Unmanned carrier

Abstract

To provide an unmanned carrier capable of arbitrarily restricting arm movement.SOLUTION: An unmanned carrier 20 tows an object 10 to be towed. The unmanned carrier 20 includes a carrier body 21, a rotation shaft 22, an arm 23, a connection mechanism 26, and a brake device 24. The carrier body 21 has a drive wheel 31. The rotation shaft is provided in the carrier body 21 vertically crossing to a traveling direction A of the carrier body 21. The arm is provided centering on the rotation shaft 22 in a freely rotatable manner. The connection mechanism 26 is provided in the arm 23 to be connected to the object 10 to be towed. The brake device 24 holds the arm 23 at an arbitrary rotation position with respect to the carrier body 21.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an automated guided vehicle that tows a towing object. [Background technology]

[0002] Conventionally, there has been known an automated guided vehicle that tows a towed object, as described in Patent Document 1 below, for example. This automated guided vehicle has an arm that is rotatable around a vertical pivot shaft provided on the vehicle body, and this arm is connected to the towed object to tow it. Since the automated guided vehicle may curve while towing the connected towed object, the arm is made to be able to rotate freely around the pivot shaft. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2023-125625 Summary of the Invention [Problem to be solved by the invention]

[0004] The above-described automatic guided vehicle has an arm that can rotate freely, but if the arm's rotation could be switched between a free state and a restricted state, the arm would be able to respond to a wider variety of situations.

[0005] The problem to be solved by the present invention is to provide an automatic guided vehicle capable of restricting the movement of the arm as desired. [Means for solving the problem]

[0006] The automated guided vehicle of the present invention is an automated guided vehicle that tows a towed object, and includes a vehicle body having drive wheels, a vertical swivel axis provided on the vehicle body that intersects with the direction of travel of the vehicle body, an arm that is rotatable around the swivel axis, a connecting mechanism provided on the arm that connects to the towed object, and a holding device that holds the arm in any swivel position relative to the vehicle body. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide an automated guided vehicle capable of arbitrarily restricting the movement of its arm. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a perspective view of a towed object towed by an automatic guided vehicle according to an embodiment of the present invention; [Figure 2] FIG. [Figure 3] FIG. [Figure 4] FIG. 2 is a front view of the positioning and holding mechanism of the automatic guided vehicle. [Figure 5] FIG. 2 is a block diagram of a transport system including the same automated guided vehicle. [Figure 6] 10A to 10F are explanatory diagrams showing the coupling operation between the automatic guided vehicle and the towing object. [Figure 7] 4A to 4F are explanatory views showing the positioning and holding operation of the positioning and holding mechanism of the automatic guided vehicle. [Figure 8] 10A to 10F are explanatory diagrams showing the towing operation of the automatic guided vehicle. [Figure 9] 10A to 10F are explanatory diagrams showing the towing operation of the automatic guided vehicle. DETAILED DESCRIPTION OF THE INVENTION

[0009] An embodiment of the present invention will now be described with reference to the drawings.

[0010] FIG. 1 shows an example of a towed object 10 to be towed by an automated guided vehicle. The towed object 10 is, for example, a cart that can travel on a running surface such as a floor, and in detail, a car truck will be used as an example. The towed object 10 comprises a long loading platform 11, a plurality of frame portions 12 disposed on the underside of the loading platform 11 at both ends in the longitudinal direction and in the center, and a plurality of wheels 13 disposed on the underside of these frame portions 12. The towed object 10 can travel in one direction or the other along the longitudinal direction (front-to-back direction) of the loading platform 11.

[0011] A connectable portion 14 to which an automatic guided vehicle can be connected is provided in the central region of at least one of the frame portions 12 in the longitudinal direction (front-rear direction) of the loading platform portion 11. This connectable portion 14 is provided with a rectangular connecting hole 15 in the center of the width direction (left-right direction) of the underside of the frame portion 12.

[0012] A marker 16 is disposed on at least one end face of the frame 12 in the longitudinal direction (front-rear direction) of the loading platform 11 at a position (offset position) offset by a predetermined distance to one side from the center of the width direction (left-right direction) of the coupled portion 14. The marker 16 has a pattern design that enables a camera equipped on the AGV to recognize the relative positional relationship between the AGV and the towing object 10, such as the relative distance and posture, when the AGV couples to the towing object 10. For example, a so-called AR marker can be used. The marker 16 is, for example, a sticker, and can be attached to the end face of the frame 12 to easily add recognition functionality. The marker 16 may include readable information, such as identification information, such as unique ID information for the towing object 10. Alternatively, an identification mark may be provided separately from the marker 16, displaying readable information, such as the identification information for the towing object 10.

[0013] The wheels 13 include a fixed wheel 13a located in the center of the longitudinal direction (front-to-back direction) of the loading platform 11 and free wheels 13b located on both ends. These fixed and free wheels 13a, 13b, are located on both sides of the width direction (left-to-right direction) of the loading platform 11. The fixed wheels 13a have a fixed rotational direction so that they rotate in the longitudinal direction (front-to-back direction) of the loading platform 11. The free wheels 13b are free to rotate about a vertical pivot axis relative to the loading platform 11, and their rotational direction changes freely in response to the traveling direction of the towed object 10. The towed object 10 can travel in one direction or the other in the longitudinal direction (front-to-back direction) of the loading platform 11 depending on the rotational direction of the fixed wheels 13a on both sides, and can turn around the center of the loading platform 11 or the center of one of the fixed wheels 13a.

[0014] Next, an automatic guided vehicle 20 is shown in FIGS.

[0015] The unmanned transport vehicle 20 is a vehicle that autonomously travels on a traveling surface such as a floor, moves to the origin where the towed object 10 is placed, automatically connects to the towed object 10 to be transported, and tows the towed object 10 to transport it to the destination.

[0016] The unmanned transport vehicle 20 comprises a transport vehicle body 21, a swivel shaft 22 arranged on the transport vehicle body 21, an arm mechanism 25 having an arm 23 rotatably attached to the swivel shaft 22 and a brake device 24 which is a holding device that brakes and holds the arm 23 in any rotation position, a connection mechanism 26 arranged on the arm 23 to the towed object 10, a positioning and holding mechanism 27 that positions and holds the arm 23 at a fixed position relative to the transport vehicle body 21, a camera 28 that recognizes the marker 16 on the towed object 10, etc.

[0017] The transport vehicle body 21 is configured by attaching a cover 30 to the outside of a main body frame that forms the skeleton. At the bottom of the transport vehicle body 21, drive wheels 31 and driven wheels 32 in front and behind the drive wheels 31 are arranged on both left and right sides that intersect with the traveling direction (forward direction) A.

[0018] The drive wheels 31 on both sides are rotatable in the forward and backward directions of the transport vehicle body 21, and are rotated and driven individually by individual drive motors, and the drive unit is made up of the drive wheels 31 on both sides and the motor drives connected thereto. Depending on the combination of the rotation direction and rotation speed of the drive wheels 31 on both sides, the transport vehicle body 21 can travel and move in various ways, such as moving forward in the forward direction A, moving backward in the reverse direction opposite to the forward direction A, curving in both the forward and reverse directions, and spinning by changing the direction of the forward direction A at a certain position.

[0019] The driven wheels 32 can freely rotate around a vertical axis relative to the transport vehicle body 21, and the direction of rotation can freely change in accordance with the travel and movement of the transport vehicle body 21, such as forward, backward, curves, and spins.

[0020] A turning space 33 is formed at the rear side of the transport vehicle body 21 opposite to the traveling direction A, and the turning shaft 22 is rotatably supported by a bearing 34 disposed on the lower side of the turning space 33 and a bearing 35 disposed on the upper side. The lower bearing 34 is attached to the main body frame, and the upper bearing 35 is attached to a support frame 36 fixed to the main body frame and disposed above the turning space 33.

[0021] Furthermore, the rotating shaft 22 is supported by upper and lower bearings 34, 35 so as to be rotatable about a vertical central axis that intersects with the traveling direction A of the transport vehicle body 21. An arm 23 is fixed to the rotating shaft 22, and the rotating shaft 22 and the arm 23 rotate together.

[0022] One fixed end of arm 23 is fixed to pivot shaft 22, and the other pivot end is disposed in pivot space 33 on transport vehicle body 21 so as to be pivotable about pivot shaft 22. Arm 23 is pivotable within a range of at least 90° to the left and right from a center line along the front-to-rear direction of transport vehicle body 21. The pivot position of arm 23 is detected by an encoder provided on arm 23. The encoder sets the position where arm 23 is disposed on the center line along the front-to-rear direction of transport vehicle body 21 as its origin (0 degrees). The center line along the front-to-rear direction of transport vehicle body 21 is a line that runs in the straight forward and backward direction of the vehicle body and passes through the center positions of drive wheels 31 on both sides (which is also the spin center when automatic transport vehicle 20 spins on the spot).

[0023] The brake device 24 is installed on the support frame 36 and applies a brake to the rotating shaft 22 to hold the arm 23 in any rotational position relative to the transport vehicle body 21. The brake device 24 is, for example, an electromagnetic brake that applies the brake when de-energized and releases the brake when energized, or that applies the brake when energized and releases the brake when de-energized. The electromagnetic brake can limit the rotation of the shaft by generating a mechanical rotational resistance force using, for example, an electromagnetic force generated by energizing a coil. The brake device 24 may also be an electric brake that applies and releases the brake by driving a motor, and the relationship between the application / inactivation of the brake and the energization / cutoff (energized / de-energized) can be selected as desired.

[0024] The holding force of the brake device 24 is within a range that restricts movement of the arm 23 in the pivoting direction due to its own weight or the like. Furthermore, the holding force of the brake device 24 may be within a range that allows the arm 23 to move in the pivoting direction when an external force greater than the action of its own weight or the like is applied to the arm 23. In other words, the holding force of the brake device 24 can be set so that the arm 23 is held with a holding force that allows the arm 23 to pivot when a load of a predetermined level or more is applied to the insert body 39 during the connecting movement of the insert body 39 by the connecting mechanism 26, and the value of the holding torque, which is the holding force, can also be set to any value, such as a value that corresponds to the towed object 10, for example.

[0025] The connecting mechanism 26 is disposed on the tip side of the arm 23. The connecting mechanism 26 includes an insert 39 connected to the towed object 10, a connecting part 40 on which the insert 39 is disposed and which is supported on the tip side of the arm 23 so as to be movable up and down, an elevating mechanism 41 which raises and lowers the connecting part 40 relative to the arm 23, and a connecting part driving part 42 which drives the elevating mechanism 41 to raise and lower the connecting part 40 (insertion 39).

[0026] The connecting part 40 has a support part 43, which is a vertically movable lift supported on the arm 23, and a protruding part 44, which protrudes from the lower end of the support part 43 toward the rear of the transport vehicle main body 21 and is a connecting device support body that supports the connecting device. An insert 39, which is inserted into the connecting hole 15 of the frame 12 of the towed object 10, is protruded from the upper surface of the protruding part 44 as a connecting device, and guide rollers 45, 46, which are located at the front and rear of the frame 12 and maintain the connected state, are arranged at the front and rear of the insert 39.

[0027] The insert 39 has a rear end connected to the protruding portion 44 and a front end protruding upward in a direction away from the protruding portion 44. The insert 39 has a tapered end portion that is the front end, and a body portion that is continuous with the rear end of the front end and extends toward the rear end. The front end is tapered in a generally triangular shape (or may be generally trapezoidal), with the center in the left-right direction protruding upward and both sides being inclined downward, and the body portion is generally rectangular (see FIG. 6). Note that the shape of the insert 39 may be, for example, a generally conical tapered shape and a generally cylindrical body portion, as long as the tip of the front end is thinner than the body portion.

[0028] The lowered position of the connecting part 40 is a disconnected position where the insert 39 on the protrusion 44 and the guide rollers 45, 46 can move forward and backward relative to the underside of the frame 12 of the towed object 10, and the raised position of the connecting part 40 is a connected position where the insert 39 on the protrusion 44 is inserted into the connecting hole 15 of the frame 12 of the towed object 10 and connected, and the guide rollers 45, 46 are positioned in front of and behind the frame 12. In the connected position, the connecting part 40 can rotate integrally with the arm 23 and rotate around the outer periphery of the transport vehicle body 21 without contacting the transport vehicle body 21.

[0029] The lifting mechanism 41 is a mechanism that raises and lowers the connecting part 40 using the driving force of the connecting part drive part 42. The lifting mechanism 41 is, for example, a cam mechanism composed of a cylindrical cam and a cam follower, and a motor serving as the connecting part drive part 42 is connected to the cylindrical cam via a belt, and the rotational drive of the motor is transmitted to the cylindrical cam, causing the cylindrical cam to rotate, thereby raising or lowering the cam follower that contacts the cam surface on the upper surface of the cylindrical cam. Then, because this cam follower is installed on the support part 43 of the connecting part 40, the connecting part 40 rises and lowers in accordance with the rise and fall of the cam follower.

[0030] Furthermore, the positioning and holding mechanism 27 is disposed between the support portion 43 of the connecting portion 40 and the rear portion of the transport vehicle body 21, and includes a positioning roller (positioning cam follower) 47, which is a positioning member disposed on the support portion 43 of the connecting portion 40, and a guide member 48 installed on the rear side of the transport vehicle body 21. The guide member 48 positions and holds the arm 23 and the connecting portion 40 on the center line along the front-to-rear direction of the transport vehicle body 21 when the connecting portion 40 is lowered to the disconnection position.

[0031] Furthermore, the camera 28 is fixedly attached to a cover (not shown) of the coupling mechanism 26. When the automated guided vehicle 20 approaches and couples with the towed object 10, the camera 28 photographs the marker 16 of the towed object 10, and the positional relationship between the automated guided vehicle 20 and the towed object 10, such as the relative distance and posture, is recognized. Based on this recognition, the movement of the automated guided vehicle 20 can be controlled, enabling stable coupling with the towed object 10.

[0032] Next, FIG. 4 shows a front view of the positioning and holding mechanism 27.

[0033] The positioning roller 47 is provided so as to be rotatable around an axis perpendicular to the front surface of the support portion 43 of the connecting portion 40. In other words, the positioning roller 47 is supported so as to be rotatable around an axis perpendicular to the ascending and descending direction of the support portion 43 of the connecting portion 40.

[0034] The guide member 48 is installed on the rear upper surface of the main frame of the transport vehicle body 21. The upper surface of the guide member 48 is provided with a guide groove 51 that is recessed toward the groove center, which is the tip of the groove, in accordance with the rotation direction of the arm 23. The guide groove 51 has inclined surfaces 52 on both sides that slope downward toward the groove center, and a groove recess 53 into which the positioning roller 47 fits is provided in the groove center between the inclined surfaces 52 on both sides. In other words, the inclined surfaces 52 on both sides form a tapered shape toward the groove recess 53 at the groove center into which the positioning roller 47 fits. The groove recess 53, which is the lowest part of the guide groove 51, is located on the center line along the front-rear direction of the transport vehicle body 21. When the positioning roller 47 is fitted in the groove recess 53 of the guide groove 51, the encoder that detects the angle of the arm 23 indicates the origin (0 degrees). Specifically, when the positioning roller 47 is fitted in the groove recess 53, the axial direction of the rotation axis of the positioning roller 47 becomes parallel to the center line of the transport vehicle body 21.

[0035] When the connecting portion 40 is raised to the connected position, the positioning roller 47 is positioned above the guide member 48, allowing the arm 23 to pivot. When the connecting portion 40 is lowered toward the disconnected position with the positioning roller 47 positioned above the guide member 48, the positioning roller 47 enters the guide groove 51 of the guide member 48 and fits into the groove recess 53 at the center of the groove, thereby restricting unnecessary pivoting or swinging of the arm 23. At this time, even if there is some variation in the pivot position of the arm 23, as long as the positioning roller 47 enters the guide groove 51, the descending positioning roller 47 is guided by the inclined surface 52 and led to the groove recess 53 at the center of the groove, and the pivot position of the arm 23 is positioned on the center line along the front-to-rear direction of the transport vehicle body 21.

[0036] Next, FIG. 5 shows a block diagram of a transport system using an automatic guided vehicle 20.

[0037] The transport system includes an automated guided vehicle (20) and a host terminal (60), and transports a towed object (10) having a coupled part (14), a marker (16), etc. from a source to a destination.

[0038] The automated guided vehicle 20 includes a drive wheel 31, a driven wheel 32, a sensor 61, an operation unit 62, an arm mechanism 25, a connecting mechanism 26, and a control device 63. The drive wheel 31 includes a wheel 64 and a drive motor 65 that drives the wheel 64. The sensor 61 includes a camera 28 and a sensor that detects obstacles. The operation unit 62 is provided on the top surface of the vehicle body 21, for example, and includes various operation buttons including a stop button. The arm mechanism 25 includes an arm 23 and a brake device 24, etc. The connecting mechanism 26 includes an insert 39 and a connecting unit drive unit 42, etc.

[0039] The control device 63 controls the automated guided vehicle 20 and includes a drive control unit 67, a coupling control unit 68, a brake control unit 69, a sensor processing unit 70, a memory unit 71, and a communication unit 72. The drive control unit 67 controls the travel and movement of the automated guided vehicle 20, including forward, backward, straight, curved, and spinning. The coupling control unit 68 controls the coupling drive unit 42, raising and lowering the insertion body 39 together with the coupling unit 40. The brake control unit 69 controls the on / off of the electromagnetic brake of the braking device 24, switching the brake on the arm 23 between an applied and released state. The sensor processing unit 70 processes signals from the camera 28 and other sensors. The memory unit 71 stores programs such as an operation program for the automated guided vehicle 20 and an image processing program for processing images captured by the camera 28. The memory unit 71 also stores the details and status of the work performed by the automated guided vehicle 20. The communication unit 72 includes a wireless communication device for communicating with the higher-level terminal 60 and other external devices, enabling connection to I / O devices.

[0040] The upper terminal 60 manages data such as a map of the floor where the automatic guided vehicle 20 performs work, and the operating status of the automatic guided vehicle 20 and the equipment.

[0041] Next, the operation of the automatic guided vehicle 20 will be described.

[0042] 2 shows the state of the automated guided vehicle 20 before it is coupled to the towed object 10, and the state after it has been released from the towed object 10. In this state, the coupling part 40 is lowered to the coupling-disconnection position, and the insert 39 of the coupling part 40 is positioned lower than the frame part 12 of the towed object 10. Furthermore, with the coupling part 40 lowered to the coupling-disconnection position, the positioning roller 47 of the positioning and holding mechanism 27 fits into the groove recess 53 at the center of the guide groove 51 of the guide member 48, and the arm 23 is held on the center line of the vehicle body 21 along the front-rear direction.

[0043] Then, the AGV 20 moves to a position facing the frame 12 on the coupled part 14 side of the towed object 10 at the location from which the towed object 10 is to be transported, with the rear side of the AGV 20 facing the towed object 10. As a result, the marker 16 of the towed object 10 comes within the field of view of the camera 28, and the camera 28 recognizes the marker 16, thereby estimating the relative positional relationship between the AGV 20 and the towed object 10.

[0044] The automated guided vehicle 20 moves back so as to approach the towed object 10 while correcting its moving position and direction based on its positional relationship with the towed object 10. As the automated guided vehicle 20 moves back, the insert 39 of the coupling part 40 and the like enter below the frame 12 of the towed object 10, and the automated guided vehicle 20 stops at a predetermined stopping position based on its positional relationship with the towed object 10. The stopping position is a position where the insert 39 of the coupling part 40 moves up to enter the coupling hole 15 of the frame 12 of the towed object 10, enabling connection.

[0045] The stopped automated guided vehicle 20 raises the coupling part 40 to the coupled position. When the coupling part 40 is raised, the front and rear guide rollers 45, 46 move upward in front of and behind the frame part 12 of the towed object 10. At this time, the front and rear guide rollers 45, 46 come into contact with the front and rear lower ends of the frame part 12 and rotate while rising so as to sandwich the frame part 12 from the front and rear. Therefore, even if there is some misalignment in the front-to-rear direction between the front and rear guide rollers 45, 46 and the front-to-rear position of the frame part 12, the coupling part 40 can move upward.

[0046] When the connecting part 40 is raised, the front and rear guide rollers 45, 46 move upward in the front and rear of the frame part 12, thereby positioning the inserting body 39 and the connecting hole 15 of the frame part 12 in the front-rear direction. Furthermore, when the automatic guided vehicle 20 moves backward to be connected, the left-right positions of the connecting part 40 of the automatic guided vehicle 20 and the connected part 14 of the towed object 10 are adjusted based on the recognition of the markers 16 by the camera 28. Therefore, even if there is some deviation in the left-right positions of the inserting body 39 and the connecting hole 15 of the frame part 12, at least the tip (top) of the approximately triangular shape of the inserting body 39 is positioned in a left-right position that can enter the connecting hole 15 of the frame part 12.

[0047] 6(a) to 6(c) show the operation of connecting the insertion body 39 to the connecting hole 15 when the left-right positions of the insertion body 39 and the connecting hole 15 are approximately aligned. The connecting unit control unit 68 operates the connecting unit drive unit 42 to raise the insertion body 39, and the brake control unit 69 controls the locking and releasing operations of the brake device 24.

[0048] As shown in Figure 6(a), the insertion body 39 rises from the starting position toward the connecting hole 15. Note that, since the brake device 24 applies a brake to the arm 23, even if the positioning roller 47, which rises together with the insertion body 39, moves upward away from the guide member 48 and the holding of the arm 23 by the positioning holding mechanism 27 is released, the arm 23 is prevented from moving in the rotation direction due to its own weight including the connecting portion 40.

[0049] As shown in Figure 6(b), when the tip of the ascending insertion body 39 reaches an intermediate position where it has entered the connecting hole 15, the brake applied by the brake device 24 to the arm 23 is released. At this stage, by releasing the brake, the insertion body 39 will not come off the connecting hole 15 even if the arm 23 moves in the rotation direction.

[0050] As shown in FIG. 6(c), when the insert 39 fits into the connecting hole 15 and reaches the completed position where it has risen to the connecting position, the rise of the connecting part 40 is stopped and the insert 39 is connected to the towed object 10.

[0051] 6(a) to 6(b) is referred to as the first connecting operation, and the operation from the state where the insert 39 is partially inserted to the completion of the connection, as shown in FIG. 6(b) to 6(c), is referred to as the second connecting operation. Furthermore, the raising operation of the connecting part 40 may be maintained from FIG. 6(a) to FIG. 6(c), or the raising operation of the connecting part 40 may be temporarily stopped at an intermediate position.

[0052] 6(d) to (f) show the connecting operation of the insert 39 to the connecting hole 15 when the tip of the insert 39 faces the connecting hole 15 but the left-right positions of the insert 39 and the connecting hole 15 are misaligned.

[0053] 6(d), when the insert 39 rises, the brake device 24 applies a brake to the arm 23, so even if the positioning roller 47, which rises together with the insert 39, moves upward away from the guide member 48 and the positioning holding mechanism 27 releases the arm 23, the arm 23 is prevented from moving in the rotation direction due to its own weight including the connecting portion 40. Therefore, the insert 39 continues to rise toward the connecting hole 15.

[0054] In FIG. 6(e), if the insert 39 rises while the brake is applied to the arm 23 and the inclined surface of the insert 39 abuts against the edge of the connecting hole 15, if the holding force of the brake device 24 is strong, there is a risk that the towed object 10 will be pushed out to the left or right, or that the towed object 10 will be pushed up while in abutting state.

[0055] Therefore, when the tip of the rising insert 39 enters the connecting hole 15, the brake applied by the brake device 24 to the arm 23 is released. At this stage, even if the arm 23 moves in the pivoting direction due to the release of the brake, the insert 39 will not come out of the connecting hole 15. Then, when the inclined surface of the insert 39 abuts against the edge of the connecting hole 15, the arm 23 moves in the pivoting direction, and the insert 39 enters the connecting hole 15 while the angle of the arm 23 is finely adjusted.

[0056] In addition, if the brake holding force of the brake device 24 is weak enough to limit the movement of the arm 23 in the rotation direction due to its own weight or the like, and the mass of the towed object 10 is large, even if the brake is left applied to the arm 23, the arm 23 will move in the rotation direction against the brake, and the insertion body 39 will be able to enter the connecting hole 15. Depending on the mass of the towed object 10, a control mode that releases the brake on the arm 23 and a control mode that leaves the brake applied may be used selectively.

[0057] As shown in FIG. 6( f ), the insert 39 fits into the connecting hole 15 and rises to the connecting position, whereby the rising of the connecting part 40 is stopped and the insert 39 is connected to the towed object 10 .

[0058] Then, the automatic guided vehicle 20 coupled with the towed object 10 moves forward, towing the towed object 10 and moving to the destination.

[0059] After the automated guided vehicle 20 has transported the towed object 10 to the destination and stopped, the automatic guided vehicle 20 lowers the coupling portion 40 to the coupling release position and releases the coupling with the towed object 10.

[0060] When the connecting part 40 descends, the front and rear guide rollers 45, 46 smoothly descend while rotating relative to the frame part 12, disengage from the frame part 12 and release the connection, and the insert 39 descends and disengages from the connecting hole 15 of the frame part 12. In addition, the positioning roller 47, which descends together with the insert 39, fits into a groove recess 53 at the center of the guide groove 51 of the guide member 48, and the arm 23 is held on the center line along the front-rear direction of the transport vehicle body 21. At this time, the positioning roller 47 may have descended into the guide groove 51 of the guide member 48 before the descending insert 39 disengages from the connecting hole 15.

[0061] 7(a) to 7(c) show the positioning and holding operation, which is the operation of returning the positioning and holding mechanism 27 to the origin when the left-right positions of the positioning roller 47 and the center of the groove of the guide member 48 are approximately aligned. Note that the connecting unit control unit 68 operates the connecting unit drive unit 42 to lower the positioning roller 47, and the brake control unit 69 controls the locking and releasing operation of the brake device 24.

[0062] As shown in FIG. 7(a), when the insert 39 descends, the brake device 24 applies a brake to the arm 23, so the positioning roller 47 descends from the starting position toward the center of the groove of the guide member 48.

[0063] 7(b), when the lower side of the descending positioning roller 47 reaches an intermediate position where it has entered the guide groove 51 of the guide member 48, the brake applied by the brake device 24 to the arm 23 is released. At this stage, by releasing the brake, even if the arm 23 moves in the rotation direction, the inclined surface 52 acts as a stopper, so that the positioning roller 47 will not come out of the guide groove 51 of the guide member 48.

[0064] As shown in Figure 7(c), the descending positioning roller 47 fits into the groove recess 53 in the center of the guide groove 51 of the guide member 48, and the arm 23 is held in its completed position on the center line along the fore-and-aft direction of the transport vehicle body 21.

[0065] 7(a) to 7(b) is referred to as a first return operation, and the operation from the state in which the positioning roller 47 is partially inserted to the completion of positioning in FIG. 7(b) to 7(c) is referred to as a second return operation. Furthermore, the downward movement of the connecting part 40 may be maintained from FIG. 7(a) to FIG. 7(c), or the downward movement of the connecting part 40 may be temporarily stopped at an intermediate position.

[0066] 7(d) to (f) show the positioning and holding operation of the positioning and holding mechanism 27 when the position of the positioning roller 47 and the center of the groove of the guide member 48 are misaligned in the left-right direction.

[0067] As shown in Figure 7(d), when the insert 39 descends, the brake device 24 applies a brake to the arm 23, so the positioning roller 47 descends toward the position of the guide groove 51, which is slightly shifted from the center of the groove of the guide member 48.

[0068] In Figure 7(e), when the positioning roller 47 descends while the brake is applied to the arm 23, enters the guide groove 51 of the guide member 48 and abuts against the inclined surface 52, if the holding force of the brake device 24 is strong, the descent of the positioning roller 47 will stop, but the drive of the connection part drive part 42 will continue to be driven in order to lower the insertion body 39 to the disconnection position, which may place unnecessary loads on various parts such as the lifting mechanism 41 and the brake device 24.

[0069] Therefore, when the lower side of the descending positioning roller 47 enters the guide groove 51 of the guide member 48, the brake applied by the brake device 24 to the arm 23 is released. At this stage, by releasing the brake, even if the arm 23 moves in the pivoting direction, the positioning roller 47 will not come out of the guide groove 51 of the guide member 48. Then, when the positioning roller 47 abuts against the inclined surface 52 within the guide groove 51 of the guide member 48, the positioning roller 47 rotates in the downward inclination direction of the inclined surface 52, and the arm 23 follows and moves in the pivoting direction, preventing unnecessary loads from being applied to various parts.

[0070] As shown in FIG. 7(f), the descending positioning roller 47 fits into the groove recess 53 at the center of the guide groove 51 of the guide member 48, and the arm 23 is held on the center line of the transport vehicle body 21 along the front-rear direction.

[0071] Then, after the automatic guided vehicle 20 is released from the towed object 10, it moves forward and moves away from the towed object 10.

[0072] 8, an operation will be described when the towing object 10 connected to the automatic guided vehicle 20 is turned at a fixed position by a predetermined angle to change the towing direction.

[0073] Figures 8(a) to (c) show the operation when the towing object 10 is turned, for example, 90°, with the turning center O of the towing object 10 as the center of the towing object 10 (the center between the fixed wheels 13a on both sides, or the center of the loading platform 11), to change the towing direction.

[0074] As shown in Figure 8(a), when the brake device 24 is not applying the brake to the arm 23, the drive control unit 67 drives the drive motor 65 to spin the unmanned guided vehicle 20 around the turning axis 22 so that the center line of the unmanned guided vehicle 20 in the fore-and-aft direction coincides with the tangent to the arc-shaped trajectory S centered on the turning center O (the turning radius connecting the turning center O and the center of the unmanned guided vehicle 20 is perpendicular to the center line of the unmanned guided vehicle 20, and the direction of travel of the unmanned guided vehicle 20 is tangent to the arc-shaped trajectory S), thereby changing the forward direction of the unmanned guided vehicle 20.

[0075] 8(b), when the automatic guided vehicle 20 has completed its spinning motion on the spot, the brake control unit 69 activates the brake device 24 to brake the arm 23, fixing the vehicle body 21 and the towed object 10 so that they move together. Once the brake device 24 has fixed the arm 23, the drive control unit 67 drives the drive motor 65 to cause the integrated automatic guided vehicle 20 to travel along an arc-shaped path S around the turning center O of the towed object 10, thereby changing the orientation of the towed object 10 around the turning center O. Then, once the automatic guided vehicle 20 has completed traveling along the arc-shaped path S and the drive control unit 67 has stopped driving the drive motor 65, the brake control unit 69 releases the brake applied to the arm 23 by the brake device 24.

[0076] As shown in Figure 8(c), when the brake device 24 releases the arm 23 from its fixed position, the drive control unit 67 drives the drive motor 65 to spin the unmanned guided vehicle 20 around the swivel axis 22, and changes the traveling direction A of the unmanned guided vehicle 20 by 90° to correspond to the changed towing direction.

[0077] 8(d) to (f) show the operation when the towing object 10 is turned, for example, 90° to change the towing direction, with the turning center O of the towing object 10 being the fixed wheel 13a located on the inside of the turning direction of the towing object 10.

[0078] As shown in Figure 8(d), when the brake device 24 is not applying the brake to the arm 23, the drive control unit 67 drives the drive motor 65 to spin the unmanned guided vehicle 20 around the turning axis 22 so that the center line of the unmanned guided vehicle 20 in the fore-and-aft direction coincides with the tangent to the arc trajectory S centered on the turning center O (the turning radius connecting the turning center O and the center of the unmanned guided vehicle 20 is perpendicular to the center line of the unmanned guided vehicle 20), thereby changing the forward direction of the unmanned guided vehicle 20.

[0079] As shown in FIG. 8(e), the automated guided vehicle 20 travels along the arcuate path S around the turning center O of the towed object 10, changing the orientation of the towed object 10 by 90°. In this operation, first, the brake device 24 brakes the arm 23, integrating the vehicle body 21 and the towed object 10 so that they move as a single unit. Next, the integrated automated guided vehicle 20 travels along the arcuate path S around the turning center O of the towed object 10, changing the orientation of the towed object 10 around the turning center O. Then, when the automated guided vehicle 20 has completed traveling along the arcuate path S and has stopped, the brake applied to the arm 23 by the brake device 24 is released.

[0080] As shown in Figure 8(f), with the brake device 24 releasing the brake on the arm 23, the automatic guided vehicle 20 spins around the pivot axis 22, and the forward direction of the automatic guided vehicle 20 changes in accordance with the changed pulling direction.

[0081] In this way, the automated guided vehicle 20 shown in Figures 8(b) and 8(e) spins on the spot, and after the automated guided vehicle 20 has completed spinning, the brake device 24 is activated to restrain the arm 23, and the automated guided vehicle 20 is made to run along the arc-shaped track S with the arm 23 fixed.This stabilizes the rotational movement of the towed object 10 about the rotation center O compared to when the automated guided vehicle 20 runs along the arc-shaped track S while the arm 23 is still able to rotate freely, and prevents the towed object 10 from shifting position.

[0082] 9 illustrates the operation of changing the towing direction by turning the towed object 10 coupled to the automatic guided vehicle 20 by a predetermined angle at a fixed position when the towed object 10 is, for example, a four-wheeled cart. In FIG. 9, (a) to (b), (c) to (d), and (e) to (f) show the operations from the spin of the automatic guided vehicle 20 to its travel along the arcuate track S, and the operation of turning the automatic guided vehicle 20 around after traveling along the arcuate track S is the same as in FIG. 8(c) and (f), and is therefore not shown.

[0083] The cart has swivelable free wheels 13b arranged at the four corners of the bottom surface of the loading platform 11 as wheels 13, and is a towed object 10 that can be pushed or towed by an external force, similar to the cart shown in Figure 1.

[0084] 9(a) and 9(b) show a case where the towing direction is changed by turning the towed object 10, for example, by 90°, with the turning center O of the towed object 10 being the center of the towed object 10 (the center of the platform 11). In this case, even if the brakes are applied to the arm 23 while the automatic guided vehicle 20 travels along the arc trajectory S around the turning center O of the towed object 10, the towed object 10 does not turn around the turning center O because all of the towed object 10 are free wheels 13b, and the position of the towed object 10 may shift.

[0085] 9(c)-(d) or (e)-(f), the rotation center O of the towed object 10 is set to one of the two free wheels 13b located on the side where the AGV 20 turns, as in the operation shown in FIG. 8. In this case, similar to the operation shown in FIG. 8, with the brake device 24 not braking the arm 23, the AGV 20 is spun around the rotation axis 22 so that the center line of the AGV 20 in the front-to-rear direction coincides with the tangent of the arc-shaped path S about the rotation center O, thereby changing the forward direction of the AGV 20. Thereafter, when the brake device 24 is activated to brake the arm 23, the AGV 20 travels along the arc-shaped path S about the rotation center O of the towed object 10. As a result, the towed object 10 turns around one of the free wheels 13b that serves as the rotation center O, stabilizing the direction change operation of the towed object 10.

[0086] When the wheel of the cart or basket, which is the towed object 10 shown in Figures 8 and 9, is used as the center of rotation O, it is up to the driver to determine which wheel to use as the center of rotation O, but it is preferable to use the wheel located on the side on which the unmanned guided vehicle 20 turns and moves as the center of rotation O.

[0087] As described above, the automatic guided vehicle 20 can brake and hold the arm 23 at any rotation position using the brake device 24, thereby preventing problems such as displacement of the towed object 10 caused by the arm 23 moving while the automatic guided vehicle 20 is operating.

[0088] The brake device 24 applies a brake to the arm 23 when the insert 39 is moved toward the connecting hole 15, and holds the arm 23 with a holding force that allows the arm 23 to pivot when a load of a predetermined level or more is applied to the insert 39 during the connecting movement of the insert 39. This restricts the pivoting movement of the arm 23 due to its own weight or the like when the insert 39 is moved toward the connecting hole 15, allowing the insert 39 to move toward the connecting hole 15, and also allows the arm 23 to pivot when a load of a predetermined level or more is applied to the insert 39. Therefore, even if there is a positional misalignment between the insert 39 and the connecting hole 15, the insert 39 is prevented from pushing up the towed object 10, and the insert 39 is guided into the connecting hole 15.

[0089] The brake device 24 applies a brake to the arm 23 when the insert 39 is moved toward the connecting hole 15, thereby restricting the movement of the arm 23 in the pivoting direction due to its own weight or the like, and allowing the insert 39 to move toward the connecting hole 15. Furthermore, by releasing the brake applied to the arm 23 when the tip side of the insert 39 moving toward the connecting hole 15 enters the connecting hole 15, the arm 23 moves in the pivoting direction, so that even if there is some misalignment between the insert 39 and the connecting hole 15, the insert 39 can enter and be connected to the connecting hole 15.

[0090] The brake device 24 applies a brake to the arm 23 when the insertion body 39 is removed from the connecting hole 15, thereby restricting the movement of the arm 23 in the pivoting direction due to its own weight or the like, and allowing the positioning roller 47 to move toward the guide groove 51 of the guide member 48. Furthermore, the brake applied to the arm 23 is released when at least a portion of the positioning roller 47 enters the guide groove 51 of the guide member 48, so that even if there is some misalignment between the positioning roller 47 and the guide groove 51 of the guide member 48, the arm 23 moves in the pivoting direction, moving the positioning roller 47 to the center of the guide groove 51 of the guide member 48, and the arm 23 can be positioned and held along the center line of the transport vehicle body 21 in the front-rear direction.

[0091] Since the holding force (holding torque) of the brake device 24 is within a range that limits the movement of the arm 23 in the pivoting direction due to its own weight or the like, the operation of connecting or disconnecting the insertion body 39 to the towed object 10 can be performed stably. Furthermore, the holding force of the brake device 24 allows the arm 23 to move in the pivoting direction when an external force greater than the action of its own weight or the like is applied to the arm 23, so even if a positional misalignment occurs between the connecting hole 15 and the insert body 39 during the connecting operation, the arm 23 will pivot in response to the external force so that the insert body 39 can be inserted into the connecting hole 15, preventing the connecting portion 40 from pushing up the towed object 10 in conjunction with the connecting operation.

[0092] When the connecting mechanism 26 is connected to the towed object 10 or when the connecting mechanism 26 is disconnected from the towed object 10, the arm 23 is kept braked, and unnecessary movement of the arm 23 is restricted, and the connecting mechanism 26 can be connected to or disconnected from the towed object 10.

[0093] The brake device 24 may be configured to have a brake holding force that can be variably controlled. The holding force may be set to two levels, for example, a first torque value that is a weak torque value that prevents the arm 23 from rotating due to its own weight or the like, and a second torque value that is a strong torque greater than the first torque value, and these levels may be switched depending on the operating conditions of the automated guided vehicle 20. For example, when the automated guided vehicle 20 towing the towed object 10 turns, the brake holding force is set to the second torque value that is a strong torque so that the towed object 10 is not swung outward due to centrifugal force. When the automated guided vehicle 20 moves backward while coupled with the towed object 10, the brake holding force is set to the second torque value that is a strong torque so that the towed object 10 moves straight in the backward direction.

[0094] Furthermore, depending on the structure of the transport vehicle body 20 and the structure of the coupled portion 14 of the towed object 10, the vertical positional relationship between the insert 39 and the coupling hole 15 and the vertical positional relationship between the positioning roller 47 and the guide member 48 may be changed.

[0095] It should be noted that the unmanned transport vehicle in this case is not limited to one in which all operations such as driving and connecting operations are performed automatically, but may include one in which some operations can be performed by an operator, and may also carry passengers such as an operator or driver as the transported object.

[0096] Although the embodiment of the present invention and its modified examples have been described above, various combinations of configurations, partial omissions, substitutions and modifications are also possible. [Explanation of symbols]

[0097] 10 Traction 13 wheels 20 Automated Guided Vehicle 21 Transport vehicle body 22 Swivel axis 23 Arm 24 Brake device as a holding device 26 Connection mechanism 27 Positioning and holding mechanism 31 Drive wheels 39 Insert 47 Positioning roller as a positioning member 48 Guide member 51 Guide groove

Claims

1. An automated guided vehicle that pulls a towing object, a transport vehicle body having drive wheels; a vertical rotation axis provided on the transport vehicle body and intersecting with the traveling direction of the transport vehicle body; an arm provided so as to be rotatable about the pivot axis; a coupling mechanism provided on the arm and coupled to the towed object; a holding device that holds the arm at an arbitrary rotation position relative to the transport vehicle body; An unmanned transport vehicle comprising:

2. The coupling mechanism has an insert that enters a coupling hole provided in the towed object to couple with the towed object, The holding device holds the arm with a holding force that allows the arm to rotate when a load equal to or greater than a predetermined value is applied to the insert when the connecting mechanism operates to connect and move the insert toward the connecting hole.

2. The automated guided vehicle according to claim 1.

3. The coupling mechanism has an insert that enters a coupling hole provided in the towed object to couple with the towed object, When the connecting mechanism operates to move the inserter toward the connecting hole, the holding device holds the arm until the tip side of the inserter moving toward the connecting hole enters the connecting hole of the towing object at an intermediate position, and releases the holding of the arm when the inserter moves further in from the intermediate position.

2. The automated guided vehicle according to claim 1.

4. a positioning and holding mechanism that includes a positioning member provided on one of the transport vehicle body and the connecting mechanism, and a guide member provided on the other, the guide member having a guide groove inclined toward a tip end of the groove, and that positions and holds the pivot position of the arm relative to the transport vehicle body by fitting the positioning member into the guide groove of the guide member; When the connecting mechanism operates to move the positioning member to the tip of the groove, the holding device holds the arm up to an intermediate position where at least a part of the positioning member enters the guide groove, and releases the holding of the arm when the positioning member moves from the intermediate position toward the tip of the groove.

2. The automated guided vehicle according to claim 1.

5. The holding force of the holding device is within a range that limits the arm from moving in the pivoting direction under its own weight.

5. An automated guided vehicle according to claim 1.

6. When the towing object connected to the transport vehicle body is turned to change the towing direction, the holding device holds the arm in a state in which the transport vehicle body spins around the turning axis so that the traveling direction of the transport vehicle body faces a tangent direction of an arc centered on the turning center of the towing object, and in a state in which the arm is held, the transport vehicle body travels on an arc track centered on the turning center of the towing object.

2. The automated guided vehicle according to claim 1.

7. Among the plurality of wheels of the towed object, the wheel located on the side on which the transport vehicle body moves and turns is set as the turning center.

7. The automated guided vehicle according to claim 6.

8. The holding device has a holding force that can be variably controlled, When the connecting mechanism is connected to the towed object or when the connecting mechanism is disconnected from the towed object, the holding force of the holding device is set to a first torque value to hold the arm, and when the holding device operates to hold the arm while the connecting mechanism is connected to the towed object, the holding force of the holding device is set to a second torque value greater than the first torque value to hold the arm.

2. The automated guided vehicle according to claim 1.

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