JP2010026628A - Unmanned carrier - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide only one guidance line for transverse traveling in an unmanned carrier for performing longitudinal traveling and transverse traveling along the guidance line laid on a road surface. <P>SOLUTION: The unmanned carrier 10 is provided with: drive wheels 12 and 13 arranged at the front and rear ends of a body 11; an guidance line sensor 14 for detecting the guidance line 31 laid on the road surface; and a control part 16 for controlling the drive wheels 12 and 13 according to the output of the guidance line sensor 14. Steering is controlled along the guidance line 31 by the control part 16 so that longitudinal traveling and traverse traveling orthogonal to the longitudinal traveling can be achieved. The control part 16 controls drive wheels 12 and 13 in backward and forward traveling by an independent steering system and controls the drive wheels 12 and 13 in a two-wheel speed difference steering system in transverse traveling while holding them in transverse parallel directions in transverse traveling. Thus, time and labor and laying costs can be reduced by providing only one guidance line 31 for transverse traveling. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an automated guided vehicle that travels back and forth and traverses along a guide line laid on a road surface.

  2. Description of the Related Art Conventionally, there is known an automatic guided vehicle that travels back and forth and traverses along two guide lines laid on a road surface (see, for example, Patent Document 1). In addition, an automatic guided vehicle that performs front and rear traveling along one guide line is known. FIGS. 8A and 8B show such an automatic guided vehicle. The automatic guided vehicle 50 is an independent steering system, and drive wheels 51 and 52 that can be independently turned are disposed at lower portions of the front and rear portions of the vehicle body. The conversion of the drive wheels 51 and 52 is to change the steering angle. A guide wire 61 such as a magnetic tape is laid on the road surface, and guide wire sensors 53 and 54 for detecting the guide wire 61 are attached to the automatic guided vehicle 50 before and after the drive wheels 51 and 52, respectively. The automatic guided vehicle 50 includes caster wheels 55 in addition to drive wheels 51 and 52 as wheels. As shown in FIG. 8A, the automatic guided vehicle 50 detects the same guide line 61A when the vehicle runs forward and backward, and the drive wheels 51, 54 are detected based on the outputs of the guide line sensors 53, 54. Each of 52 is controlled to turn and travels along one guide line 61A. Further, as shown in FIG. 8B, when the automatic guided vehicle 50 travels in a traverse direction, the guide line sensor 53 detects the guide line 61 </ b> B, and the driving wheel 51 performs the turn control based on the output of the guide line sensor 53. At the same time, the guide line sensor 54 detects another guide line 61C, and the driving wheel 52 is controlled to be turned based on the output of the guide line sensor 54, and travels along the two parallel guide lines 61B and 61C. To do.

  Therefore, the guide wire 61 is sufficient to lay one guide wire 61A for the front-rear travel of the automated guided vehicle 50, but for the transverse travel, the two guide wires 61B, 61C are connected to the front and rear drive wheels 51, The guide wires 61B and 61C have to be laid in parallel with the interval of 52, and labor and cost have been required for laying the guide wires 61B and 61C.

FIG. 9 shows a traveling state when the automatic guided vehicle 50 travels for a while after switching from the forward traveling to the transverse traveling. The automatic guided vehicle 50 travels so that the drive wheels 51 and 52 are along the guide lines 61B and 61C, respectively. However, due to a difference in rotational speed between the drive wheels 51 and 52, the yaw angle θ is gradually generated in plan view. It was in a tilted state, and it was not possible to travel stably on a straight line. In recent years, there has been an increase in the layout of donating to a transport destination in the back of a passage by traversing, and stabilization of traversing has been required.
JP-A-8-123550

  The present invention solves the above problem, and in an automated guided vehicle that travels back and forth and traverses along a guide line laid on the road surface, the traverse travel is reduced to one. The goal is to be able to run in a straight line with stability at times.

  In order to achieve the above object, a first aspect of the present invention is directed to convertible drive wheels disposed in front and rear portions of a vehicle body, a guide line sensor for detecting a guide line laid on a road surface, and the guide line sensor. A control unit that controls the drive wheel based on the output of the automatic guided vehicle, the steering unit is controlled along the guide line by the control unit to perform the front-rear traveling and the transverse traveling orthogonal to the front-rear direction, The control unit controls the drive wheels by an independent steering system during front-rear travel, and holds the drive wheels in a parallel orientation for traversal during traverse travel, and the two-wheel speed difference steering system. It is to be controlled by.

  According to a second aspect of the present invention, in the automatic guided vehicle according to the first aspect, a steering lock mechanism that locks a direction of the driving wheel is provided, and the control unit releases the steering lock mechanism during front-rear traveling to perform the driving. The wheels can be turned freely, and the steering lock mechanism is operated during traversing to lock the drive wheels in directions parallel to each other.

  A third aspect of the present invention is the automatic guided vehicle according to the first or second aspect, further comprising a lift-up mechanism that lifts the driving wheel from the road surface, and the control unit switches between front-rear traveling and lateral traveling. Sometimes, the lift-up mechanism lifts the drive wheel from the road surface.

  According to the first aspect of the present invention, since the two driving wheels are held in the same direction and controlled by the two-wheel speed difference steering system when traversing, a single guiding wire for traversing traveling can be provided. Save time and money.

  According to the second aspect of the present invention, since the driving wheels are locked in parallel to each other during traversing traveling, stable straight traveling can be performed, and long-distance traveling can be performed.

  According to the invention of claim 3, since the driving wheel is lifted from the road surface by the lift-up mechanism at the time of switching between the forward and backward traveling and the transverse traveling, the stationary state is not brought about and the driving wheel and the guide wire are prevented from being damaged. Is done.

  Hereinafter, an automatic guided vehicle according to a first embodiment of the present invention will be described. Fig.1 (a) (b) shows the structure of the automatic guided vehicle of this embodiment. The automatic guided vehicle 10 includes convertible drive wheels 12 and 13 disposed at lower portions of the front and rear portions of a vehicle body 11, a guide line sensor 14 that detects a guide line 31 laid on a road surface, and a guide line sensor 14 The control part 16 which controls the drive wheels 12 and 13 based on the output of this is provided. The guide line sensor 14 includes a front / rear travel guide line sensor 14A provided on the drive wheels 12 and 13 and a transverse travel guide line sensor 14B provided on the lower portion of the vehicle body 11. In addition, the automatic guided vehicle 10 includes an address sensor 15 that receives information on an address mark 32 disposed on a road surface at a lower portion of the vehicle body 11. The address sensor 15 includes a front / rear travel address sensor 15A and a traversing travel address sensor 15B.

  The automatic guided vehicle 10 is, for example, a load transport vehicle used in a factory, a warehouse, or the like, and can automatically run unattended. The front drive wheel 12 and the rear drive wheel 13 of the automatic guided vehicle 10 are disposed at the lower part of the vehicle body 11 through a steering shaft 17 and are converted by a steering motor 18. A drive traveling motor 19 is attached to the drive wheels 12 and 13. The drive wheels 12 and 13, the steering shaft 17, the steering motor 18 and the traveling motor 19 constitute a drive unit 20 that causes the automatic guided vehicle 10 to travel. The automatic guided vehicle 10 includes, as wheels, caster wheels 21 in addition to drive wheels 12 and 13, and a battery (not shown) that supplies power to the steering motor 18, the traveling motor 19, and the like in the vehicle body 11. .

  The guide wire 31 is an elongate derivative for guidance control, which is laid on the road surface of the traveling route of the automatic guided vehicle 10, and is, for example, a magnetic tape. The guide wire sensor 14 is a sensor that detects the guide wire 31. For example, when the guide wire 31 is a magnetic tape, the guide wire sensor 14 is a magnetic sensor that detects magnetism generated by the magnetic tape. The front / rear travel guide line sensor 14 </ b> A is attached in front of and behind the drive wheels 12 and 13, and is converted together with the drive wheels 12 and 13. The traversing travel guide line sensor 14B is usually disposed at the lower part of the vehicle body 11 between the front and rear drive wheels 12 and 13 separately from the front and rear travel guide line sensor 14A. The address mark 32 is, for example, RFID (Radio Frequency Identification) laid on the road surface of the traveling route of the automated guided vehicle 10 and has information for instructing the automated guided vehicle 10 on the traveling direction and the like. . The information of the address mark 32 is received by the front / rear travel address sensor 15A during front / rear travel, and is received by the traverse travel address sensor 15B during traverse travel.

  FIG. 2 shows an input / output configuration of the control unit 16. The control unit 16 is, for example, a programmable controller, and the control unit 16 is connected to the front / rear travel guide line sensor 14A, the traversing travel guide line sensor 14B, the front / rear travel address sensor 15A, the traversing travel address sensor 15B, and the like. A steering motor 18, a traveling motor 19, etc. are connected via a drive circuit 22. The drive circuit 22 is, for example, an inverter circuit for driving a motor. The control unit 16 controls the steering motor 18 based on the outputs of the guide wire sensors 14 and 15, thereby controlling the direction of the driving wheels 12 and 13, and controlling the traveling motor 19 to drive the driving wheels 12 and 13. Control the drive. The automatic guided vehicle 10 travels in the front-rear direction and the traverse direction orthogonal to the front-rear direction by controlling the steering along the guide line 31 by the control unit 16. The control unit 16 has a function of switching steering control between an independent steering system and a two-wheel speed difference steering system. The independent steering system is a system in which the driving wheels 12 and 13 are independently converted to determine the traveling direction, and can be turned on the spot in addition to normal turning, and space required for the automatic guided vehicle 10 to travel. There is an advantage that can be narrowed. The two-wheel speed difference steering method is based on the difference in rotational speed between the two wheels without turning the driving wheels 12 and 13 and the driving wheels 12 and 13 are arranged substantially side by side in the traveling direction. This is a method for determining the direction of travel. The control unit 16 controls the drive wheels 12 and 13 by an independent steering method when the automatic guided vehicle 10 travels forward and backward, and holds the drive wheels 12 and 13 in a parallel direction for traversal and travels while traversing. The wheels 12 and 13 are controlled by a two-wheel speed difference steering system.

  Next, the travel of the automatic guided vehicle 10 will be described in detail. FIGS. 3A to 3D show time-series order switching of the automatic guided vehicle 10 from forward traveling to traversing traveling. As shown in FIG. 3A, when the automatic guided vehicle 10 travels forward, the front / rear travel guideline sensor 14A detects the front / rear travel guideline 31A. The control unit 16 controls the steering along the front / rear driving guide line 31A by individually turning the driving wheels 12 and 13 of the front / rear part by an independent steering system based on the output from the front / rear driving guide line sensor 14A. At the same time, the traveling motor 19 is controlled to cause the automatic guided vehicle 10 to travel forward. At this time, the caster wheel 21 rolls in the traveling direction. When the automatic guided vehicle 10 travels backward, the control unit 16 controls the drive wheels 12 and 13 by an independent steering method as in forward travel.

  Subsequently, as shown in FIG. 3B, an address mark 32 is provided on a road surface at a predetermined point on the travel route, and the front / rear travel address sensor 15A detects the address mark 32. This point is, for example, a change point from forward travel to traverse travel, and the address mark 32 stores information instructing traverse travel on the right in the forward direction in an encoded manner. The front / rear travel address sensor 15A receives the information. Based on the information received by the front / rear travel address sensor 15A, the control unit 16 stops the forward travel by the drive wheels 12 and 13 and converts the drive wheels 12 and 13 to the transverse direction. The drive wheels 12 and 13 have a steering angle of approximately 90 ° in the transverse direction.

  Subsequently, as shown in FIG. 3 (c), when the drive wheels 12 and 13 are turned to the direction for traversal, the control unit 16 stops the rotation of the steering motor 18 and traverses the drive wheels 12 and 13 to each other. The steering control is switched from the independent steering system to the two-wheel speed difference steering system.

  Subsequently, as shown in FIG. 3D, the traversing travel guide line sensor 14B detects the traversing travel guide line 31B. The control unit 16 controls the drive wheels 12 and 13 by the two-wheel speed difference steering system along one traverse travel guide line 31B based on the output from the traverse travel guide line sensor 14B, and a travel motor 19 To control the automatic guided vehicle 10 to traverse. At this time, the caster wheel rolls in the traveling direction of the transverse traveling. The automatic guided vehicle 10 goes straight when the drive wheels 12 and 13 are driven at the same rotational speed, and the traveling direction changes when a rotational speed difference is given. Note that the switching from the transverse traveling to the front / rear traveling is performed in a generally reverse procedure of the above-described switching from the front / rear traveling to the transverse traveling based on the information received by the transverse traveling address sensor 15B.

  In this way, the automatic guided vehicle 10 holds the drive wheels 12 and 13 in the same direction and controls by the two-wheel speed difference steering system when traveling in the transverse direction, so that the guide line 31B for the transverse traveling can be made one. The labor and cost of laying the guide wire 31 can be reduced.

  The automatic guided vehicle 10 may include a mechanism that mechanically locks the directions of the drive wheels 12 and 13 in order to securely hold the drive wheels 12 and 13 in the same direction. FIG. 4 shows an example of such a steering lock mechanism. The steering lock mechanism 23 includes a positioning block 231 and a stopper 232 that can be engaged with each other. The positioning block 231 is fixed to the steering shaft 17, and the stopper 232 is attached to the vehicle body 11 via an operating mechanism of the stopper 232. In FIG. 4, a brake 24 for braking the drive wheel 12 (or 13) is provided.

  Next, the operation of the steering lock mechanism 23 will be described. FIGS. 5A, 5B, and 5C show the operation from the released state to the activated state of the steering lock mechanism 23 in chronological order. The operation of the steering lock mechanism 23 is controlled by the control unit 16. As shown in FIG. 5A, when the automatic guided vehicle 10 travels forward and backward, the steering lock mechanism 23 is released, the steering shaft 17 is rotatable with respect to the vehicle body 11, and the drive wheels 12, 13 are driven. Is freely convertible. As shown in FIG. 5B, when switching from front / rear running to transverse running, the steering shaft 17 is rotated by approximately 90 °, and the drive wheels 12 and 13 are turned to the transverse direction. As shown in FIG. 5C, the stopper 232 is rotated around the fulcrum 234 by the stopper operating cylinder 233 and is engaged with the positioning block 231. The stopper operating cylinder 233 has a proximal end attached to the vehicle body side. For example, the positioning block 231 is an engaging concave portion and the stopper 232 is an engaging convex portion. When they are engaged with each other, the steering shaft 17 is fixed to the vehicle body, and the drive wheels 12 and 13 are traversed with each other. Locked in parallel orientation. Accordingly, the drive wheels 12 and 13 are not turned and are steered only by the two-wheel speed difference. For this reason, the automatic guided vehicle 10 does not generate a yaw angle in a straight line even when traveling long distances.

  Thus, since the automatic guided vehicle 10 locks the drive wheels 12 and 13 in a parallel direction during traversal travel, the automatic guided vehicle 10 can travel stably in a straight line and can travel long distances.

  Next, an automatic guided vehicle according to the second embodiment of the present invention will be described. 6A and 6B show the configuration of the automatic guided vehicle of the present embodiment. Note that the address sensor 15 and the address mark 32 are the same as those in the first embodiment, and are not shown. In addition to the same configuration as the automatic guided vehicle 10 of the first embodiment, the automatic guided vehicle 40 of the present embodiment includes a lift-up mechanism 41 that lifts the drive wheels 12 and 13 from the road surface. The automatic guided vehicle 40 includes three or more, for example, four caster wheels 21 so that the vehicle body 11 can be supported from the road surface only by the caster wheels 21. As shown in FIG. 6B, the lift-up mechanism 41 includes, for example, a parallel crank mechanism 411 and a lift-up cylinder 412 that operates the parallel crank mechanism 411. The drive wheels 12 and 13 are supported on the lower part of the vehicle body 11 by the parallel crank mechanism 411 via the steering shaft 17, and are raised and lowered by the expansion and contraction of the lift-up cylinder 412. The control unit 16 causes the lift-up mechanism 41 to lift the drive wheels 12 and 13 from the road surface when switching between front and rear traveling and traversing traveling. When the drive wheels 12 and 13 are lifted from the road surface, the vehicle body 11 is supported from the road surface by the caster wheels 21.

  If the lift-up mechanism 41 is not provided, the automatic guided vehicle may be in a state where the driving wheels are stationary on the road surface when switching between the forward and backward traveling and the transverse traveling, and the driving wheels and the guide wire 31 may be damaged. The automatic guided vehicle 40 of the present embodiment lifts the drive wheels 12 and 13 from the road surface by the lift-up mechanism 41 at the time of switching between the front and rear traveling and the transverse traveling. 13 and the guide wire 31 are prevented from being damaged.

  FIG. 7 shows another example of the lift-up mechanism. The automatic guided vehicle 40 includes a plurality of jacks 42 that can be expanded and contracted as a lift-up mechanism at the lower part of the vehicle body 11. As for the number of caster wheels 21, it is not necessary to consider the support of the vehicle body 11 by the caster wheels 21. The jack 42 supports the vehicle body 11 from the road surface when extended, and the drive wheels 12 and 13 are lifted from the road surface together with the vehicle body 11 at that time.

  In addition, this invention is not restricted to the structure of said embodiment, A various deformation | transformation is possible in the range which does not change the summary of invention. For example, the stopper actuating cylinder 233 and the lift-up cylinder 412 may be hydraulically driven or electrically or pneumatically driven.

(A) is a plane perspective view of the automatic guided vehicle according to the first embodiment of the present invention, (b) is a side view of the automatic guided vehicle. The control block diagram of the automatic guided vehicle. (A) is a plan perspective view when the automatic guided vehicle is traveling forward, (b) and (c) are plan perspective views when switching from forward travel to traverse travel, and (d) is a plan perspective view during traverse travel. . The elevation sectional view showing the position of the steering lock mechanism of the automatic guided vehicle. (A) And (b) is a top view which shows the cancellation | release state of a steering lock mechanism, (c) is a top view which shows the operation state of the mechanism. (A) is a plane perspective view of an example of the automatic guided vehicle according to the second embodiment of the present invention, and (b) is a side view of a lift-up mechanism of the automatic guided vehicle. (A) is a plane perspective view of another example of the automatic guided vehicle according to the embodiment, and (b) is a side view of a jack of the automatic guided vehicle. (A) is a plane perspective view at the time of front-and-rear driving | running | working of the conventional automatic guided vehicle, (b) is a plane perspective view at the time of transverse running of the automatic guided vehicle. The plane see-through | perspective view of the conventional automatic guided vehicle when carrying out the long-distance traverse driving | running | working.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Automatic guided vehicle 11 Car body 12, 13 Drive wheel 14 (14A, 14B) Guide line sensor 15 (15A, 15B) Address sensor 16 Control part 23 Steering lock mechanism 31 (31A, 31B) Guide line 32 Address mark 41 Lift-up mechanism

Claims (3)

A convertible drive wheel disposed at the front and rear of the vehicle body, a guide line sensor for detecting a guide line laid on the road surface, and a control unit for controlling the drive wheel based on the output of the guide line sensor; In the automatic guided vehicle in which the steering is controlled along the guide line by the control unit and the vehicle travels in the front-rear direction and the transverse direction orthogonal to the front-rear direction,
The control unit controls the drive wheels by an independent steering system during front-rear travel, and holds the drive wheels in a parallel orientation for traversal during traverse travel, and the two-wheel speed difference steering system. An automatic guided vehicle controlled by A steering lock mechanism for locking the direction of the drive wheel;
The control unit releases the steering lock mechanism during front-rear travel so that the drive wheels can be freely turned, and operates the steering lock mechanism during traverse travel to lock the drive wheels in parallel directions. The automatic guided vehicle according to claim 1. A lift-up mechanism for lifting the drive wheel from the road surface;
3. The automatic guided vehicle according to claim 1, wherein the control unit causes the lift-up mechanism to lift the driving wheel from a road surface when switching between front and rear traveling and traversing traveling.

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