JP7583371B2 - Picking Device - Google Patents

Description

The present invention relates to a picking device that has the ability to reliably detect abnormal situations that occur in real time when picking various items that are bulk loaded into transport containers.

As an example of this type of picking device, as described in Patent Document 1, a picking device equipped with a picking head that can move in the X-axis and Y-axis directions that are mutually perpendicular on a horizontal plane, and in the Z-axis direction that is perpendicular to the horizontal plane, is known. In a conventional picking device, for example, as described in Patent Document 1, an X-axis guide rail is installed at a height that does not interfere with a transport container set in a predetermined position, a Y-axis guide rail supported by the X-axis guide rail and capable of reciprocating in the X-axis direction, a Z-axis guide rail supported by the Y-axis guide rail and capable of reciprocating in the Y-axis direction, a Z-axis lifting column supported by the Z-axis guide rail so as to be freely raised and lowered in the Z-axis direction, and a picking head attached to the lower end of the Z-axis lifting column. In this configuration, the Z-axis lifting column and the picking head at its lower end constitute a picking hand.

In the above-mentioned picking device, when, for example, a target item is lifted from an incoming container and lowered to a predetermined position in an outgoing container, serious abnormalities such as the item falling off the picking head can occur. In addition, when the picking head is equipped with multiple suction devices, the item can tilt from the normal holding state in which it is picked up by all the suction devices, or when a packaged item is handled, the packaging can break and the item can hang down from the picking head. These abnormalities often occur when the picking head lifts an item from inside the container to a predetermined height above the container, and there is a demand for a picking device that has the function of detecting such abnormalities reliably in real time.

JP 2020-70155 A

It is clear that the desired functions of the above-mentioned picking device can be realized by using a force sensor or an acceleration sensor, but in reality, it is very difficult and impractical to attach and wire the sensor to the relatively small picking head at the end of the picking device, which enters a container in which many items are piled up loosely and picks specific items, and there is also a risk of adversely affecting the original function of the picking head. Therefore, it is possible to attach the sensor at a location away from the picking head, but in a conventional picking device such as that described in Patent Document 1, the closest thing to the picking head is the Z-axis lifting column to the bottom of which the picking head is attached, that is, the picking hand main body. However, since this picking hand main body also enters the container in which the items to be picked are stored together with the picking head, it is constructed as a column of the minimum necessary thickness, and it is desirable to avoid attaching a sensor that would cause a part of the circumferential surface of the picking hand main body to bulge if possible.

Of course, there are sensors that are relatively small, but in reality, in addition to a power supply circuit to power the sensor, a control circuit is required to compare the values of the detection signals in each of the sensor's X, Y and Z directions with preset thresholds to determine whether or not the signals are abnormal and exceed the thresholds, and to determine the type of abnormality from a database. It is possible to configure these power supply circuit and control circuit in a separate location from the sensor itself and connect them by wiring, but for a picking device that is constantly performing complex movements during operation, additional wiring can also cause breakdowns and is something that should be avoided if possible.

Therefore, it would be conceivable to attach an acceleration sensor to a component one level higher than the picking hand, i.e., the component that supports the picking hand. However, in a picking device with a conventional configuration such as that shown in Patent Document 1, the picking hand is supported by the Z-axis guide rail, and this Z-axis guide rail is a columnar body that stands vertically upward from its lower end supported by the Y-axis guide rail. Therefore, even if an acceleration sensor were attached to the upper end (free end) where vibrations are most easily detected, the total length of the vertical vibration propagation path from the picking head to be detected by the vibration detection system to the acceleration sensor on the Z-axis guide rail would be significantly different between a state in which the picking head has descended to its lowest point relative to the Z-axis guide rail, where it reaches the bottom of the container, and a state in which the picking head has ascended to its highest point, where the picking head and the item it holds are hoisted to a predetermined height above the container. Therefore, if an attempt is made to detect relatively minor abnormal conditions such as those described above using the abnormal vibration values detected by the acceleration sensor, rather than severe abnormal situations that cause large abnormal vibrations, such as when an item falls while being lifted from the picking head, it becomes necessary to automatically adjust the abnormality detection threshold value in accordance with the height of the picking head, which would make the control system complicated and difficult to implement.

The present invention proposes a picking device that can solve the above-mentioned problems of the prior art. To facilitate understanding of the relationship with the embodiments described below, the picking device of the present invention will be described with reference symbols used in the description of the embodiments in parentheses. The picking device is equipped with a picking head (17) that is movable in X-axis and Y-axis directions that are perpendicular to each other on a horizontal plane, and in a Z-axis direction that is perpendicular to the horizontal plane, and is made up of an X-axis guide rail (2) installed at a constant height parallel to the X-axis direction, a Z-axis guide rail (7) whose lower end is supported on the X-axis guide rail (2) so as to be freely movable laterally in the X-axis direction and standing in the Z-axis direction, a cantilevered Y-axis guide rail (8) whose one end is supported on the Z-axis guide rail (7) so as to be freely raised and lowered in the Z-axis direction and extends in the horizontal Y-axis direction away from the Z-axis guide rail (7), and a picking hand (9) supported on the Y-axis guide rail (8), and an acceleration sensor (47) for detecting acceleration in each of the X, Y and Z directions is attached to the Y-axis guide rail (8).
The Y-axis guide rail (8) is made of a hollow structure having a cavity (45) that is continuous in the longitudinal direction, and the acceleration sensor (47) is arranged in the cavity (45) of the Y-axis guide rail (8) .

According to the above-mentioned configuration of the present invention, the means for supporting the picking hand is not a Z-axis guide rail as in the conventional case, but a cantilevered Y-axis guide rail that moves up and down along the Z-axis guide rail. The acceleration sensor is attached to the Y-axis guide rail. According to this configuration, the length of the vibration propagation path in the vertical direction between the acceleration sensor and the picking head at the lower end of the picking hand is constant regardless of the height at which the picking head is located within the lifting area, from the lower limit position where the picking head reaches the bottom of the container to the upper limit position where the picking head reaches a predetermined height above the container together with the picked and held item. Therefore, when trying to determine a relatively minor abnormal state that occurs during the lifting of an item as described above using the vibration value detected by the acceleration sensor, it is not necessary to automatically adjust the abnormality detection threshold value corresponding to the height of the picking head as in the conventional case. In other words, even if the relatively minor abnormal state as described above is one of the various lifting abnormalities that are most likely to occur when the picking head lifts an item, the lifting abnormal state can be reliably detected by setting the abnormality detection threshold value constant in accordance with the abnormality.

In addition, when the item lifted by the picking head is to be transported into the receiving container, the picking hand lifting the item must be moved in the Y-axis and X-axis directions, and then lowered in the Z-axis direction again. Naturally, the acceleration sensor can detect various abnormalities occurring in the lifted item during these processes. Thus, when the lifted item is moved in the X-axis and Z-axis directions, the length of the vibration propagation path between the acceleration sensor and the upper end of the picking hand does not change, but when the picking hand is moved in the Y-axis direction, the length of the vibration propagation path between the acceleration sensor and the upper end of the picking hand changes. The movement range of the picking hand in the Y-axis direction can be made shorter than the movement range in the X-axis direction and the lift range in the Z-axis direction, for example, by making it the area in the short side direction of the opening of the container to be picked, which has a rectangular planar shape. Furthermore, the vibration propagation path from the top end of the picking hand to the acceleration sensor on the Y-axis guide rail is extremely short compared to the total length of the vibration propagation path from the picking head to the acceleration sensor on the Y-axis guide rail, so in practice, it is possible to detect abnormalities as expected without automatically fine-tuning the abnormality detection threshold value to correspond to the position of the picking hand in the Y-axis direction.

Furthermore, according to the configuration of the present invention, the Y-axis guide rail 8 is made up of a hollow structure having a cavity 45 that continues in the length direction, and the acceleration sensor 47 is arranged in the cavity 45 of the Y-axis guide rail 8. Therefore, according to the configuration of the present invention, the acceleration sensor and its associated circuits are protected, and failures due to unexpected contact with other objects can be prevented.

When implementing the present invention, it is desirable to mount the acceleration sensor (47) in the center of the picking hand movement area on the Y-axis guide rail (8) or within the range from the center to the free end of the Y-axis guide rail (8) opposite to the end supported by the Z-axis guide rail (7). If the acceleration sensor is mounted in the center of the picking hand movement area on the Y-axis guide rail, the length of the vibration propagation path in the Y-axis direction accompanying the movement of the picking hand in the Y-axis direction is at most half the maximum movement distance of the picking hand in the Y-axis direction, reducing the amount of fluctuation in the vibration propagation path from the picking head to the acceleration sensor on the Y-axis guide rail, thereby improving the accuracy of abnormality detection. Of course, the acceleration sensor can also be mounted on the free end side of the Y-axis guide rail in the picking hand movement area on the Y-axis guide rail. In this case, the amount of fluctuation in the vibration propagation path from the picking head to the acceleration sensor on the Y-axis guide rail increases slightly, but on the other hand, the vibration is easier to detect as it approaches the free end side of the cantilevered Y-axis guide rail, so that the accuracy of abnormality detection can be improved in this respect.

Furthermore, the Y-axis guide rail (8) is provided, on the side opposite to the side where the picking hand (9) is located, with an opening (46) that is horizontally elongated along the length of the Y-axis guide rail (8) and communicates with the hollow portion (45), and a dovetail groove (55) for mounting a component that is continuous in the length direction of the Y-axis guide rail (8) below the opening (46). The board support base (36) that enters the hollow portion (45) via the opening (46) is provided with an attachment plate portion (42) that is connected downward outside the opening (46), and this attachment The plate portion (42) is attached to a female threaded body (56) that fits into the component mounting dovetail groove (55) with a mounting screw (57), and an acceleration sensor mounting board (37) that is equipped with the acceleration sensor (47) and has a length shorter than the overall length of the Y-axis guide rail (8) of the opening (46) in the longitudinal direction is supported on the board support base (36), and the acceleration sensor mounting board (37) can be configured to be pulled out of the hollow portion (45) together with the board support base (36) by removing the mounting screw (57). Basically, it is possible to attach the acceleration sensor mounting board directly to the inner wall surface of the hollow portion of the Y-axis guide rail, but with the above configuration, the acceleration sensor mounting board is supported by the board support stand, and this board support stand is inserted into the hollow portion through the opening of the Y-axis guide rail together with the acceleration sensor mounting board, and the mounting plate portion is fixed to the Y-axis guide rail by the female thread that fits into the dovetail groove for mounting the component, and the mounting screw, outside the Y-axis guide rail, making the work easy and also making it easy to remove the acceleration sensor mounting board for maintenance.

The board support base (36) and the acceleration sensor mounting board (37) supported thereon can also be configured to protrude outward from the opening (46). If the acceleration sensor mounting board is narrowed and configured to have an elongated shape, it is possible to install the acceleration sensor mounting board inside the cavity in the Y-axis guide rail even if the inner width of the cavity is narrow, but the opening for inserting and removing the board support base supporting the acceleration sensor mounting board into and from the cavity also becomes longer, which may reduce the strength of the Y-shaped guide rail. In addition, if the acceleration sensor mounting board becomes elongated, it becomes difficult to arrange various electrical components and form wiring necessary for forming a control circuit required for the acceleration sensor installed on this board. However, if it is acceptable for the board support base and the acceleration sensor mounting board supported thereon to protrude outward from the opening as described above, it becomes possible to provide a width that is convenient for arranging electrical components and forming wiring. In addition, when the board support stand and the acceleration sensor mounting board supported on it are inserted or removed from the hollow portion of the Y-axis guide rail through the opening, the work can be performed while holding the part that protrudes outward from the opening, making the work easy to perform.

In addition, the substrate support base (36) can be provided with support plate portions (43, 44) that hang down outside the opening (46) on both sides of the mounting plate portion (42), and the lower sides of the pair of support plate portions (43, 44) can be provided with inwardly bent plate portions (43a, 44a) that are supported by the lower side (55a) of the member mounting dovetail groove (55). With this configuration, even if the mounting plate portion that is screwed to the Y-axis guide rail side is attached with a single screw, the substrate support base can be reliably and easily attached in a direction parallel to the Y-axis guide rail, and workability is significantly improved compared to when multiple screws are required for attachment.

It is desirable to detachably attach a cover (39) that covers the opening (46) to the side of the Y-axis guide rail (8) that has the opening (46) in order to protect the acceleration sensor mounting board from dust and other particles. In particular, when the board support stand and the acceleration sensor mounting board supported on it are configured to protrude outward from the opening as described above, the cover must also be formed in an outwardly protruding shape, but this can prevent malfunctions caused by other objects accidentally coming into contact with the protruding acceleration sensor mounting board, etc.

FIG. 1 is a front view of the entire picking device. FIG. 2 is a plan view of the same. FIG. 3 is a right side view of the same. FIG. 4 is a right side view showing the details of the picking hand supported by the Y-axis guide rail. FIG. 5 is a partial vertical sectional front view showing a support structure for the Y-axis guide rail relative to the Z-axis guide rail. FIG. 6 is a left side view of the essential parts, showing the state in which the acceleration sensor unit is attached to the Y-axis guide rail with the cover removed. FIG. 7 is a cross-sectional plan view of FIG. 6 with some parts omitted. FIG. 8 is an enlarged longitudinal front view of the position of the substrate support mounting screws in FIG. 9 is an enlarged longitudinal sectional front view of the essential parts at a position in front of the substrate support table in FIG. FIG. 10 is a perspective view showing a substrate support stand of the acceleration sensor unit of FIG.

A preferred embodiment of a picking device to which the configuration of the present invention can be applied will be described below with reference to the attached drawings. In Figs. 1 to 3, 1A is a transport container that is the object of the item removal operation, and 1B is a transport container that is the object of the item loading operation to receive the removed items. Each of these transport containers 1A, 1B has a rectangular shape in plan view, and is set in a fixed work position in a line state with their short sides adjacent to each other. Although not shown in the drawings, each transport container 1A, 1B is handled by a loading/unloading conveyor for the fixed work positions PA, PB.

The picking device according to the present invention is disposed so as to include the fixed work positions PA, PB of each transport container 1A, 1B, and the picking device is configured as follows, with the serial direction of the fixed work positions PA, PB on a horizontal plane, i.e., the long side direction of each transport container 1A, 1B, being the X-axis direction, the direction perpendicular to the X-axis direction on the horizontal plane, i.e., the short side direction of each transport container 1A, 1B, being the Y-axis direction, and the vertical direction perpendicular to the horizontal plane being the Z-axis direction. An X-axis guide rail 2 is supported by a stand 3 at a height an appropriate distance above the upper end of the transport container 1A, 1B at the fixed work positions PA, PB, parallel to the X-axis direction, so that the X-axis direction surrounding the fixed work positions PA, PB overlaps with one long side of a long rectangle in a plan view. The stand 3 supports both ends and the middle position of the X-axis guide rail 2, and is a framework structure assembled from upper beams 4a-4c and lower beams 5a-5c that are parallel to the Y-axis direction, and a required number of columns 6.

The lower end of the Z-axis guide rail 7 standing in the Z direction is supported on the X-axis guide rail 2 so that it can move back and forth in the X-axis direction. One end of the Y-axis guide rail 8 parallel to the Y-axis direction is supported on the Z-axis guide rail 7 so that it can move up and down in the Z-axis direction. The upper end of the picking hand 9 long in the Z-axis direction is supported on the Y-axis guide rail 8 so that it can move back and forth in the Y-axis direction. The Z-axis guide rail 7 has a base 10 provided at its lower end supported on rail materials 2a and 2b provided on the X-axis guide rail 2 so that it can move back and forth in the X-axis direction. The rack gear in the X-axis direction laid on the X-axis guide rail 2 engages with a pinion gear driven in forward and reverse rotation by a motor 11 (see FIG. 3) mounted on the base 10, and the Z-axis guide rail 7 can be moved back and forth in the X-axis direction by operating the motor 11.

The Z-axis guide rail 7 has pulleys 12a and 12b supported by a Y-axis shaft at both upper and lower ends, and a motor 13 (see FIG. 3) that drives the upper pulley 12a in forward and reverse rotation is mounted, and an endless belt 14 is stretched between the upper and lower pulleys 12a and 12b. As shown in FIG. 5, a platform 15 is provided at the base end of the Y-axis guide rail 8, which is supported so as to be freely raised and lowered in the Z-axis direction by rail materials 7a and 7b laid on the Z-axis guide rail 7, and one of the left and right lifting path parts of the endless belt 14 is fixed to this platform 15. Therefore, by operating the motor 13 to rotate the endless belt 14 forward and backward, the Y-axis guide rail 8 can be raised and lowered in the Z-axis direction. The picking hand 9 is a columnar body that is long in the Z-axis direction, and a platform 16 supported by the Y-axis guide rail 8 is attached to its upper end, and a picking head 17 is attached to its lower end.

As shown in Figures 4 and 5, the picking hand base 16 is supported by rail materials 8a, 8b laid on both the upper and lower sides of the Y-axis guide rail 8 so that it can move back and forth in the Y-axis direction. It is equipped with a pinion gear 19 that engages with a rack gear 18 laid on the front side of the Y-axis guide rail 8, and a motor 20 that stands in the Z-axis direction and drives the pinion gear 19 to rotate forward and backward. By operating the motor 20 to rotate the pinion gear 19 forward and backward, the picking hand 9 can be moved back and forth in the Y-axis direction.

The picking hand 9 is composed of an upper end shaft 21 in the Z-axis direction at its upper end, an intermediate shaft 22 concentrically connected to the lower end of the upper end shaft 21, and a columnar main shaft 23 concentrically connected to the lower end of the intermediate shaft 22. The picking head 17 is supported at the lower end of the columnar main shaft 23 so that it can tilt freely around a horizontal support shaft 17a, and is equipped with a rotation drive means 24 that rotates the picking hand 9 and a tilt drive means 25 that tilts the picking head 17. The picking head 17 in this embodiment uses three negative pressure suction devices 34a to 34c that negatively suction the surface of an item.

The upper shaft 21 of the picking hand 9 is rotatably supported on the picking hand base 16 by a pair of upper and lower bearings 26a, 26b, and the picking hand rotation drive means 24 is composed of a motor 27 standing in the Z-axis direction and supported by the picking hand base 16 on one side of the upper shaft 21 in the Y-axis direction, a transmission pulley 28a attached to the output shaft of the motor 27, a passive pulley 28b attached to the upper shaft 21 directly below the upper bearing 26a, and an endless belt 29 stretched between both pulleys 28a, 28b, and is configured so that the picking hand 9 can be driven to rotate in both forward and reverse directions about its axis in the Z-axis direction by operating the motor 27 to rotate the endless belt 29 forward and reverse. The picking head tilt drive means 25 is composed of a drive shaft 30 that penetrates the intermediate shaft portion 22 in the horizontal direction in a direction parallel to the horizontal support shaft 17a of the picking head 17, a pair of levers 31a, 31b that are arranged to sandwich the intermediate shaft portion 22 and are fixed to the drive shaft 30, two push-pull rods 32a, 32b that interlock and connect the free ends of both levers 31a, 31b to corresponding locations of the picking head 17, and a horizontal motor 33 that drives the drive shaft 30 to rotate forward and backward within a certain angle range. The pair of levers 31a, 31b extend in opposite directions from the drive shaft 30 as shown in FIG. 5, and are configured to push and pull the two push-pull rods 32a, 32b in up-down opposite directions. Therefore, the lower ends of the two push-pull rods 32a and 32b are pivotally connected to the upper side of the picking head 17 in a state where they are distributed on both the front and rear sides perpendicular to the axis of the horizontal support shaft 17a, which is the central axis of tilting of the picking head 17.

The picking device configured as described above is used to, for example, adsorb and lift a selected specific item from among bulk items (items that are adsorbed and lifted by the three negative pressure suction devices 34a to 34c of the picking head 17) in a transport container 1A that is the target of an item removal operation and is set in a predetermined orientation at the fixed work position PA shown in Figures 1 and 2, using the picking head 17 of the picking hand 9, and then transport this picked specific item to a predetermined position in a transport container 1B that is the target of an item delivery operation and is set at the adjacent fixed work position PB. In this case, when moving the picking head 17 of the picking hand 9 in the X-axis direction, the motor 11 of the Z-axis guide rail stand 10 is operated to move the Z-axis guide rail 7 along the rail materials 2a and 2b of the X-axis guide rail 2, and when moving the picking head 17 of the picking hand 9 in the Y-axis direction, the motor 20 of the picking hand stand 16 is operated to move the picking hand 9 back and forth in the Y-axis direction along the rail materials 8a and 8b of the Y-axis guide rail 8. Furthermore, when moving the picking head 17 of the picking hand 9 in the Z-axis direction, the motor 13 at the upper end of the Z-axis guide rail stand 15 is operated to move the Y-axis guide rail 8 up and down in the Z-axis direction.

The above-mentioned picking of a specific item in the transport container 1A and the operation of transporting the picked specific item to a predetermined position in the transport container 1B are generally performed with the picking head 17 in a horizontal position before tilting and in an orientation in which it is ready to rotate. However, depending on the position and orientation of the item to be picked, the tilting drive means 25 of the picking head 17 can be operated to tilt the picking head 17 around the horizontal support shaft 17a by any angle within the tilt tolerance range, or the rotation drive means 24 of the picking hand 9 can be operated to rotate the picking head 17 within a predetermined angle range.

In the above embodiment, the picking head 17 is configured with three negative pressure suction devices 34a-34c arranged at equal intervals around the rotation axis, but this is only one example. Depending on the properties, size, weight, etc. of the items to be handled, a conventional magnetic suction type or a gripping type that uses multiple open and closed fingers to grip the items can also be used.

An embodiment in which the configuration of the present invention is incorporated into the picking device described above will be described below. As shown in Figures 1, 2 and 5, an acceleration sensor unit 35 is attached near the free end of the Y-axis guide rail 8, on the side opposite the side where the picking hand 9 is located (the back side). Only the cover 39 is visible from the outside. The detailed structure of this acceleration sensor unit 35 will be described with reference to Figures 6 to 10. The acceleration sensor unit 35 is composed of a board support stand 36, an acceleration sensor mounting board 37, a power supply board 38, and a cover 39. Only the cover 39 is visible from the outside shown in Figures 1, 2 and 5. The board support base 36 has a rectangular body 40 of the same size as the rectangular acceleration sensor mounting board 37, and cuts 40a and 40b are formed at right angles from one long side at a position equidistant from both ends of the long side of the rectangular body 40. The part between the cuts 40a and 40b is bent downward at a right angle to form a vertical plate 41. Two cuts 41a and 41b are formed at right angles from the lower side to divide the vertical plate 41 into three parts in the length direction, and the central part between the cuts 41a and 41b is an attachment plate 42 with an attachment hole 42a at the center position in the width direction. The vertical plate on the outside of the cuts 41a and 41b is a support plate 43 and 44 with bent plate parts 43a and 44a bent inward at a right angle from the lower side at a certain width.

The Y-axis guide rail 8 to which the acceleration sensor unit 35 is attached is configured with multiple cavities formed by a wall plate portion of a constant thickness around the entire length, as shown in Figure 8, and the acceleration sensor unit 35 is attached to the largest and slightly vertically elongated main cavity portion 45 located in the center of the height direction of the Y-axis guide rail 8, but the width of the acceleration sensor unit 35 is slightly larger than the width of the main cavity portion 45. Therefore, a horizontally elongated opening 46 with a length and height greater than the overall length and height of the acceleration sensor unit 35 is provided in the rear wall plate portion 8c of the Y-axis guide rail 8, as shown in Figure 6.

The acceleration sensor mounting board 37 is composed of an acceleration sensor 47 installed at one end of the acceleration sensor mounting board 37 in the longitudinal direction, a control circuit 48 that processes the output signal from the acceleration sensor 47 and outputs an abnormality detection signal, and a connector 49 for connecting a LAN cable for outputting control signals installed on the other end of the acceleration sensor mounting board 37 in the longitudinal direction. The power supply board 38 is the same width as the acceleration sensor mounting board 37 but slightly less than half the length. It is composed of parts and circuits for supplying the power required by the acceleration sensor mounting board 37 to the acceleration sensor mounting board 37 side, and is supported on the upper side of the acceleration sensor mounting board 37 via a plurality of power supply board support spacers 50 arranged along both long sides of the acceleration sensor mounting board 37. These power supply board support spacers 50 can be used as a means for forming an electric path between the power supply board 38 and the acceleration sensor mounting board 37. The acceleration sensor mounting board 37 is supported parallel to the board support stand 36 at a constant height by lower mounting screws 52 that penetrate upward from the bottom into mounting holes 36a provided at the four corners of the board support stand 36 and are screwed into the lower ends of the long hexagonal nuts 51 that also serve as spacers and are located above each mounting hole 36a, and upper mounting screws 53 that penetrate downward from the top into mounting holes 37a provided at the four corners of the acceleration sensor mounting board 37 and are screwed into the upper ends of the long hexagonal nuts 51 that also serve as spacers.

The rear wall plate portion 8c of the Y-axis guide rail 8 is provided with dovetail grooves 54, 55 for mounting components that are continuous parallel to the length of the Y-axis guide rail 8 above and below the horizontally elongated opening 46. When using these dovetail grooves 54, 55 for mounting components, the components can be screwed to the rear wall plate portion 8c of the Y-axis guide rail 8 using the female threaded body 56 that is fitted into the wide groove portion 54a, 55a at the back end so as to be freely movable in the length direction, as is well known in the art. The substrate support base 36 and cover 39 of the acceleration sensor unit 35 are attached to the rear wall plate portion 8c of the Y-axis guide rail 8 using the dovetail groove 55 for mounting components and the female threaded bodies 56, 62a, 62b on the lower side of the horizontally elongated opening 46, and the mounting screws 57, 58a, 58b.

That is, as shown in Figures 6 to 9, the board support base 36 supporting the acceleration sensor mounting board 37 and the power supply board 38 is inserted into the main cavity 45 of the Y-axis guide rail 8 through the horizontal opening 46. In this case, the rectangular body 40 of the board support base 36 is slid and inserted on the lower side 46a of the horizontal opening 46, and the vertical plate portion 41 (the mounting plate portion 42 and the support plate portions 43, 44 on both sides) of the board support base 36 is abutted against the rear wall plate portion 8c of the Y-axis guide rail 8. At this time, the bent plate portions 43a, 44a of the pair of left and right support plate portions 43, 44 can be inserted into the member mounting dovetail groove 55 and supported on the lower side 55a of the member mounting dovetail groove 55, as shown in Figure 9. In this state, the board support base 36 is slid in the length direction of the Y-axis guide rail 8 to align the lengthwise center position of the board support base 36 with the lengthwise center position of the horizontally elongated opening 46, the female screw body 56 previously fitted in the member mounting dovetail groove 55 is positioned on the back side of the mounting plate portion 42 and in a position approximately concentric with the mounting hole 52a, and the fastening screw 57 is screwed into the screw hole of the female screw body 56 through the mounting hole 52a, thereby completing the mounting of the board support base 36 and the acceleration sensor mounting board 37 and power supply board 38 supported thereon to the Y-axis guide rail 8. In this mounting completed state, the parts of the board support base 36, acceleration sensor mounting board 37, and power supply board 38 that protrude outward from the vertical plate portion 41 of the board support base 36 protrude outward from the horizontally elongated opening 46.

Finally, the cover 39 is attached. This cover 39 is composed of a rectangular cover top plate 59 that is longer and taller than the horizontal opening 46, four cover peripheral side plates 60 that are bent inward from the periphery of the cover top plate 59, and mounting plate portions 61a, 61b with mounting holes that are bent downward at right angles from both ends of the lower peripheral side plate 60 in the longitudinal direction. Both mounting plate portions 61a, 61b can be attached to the member mounting dovetail groove 55 of the Y-axis guide rail 8 using the female threaded bodies 62a, 62b and fastening screws 58a, 58b that are previously fitted into the member mounting dovetail groove 55, as in the case of attaching the board support base 36. When attaching this cover 39, the center position of the length of the cover 39 is aligned with the center position of the length of the horizontal opening 46, as in the case of attaching the board support base 36. The cover 39 attached in this manner has its inner end of the cover peripheral side plate portion 60 adjacent to the rear wall plate portion 8c of the Y-axis guide rail 8 outside the horizontal opening 46, and the cover top plate portion 59 is positioned at a predetermined distance from the outside of the board support base 36, acceleration sensor mounting board 37, and power supply board 38, which protrude outward from the horizontal opening 46, so as not to interfere with these.

As described above, by attaching the acceleration sensor unit 35 near the free end of the Y-axis guide rail 8, when the picking head 17 is moved in the three X, Y and Z directions to automatically perform the picking operation of adsorbing and lifting a specific item from within the transport container 1A that is the target of the item removal operation using the negative pressure suction devices 34a-34c of the picking head 17, and the operation of transporting this lifted specific item to a predetermined location within the transport container 1B that is the target of the item delivery operation, the picking head 17 generates vibrations in the three X, Y and Z directions due to various abnormal phenomena. Various abnormal phenomena include the picking head 17 not stopping at a predetermined position when moving in the three X, Y and Z axes inside containers 1A and 1B, causing the picking head 17 to come into contact with the surrounding wall of the container; the picking head 17 coming into contact with an item that is not the target of the work; an item falling off the picking head 17 during the item lifting operation; an item falling off one or two of the three negative pressure suction devices 34a-34c of the picking head, causing the position of the item to change while being lifted; and when picking a packaged item, the packaging of the item is damaged, causing the position of the item to change while being lifted.

The vibration of the picking head 17 when these various abnormal phenomena occur is transmitted from the picking hand 9 via the Y-axis guide rail stand 15 to the Y-axis guide rail 8, and the vibration of this Y-axis guide rail 8 is detected by the acceleration sensor 47 mounted on the acceleration sensor installation board 37 of the acceleration sensor unit 35. The vibration detected by this acceleration sensor 47 is compared and calculated in the control circuit 48 with vibration data verified in advance for each abnormal phenomenon, and it is determined whether or not it should actually be regarded as an abnormal phenomenon. Depending on the result of the determination, an emergency stop is made to the entire picking device, the movement speed of the picking head 17 is slowed down, the picking head 17 is moved to a separately set abnormality processing location instead of the target container, or simply a warning of the occurrence of an abnormality (such as turning on a warning light or sounding a warning buzzer) is automatically executed.

It is desirable to transmit the vibration of the picking head 17 to the acceleration sensor 47 without attenuating it as much as possible. According to the configuration of the present invention described above, no matter where the picking head 17 is located in the maximum allowable three-dimensional movement space, the vertical distance from the picking head 17 to the Y-axis guide rail 8 holding the acceleration sensor 47, i.e., the vertical vibration propagation path length, is constant, and the vibration propagation path length changes when the picking hand 9 moves in the Y-axis direction. In the above embodiment, the vibration propagation path length in the Y-axis direction between the picking hand stand 16 at the upper end of the picking hand 9 and the acceleration sensor 47 changes only when the picking hand 9 moves in the Y-axis direction on the Y-axis guide rail 8. As already described in detail, the movement range of the picking head 17 in the Y-axis direction is the short side length in the internal space of the transport container 1A, 1B to be worked on, and is therefore smaller than the movement range in the X-axis direction and the Z-axis direction.

Considering this point, if the mounting position of the acceleration sensor unit 35 on the Y-axis guide rail 8 is the center position of the range of the movement path of the picking hand 9 in the Y-axis direction on this Y-axis guide rail 8, the maximum length of the vibration propagation path in the Y-axis direction will be half the length of the range of the movement path of the picking hand 9 in the Y-axis direction on the Y-axis guide rail 8, so the degree of attenuation of the vibration propagated to the acceleration sensor 47 while the picking head 17 moves in the Y-axis direction will be halved, making it possible to detect abnormalities with high accuracy. Of course, it is desirable to basically mount the acceleration sensor unit 35 on the free end side of the Y-axis guide rail 8, rather than the base end side where the Y-axis guide rail mount part 15 is located. In other words, since the Y-axis guide rail 8 is a cantilever structure rather than a double-support structure, the free end side has higher vibration performance than the base end side, so even subtle vibrations of the picking head 17 can be easily captured by the acceleration sensor 47.

The picking device of the present invention can be used as a suitable picking device for accurately detecting various abnormal phenomena that occur when transporting items held by the picking head and automatically taking appropriate measures.

DESCRIPTION OF SYMBOLS 1A Transport container to be used for removing goods from 1B Transport container to be used for loading goods 2 X-axis guide rail 2a, 2b Rail material 3 Frame 4a-4c Upper beam material 5a-5c Lower beam material 6 Pillar material 7 Z-axis guide rail 7a, 7b Rail material 8 Y-axis guide rail 8a, 8b Rail material 8c Back wall plate portion of Y-axis guide rail 9 Picking hand 10 Z-axis guide rail frame portion 11, 13, 18, 20, 27, 33 Motor 12a, 12b, 28a, 28b Pulley 14, 29 Endless belt 15 Y-axis guide rail frame portion 16 Picking hand frame portion 17 Picking head 17a Horizontal support shaft 19 Pinion gear 21 Upper end shaft portion 22 Intermediate shaft portion 23 Columnar main body shaft portion 24 Picking hand rotation drive means 25 Picking head tilt drive means 26a, 26b Pair of upper and lower bearings 30 Drive shaft 31a, 31b Pair of levers 32a, 32b Two push-pull rods 34a to 34c Negative pressure suction device 35 Acceleration sensor unit 36 Board support base 36a Mounting hole 37 Acceleration sensor installation board 37a Mounting hole 38 Power supply board 39 Cover 40 Rectangular main body 40a, 40b, 41a, 41b Cutout portion 41 Vertical plate portion 42 Mounting plate portion 42a Mounting hole 43, 44 Support plate portion 43a, 44a Bent plate portion 45 Main cavity portion 46 Horizontally elongated opening 46a Lower side 47 Acceleration sensor 48 Control circuit 49 Connector for connecting LAN cable for outputting control signal 50 Spacer for supporting power supply board 51 Long hexagonal nut also used as spacer 52 Lower mounting screw 53 Upper mounting screw 54, 55 Dovetail groove for mounting member 55a Lower side of dovetail groove 56, 62a, 62b Female threaded body 57, 58a, 58b Mounting screw 59 Cover top plate portion 60 Cover peripheral side plate portion 61a, 61b Mounting plate portion

Claims (6)

A picking device equipped with a picking head movable in X-axis and Y-axis directions perpendicular to each other on a horizontal plane, and in a Z-axis direction perpendicular to the horizontal plane, the picking device comprising an X-axis guide rail installed at a constant height parallel to the X-axis direction, a Z-axis guide rail whose lower end is supported by the X-axis guide rail so as to be freely movable laterally in the X-axis direction and standing in the Z-axis direction, a cantilevered Y-axis guide rail whose one end is supported by the Z-axis guide rail so as to be freely raised and lowered in the Z-axis direction and extends in the horizontal Y-axis direction away from the Z-axis guide rail, and a picking hand supported by the Y-axis guide rail, and an acceleration sensor for detecting acceleration in each of the X, Y and Z directions is attached to the Y-axis guide rail,
A picking device , wherein the Y-axis guide rail is made of a hollow structure having a cavity that is continuous in the longitudinal direction, and the acceleration sensor is disposed in the cavity of the Y-axis guide rail . The picking device according to claim 1, wherein the acceleration sensor is attached to the center of the picking hand movement area on the Y-axis guide rail, or within a range from the center to the free end of the Y-axis guide rail opposite the end supported by the Z-axis guide rail. 3. The picking device according to claim 1, wherein the Y-axis guide rail has, on a side opposite to the side where the picking hand is located, an opening that is long horizontally along the length of the Y-axis guide rail and communicates with the hollow portion, and a component mounting dovetail groove that continues in the length direction of the Y-axis guide rail below the opening, a substrate support base that enters the hollow portion via the opening is provided with a mounting plate portion that is connected downward outside the opening, and this mounting plate portion is attached to a female threaded body that fits into the component mounting dovetail groove by a mounting screw, an acceleration sensor mounting substrate that includes the acceleration sensor and has a length shorter than the entire length of the opening in the length direction of the Y-axis guide rail is supported on the substrate support base, and the acceleration sensor mounting substrate can be pulled out of the hollow portion together with the substrate support base by removing the mounting screw . 4. The picking device according to claim 3, wherein the substrate support table and the acceleration sensor mounting substrate supported thereon protrude outward from the opening . A picking device as described in claim 3 or 4, wherein the substrate support base has support plate portions attached to both sides of the mounting plate portion, hanging down outside the opening, and the lower edges of these pair of support plate portions are attached with inwardly bent plate portions supported by the lower edges of the dovetail grooves for mounting components . The picking device according to any one of claims 3 to 5, wherein a cover for closing the opening is removably attached to a side of the Y-axis guide rail that has the opening .

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