3, when the controller 30 detects the learning start mark 43, the controller 30 calculates its own position from the odometry information in step S10. This provides position data (x, y, θ) of the center point Pd of the left and right drive wheels 22, 23.

In step S11, the controller 30 determines the center point Pd
From the position data (x, y, θ) at the center point Pg of the guide sensor 28,
, ´, y´, θ´) and save it.

In step S12, the controller 30 continues guidance by the first guide wire 41.
In step S13, the controller 30 determines whether or not the vehicle has traveled a certain distance (approximately the distance to the tip of the first guide line 41) from the point where the learning start mark 43 was detected. If the travel has not been completed, the process returns to step S10. Then, steps S10, S11, S12,
The process of S13 is repeated. When traveling of the fixed distance is completed in step S13, the controller 30 determines that traveling of the traveling learning section is completed and proceeds to step S14.

In step S14, the controller 30 calculates an approximation line from the stored position data (x', y') of the guide sensor center point Pg. Specifically, the controller 30 calculates the line by the least squares method or the like.

In step S15, the controller 30 sets the approximate straight line as the virtual guide line Lvg1.
In step S16, the controller 30 determines the left and right driving wheels 22 from the odometry information.
, 23, the position (self-position) of the center point Pd is calculated.

In step S17, the controller 30 issues a turning command to correct the lateral deviation from the virtual guide line Lvg1, and guides the position of the guide sensor center point Pg calculated from the position of the center point Pd of the left and right drive wheels 22, 23 to approach the virtual guide line Lvg1.

In step S18, the controller 30 determines whether or not the vehicle has traveled distance A from the point where the learning start mark 43 was detected, and returns to step S16 if the vehicle has not traveled distance A. Then, by repeating the processes of steps S16, S17, and S18, the controller 30 continues traveling based on the odometry information without detecting the first guide line 41 with the guide sensor 28 for a certain distance so that the guide sensor 28 does not read the first guide line 41 in the traveling direction learning section.

When the vehicle travels the travel distance A in step S18, the controller 30
In 19, it is determined whether the guide sensor 28 has detected the second guide line 42, and a transfer destination is detected.

If the second guide line 42 is not detected in step S19, the controller 30 calculates the position (self-position) of the center point Pd of the left and right drive wheels 22, 23 from the odometry information while continuing the guidance by the virtual guide line Lvg1 in step S20. That is, the controller 30 continues the self-position determination.

In step S21, the controller 30 issues a turning command to correct the lateral deviation from the virtual guide line Lvg1.
In step S22, the controller 30 determines whether or not the distance B has been traveled from the point where the learning start mark 43 was detected, and returns to step S19 if the distance B has not been traveled. Then, while repeating the processes of steps S19, S20, S21, and S22, when the guide sensor 28 detects the second guide line 42 in step S19, the controller 30 returns to guiding along the second guide line 42 in step S24 because the second guide line 42 has been found.

On the other hand, if the guide sensor 28 cannot detect the second guide line 42 even after traveling the predetermined distance B in step S22, the controller 30 stops traveling in step S23.

The calculation of the approximation line and the setting of the virtual guide line Lvg1 in steps S14 and S15 in FIG. 3 will be described with reference to FIG.
The positions of the center point Pd of the left and right drive wheels 22, 23 in the time series are (x1, y1), ...
The positions of the guide sensor center point Pg in the time series corresponding to these positions are expressed as (x1', y1'), ..., (x5', y5'). The positions of the guide sensor center point Pg (x1', y1'), ..., (x5', y5') are linearly approximated by the least squares method. The imaginary guide line Lvg1 is obtained by extending this straight line forward from the first guide line 41.
That is, the virtual guide line Lvg1 of the non-guide line section is calculated by connecting each position obtained in time series of the guide sensor center point Pg in the traveling direction learning section.

In this way, the guided automatic guided vehicle travels along the obtained virtual guide line Lvg1, thereby performing straight-line autonomous travel by estimating the travel direction.
In the conventional case shown in FIG. 14, an unmanned guided vehicle that travels along a preset route can autonomously travel in a certain section where it is not possible to install guide lines without requiring a dedicated sensor.

However, the guide line needs to be constructed in a special shape. Also, in order to secure a return travel section using the second guide line, the width of the machine's aisle needs to be large on both the left and right sides. Furthermore, a section is required to adjust the machine's posture before the start of the non-guide line section. In other words, the machine's posture needs to be adjusted so that it is in the same direction as the extension direction of the guide line, and if the machine enters the non-guide line section diagonally, it will run diagonally. Also, due to the influence of the machine's posture at the start of the non-guide line section, the machine's arrival position at the end of the non-guide line section may exceed the travel guide width constructed in a special shape.

In this embodiment, in FIG. 4A, the posture of the machine base 21 is aligned with the extension direction of the first guide line 41. However, as shown in FIGS. 4B and 4C, even if the posture of the machine base 21 is inclined with respect to the extension direction of the first guide line 41 before the non-guide line section, the second guide line 42 is aligned with the extension direction of the first guide line 41.
The posture is correct just before the guide line. For this purpose, the vehicle is generated based on the direction in which the vehicle is moving, taking into consideration the estimation of the vehicle's own position based on the odometry information of the vehicle and the detection state of the guide line during the travel of the learning section before entering the non-guide line section. In other words, the extension direction of the first guide line 41 is learned to guide the vehicle along the virtual guide line Lvg1, and the vehicle is guided along the virtual guide line Lvg1 drawn on the extension line of the first guide line 41. By doing this, even if the machine base 21 is initially facing diagonally, the obtained virtual guide line Lvg1 is always straight, so that the vehicle can move onto the desired second guide line 42. In this way, it is not necessary to lay the return pattern 202 in FIG. 14, and the virtual guide line Lvg1 can be drawn straight, regardless of the installation method of the guide line, and it is not necessary to mount a dedicated sensor.

In other words, in a non-guide line section, if the vehicle simply travels straight ahead, there are cases where the vehicle cannot reach the target second guide line 42 due to variations in the vehicle's posture at the start of travel in the non-guide line section. In response to this, during travel before entering the non-guide line section, the vehicle's own position is estimated by the rotation sensors 31, 32 (position estimation of the center point Pd of the left and right drive wheels 22, 23) while the vehicle is located at the first guide line 41 based on the odometry information and the detection state of the first guide line 41 by the guide sensor 28.
Here, the present automated guided vehicle system 10 is provided with guide lines 41, 42 installed on the floor and a guide sensor 28 that recognizes the guide lines 41, 42, as well as a mark 43 installed on the floor and a mark sensor 29 that recognizes the mark 43.

As shown in FIG. 6(a), in the absence of the function of this embodiment, if the posture of the machine base 21 deviates from the direction in which the first guide line 41 extends when the machine base 21 starts traveling in the non-guide line section, it is difficult to transfer to the second guide line 42. In contrast, as shown in FIG. 6(b) and (c), the machine base 21 can travel on the extension line of the traveling direction learning section regardless of the posture of the machine base 21 when the machine base 21 starts traveling in the non-guide line section. In other words, even if the machine base posture is tilted from the target when the machine base 21 reaches the end of the first guide line 41, the machine base 21 can reach the second guide line 42 while being guided. At this time, a certain length is required for the posture of the machine base 21 to be corrected, but the traveling direction learning section can be shorter than the distance until the posture of the machine base 21 is corrected. The length of the traveling direction learning section is preferably approximately equal to the length of the non-guide line section.

As shown in Fig. 7(a) and (b), the length of the driving direction learning section can be changed according to the distance of the non-guide line section. As shown in Fig. 7(c), the longer the distance of the driving direction learning section, the smaller the lateral variation of the virtual guide line Lvg1 becomes.
As shown in Fig. 7(b), if the length of the non-guide line section is extended without changing the length of the traveling direction learning section, the range of variation becomes larger. However, as shown in Fig. 7(c), if the traveling direction learning section is lengthened and the length of the non-guide line section is increased, the range of variation can be reduced.

In this way, by extending the driving direction learning section and the non-guide line section, the distance between the plot points becomes longer even if the number of plot points at the position of the drive wheel center point Pd (position of the guide sensor center point Pg) remains the same, thereby improving accuracy and reducing the range of variation.

As shown in FIG. 8A, when only the right tire is worn, the vehicle will lean to the right even when driving straight. Here, as shown in FIG. 8B, when the imaginary guide line Lvg1 is drawn in a state where only the right tire is worn, the imaginary guide line Lvg1 is calculated to be inclined to the left.
g1 tilts to the left, and as shown by the actual travel trajectory in FIG. 8(c), the automated guided vehicle 2
In particular, it is advantageous for the left and right wheel wear even if it is not completely cancelled out. That is, it is advantageous in the case where the non-guide line section is shorter than the travel direction learning section.

In other words, when the tire on one side in FIG. 8(a) wears out, the left and right rotation sensors 31,
Even if feedback control is performed at the same rotation speed by the tire rotation speed control unit 32, the vehicle will turn toward the wheel with the smaller diameter. As shown in FIG. 8B, when the vehicle estimates its own position and draws the virtual guide line Lvg1 in the section where learning is performed to draw the virtual guide line Lvg1, the estimated own position is calculated from the tire rotation speed, but it turns due to wear. Here, as shown in FIG. 8C, the virtual guide line Lvg1 is drawn on the opposite side to the direction in which the vehicle 21 turns. Ideally, if the length of the travel direction learning section is equal to the length of the non-guide line section, the phenomenon in which the vehicle 21 actually turns and the influence of wear on the left and right wheels are canceled out as shown in FIG. 8C, and the vehicle can reach the second guide line 42 as the actual travel trajectory.

This will be explained using FIG.
FIG. 9 shows a case where only the right wheel is worn.
The position of the guide sensor center point Pg, which is determined from the position of the drive wheel center point Pd calculated from the odometry information, deviates from the first guide line 41 due to wear of the right wheel.

The position of the guide sensor center point Pg is (x1', y1'), (x2', y2'), . . .
, (x5', y5'), the positions of these points are used to calculate an approximation line for the non-guide line section. Then, this approximation line is translated from the current position of the guide sensor center point Pg in the extension direction of the first guide line 41, and set as the virtual guide line Lvg1.
Run along the imaginary guide line Lvg1.

Even if the right wheel is worn, the vehicle itself runs along the virtual guide line Lvg1. The position of the guide sensor center point Pg calculated from the odometry information gradually shifts due to the wear of the right wheel, so the calculated approximation line does not lie on an extension of the actual driving direction learning section (see FIG. 9).

Even in the non-guide line section, the right wheel wear will cause the vehicle to gradually lean to the right, but because the virtual guide line Lvg1 is drawn with a leftward inclination, the deviations are cancelled out and the vehicle itself will tend to head in the target direction (see Figure 8 (c)).

In this way, by using the rotation sensors 31 and 32 for acquiring odometry information, a self-position estimation sensor dedicated to traveling in non-guide line sections is not required, and therefore it can be realized at low cost. There is no need to construct the guide lines in a special shape. In addition, there is no need to lay the return pattern 202 in FIG. 14, and the installation length of the guide lines can be reduced. Since there is no need to adjust the posture of the machine base 21 in advance, although a traveling direction learning section is necessary, the state before starting traveling in non-guide line sections can be set arbitrarily.

Conventionally, if the vehicle only travels in one direction, it is sufficient to provide a return pattern 202 on one side.
To perform reciprocating movement, it is necessary to provide a return pattern 202 on the opposite side as well, which makes it impossible to accommodate reciprocating movement.

In this embodiment, as shown in FIG. 10, the first guide line 41 and the second guide line 42
By providing a running direction learning section on the side, it becomes possible to accommodate round trip running. It is only necessary to lay the first guide line 41 straight, and no special construction is required for the running direction learning section.
By doing this, even in non-guide line sections where there are no guide lines, by using the virtual guide line Lvg1 as a target for guidance, it is not necessary to make the guide line a special shape, and round trip driving is possible.

In FIG. 1, the longer the distance in the x-axis direction between the center point Pd of the drive wheels 22, 23 and the center point Pg of the guide sensor 28, the longer it takes for the posture of the machine base 21 to be adjusted.
The longer the distance in the x-axis direction between the center point Pd of the drive wheels 22, 23 and the center point Pg of the guide sensor 28, the more stable the running becomes. Furthermore, the coordinate at the center point Pg of the guide sensor 28 is obtained using the attitude angle θ in addition to the coordinate (x, y) at the center point Pd of the drive wheels 22, 23. As explained in Figures 5 and 9 regarding the coordinate at the center point Pg of the guide sensor 28, a straight line is calculated from multiple plot points by the least squares method, and a virtual guide line Lvg1 is obtained.

According to the above embodiment, the following effects can be obtained.
(1) The automated guided vehicle 20 travels along the guide lines 41, 42 extending on the floor while detecting the guide lines 41, 42 with the guide sensor 28.
The non-guide line section is from the section where the vehicle travels while detecting the first guide line 41 by the guide sensor 28 to the section where the vehicle travels while detecting the second guide line 42 by the guide sensor 28. Before this non-guide line section, the guide sensor 2 detects the mark 43 on the road surface while the vehicle travels in a straight line in the travel direction learning section.
8, the first guide line 41 is detected while the driving direction is learned from the odometry information to set a virtual guide line Lvg1 in the non-guide line section, and the non-guide line section is set as the virtual guide line Lvg
It was made to run along route 1.

Therefore, when simply traveling straight from the first guide line 41 to the second guide line 42, if the posture of the machine base 21 at the start of traveling in the non-guide line section is deviated from the extending direction of the guide line, it is difficult to detect the second guide line 42. In contrast, by learning the traveling direction during straight traveling in the traveling direction learning section and setting the virtual guide line Lvg1 in the non-guide line section, it becomes easier to detect the second guide line 42 without being affected by the posture of the machine base 21 at the start of traveling in the non-guide line section. As a result, it is possible to easily move from the first guide line 41 to the second guide line 42 via the non-guide line section where no guide line is provided in the traveling route.

(2) By executing the processing of steps S19, S20, S21, S22, and S23 in Figure 3, when driving along the virtual guide line Lvg1 in a non-guide line section, if the guide sensor 28 cannot detect the second guide line 42 even after driving a predetermined distance, the vehicle will stop, which is practical.

The embodiment is not limited to the above, and may be embodied as follows, for example.
This can also be applied to non-guide line sections in cases other than straight driving.
For example, as shown in FIG. 11(a), in the prior art, a first guide wire 41 and a second guide wire 44
In the 90-degree program steering operation, when the vehicle travels on an orthogonal path, the vehicle may cross the second guide line 44 depending on the vehicle's posture at the start of the program steering. In contrast, in the present invention, as shown in FIG. 11(b), the vehicle learns the traveling direction from the odometry information while detecting the first guide line 41 with the guide sensor 28 during straight traveling in the traveling direction learning section that starts when the vehicle detects the mark 45 on the road surface. Then, a virtual guide line Lvg2 is set in the non-guide line section, and the vehicle travels along the virtual guide line Lvg2 in the non-guide line section. Therefore, the vehicle can reach the target position regardless of the vehicle's posture at the start of the 90-degree program steering. The mark 45 in FIG. 11(b) includes information indicating that the vehicle is about to perform the 90-degree program steering operation.

As shown in FIG. 12(a), in the conventional 180-degree program steering operation in which the first guide line 41 and the second guide line 46 run on parallel paths, depending on the machine's posture at the start of the program steering, the machine may bend too much and not reach the second guide line 46.
In contrast, in the present invention, as shown in Fig. 12(b), the driving direction is learned from odometry information while the guide sensor 28 detects the first guide line 41 during straight-line driving in the driving direction learning section that begins when the mark 47 on the road surface is detected. Then, a virtual guide line Lvg3 is set in the non-guide line section, and the vehicle travels along the virtual guide line Lvg3 in the non-guide line section. This makes it possible to reach the target position regardless of the machine posture at the start of the 180-degree program steering. The mark 47 in Fig. 12(b) includes information indicating that the vehicle is about to perform the 180-degree program steering operation.

In addition, to explain the program steering, as shown in FIG. 13(a) and (b), the detection of the mark 50 is used as a trigger to continue turning at a fixed angle for a fixed distance,
This function then switches to straight-line driving, allowing the vehicle to move onto an orthogonal or parallel road without using guide lines.

The programmed steering function is a function for turning with the steering fixed in advance, and even in this case, if the machine base 21 is tilted, the steering direction will be fixed from that point and the machine will turn, so that the machine will deviate from the target second guide lines 44, 46.

The imaginary guide lines Lvg2 and Lvg3 obtained in the driving direction learning section are obtained by rotating the arc line R (see FIG. 11(a) and FIG. 12(a)) by the difference in the posture of the vehicle. That is, the imaginary guide line Lvg2 and Lvg3 are obtained by rotating the arc line R (see FIG. 11(a) and FIG. 12(a)) by the difference in the posture of the vehicle.
Set g2 and Lvg3.

In this way, a virtual guide line may be set according to the learned driving direction and a command to turn at a constant angle and for a constant distance, and then the virtual guide line may be transferred to the second guide line.
The driving direction is learned, and the virtual guide line Lvg2 is set according to the program steering command.
, Lvg3, it is possible to transfer to the second guide line regardless of the posture of the machine base 21.

Regarding the vehicle's suspension, the left and right fixed wheels are driven by separate motors and steered by the speed difference (two-wheel speed difference system), but the steering may be performed by turning the turning wheels with a steering motor (a steering wheel system is also acceptable). In other words, it is preferable to have one or more driving wheels for driving and turning, and one or more driven wheels for stable driving.

〇An automated guided vehicle does not have to be an unmanned towing vehicle.

10...automatic guided vehicle, 28...guide sensor, 41...first guide line, 42...second guide line, 43...mark, 44...second guide line, 45...mark, 46...second guide line, 47
...mark, Lvg1...virtual guide line, Lvg2...virtual guide line, Lvg3...virtual guide line.

Claims (3)

An automated guided vehicle that runs along a guide line extending on a floor while detecting the guide line with an on-board guide sensor,
the travel route has a non-guide line section in the middle where the guide line is not provided,
The vehicle is configured to detect the first guide line with the vehicle-mounted guide sensor while traveling in a straight line in a traveling direction learning section that begins when a mark on the road surface is detected just before the non-guide line section in which the vehicle-mounted guide sensor detects a first guide line to a section in which the vehicle-mounted guide sensor detects a second guide line , and calculates a plurality of positions of the center point of the vehicle-mounted guide sensor in the traveling direction learning section in a time series using odometry information while detecting the first guide line with the vehicle-mounted guide sensor during straight-line traveling in the traveling direction learning section, and learns the extension direction of the first guide line by generating an approximate straight line from each position obtained in the time series, and sets a virtual guide line in the non-guide line section by extending the approximate straight line forward from the first guide line, and travels along the virtual guide line in the non-guide line section. The unmanned guided vehicle according to claim 1, characterized in that when traveling along the virtual guide line in the non-guide line section, if the vehicle-mounted guide sensor cannot detect the second guide line even after traveling a predetermined distance, the unmanned guided vehicle stops. 2. The automated guided vehicle according to claim 1, wherein the virtual guide line is set in accordance with the learned traveling direction and a turning command that continues for a fixed angle and a fixed distance.