JP2018185659A - Automatic traveling device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an automatic traveling device capable of suppressing meandering by simple control and traveling along a target even when a towing object whose traveling direction is not determined is towed.SOLUTION: An automatic traveling device towing a towing object and traveling along a traveling route while correcting deviation from the traveling route by right and left turning operation comprises: a recording unit which records an amount of turn at each point of time; an amount-of-deviation detection unit which detects an amount of deviation from the traveling route; and a traveling control unit which controls the traveling operation of the automatic traveling device. The traveling control unit calculates an amount of turning for correction corresponding to turning with a magnitude of less than a first amount of turning and in a direction opposite to turning in the first point of time dating back from the current point of time by a prescribed time on the basis of the first amount of turning in the first point of time, calculates an amount of turning for output on the basis of at least the amount of turning for correction, and controls the traveling operation of the automatic traveling device so as to perform turning operation according to the amount of turning for output.SELECTED DRAWING: Figure 6A

Description

  The present invention relates to an automatic travel device that travels along a travel route by pulling an object to be pulled.

Automatic transfer systems using automatic guided vehicles are used in factories and warehouses. The automatic guided vehicle travels autonomously along a designated travel route.
There has been proposed a method for controlling the steering angle of a wheel so that an automated guided vehicle having a plurality of wheels travels along a line (also referred to as a guide line or a guide) (see, for example, Patent Documents 1 and 2).
In Patent Document 1, since the control system is non-linear, there is a risk that steering control along the guide line cannot be performed or hunting may occur in the conventional control system, so fuzzy inference is performed and steering is performed based on the inference result. Controlling the corner is described.
In Patent Document 2, in an unmanned forklift (automatic guided vehicle) of three-wheel steering, the number of overshoots in steering control along the guide is reduced, the correction distance is shortened, and the vehicle body attitude angle movement is reduced. A method for steering control of each wheel is described.

Japanese Patent No. 2712739 JP 2000-148247 A

There are various types of automatic transfer systems using automatic guided vehicles used in factories and warehouses. In addition to the method of loading and transporting cargo directly on the automated guided vehicles themselves, tow trucks loaded with cargo are pulled. Therefore, there is a strong demand for a method of transporting.
The inventors have studied the automatic guided vehicle by adopting a configuration that pulls the carriage, and experienced that the carriage that should travel along the straight traveling route may meander. This is because the large inertial force of the cart has a great influence on the running state of the automatic guided vehicle. This problem becomes more prominent as the ratio of the weight of the cart to the weight of the automatic guided vehicle increases. Once the meandering starts, the oscillating width gradually increases and the meandering does not converge, and the automatic guided vehicle cannot control the traveling of the carriage, and in extreme cases, may deviate from the traveling route. In such an automatic guided vehicle that pulls a carriage, it is generally very difficult to control traveling while suppressing meandering, and even if possible, very complicated control is required.

For example, the control methods of Patent Document 1 and Patent Document 2 do not assume the occurrence of meandering by pulling a carriage in the first place, and even if it is used to suppress the occurrence of meandering, there are many parameters used for control. It becomes a very complicated control method such as complication.
The present invention has been made in consideration of the above circumstances, and in an automatic guided vehicle that pulls a carriage, an automatic traveling device that can suppress meandering with simple control and can travel along a traveling route. It is to provide.

  The present invention is an automatic travel device that travels along the line while towing a towed object and correcting a deviation from a travel route by a left and right turning operation, and records a turning amount at each time point. And a shift amount detection unit that detects a shift amount from the travel route, and a travel control unit that controls a travel operation of the automatic travel device, wherein the travel control unit is a first that goes back a predetermined time from the current time. Based on the first turning amount at the time, a compensation turning amount that is smaller than the first turning amount and corresponds to turning in the opposite direction to the turning at the first time point is calculated, and at least the compensation turning amount An automatic traveling device that calculates an output turning amount based on the output and controls a traveling operation of the automatic traveling device so as to perform a turning operation according to the output turning amount is provided.

  In the automatic travel device according to the present invention, the travel control unit has a magnitude less than the first turn amount and a value at the first time point based on the first turn amount at the first time point that is a predetermined time back from the current time point. Compensation turning amount corresponding to turning in a direction opposite to turning is calculated, output turning amount is calculated based on at least the compensation turning amount, and the automatic traveling device is configured to perform turning operation according to the output turning amount. Since the traveling operation is controlled, even when the towed object is towed, meandering can be suppressed with simple control and the vehicle can travel along the traveling route.

It is a side view which shows a mode that the automatic guided vehicle by this embodiment pulls a trolley | bogie. It is a front view which shows a mode that the automatic guided vehicle by this embodiment pulls a trolley | bogie. It is a top view which shows a mode that the automatic guided vehicle by this embodiment pulls a trolley | bogie. It is explanatory drawing which expanded the part of the pulling arm of the automatic guided vehicle by this embodiment. It is a side view which shows the automatic guided vehicle by this embodiment. It is a side view which shows the external appearance of the trolley | bogie shown to FIG. 1A-FIG. 1C. It is explanatory drawing which shows arrangement | positioning of each part which looked at the automatic guided vehicle by this embodiment from the bottom face side. It is a block diagram which shows the structure of the automatic guided vehicle shown to FIG. 1A-FIG. 1E. FIG. 4 is an enlarged view of the line sensor shown in FIG. 3. It is explanatory drawing which shows the signal which each detection element of the line sensor shown to FIG. 5A outputs. It is explanatory drawing which shows a mode that the traveling control part which concerns on this embodiment drives an automatic guided vehicle, converging meandering. FIG. 6B is an explanatory diagram showing a state in which meandering is amplified with traveling when the configuration of the meandering control value calculation unit is lacking as a comparative example for FIG. 6A. In this embodiment, it is a flowchart which shows the process in which a driving | running | working control part drives an automatic guided vehicle along a line. (Embodiment 1) In this embodiment, it is a flowchart which shows the traveling control based on the basic turning amount. (Embodiment 2) In this embodiment, it is a flowchart which shows the traveling control based on compensation turning amount. In this embodiment, it is explanatory drawing which shows the structure of the wheel of an automatic guided vehicle. (Embodiment 3) In this embodiment, it is a flowchart which shows the process corresponding to FIG. (Embodiment 3) FIG. 5 is a block diagram of a configuration including a meandering determination unit according to this embodiment corresponding to FIG. 4. (Embodiment 4) In this embodiment, it is a flowchart which shows the process corresponding to FIG. (Embodiment 4)

(Embodiment 1)
In this embodiment, the characteristics of the present invention will be described by taking as an example a case where an automatic guided vehicle as one aspect of an automatic traveling apparatus pulls a carriage (roll box carriage) as one aspect of an object to be pulled. In addition, the following description is an illustration in all the points, Comprising: It should not be interpreted as limiting this invention.
First, the roll box cart will be described below. Roll box carts (also called roll box pallets or “car carts”, also simply referred to as carts in this specification) are mainly used for temporary storage in sorting areas and transportation to trucks. It is a cart equipped with a load carrying part, and can be moved manually with the load loaded. In this type of cart, all wheels are free casters in consideration of handling such as stationary turning (spin turn) in a narrow space. In addition, this type of truck is originally supposed to be transported by human power and is not supposed to run autonomously. Generally, however, cargo is loaded in factories and warehouses that handle a large amount of luggage. There are cases where it is desired to efficiently transport the carriage using an automatic guided vehicle.
In that case, the following method can be taken. For example, this is a technique in which an automatic guided vehicle is connected to a cart via a coupler and pulled. As another method, there is a method in which the automatic guided vehicle includes a lifting device, and the cart is lifted completely from below and transported.

The method of completely lifting the carriage from below and transporting it does not tow the carriage, so spin turn can be realized relatively easily, but a powerful elevator that can lift the carriage that contains luggage is an automated guided vehicle. Therefore, the automatic guided vehicle becomes larger and the cost becomes higher.
On the other hand, the method in which the automatic guided vehicle pulls the carriage has a problem that it is difficult to achieve both spin-turn performance and straight traveling performance.
The reason for this is that, first of all, since all the wheels of the carriage are free casters in order to realize the spin turn, compared to the configuration in which the movable range of the front wheels or the rear wheels is limited, the straight movement stability of the carriage itself in the first place There is a very bad thing.

  Second, it is ideal to make the turning center of the automated guided vehicle as close as possible to the turning center of the spin turn of the carriage as much as possible in order to improve the spin turn characteristics. In order to prevent the vehicle from colliding with an obstacle, it is desirable to take a form in which the majority (more than half) of the automatic guided vehicle sinks under the carriage. In addition, in order to efficiently transmit the rotational force for the spin turn from the automatic guided vehicle to the carriage, the automated guided vehicle is separated from the center of the spin turn of the carriage as well as one point of the carriage. It is desirable to connect with two or more parts. However, the above-mentioned features for improving the spin turn performance contribute to efficiently transmitting the turning force on the automatic guided vehicle side as the turning force for spin turning on the cart side. Since the turning force that the side has as inertia becomes easy to be transmitted to the automatic guided vehicle side, the automatic guided vehicle is easily affected by the inertia of the carriage, which causes deterioration in straight-line stability.

Moreover, the cart loaded with cargo may have a larger mass than the automatic guided vehicle (for example, about 2 to 4 times the mass of the automatic guided vehicle). In such a case, the method of completely lifting the carriage from below and transporting it does not cause much problem because it does not pull the carriage, but in the method where the automated guided vehicle pulls the carriage, the carriage is equivalent to the mass of the carriage. In combination with the low stability of straight-running due to the above-mentioned spin-turn characteristics, the automatic guided vehicle is supposed to proceed due to the influence of the inertial force of the carriage when it changes suddenly. It may be difficult to go in the direction. In such a case, once the meandering starts, the swaying width gradually increases and the meandering does not converge, and it is impossible to control the travel of the cart with a small and light automated guided vehicle compared to the cart. May deviate completely.
In this way, it is not easy to pull the carriage and travel along the travel route.

The present invention will be described in detail below with reference to the drawings.
FIG. 1A to FIG. 1E are explanatory views showing a state in which the automatic guided vehicle according to this embodiment pulls the carriage. 1A and 1B, the front arm restraining members 17G and 17W are indicated by chain lines in a transparent state so that the state of connection between the pulling arm and the arm restraining member can be understood. Similarly, in FIG. 1C, the cart on the near side in plan view is indicated by a chain line in a transparent state. In FIG. 1C, the driving wheels and auxiliary wheels are hidden behind the automatic guided vehicle 11 in a plan view, but are shown by chain lines so that the positions thereof can be understood. FIG. 2 is a side view showing the appearance of the carriage 13 shown in a simplified manner in FIGS. 1A to 1C.

As shown in FIGS. 1A to 1E, the automatic guided vehicle 11 has a low-profile rectangular parallelepiped shape that can be embedded between the floor surface and the bottom surface of the carriage 13. On the upper surface of the automatic guided vehicle 11, a pair of left and right pulling arms 15 for pulling the bottom surface of the carriage 13 are provided so as to be lifted and lowered. The elevating mechanism 16 raises and lowers the pulling arm 15.
When connecting to the carriage 13, the carriage 13 is assumed to be stationary in a predetermined direction at a predetermined position on the line. The automatic guided vehicle 11 travels along the line and enters under the stationary carriage 13 from the direction indicated by the arrow Dg in FIG. 1C.
A proximity sensor 27 (see FIG. 1E) that detects the proximity of the bottom surface of the carriage 13 is disposed on the upper portion of the pulling arm 15. When the automatic guided vehicle 11 sinks under the carriage 13 and the proximity sensor 27 detects the rear end of the bottom surface of the carriage 13, the automatic guided vehicle 11 slowly advances further from the position to a connection position ahead by a predetermined distance. Stop. As shown in FIG. 1C, arm restraining members 17G and 17W are arranged vertically and horizontally below the bottom surface of the carriage 13.

  The automatic guided vehicle 11 stops at the connection position, raises the pulling arm 15, and sandwiches an arm restraining member 17 </ b> W extending in the arrow Dw direction (that is, the left-right direction) in FIG. That is, in the pulling arm 15, the front first portion 15A and the rear second portion 15B are positioned before and after the arm restraining member 17W. As a result, the automatic guided vehicle 11 and the carriage 13 are connected to each other with a predetermined space in the front-rear direction. Further, the pulling arm 15 is connected with a predetermined interval in the left-right direction by four arm restraining members 17G extending in the arrow Dg direction in FIG. 1C. 1A and 1B show a state in which the pulling arm 15 is lifted and the arm restraining member 17W is sandwiched back and forth, that is, the automatic guided vehicle 11 and the carriage 13 are connected.

The carriage 13 is of a type generally used in warehouses, and has four casters 13A that are free wheels. As the caster 13A, a wheel having a wheel diameter of φ150 mm is generally used. In that case, the frame height from the floor is 210 mm.
The carriage 13 has a structure in which the car portion on the bottom plate can be folded. The automatic guided vehicle 11 is structured to sink under the bottom plate 13B of the carriage 13 when the carriage 13 is pulled. For this reason, the automatic guided vehicle 11 is configured with a low profile design with a frame height of less than 210 mm, and is smaller and lighter than the cart 13 loaded with luggage.

  As shown in FIGS. 1B and 1C, in this embodiment, the traction arm 15 is connected to the arm restraining member 17W of the carriage 13 at two places on the left and right. However, an aspect in which the pulling arm 15 is constituted by an integral member extending in the left-right direction is also conceivable. In any aspect, it is desirable to connect the vehicle 13 with a spread in the left-right direction in order to spin-turn the carriage 13.

The reason for this will be described below. If the automatic guided vehicle 11 is connected to the carriage 13 at one place, the connection position is necessarily the center of the bottom surface of the carriage 13 (that is, the spin turn) so that the rotational moment acting on the carriage 13 becomes zero in the straight traction state. Is located on a straight line extending in the direction of travel from the center of rotation).
In such a case, even if the automated guided vehicle 11 turns, the force transmitted to the carriage 13 is only applied in a direction slightly deviated from the traveling direction, and the turning force of the automated guided vehicle 11 can be efficiently increased. It cannot be transmitted to the carriage, and it is technically difficult to make the force component in the traveling direction completely zero, and the vehicle travels to some extent in the traveling direction when turning. For this reason, stationary turning (spin turn) becomes difficult in the method in which the automatic guided vehicle 11 is connected to the carriage 13 at one place.

On the other hand, when the automatic guided vehicle 11 is connected to the carriage 13 at two places, the connection position is necessarily symmetric with respect to a straight line extending in the traveling direction from the center of the bottom surface of the carriage 13 (that is, the turning center of the spin turn). Two places are connection positions. In the straight traction state, force is evenly applied to the connection positions of these two locations, so that the rotational moment acting on the carriage 13 becomes zero and stable straight movement is possible, and at the time of turning, the center of the bottom surface of the carriage 13 (that is, Since a force is applied to a position shifted from a straight line extending in the traveling direction from the turning center of the spin turn), the turning force of the automatic guided vehicle 11 can be efficiently transmitted to the carriage.
Further, for example, when turning right, the direction of the force applied to the carriage 13 can be reversed at each connection position such that the left connection position is forward in the traveling direction and the right connection position is backward in the traveling direction. Therefore, it becomes relatively easy to cancel the force components in the traveling direction to zero by canceling each other with the force applied to each connection position. For this reason, stationary turning (spin turn) is facilitated by the method in which the automatic guided vehicle 11 is connected to the carriage 13 at two places.

Further, it is desirable that a certain amount of clearance is secured in the front-rear direction in a state where the pulling arm 15 and the arm restraining member 17W on the cart 13 side are joined.
In FIG. 1D, gaps in the front-rear direction are indicated by D1 and D2, respectively. The traction arm 15 is connected to the arm restraining member 17W so as to sandwich the arm restraining member 17W in the front-rear direction while leaving a gap, so that the arm restraining member 17W is not completely rigidly fixed to the traction arm 15. The traction arm 15 is connected to the traction arm 15 so as to be freely movable by the gap. That is, the automatic guided vehicle 11 is connected to the carriage 13 with a degree of freedom (play). If there is no gap in the front-rear direction, there is no degree of freedom (play) between the automatic guided vehicle 11 and the carriage 13, and the traveling performance of the automatic guided vehicle 11 is reduced.

  The reason for this will be described below. In one example, the mass of the carriage 13 full of cargo is 250 kg with respect to the mass of the automatic guided vehicle 11 of 60 kg. If there is no degree of freedom (play) between the automatic guided vehicle 11 and the carriage 13, the traveling direction of the automated guided vehicle 11 is restricted so that it is exactly the same as the traveling direction of the carriage 13. During the turning of the automatic traveling device, the full load due to the inertial force in the traveling direction of the cart 13 having a large weight is instantaneously transmitted to the automatic guided vehicle 11 side without any time delay. In this case, if the automatic guided vehicle 11 does not have a driving force corresponding to this load, the vehicle cannot turn and deviates from the travel route. It is not easy to mount a powerful drive unit on a small automatic guided vehicle 11 compared to the carriage 13, and even if it can be mounted, it requires a large motor output and battery capacity to generate a large driving force. The efficiency of use is also reduced. Further, even if the driving force is sufficiently strong, the weight of the carriage 13 is overwhelmingly larger than the weight of the automatic guided vehicle 11, so that there is a case where the wheel does not rotate and the driving force cannot be exhibited.

  On the other hand, when there is a degree of freedom (play) between the automatic guided vehicle 11 and the cart 13, the traveling direction of the automatic guided vehicle 11 does not have to be exactly the same as the traveling direction of the cart 13, and the movable range is not limited. You will have a degree of freedom. In this case, the full load corresponding to the inertial force of the carriage 13 is not instantaneously transmitted to the automatic guided vehicle 11 side during turning of the automatic traveling device during traveling, and the automatic guided vehicle 11 starts turning to generate the turning force. From the start of transmission to 13, there will be a grace time until the full use of the movable range and the restraint. Since the braking is possible if the integrated turning force transmitted from the automatic guided vehicle 11 to the carriage 13 within this grace period is sufficiently large, there is a degree of freedom (play) between the automatic guided vehicle 11 and the carriage 13. Compared to the case where there is not, the automatic guided vehicle 11 can control the traveling with a much smaller driving force, and the traveling performance is improved. However, giving freedom (play) between the automatic guided vehicle 11 and the cart 13 means that the traveling directions of the automatic guided vehicle 11 and the cart 13 are allowed to be different. If the control is not performed properly, it is necessary to note that there is a point that it becomes difficult in terms of control, for example, the carriage 13 may swing from side to side and cause meandering.

≪Configuration of automated guided vehicle≫
The configuration of the automatic guided vehicle 11 according to this embodiment will be further described.
The automatic guided vehicle 11 according to this embodiment travels along a travel guide line 51 laid on the floor surface.
The line 51 is arranged on a travel route through which the automatic guided vehicle 11 passes, and in this embodiment, the line 51 is composed of a magnetic tape affixed on the travel route.

FIG. 3 is an explanatory diagram showing the arrangement of each part of the automatic guided vehicle 11 when the automatic guided vehicle 11 relating to traveling is viewed from the bottom surface side. FIG. 4 is a block diagram showing the configuration of the automatic guided vehicle 11.
As shown in FIGS. 3 and 4, the automatic guided vehicle 11 includes a left motor 45 </ b> L and a right motor 45 </ b> R that perform operations such as advancing and turning. Furthermore, a left driving wheel 19L driven by the motor 45L, a right driving wheel 19R driven by the motor 45R, and a driven auxiliary wheel 21 are provided.
The automatic guided vehicle 11 includes a sensor unit 23 including a line sensor 25 and a proximity sensor 27 that detect a line 51 arranged on the traveling surface.

Furthermore, the automatic guided vehicle 11 includes a control board 30 (see FIG. 3). The control board 30 communicates with a travel control unit 31 that is a circuit that controls travel and operation, a storage unit 37 that stores control data, the travel drive unit 43 that operates the motors 45L and 45R, and external devices. A communication unit 49 is mounted.
Furthermore, the automatic guided vehicle 11 includes a battery 47 that supplies electric power to each unit, such as the control board 30, the sensor unit 23, the travel drive unit 43, and the motors 45L and 45R.
In the motors 45L and 45R, the traveling control unit 31 can independently control forward and reverse rotational directions and rotational speeds. The traveling control unit 31 causes the automatic guided vehicle 11 to move forward, backward, and turn by controlling the rotational directions and rotational speeds of the two motors 45L and 45R corresponding to the drive wheels 19L and 19R in association with each other.

The automatic guided vehicle 11 travels on the floor surface by auxiliary wheels 21 that support the automatic guided vehicle 11 together with the drive wheels 19L and 19R. The auxiliary wheel 21 may be a free caster, but the direction of the wheel does not need to change as long as it slides on the floor surface during stationary turning.
The traveling control unit 31 controls the automatic guided vehicle 11 to travel along the line 51 based on the detection result of the line 51 (see FIG. 3) by the line sensor 25. Further, it communicates with an external management device (not shown) via the communication unit 49 to determine a target travel route, to connect with the cart 13 stationary at a predetermined position, or to disconnect the cart 13. Or

As shown in FIG. 4, the travel control unit 31 includes functions of a travel control value calculation unit 33 and a meander control value calculation unit 35. The storage unit 37 includes a control value buffer 39 and a parameter storage unit 41.
In this embodiment, the traveling control unit 31 is mainly configured by a computer such as a CPU and a microcomputer, and includes peripheral circuits such as a RAM, an input / output interface circuit, and a timer circuit. The storage unit 37 is a nonvolatile storage device, and a flash memory or a hard disk device is applied in this embodiment.
The travel control value calculation unit 33 uses a known feedback control method such as PID control to correct the left and right necessary for correcting the positional deviation between the reference position with respect to the line 51 that is the target position in the arrow Dw direction and the automatic guided vehicle 11. Processing to determine the rotation direction and rotation speed of the drive wheels 19L and 19R is performed. The feedback control method is not limited to the above-described PID control, and may be PI control, P control, on / off control, PD control, or the like.

When the automatic guided vehicle 11 travels alone without pulling the carriage 13, the travel control value calculation unit 33 is sufficient to travel along the line 51. The function of the meandering control value calculation unit 35 may be omitted.
Generally, PID control is widely used for traveling control of the automatic guided vehicle 11. In the PID control, based on the amount of deviation (deviation) of the output with respect to the target value, a feedback is performed by combining three elements of the deviation (Proportion), integral (Integral), and differential (Differential) at a suitable ratio. It is. The ratio of the feedback amount of the deviation proportional element, the feedback amount of the integral element, and the feedback amount of the differential element is appropriately selected so that the automatic guided vehicle travels along the line reliably and smoothly. By doing so, the automated guided vehicle can travel along the target line accurately and quickly. A technique for selecting a suitable feedback amount ratio is known as linear control theory.

However, when the automatic guided vehicle 11 travels while pulling the carriage 13, a gap is required between the pulling arm 15 and the arm restraining member 17W as described above. The presence of the gap means that the control system does not respond linearly to the feedback amount. Therefore, the control system that pulls the large mass carriage 13 loaded with cargo is a non-linear control system that deviates from linear control. There are some known control methods applicable to the non-linear control system, but the processing load of the travel control unit increases due to complicated processing.
Therefore, in this embodiment, by adding the process of the meandering control value calculation unit 35 to the process of the traveling control value calculation unit 33, the meandering of the carriage 13 is suppressed by a simple process.

Although details will be described later, the meandering control value calculation unit 35 is a control value for suppressing meandering based on the most recent state, a past state that is traced back by a predetermined time, and a parameter related to the travel characteristics of the automatic guided vehicle 11. Is calculated.
The control value buffer 39 is a memory buffer for storing numerical values (for example, turning amount) related to control obtained by the traveling control value calculation unit 33. A predetermined number (predetermined time) of numerical values can be continuously stored by a method such as a known ring buffer. By referring to the data stored in the control value buffer 39, meandering can be suppressed using the past state.
The parameter storage unit 41 stores parameters relating to travel control of the automatic guided vehicle 11. The parameter may be a fixed value stored in advance, but may be appropriately updated by the traveling control unit 31 according to, for example, the characteristics of the towed carriage 13. For example, the size of the gap in the front-rear direction between the pulling arm 15 and the arm restraining member 17W is stored in advance. If all the carriages 13 have the same dimensions, a fixed value is sufficient for this parameter. The load of the towed carriage 13 may be stored as a parameter. In that case, the load changes according to the amount of cargo loaded on the carriage 13. Therefore, when connected to the new carriage 13, the travel control unit 31 may measure the electric power of the motors 45L and 45R required for activation during towing and update the parameters.

The travel drive unit 43 is a circuit for operating the motors 45L and 45R, and is generally called a motor driver or a motor controller. In response to a signal that changes the duty ratio of the voltage or PWM signal from the traveling control unit 31, the motors 45L and 45R are rotated or stopped at the respective rotational directions and rotational speeds according to the voltage or duty ratio.
The communication unit 49 is a communication interface circuit. The communication system is not limited, but as an example, it is compliant with the IEEE802.11n standard frequently used in wireless LANs or similar communication standards.
The battery 47 is preferably rechargeable, for example, a lithium ion battery that is small and light with respect to energy capacity.

≪Line sensor≫
FIG. 5A is an enlarged view of the line sensor 25. The line sensor 25 is provided on the bottom surface of the automatic guided vehicle 11 and faces the floor surface. The line sensor 25 is composed of a plurality of detection elements 25A arranged in a line in the direction indicated by the arrow Dw in FIG. The arrow Dw is a direction perpendicular to the forward direction of the automatic guided vehicle 11 indicated by the arrow Dg. Each of the detection elements 25A is an element that outputs a detection signal when the line 51 exists on the opposite floor surface. In the present embodiment, each of the detection elements 25A is a Hall element, and when facing the line 51 (magnetic tape), detects the magnetism of the line 51 and outputs a detection signal.

More specifically, the number and interval of the detection elements 25A are larger in the line sensor 25 than the width of the line 51 in the Dw direction, and the left and right ends of the line 51 can be detected in the Dw direction of the line 51. It is set like this.
FIG. 5B is an explanatory diagram illustrating a signal that each detection element 25 </ b> A outputs to the traveling control unit 31 when the automatic guided vehicle 11 is at a reference position with respect to the width direction of the line 51. The number “0” (zero) shown in FIG. 5B represents an output signal when the corresponding detection element 25 </ b> A does not detect the line 51. On the other hand, the number “1” represents an output signal when the corresponding detection element 25 </ b> A detects the line 51. That is, the output signal of each detection element 25A is a binary signal corresponding to whether or not the line 51 is detected.

As shown in FIG. 5B, the signal of the adjacent detection element 25 </ b> A changes from “0” to “1” at locations corresponding to the left end and the right end of the line 51. That is, in the line sensor 25, when the automatic guided vehicle 11 is at the reference position in the width direction of the line 51, the predetermined detection element 25 </ b> A detects the left and right ends of the line 51.
Even if the automatic guided vehicle 11 deviates from the reference position in the width direction of the line 51, as long as the line sensor 25 detects the left or right end of the line 51, the output signal of each adjacent detection element 25A is “0”. There is a place where the value changes from “1” to “1”. Based on the location of the change and the direction of the change, the traveling control unit 31 can obtain the direction of deviation and the amount of deviation from the reference position. The direction of change is “0” to “1” or “1” to “0”.
The traveling control unit 31 can obtain a change in the amount of deviation by storing the movement of the portion of change with the passage of time. From the change in the deviation amount, it can be determined whether the automatic guided vehicle 11 is approaching the reference position or is moving away from the reference position.

≪Processing of travel control part≫
In this embodiment, the control in which the traveling control unit 31 controls the automatic guided vehicle 11 connected to the carriage 13 to travel along the line 51 will be described.
FIG. 6A is an explanatory diagram showing a state in which the traveling control unit 31 according to this embodiment causes the automatic guided vehicle 11 to travel along a straight line 51 while converging the meandering. FIG. 6B is a comparative example with respect to FIG. 6A, and is an explanatory diagram showing a state where meandering is amplified with traveling when the traveling control unit 31 lacks the configuration of the meandering control value calculating unit 35.

FIG. 6A shows the positions of the automatic guided vehicle 11 and the carriage 13 with respect to the line 51 at the times T1 to T4. In addition, a position on the extension of each axle of the left and right drive wheels 19L and 19R of the automatic guided vehicle 11 and through which an intermediate point between the left and right drive wheels 19L and 19R passes is indicated by a two-dot chain line. FIG. 6B shows the positions of the automatic guided vehicle 11 and the carriage 13 with respect to the line 51 at the times T1 ′ to T4 ′, as in FIG. 6A.
In order to facilitate understanding, the control shown in FIG. 6B as a comparative example will be described first. The control shown in FIG. 6B corresponds to the traveling control by the traveling control unit 31 lacking the configuration of the meandering control value calculating unit 35 and only the traveling control value calculating unit 33, that is, the control based on the linear control system. The behavior of the time series T1 ′ to T4 ′ shown in FIG. 6B will be described below.

Time T1 ′: Since the vehicle has moved away from the line 51, the traveling control value calculation unit 33 makes a turn corresponding to the distance, and the basic turning amount Rb calculated at that time so as to bring the automatic guided vehicle 11 closer to the line 51. 'Is calculated. Expressed as a formula:
Ro ′ (T1 ′) = Rb ′ (T1 ′) (1 ′)
It is.
In equation (1 ′), Ro ′ (T1 ′) represents the output turning amount at time T1 ′, and Rb ′ (T1 ′) represents the basic turning amount Rb ′ at time T1 ′. The automatic guided vehicle 11 is turned by the obtained output turning amount Ro ′.
By turning at time T1 ′, the left front part of the pulling arm 15 comes into contact with the front of the arm restraining member 17W and the right rear part of the pulling arm 15 comes into contact with the rear of the arm restricting member 17W, and the carriage 13 is counterclockwise in plan view. A force for rotating around is received from the automatic guided vehicle 11. The automatic guided vehicle 11 turns toward the line 51, and the amount of deviation takes the maximum distance d1 ′.

  Time T <b> 2 ′: The automatic guided vehicle 11 that has turned in a direction approaching the line 51 at time T <b> 1 ′ travels substantially straight to approach the line 51 asymptotically. On the other hand, due to the rotational inertia applied at time T1 ', the carriage 13 tries to advance while continuing the counterclockwise turn. Therefore, the arm restraining member 17W that has been in contact with the left front portion of the pulling arm 15 is displaced rearward and contacts the rear portion of the pulling arm at time T2 '. By this contact, the automatic guided vehicle 11 receives a force in the direction of overshooting over the line 51. That is, it is pushed in the direction of overshooting beyond the target line 51.

  Time T <b> 3 ′: The travel control value calculation unit 33 of the automatic guided vehicle 11 that has been pushed from the carriage 13 in the overshooting direction corrects the automatic guided vehicle 11 to a course closer to the line 51 by feedback control. Therefore, the vehicle is turned with the turning direction (clockwise at time T3 ') calculated at that time and the basic turning amount Rb that is the turning amount. Then, the right front part of the tow arm 15 comes into contact with the front of the arm restraining member 17W, and the left rear part of the tow arm 15 comes into contact with the rear of the arm restraining member 17W, and the carriage 13 applies a force to rotate clockwise. Receive from 11. The automatic guided vehicle 11 turns toward the line 51, and the amount of deviation takes a maximum distance d2 '.

Time T4 ′: The automated guided vehicle 11 that has turned in the direction approaching the line 51 at time T3 ′ travels substantially straight to approach the line 51, but the carriage 13 turns clockwise due to the inertia of rotation applied at time T3 ′. Try to proceed while continuing. Therefore, the arm restraining member 17W that has been in contact with the right front portion of the pulling arm 15 is displaced rearward and contacts the rear portion of the pulling arm at time T4 ′. Under the influence of the contact, the automatic guided vehicle 11 receives a force in the direction of overshooting over the line 51. That is, it is pushed in the direction of overshooting beyond the target line 51.
As described above, when the force in the overshooting direction gradually increases with time, the meandering does not converge, and the automatic guided vehicle 11 cannot travel along the line 51.
Therefore, the traveling control unit 31 according to this embodiment performs traveling control by adding the meandering control value calculating unit 35. Hereinafter, the traveling control including the meandering control value calculation unit 35 will be described with reference to FIG. 6A.

  Time T1: Since the vehicle has moved away from the line 51, the traveling control value calculation unit 33 turns the basic turning amount Rb calculated at that time so that the unmanned transport vehicle 11 approaches the line 51 by making a turn corresponding to the distance. calculate. Then, the basic turning amount Rb calculated at time T 1 is stored in the control value buffer 39. The meandering control value calculation unit 35 outputs the output turning amount Ro to turn the automatic guided vehicle 11 based on the calculated basic turning amount Rb and the compensated turning amount Rc based on the turning amount at a time point that is a predetermined time back from the time T1. Is calculated. In order to simplify the explanation, the compensated turning amount Rc is set to zero at time T1.

Ro (T1) = Rb (T1) (1)
In equation (1), Ro (T1) represents the output turning amount at time T1, and Rb (T1) represents the basic turning amount Rb at time T1.
The output turning amount Ro calculated at time T1 is stored in the control value buffer 39. Then, the automatic guided vehicle 11 is turned by the obtained output turning amount Ro.

  By turning at time T1, the left front part of the traction arm 15 comes into contact with the front of the arm restraining member 17W, and the right rear part of the traction arm 15 comes into contact with the rear of the arm restraining member 17W. Add rotation around. The automatic guided vehicle 11 turns toward the line 51, and the amount of deviation takes the maximum distance d1.

Time T2: The automatic guided vehicle 11 that has turned in a direction approaching the line 51 at time T1 goes straight to approach the line 51 asymptotically. On the other hand, due to the inertia of rotation applied at time T1, the carriage 13 continues to turn counterclockwise. Therefore, the arm restraining member 17W that has been in contact with the left front portion of the pulling arm 15 is displaced rearward and contacts the rear portion of the pulling arm at time T2.
On the other hand, the meandering control value calculation unit 35 reads the turning amount at the time T1 that is traced back by a predetermined time from the control value buffer 39 to obtain the compensation turning amount Rc. Here, the turning amount read from the control value buffer 39 may be the basic turning amount Rb or the output turning amount Ro.

  This is because if the basic turning amount Rb is known, the output turning amount Ro can be calculated using a relational expression. In this case, in particular, Ro (T1) = Rb (T1) from the expression (1). Therefore, both values are equal. The magnitude of the overshoot force that contacts the rear portion of the traction arm at time T2 has a positive correlation that increases as the output turning amount Ro (T1) at time T1 increases, and the output turning amount Ro (T1 The magnitude of the overshoot can be calculated from the correlation with the value of. Here, assuming that the correlation between the value of the output turning amount Ro (T1) and the overshoot is proportional, the magnification is α. The compensation turning amount Rc is opposite to the turning amount at time T1 read from the control value buffer 39 so that the overshoot is canceled, and the magnitude thereof is set to satisfy the following relationship.

Rc (T2) = − αRo (T1) (2)
The positive and negative signs correspond to the forward and reverse directions of the turning direction.
Here, assuming that the basic turning amount at time T2 is Rb (T2) and the output turning amount at time T2 is Ro (T2), Ro (T2) is expressed by the following equation.
Ro (T2) = Rb (T2) + Rc (T2) (3)

The meander control value calculation unit 35 turns the automatic guided vehicle 11 with the turning direction and the turning amount corresponding to the calculated compensation turning amount Rc.
Here, from the equation (2), Ro (T2) = Rb (T2) −αRo (T1) (4)
In order to cancel not only the basic turning amount Rb (T2) but also the overshoot at the time T2, the turning is controlled in consideration of the compensation turning amount proportional to the turning amount Ro (T1) at the output turning amount time T1. Therefore, the influence of overshoot can be suppressed small.

Time T3: Turning due to the inertia of the carriage 13 is suppressed by turning according to the compensated turning amount Rc at time T2, and the shift amount of the automatic guided vehicle 11 at time T3 is smaller than the deviation at time T2. Since overshoot correction is performed at time T3 as well as at time T2, the amount of deviation gradually decreases after T3.
Time T4: When the automated guided vehicle 11 approaches the line 51 and the amount of deviation becomes sufficiently small, the meandering of the automated guided vehicle 11 is sufficiently attenuated, and thereafter travels normally along the line 51.

  As shown in FIG. 6A, when the automatic guided vehicle 11 travels along the line 51, the traveling control unit 31 adds the straight component and the turning component based on the output turning amount, and sets the rotation speeds of the motor 45L and the motor 45R. Calculate and update sequentially. The rectilinear component is a rotation speed for rotating the motors 45L and 45R at the same predetermined speed for advancing. The turning component based on the output turning amount is a rotational speed for changing the course of the automatic guided vehicle 11 and is sequentially calculated as a difference between the rotational speeds of the motor 45L and the motor 45R.

  The feature of this embodiment is that the turning in the reverse direction is controlled at this timing in consideration of the force applied in the overshooting direction when the arm restraining member 17W comes into contact with the rear portion of the traction arm at time T2. This is to prevent the occurrence of overshoot. According to the inventor's observation, the magnitude of the overshoot force is generally proportional to the turning force at time T1, but the overshoot timing T2 is substantially constant regardless of the magnitude of the turning force. For this reason, such a simple control method is very effective.

≪Flowchart≫
Hereinafter, control in which the traveling control unit 31 according to this embodiment travels the automatic guided vehicle 11 along the line 51 will be described with reference to a flowchart.
FIG. 7 is a flowchart illustrating a process in which the traveling control unit 31 causes the automatic guided vehicle 11 to travel along the line 51 in this embodiment.
The flowchart in FIG. 7 represents the entire process in an infinite loop. Specifically, this loop indicates that the processing shown in FIG. 7 is repeatedly executed by means such as timer interruption, preferably at substantially constant time intervals. As an example, the time interval for repeatedly executing the process of FIG. 7 is 10 milliseconds. The traveling control unit 31 multitasks other processes in parallel while repeating the process shown in FIG. Examples of other processes include a process of changing the straight component in response to start and stop instructions, a process of selecting a target when the vehicle should travel along any one line at the branch point of the line 51, etc. It is.

In FIG. 7, the traveling control unit 31 refers to an instruction for the automatic guided vehicle 11 (step S11). The instruction is, for example, an instruction received from an external management device via the communication unit 49, and is an instruction indicating a travel route along the line 51, or an instruction for starting and stopping.
Based on the instruction, it is determined whether or not the vehicle should travel along the line 51 at the present time (step S13). If it is not the case where it should drive along a line (No of step S13), the process at that time is skipped and it waits while processing another task until the next process (for example, after 10 milliseconds).

  On the other hand, if it is a case where it should drive along the line 51 (Yes of step S13), the traveling control part 31 will read the signal of each detection element 25A of the line sensor 25 as the traveling control value calculation part 33. FIG. And the deviation | shift amount from the position of the target line 51 about the present position of the automatic guided vehicle 11 is acquired (step S15). The amount of deviation includes the magnitude of the deviation from the reference position of the line 51 and the direction of deviation.

  Based on the acquired deviation amount, a turning amount corresponding to the deviation amount for bringing the automatic guided vehicle 11 closer to the target line 51 is calculated as a basic turning amount Rb (step S17). The basic turning amount Rb may be calculated using, for example, known PID control. The basic turning amount Rb is the same type as the turning component described above, and is finally calculated as a difference between the rotational speeds of the motor 45L and the motor 45R. The difference in rotational speed is not only a numerical value, but includes which of the motor 45L and the motor 45R is made faster and which is made slower. In other words, the basic turning amount Rb includes not only the turning magnitude but also the turning direction.

Then, the travel control unit 31 as the travel control value calculation unit 33 stores the basic turning amount Rb calculated at the present time in the control value buffer 39 (step S19).
Subsequently, the traveling control unit 31 as the meandering control value calculation unit 35 reads a past turning amount (first turning amount at the first time point) that is traced back for a predetermined time from the control value buffer 39 (step S21). It is desirable to determine how much time should go back in consideration of the traveling speed when the automated guided vehicle 11 pulls the carriage 13 and the mass of the carriage 13 including cargo. As an example, the time to go back is 500 milliseconds. According to the inventor's experience, the shortest overshoot or undershoot period or the overshoot or undershoot force observed when the automatic guided vehicle 11 travels alone along the line 51 is maximized. It is preferable to set the same time as the period.

In this embodiment, the control value buffer 39 is configured as a ring buffer and has a capacity capable of storing a sufficient number of turning amounts to go back for a predetermined time (for example, the above-mentioned 500 milliseconds). For example, when the basic turning amount Rb is calculated every 10 milliseconds and stored in the control value buffer 39, and the past basic turning amount Rb traced back by 500 milliseconds is read, the control value buffer 39 has 50 basic turning amounts. It has at least a capacity for storing Rb.
The control value buffer 39 may store an output turning amount Ro described later in addition to the basic turning amount Rb or instead of the basic turning amount Rb. The turning amount read from the control value buffer 39 in step S21 may be the basic turning amount Rb or the output turning amount Ro.

Subsequently, the traveling control unit 31 as the meandering control value calculation unit 35 calculates the compensation turning amount Rc based on the turning amount read from the control value buffer 39 (step S23).
When the turning amount read from the control value buffer 39 is the basic turning amount Rb, the compensation turning amount Rc is calculated in the same manner as the above-described equation (2). That is,
Rc (T2) = − αRb (T1) (2)
Here, the current time is T2, and the past time to be referred to is T1.

Then, the travel control unit 31 as the meandering control value calculation unit 35 calculates the difference between the rotation speeds of the motor 45L and the motor 45R to be output at the present time, that is, the output turning amount Ro (step S25). When the turning amount read from the control value buffer 39 is the basic turning amount Rb, the calculation of the output turning amount Ro is the same as the above-described equation (4). That is,
Ro (T2) = Rb (T2) −αRo (T1) (4)
Although not shown in FIG. 7, when the turning amount read from the control value buffer 39 is the output turning amount Ro, the output turning amount at this point in place of or in addition to the processing in step S19. May be stored in the control value buffer 39.

Subsequently, the travel control unit 31 uses the calculated output turning amount as a turning component, adds the turning component to the straight traveling component, calculates the rotation speeds of the motor 45L and the motor 45R, and calculates the motor 45L and the motor 45R at the calculated rotation speed. Is controlled (step S27).
For example, it is assumed that the linear component is 60 rpm for both the motors 45L and 45R. It is assumed that the automatic guided vehicle 11 is shifted to the right side from the line 51 at the present time. In this case, it is assumed that the output turning amount Ro calculated by the traveling control unit 31 has a rotational speed difference of −4 rpm. The output turning amount Ro is such that the automatic guided vehicle 11 turns leftward, that is, counterclockwise.
As a result, in step S27, the traveling control unit 31 updates the rotational speed of the motor 45L to 58 rpm, which reduces the rotational speed of the motor 45L by 1/2 of the output turning amount Ro from the straight component. On the other hand, the rotational speed of the motor 45R is updated to 62 rpm, which is increased from the linear component by 1/2 of the output turning amount Ro.
Then, the routine returns to the top, and executes the next process after a predetermined time (for example, after 10 milliseconds) has elapsed.

(Embodiment 2)
In the first embodiment, an output turning amount Ro obtained by combining the basic turning amount Rb and the compensation turning amount Rc is calculated, and feedback control related to the basic turning amount Rb and correction related to the compensation turning amount Rc are always performed simultaneously. However, a mode in which both are executed at different timings is also conceivable.
FIG. 8A and FIG. 8B are flowcharts showing processing of this embodiment corresponding to the first embodiment. 8A performs feedback control of traveling operation based on the basic turning amount, and FIG. 8B performs compensation control of traveling operation based on the compensated turning amount. In FIG. 8A and FIG. 8B, the process corresponding to FIG.

In FIG. 8A, since the feedback control based on only the basic turning amount is performed, the basic turning amount is set as the output turning amount.
On the other hand, in FIG. 8B, since compensation control is performed based only on the compensated turning amount, the compensated turning amount is set as the output turning amount.
In these respects, step S25 in FIGS. 8A and 8B is not completely the same as the process of step S25 in FIG.

  As in FIG. 7 in the embodiment, the processes in FIGS. 8A and 8B are both repeatedly executed by means such as timer interruption, preferably at substantially constant time intervals. However, both are executed separately.

(Embodiment 3)
In the first embodiment, the left and right drive wheels 19L and 19R of the automatic guided vehicle 11 are independently driven to turn, but the essence of the present invention is not limited to the configuration.
FIG. 9 is an explanatory diagram showing the configuration of the wheels on which the automatic guided vehicle 11 travels in this embodiment. For example, as shown in FIG. 9, the left and right drive wheels 19 </ b> L and 19 </ b> R of the automatic guided vehicle 11 are driven by a common motor 45. The turning uses a steering motor (not shown in FIG. 9) that changes the direction of the auxiliary wheels 21. The automatic guided vehicle 11 is turned by controlling the steering angle θ of the auxiliary wheel. In FIG. 9, the auxiliary wheel 21 is in front of the drive wheels 19L and 19R. However, the embodiment is not limited thereto, and the auxiliary wheel 21 may be in the rear of the drive wheels 19L and 19R.

The automatic guided vehicle 11 having the configuration shown in FIG. 9 cannot be spin-turned, but can apply meandering control similar to that described in the first embodiment to suppress meandering when the cart 13 is pulled.
FIG. 10 is a flowchart showing processing of the travel control unit 31 corresponding to FIG. 7 in this embodiment. Steps S31 to S47 in FIG. 10 are the same as steps S11 to S27 in FIG. 7, respectively, but the steering angle is used as various control amounts in FIG. 10 with respect to the turning amount in FIG. Specifically, the basic steering angle corresponding to the basic turning amount, the compensating steering amount with respect to the compensating turning amount, and the output steering angle corresponding to the output turning amount are used in FIG.
Although the steering angle is used as the control amount instead of the turning amount of the first embodiment, the concept of travel control is the same as that of the first embodiment.

(Embodiment 4)
In this embodiment, in addition to the configuration shown in FIG. 4 of the first embodiment, the traveling control unit 31 further includes a meandering determination unit that determines whether the automatic guided vehicle 11 is meandering.
The meander control value calculation unit 35 functions only when the automatic guided vehicle 11 meanders. The reason for this is that when the meandering is sufficiently small, the meandering control of the present invention is not necessarily required, and it is possible to control the traveling by the conventional PID control, and when the meandering control is performed in a state where the meandering is not actually performed. Unnecessary turning operations are frequently repeated, but this is not desirable, and in some cases, traveling stability may be impaired.
The meandering determination unit determines whether or not the automatic guided vehicle 11 is meandering while traveling based on the traveling control value or the detection of the line sensor 25.

  The determination of meandering can be performed based on, for example, that the line 51 has changed within a predetermined period from the right side to the left side of the reference position while the automatic guided vehicle 11 is traveling. Furthermore, the determination may be made based on the fact that the movement from the right side to the left side with respect to the reference position within the predetermined period and then the movement from the left side to the right side continues for a predetermined number of times.

FIG. 12 is a flowchart showing processing of the travel control unit 31 corresponding to FIG. 7 in this embodiment. Steps S51 to S59 and S61 to S67 in FIG. 12 correspond to steps S11 to S19 and S21 to S27 in FIG. 7, respectively. Step S60 in FIG. 12 does not have a process corresponding to FIG.
In FIG. 12, the traveling control unit 31 determines whether the automatic guided vehicle 11 is meandering as the meandering determination unit 36. If it is determined that it is meandering (Yes in step S60), the routine proceeds to step S61, and thereafter the same processing as in FIG. 7 is performed.

  On the other hand, if it is determined in step S60 that the automatic guided vehicle 11 is not meandering, the routine proceeds to step S65. In this case, the output turning amount is calculated in the same manner as when α = 0 (accordingly, the compensation turning amount Rc = 0) in the equations (1) and (4) (step S65), and the motor 45L is calculated based on the result. And the rotation speed of 45R is updated.

That is, when the travel control unit 31 as the meander determination unit 36 determines that the automatic guided vehicle 11 is not meandering, the travel control value calculation unit 33 performs the travel control by, for example, known PID control. When α = 0, the compensation turning amount Rc is always zero, that is, invalid.
According to this embodiment, control for suppressing meandering is executed only when the automatic guided vehicle meanders.

As mentioned above,
(I) An automatic travel device according to the present invention is an automatic travel device that travels along the travel route while towing a to-be-triggered object and correcting a deviation from the travel route by a left and right turning operation. A recording unit that records a turning amount of the vehicle, a deviation amount detection unit that detects a deviation amount from the travel route, and a travel control unit that controls a travel operation of the automatic travel device, Based on the first turning amount at a first time point that is a predetermined time later than the first turning amount, the compensation turning amount corresponding to the turning in the direction opposite to the turning at the first time point is smaller than the first turning amount. And calculating an output turning amount based on at least the compensation turning amount, and controlling the traveling operation of the automatic traveling device so as to perform a turning operation according to the output turning amount.

In the present invention, the line is a line installed along a target travel route on the travel surface of the automatic travel device.
The turning operation is an operation in which the automatic traveling device changes the direction of the vehicle body in order to change the traveling direction. An example of the specific mode is that the automatic traveling device has driving wheels that can be driven independently on the left and right sides, and the rotational speeds of the left and right driving wheels are different, or the rotational directions are different, and the direction of the automatic traveling device is It is an operation to switch. There is also an aspect in which the direction is changed by changing the direction of the driving wheel or auxiliary wheel. However, in order to enable stationary turning, which is a compact direction change, the left and right drive wheels are driven independently and the turning speed and direction of both are changed to perform turning operations in many cases. That is, in many cases, the structure of turning by changing the direction of the drive wheel is not adopted.

Further, the turning amount at each time point is data that the traveling control unit has internally, and represents to what side the automatic traveling device should be changed to what size. For example, the turning amount may be a basic turning amount calculated based on a deviation amount from the line, or an output turning amount obtained based on the basic turning amount and the compensation turning amount. .
The recording unit for recording the turning amount at each time point provides the turning amount stored at a future time point when the time has passed. The control value buffer in the above-described embodiment corresponds to this recording unit.
Furthermore, the amount of deviation from the line indicates how much the deviation from the target travel route is to which side. The deviation amount detection unit is a means for detecting a deviation amount from the line, and the line sensor in the above-described embodiment corresponds to this deviation amount detection unit.

The first turning amount is the turning amount at a first time point that is a predetermined time back from the current time point. That is, it may be the basic turning amount at the first time point or the output turning amount at the first time point.
The compensated turning amount is a turning amount smaller than the first turning amount in the opposite direction to the first turning amount in order to prevent meandering by compensating the turning operation performed at the first time point in the past. is there.
Furthermore, the output turning amount represents the direction and magnitude of the turning operation that the automatic traveling apparatus should perform at a certain point in time.

Furthermore, the preferable aspect of this invention is demonstrated.
(Ii) The travel control unit may calculate the compensated turning amount as the output turning amount.
In this way, it is possible to prevent the meandering of the automatic travel device by compensating the turning operation at the first time point that is a predetermined time back from the current time point.

(Iii) The travel control unit may calculate a basic turning amount based on the deviation amount, and calculate the output turning amount based on the basic turning amount and the compensation turning amount.
Here, the basic turning amount is a turning amount suitable for correcting the deviation from the line of the automatic travel device based on the deviation amount from the line at a certain time.
In this way, the course of the automatic travel device is determined in a direction in which the deviation from the line is corrected based on the amount of deviation from the current line, and the turning operation at the first time point that is a predetermined time backward from the current time is compensated. Thus, meandering of the automatic traveling device can be prevented.

(Iv) The compensation turning amount may be determined so as to have a monotonically increasing correlation with the first turning amount.
In this way, the larger the first turning amount at the first time point in the past, the larger the compensated turning amount is calculated, so that the turning operation at the first time point can be appropriately compensated.

(V) The compensation turning amount may be determined so as to have a proportional correlation with the first turning amount.
In this way, since the compensated turning amount proportional to the first turning amount at the first time point in the past is calculated, the turning motion at the first time point can be appropriately compensated.

(Vi) further comprising a meandering detection unit for detecting meandering of the automatic traveling device, wherein the traveling control unit enables the compensation turning amount when the meandering detection unit detects meandering, and the meandering detection unit When the meandering is not detected, the compensation turning amount may be invalidated.
Here, meandering means that the automatic travel device cannot travel along the target travel route, but travels while overshooting and undershooting repeatedly by overshooting the target. Also, enabling the compensated turning amount means calculating by incorporating an element related to the compensated turning amount when calculating the output turning amount, and disabling the compensating turning amount means compensating turning when calculating the output turning amount. It means to calculate without incorporating the quantity element.
In this way, the compensated turning amount is made effective only when the self-propelled traveling device is meandering to compensate for the turning operation at the first time point that is a predetermined time backward from the current time. It is possible to disable the simple control.

(Vii) The automatic travel device may travel along a line arranged on the travel route, and the shift amount detection unit may detect a shift amount from the line.
If it does in this way, a travel route can be specified by arranging a line on a travel surface, and an automatic travel device can be made to run along the travel route.
(Viii) It further has a connection part connected to the to-be-towed object for towing, and the connection part is located on the rear side with respect to the traveling direction of the automatic travel device from the first part. It has a 2nd part, and it may connect to the to-be-drawn object by pinching the to-be-connected part of the to-be-drawn object in the direction of order by the 1st part and the 2nd part.
In this way, by sandwiching the connected part of the to-be-drawn object in the front-rear direction, the to-be-to-be-drawn object can be reliably pulled with respect to the left and right turning operation and can be run while correcting the deviation by the turning operation. Become.

(Ix) The space | interval of the front-back direction between the said 1st part and the said 2nd part may be larger than the width | variety of the front-back direction of the said to-be-connected part.
In this way, there is a margin between the connecting portion of the automatic traveling device and the connected portion of the towed object in the front-rear direction. For example, even if the weight of the towed object is greater than the weight of the automatic traveling device, Towable.

(X) a first connection part connected to the first connected part of the towed object and a second connected part located on the right side of the traveling direction with respect to the first connecting part. You may provide two connection parts.
In this way, the towed object is pulled by the first connection part and the second connection part located on the left and right, so that the to-be-drawn object can be swung along with the turning operation and can travel smoothly.
Preferred embodiments of the present invention include combinations of any of the plurality of embodiments described above.
In addition to the embodiments described above, there can be various modifications of the present invention. These modifications should not be construed as not belonging to the scope of the present invention. The present invention should include the meaning equivalent to the scope of the claims and all modifications within the scope.

11: Automated guided vehicle, 13: Cart, 13A: Caster, 13B: Bottom plate, 15: Traction arm, 15A: First part, 15B: Second part, 16: Lifting mechanism, 17G, 17W: Arm restraining member, 19L, 19R: Drive wheel, 21: Auxiliary wheel, 23: Sensor unit, 25: Line sensor, 25A: Detection element, 27: Proximity sensor, 30: Control board, 31: Travel control unit, 33: Travel control value calculation unit, 35 : Meander control value calculation unit, 36: meander determination unit, 37: storage unit, 39: control value buffer, 41: parameter storage unit, 43: travel drive unit, 45, 45L, 45R: motor, 47: battery, 49: Communication unit 51: Line, 51A: Detection element T1, T2, T3, T4: Time d1, d2, d3: Distance

Claims (10)

An automatic travel device that travels along the travel route while towing a to-be-triggered object and correcting a deviation from the travel route by a left and right turning operation,
A recording unit for recording the turning amount at each time point;
A deviation amount detection unit for detecting a deviation amount from the travel route;
A travel control unit for controlling the travel operation of the automatic travel device,
The travel controller is
Based on a first turning amount at a first time point that is a predetermined time after the current time, a compensated turning amount that is smaller than the first turning amount and that corresponds to turning in the direction opposite to the turning at the first time point. To calculate
An automatic traveling device that calculates an output turning amount based on at least the compensated turning amount and controls a traveling operation of the automatic traveling device so as to perform a turning operation according to the output turning amount. The travel controller is
The automatic travel device according to claim 1, wherein the compensation turning amount is calculated as the output turning amount. The travel controller is
Calculate the basic turning amount based on the deviation amount,
The automatic travel device according to claim 1, wherein the output turning amount is calculated based on the basic turning amount and the compensation turning amount.   The automatic traveling apparatus according to any one of claims 1 to 3, wherein the compensation turning amount has a monotonically increasing correlation with the first turning amount.   The automatic travel device according to claim 4, wherein the compensated turning amount has a proportional correlation with the first turning amount. Further comprising a meandering detector for detecting meandering of the automatic travel device;
The travel controller is
When the meandering detection unit detects meandering, the compensation turning amount is enabled,
The automatic travel device according to any one of claims 1 to 5, wherein when the meandering detection unit does not detect meandering, the compensation turning amount is invalidated. An automatic travel device that travels along a line arranged on the travel route,
The automatic travel device according to any one of claims 1 to 6, wherein the shift amount detection unit detects a shift amount from the line. It further comprises a connection part for connecting to the towed object,
The connecting portion includes a first portion and a second portion located on the rear side of the traveling direction of the automatic travel device with respect to the first portion,
The automatic travel device according to any one of claims 1 to 7, wherein the automatic travel device is connected to the pulled object by sandwiching a connected portion of the pulled object in the front-rear direction between the first part and the second part.   The automatic travel device according to claim 8, wherein a distance in the front-rear direction between the first portion and the second portion is larger than a width in the front-rear direction of the connected portion.   The 1st connection part connected with the 1st to-be-connected part of the said towed object, and the 2nd connection connected with the 2nd to-be-connected part located in the right side to the direction of movement rather than the 1st connection part The automatic travel device according to claim 8 or 9, comprising a unit.