JP7645490B2 - Working device, working system and working method - Google Patents

Description

The present invention relates to a work device, a work system, and a work method for performing work on a workpiece positioned at a work position.

Conventionally, there is known a working device that transports a workpiece using a transport unit such as a belt conveyor, positions the workpiece at a working position, and performs the required work on the workpiece positioned at the working position. An example of such a working device is a component mounting device that transports and positions a circuit board as the workpiece, and mounts components on the board. In such a working device, the workpiece is positioned at the working position by starting the transport of the workpiece by the transport unit, and then stopping the operation of the transport unit when the workpiece reaches the working position (see, for example, Patent Document 1 below).

However, in a work device such as the one described above, work may be interrupted for some reason while it is being performed. If the worker picks up the workpiece during this interruption, the workpiece may shift from its original position (working position), and accurate work on the workpiece may not be possible after the work is resumed. For this reason, in conventional work devices, when work is interrupted, the transport section is made to perform a repositioning operation to reposition the workpiece at the working position before the work is resumed.

Patent No. 6617068

However, if the transport unit had to perform a repositioning operation every time an interrupted operation was resumed, it would result in lost work time if the workpiece had not moved from its work position, resulting in a corresponding decrease in the productivity of the work device.

The present invention aims to provide a work device, a work system, and a work method that can prevent time loss when resuming interrupted work and improve productivity.

The working device of the present invention includes a transport unit that transports a workpiece and positions it at a working position, a working unit that performs work on the workpiece positioned at the working position by the transport unit, a work detection means that detects the workpiece positioned by the transport unit, and a determination unit that, after work by the working unit is interrupted and before the work is resumed, determines whether the workpiece is positioned at the working position based on the detection result by the work detection means.

The work system of the present invention includes a transport unit that transports a workpiece and positions it at a work position, a work unit that performs work on the workpiece positioned at the work position by the transport unit, a work detection means that detects the workpiece positioned by the transport unit, a judgment unit that judges whether the workpiece is located at the work position based on the detection result by the work detection means after the work by the work unit is interrupted and before the work is resumed, and an operation control unit that controls the operation of the transport unit and the work unit, and when the judgment unit judges that the workpiece is not located at the work position, the operation control unit causes the transport unit to perform a repositioning operation to reposition the workpiece at the work position and then resumes the work, and when the judgment unit judges that the workpiece is located at the work position, the operation control unit causes the work unit to resume the work without causing the transport unit to perform the repositioning operation.

The working method of the present invention is a working method using a working device that includes a transport unit that transports a workpiece and positions it at a working position, a working unit that performs work on the workpiece positioned at the working position by the transport unit, and a work detection means that detects the workpiece positioned by the transport unit, and includes a determination step of determining whether the workpiece is located at the working position based on the detection result by the work detection means after the work by the working unit is interrupted and before the work is resumed, and a work resumption step of causing the working unit to resume work after the transport unit performs a repositioning operation to reposition the workpiece at the working position if it is determined in the determination step that the workpiece is located at the working position, and causing the working unit to resume work without causing the transport unit to perform the repositioning operation if it is determined in the determination step that the workpiece is located at the working position.

The present invention can prevent time loss when resuming interrupted work, thereby improving productivity.

FIG. 1 is a schematic configuration diagram of a working system according to an embodiment of the present invention; FIG. 1 is a perspective view of a main part of a component mounting device constituting a working system according to an embodiment of the present invention; FIG. 1 is a plan view of a main part of a component mounting device according to an embodiment of the present invention. FIG. 2 is a block diagram showing a control system of a component mounting device according to an embodiment of the present invention. 1A, 1B, and 1C are plan views illustrating a substrate transport operation by a transport unit included in a component mounting device according to an embodiment of the present invention. 1A, 1B, and 1C are plan views showing examples of positions of a board when a component mounting device according to an embodiment of the present invention resumes an interrupted operation. FIG. 13 is a diagram showing an example of a determination criterion table used by a determination unit included in the component mounting device according to the embodiment of the present invention. A flowchart showing the procedure for performing a component mounting operation by a component mounting device according to an embodiment of the present invention.

Below, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a work system 1 in one embodiment of the present invention. The work system 1 comprises a solder printer 1A, a component mounting device 1B, an inspection device 1C, and a host computer 1D. The solder printer 1A is a device that prints solder on a board KB, and the component mounting device 1B is a device that mounts components BH on the board KB received from the solder printer 1A. The inspection device 1C is a device that inspects the components BH on the board KB received from the component mounting device 1B, and the host computer 1D is a device that provides overall control of the devices that make up the work system 1.

The part mounting device 1B in the work system 1 is an example of a work device in this embodiment. As shown in Figures 2 and 3, the part mounting device 1B is equipped with a base 11, a transport unit 12, a parts feeder 13, a mounting work unit 14, a board camera 15, and a part camera 16. The transport unit 12, the parts feeder 13, and the mounting work unit 14 are controlled and operated by a control device 17 (Figures 2 and 4) provided in the base 11, and the board camera 15 and the part camera 16 are each controlled by the control device 17 to perform imaging operations.

2 and 3, the conveying section 12 is equipped with a pair of belt conveyors 12a. The pair of belt conveyors 12a are arranged to extend horizontally on the base 11, and convey the board KB sent from the upstream side (arrow A1 shown in FIG. 5(a)), and position the board KB at a predetermined work position set on the conveying path (FIG. 5(b)). The board KB positioned at the work position is loaded with components BH as described below. When the loading work of the components BH is completed, the conveying section 12 conveys the board KB downstream (arrow A2 shown in FIG. 5(c)). For the sake of convenience, the conveying direction of the board KB by the conveying section 12 (left-right direction as seen by the worker OP in FIG. 2 and FIG. 3) is the X direction, and the up-down direction is the Z direction. In addition, the direction perpendicular to both the X direction and the Z direction (front-back direction as seen by the worker OP) is the Y direction.

In Figures 3 and 5(a), the transport section 12 is provided with multiple optical sensors 18 (front detection sensor 18a and rear detection sensor 18b). Each optical sensor 18 has a projector 18T that projects inspection light LT and a receiver 18J that receives the inspection light LT projected by the projector 18T. The projector 18T is provided in a position where the projected inspection light LT crosses above the two belt conveyors 12a that make up the transport section 12 in the Y direction. The receiver 18J is provided in a position opposite the projector 18T in the Y direction.

The optical receiver 18J is off when it receives the inspection light LT, and is on when it does not receive the inspection light LT. The on/off state of the optical receiver 18J is notified to the control device 17. Therefore, based on the on/off state of the optical receiver 18J, the control device 17 can detect whether the board KB is positioned to block the inspection light LT.

In Figures 5(a), (b), and (c), the leading edge detection sensor 18a is provided at a position that detects the leading edge Ea of the substrate KB when the substrate KB transported by the transport unit 12 reaches the working position. In other words, the leading edge detection sensor 18a is provided at a position where its inspection light LT is blocked by the leading edge Ea of the substrate KB when the substrate KB transported by the transport unit 12 reaches the working position (the leading edge detection sensor 18a switches from off to on).

As shown in Figs. 5(a), (b) and (c), the tail detection sensor 18b is located at a position where the inspection light LT is blocked slightly forward (downstream) of the tail Eb of the board KB when it is positioned at the work position. In other words, the tail detection sensor 18b is located at a position where it can detect the tail Eb of the board KB when the board KB located at the work position moves slightly downstream. When the board KB is positioned at the work position, the tail detection sensor 18b is off before the front Ea of the board KB crosses the inspection light LT (Fig. 5(a)), but turns on after the front Ea of the board KB crosses the inspection light LT, and remains on even when the board KB reaches the work position and is stopped at that position (Fig. 5(b)).

As shown in Figures 2 and 3, a feeder base 11F is provided on the base 11, and the part feeder 13 is attached to the feeder base 11F. A plurality of part feeders 13 can be attached to the feeder base 11F and arranged in the X direction (Figures 2 and 3). The part feeder 13 has a part supply port 13K at the end closer to the conveying section 12, and continuously supplies parts BH to the part supply port 13K.

In Figures 2 and 3, the mounting work unit 14 includes a head moving mechanism 21 installed on the base 11 and a mounting head 22 that is moved by the head moving mechanism 21. The head moving mechanism 21 is composed of a fixed beam 21A fixed to the base 11 and extending in the Y direction, and a movable beam 21B that is supported at one end by the fixed beam 21A and extends in the X direction.

In Figures 2 and 3, the mounting head 22 is attached to the movable beam 21B. The movable beam 21B is movable in the direction in which the fixed beam 21A extends (Y direction), and the mounting head 22 is movable in the direction in which the movable beam 21B extends (X direction). Therefore, the mounting head 22 can move in the upper area of the base 11 within a horizontal plane (within the XY plane).

In FIG. 2, the mounting head 22 has multiple nozzles 22N extending downward. The mounting head 22 can raise and lower the nozzles 22N using a built-in nozzle drive mechanism (not shown), and can also rotate the nozzles 22N around a vertical axis extending in the Z direction. The mounting head 22 can also generate an adsorption force at the lower end of the nozzle 22N by supplying vacuum pressure into the nozzles 22N through a valve mechanism (not shown).

The mounting work unit 14 mounts the component BH at each of the multiple target mounting positions set on the board KB by repeatedly performing the mounting turn (mounting turn) of mounting the component BH on the board KB positioned at the work position by the transport unit 12. One mounting turn consists of a pick-up operation, a moving operation, and a mounting operation. The pick-up operation is an operation in which the mounting head 22 lowers the nozzle 22N from above the parts feeder 13 and adsorbs the component BH to the lower end of the nozzle 22N, thereby removing the component BH from the parts feeder 13. The moving operation is an operation in which, after the pick-up operation, the mounting head 22 is driven by the head moving mechanism 21 to move above the board KB. The mounting operation is an operation in which the mounting head 22, having moved above the board KB, lowers the nozzle 22N and releases the adsorption of the component BH, thereby mounting the component BH at the target mounting position.

The board camera 15 is attached to the mounting head 22 and moves integrally with the mounting head 22. The imaging field of the board camera 15 faces downward, and captures from above the two board marks MK on the board KB positioned at the work position. After the board camera 15 captures the images of the board marks MK to obtain image data of the board marks MK, it transmits the image data to the control device 17.

In Figures 2 and 3, the part camera 16 is provided in the area between the transport section 12 and the feeder base 11F on the base 11. When the mounting head 22 moves from the area above the part feeder 13 to the area above the board KB during the movement operation of the mounting turn, the part camera 16 captures an image of the part BH from below. After the part camera 16 captures an image of the part BH to obtain image data of the part BH, it transmits the image data to the control device 17.

In FIG. 4, the control device 17 includes a memory unit 31, an operation control unit 32, and a judgment unit 33. The memory unit 31 stores a component mounting program that defines the procedure for executing the component mounting work, as well as various data (component data) such as the type and size of the components BH to be mounted on the board KB. The operation control unit 32 operates each unit of the component mounting device 1B in accordance with the component mounting program stored in the memory unit 31, and executes the component mounting work based on the component data.

When the transport unit 12 positions the substrate KB at the work position, the operation control unit 32 controls the transport unit 12 based on the change in the on/off state of the leading detection sensor 18a. The leading detection sensor 18a is off before the substrate KB transported by the transport unit 12 reaches the work position (FIG. 5(a)), but turns on when the substrate KB reaches the work position (FIG. 5(b)). Therefore, the operation control unit 32 can position the substrate KB at the work position by stopping the operation of the transport unit 12 (transport operation of the substrate KB) when the leading detection sensor 18a switches from off to on after the transport unit 12 begins to load the substrate KB.

When the work (loading turn) by the loading work unit 14 is interrupted for some reason and then the interrupted work is resumed, the judgment unit 33 judges whether the board KB (board KB before the work is resumed) is located at the work position. Specifically, it judges whether the board KB is located at the work position based on the detection results of the two optical sensors 18 (the front end detection sensor 18a and the rear end detection sensor 18b).

As described above, the leading edge detection sensor 18a is positioned to detect the leading edge Ea of the substrate KB when the substrate KB transported by the transport unit 12 reaches the working position, and the trailing edge detection sensor 18b is positioned to detect the trailing edge Eb of the substrate KB when the substrate KB located at the working position moves downstream. Therefore, after the substrate KB is positioned at the working position, if the substrate KB remains at the working position, both the leading edge detection sensor 18a and the trailing edge detection sensor 18b remain on (Figure 6(a)).

In contrast, if the board KB is positioned at the work position and then moves upstream of the work position, the tail detection sensor 18b remains on, but the front detection sensor 18a switches from on to off (Fig. 6(a) → Fig. 6(b)). Also, if the board KB is positioned at the work position and then moves downstream of the work position, the front detection sensor 18a remains on, but the tail detection sensor 18b switches from on to off (Fig. 6(a) → Fig. 6(c)).

Figure 7 shows a judgment criteria table 33T that shows the combinations of on/off of the two optical sensors 18 (the front detection sensor 18a and the rear detection sensor 18b) and the positions of the board KB that correspond to these combinations. This judgment criteria table is stored in the control device 17 (Figure 4), and the judgment unit 33 uses this judgment criteria table 33T to judge whether the board KB is located at the work position when the work by the mounting work unit 14 is interrupted and then resumed. Specifically, when the front detection sensor 18a and the rear detection sensor 18b are both on at the time of resuming the work, the judgment unit 33 judges that the board KB is located at the work position (Figure 6(a)). Also, when the front detection sensor 18a is off and the rear detection sensor 18b is on, the judgment unit 33 judges that the board KB is shifted upstream from the work position (Figure 6(b)). Furthermore, when the leading edge detection sensor 18a is on and the trailing edge detection sensor 18b is off, it is determined that the board KB has shifted downstream from the work position (Figure 6(c)).

In this embodiment, the multiple (two) optical sensors 18 (the leading edge detection sensor 18a and the trailing edge detection sensor 18b) serve as a workpiece detection means for detecting the substrate KB as the workpiece positioned by the transport unit 12.

Next, the procedure (operation method) for performing the component mounting operation by the component mounting device 1B will be described based on the flowchart shown in FIG. 8. When starting the component mounting operation, the operation control unit 32 first operates the transport unit 12 to receive and transport the board KB supplied from the upstream side (FIG. 5(a)). Then, when the leading edge detection sensor 18a detects the leading edge Ea of the board KB, the operation of the transport unit 12 is stopped, thereby positioning the board KB at the operation position (step ST1: board positioning process).

After positioning the board KB at the work position, the operation control unit 32 operates the mounting work unit 14 to perform a mounting turn (step ST2, work execution process). Each time a mounting turn is completed, the operation control unit 32 determines whether the last component BH to be mounted on the board KB has been mounted on the board KB (step ST3). If the last component BH has not been mounted on the board, the operation control unit 32 returns to step ST2 and repeats the mounting turn.

During each mounting turn, image data of the component BH captured by the component camera 16 while the mounting head 22 is moving is sent to the control device 17, and the control device 17 performs component recognition for that component BH. Information on the position and attitude of the component BH relative to the nozzle 22N obtained from this component recognition is used for correcting the position of the nozzle 22N when the component BH is mounted on the board KB during the mounting operation of the mounting turn.

When the operation control unit 32 determines in step ST3 that the last component BH to be mounted on the board KB has been mounted on the board KB, it ends the mounting turn. It then operates the transport unit 12 to transport the board KB downstream (step ST4: board removal process). This completes the component mounting operation for one board KB.

When an operation input is made to interrupt the work (loading turn) performed by the loading work unit 14 while the work (loading turn) is being repeated as described above, the operation control unit 32 interrupts the work performed by the loading work unit 14 (step ST11, work interruption process) and monitors whether an operation input (cancellation input) to cancel the interruption is made by the worker OP or the like (step ST12, cancellation input monitoring process). Then, when the operation control unit 32 detects that a cancellation input has been made, the judgment unit 33 judges whether the board KB is located at the work position based on the detection results of the two optical sensors 18 (the front detection sensor 18a and the rear detection sensor 18b). That is, the judgment unit 33 judges whether the board KB is located at the work position based on whether there has been a change in the detection results of the multiple (two) optical sensors 18 between the time the work is interrupted and the time the work is resumed (step ST13, judgment process).

In step ST13, the determination unit 33 checks whether one of the leading detection sensor 18a and the trailing detection sensor 18b, which were turned on when the board KB was positioned at the work position, is turned off. If the result of the detection by the two optical sensors 18 changes, that is, if one of the leading detection sensor 18a and the trailing detection sensor 18b is turned off (changed from on to off), the determination unit 33 determines that the board KB has moved upstream or downstream from the work position during the interruption of work (i.e., the board KB is not at the work position), and the operation control unit 32 causes the transport unit 12 to perform a repositioning operation to position (reposition) the board KB at the work position again (step ST14. Repositioning process).

This repositioning operation is performed by first moving the board KB upstream and then downstream (FIG. 5(a)→FIG. 5(b)), and stopping the operation of the transport unit 12 when the front end detection sensor 18a switches from off to on. After the transport unit 12 performs the repositioning operation of the board KB in step ST14, the operation control unit 32 moves the board camera 15 above the board KB and checks whether the board KB is located at the work position (step ST16) by capturing an image of the two board marks MK on the board KB with the board camera 15 (step ST15). If the result is that the board KB is not located at the work position, the operation is terminated with an error due to some mechanical abnormality (step ST17), but if the board KB is located at the work position, the mounting operation unit 14 is caused to resume work (step ST18. Work resumption process).

After causing the mounting work unit 14 to resume work, if the operation control unit 32 determines in step ST3 that the last component BH has been mounted on the board KB, it ends the mounting turn. Then it operates the transport unit 12 to transport the board KB away (step ST4).

On the other hand, in step ST13, if there is no change in the detection results of the two optical sensors 18, that is, if both the front end detection sensor 18a and the rear end detection sensor 18b are on (remain on), the judgment unit 33 judges that the board KB has not moved from the work position during the interruption of the work (i.e., the board KB is located at the work position), and the operation control unit 32 makes the board camera 15 take an image of the board mark MK without making the transport unit 12 perform a repositioning operation of the board KB (step ST15), and checks whether the board KB is located at the work position (step ST16). Then, if the board KB is not located at the work position, the operation control unit 32 ends the work with an error (step ST17), and if the board KB is located at the work position, the mounting work unit 14 resumes the work (step ST18. Work resumption process). After making the mounting work unit 14 resume the work, if the operation control unit 32 judges that the last part BH has been mounted on the board KB (step ST3), it ends the mounting turn. Then, the transport unit 12 is operated to transport the substrate KB (step ST4).

In this way, in the component mounting device 1B of this embodiment, after the work by the mounting work unit 14 is interrupted and before the work is resumed, it is determined whether or not the board KB is located at the work position based on the detection results of the two optical sensors 18, which are the work detection means (more specifically, based on whether or not there is a change in the detection results of the two optical sensors 18 between the time the work is interrupted and the time the work is resumed) (step ST13). Then, if it is determined that the board KB is not located at the work position, the transport unit 12 is made to perform a repositioning operation to reposition the board KB at the work position, and then the work is resumed (step ST13 → step ST14 → step ST15 → step ST16 → step ST18), and if it is determined that the board KB is located at the work position, the work is resumed without the transport unit 12 performing the repositioning operation (step ST13 → step ST15 → step ST16 → step ST18).

In other words, in the component mounting device 1B (work system 1, work method) in this embodiment, it is checked whether the board KB is located at the work position before the interrupted work is resumed. If the result shows that the board KB was not located at the work position before the work was resumed, the work is resumed after the board KB is repositioned as in the conventional manner, but if the board KB was located at the work position before the work was resumed, the work is resumed without the board KB being repositioned. Therefore, if the board KB has not moved from the work position during the interruption of the work, unnecessary repositioning of the board KB is not performed, and no time is lost.

As described above, in the component mounting device 1B (working system 1, working method) in this embodiment, before resuming the interrupted work, it is checked whether the board KB is located at the work position, and if the result shows that the board KB is not located at the work position, a repositioning operation is performed to reposition the board KB at the work position before the work is resumed, but if the board KB is located at the work position, the work is resumed without repositioning. Therefore, when resuming the work, it is possible to avoid the waste of repositioning the board KB even if the board KB has not moved from the work position during the interruption of the work, preventing time loss when resuming the interrupted work and improving the productivity of the component mounting device 1B.

Although the embodiment of the present invention has been described so far, the present invention is not limited to the above, and various modifications are possible. For example, in the above embodiment, the transport unit 12 that transports the board KB and positions it at the work position, the mounting work unit 14 as a work unit that performs work on the board KB positioned at the work position by the transport unit 12, the work detection means (multiple optical sensors 18) that detects the board KB positioned by the transport unit 12, the judgment unit 33 that judges whether the board KB is positioned at the work position based on the detection result by the work detection means after the work by the mounting work unit 14 is interrupted and before the work is resumed, and the operation control unit 32 that controls the operation of the transport unit 12 and the mounting work unit 14 are all configured to be provided in the component mounting device 1B, but these configurations may be provided anywhere in the entire work system 1. For example, the judgment unit 33 of the above configuration may be provided in the host computer 1D.

In addition, in the above embodiment, the transport unit 12 that transports the board KB and positions it at the work position is comprised of a belt conveyor 12a, but this is just one example, and the transport unit 12 does not have to be comprised of a belt conveyor 12a. Also, in the above embodiment, the working device is the component mounting device 1B, and the workpiece transported by the transport unit 12 is the board KB, but the working device does not have to be the component mounting device 1B, and the workpiece does not have to be the board KB.

To provide a work device, work system, and work method that can prevent time loss when resuming interrupted work and improve productivity.

1 Working system 1B Parts mounting device (working device)
12 Transport section 14 Loading work section (work section)
18 Optical sensor (work detection means)
18a Front end detection sensor 18b Rear end detection sensor 32 Operation control unit 33 Determination unit KB Circuit board (work)
Ea Leading part Eb Rear part

Claims (7)

A transport unit that transports the workpiece and positions it at a work position;
a working unit that performs an operation on the workpiece positioned at the work position by the transport unit;
a workpiece detection means for detecting the workpiece positioned by the transport unit;
a determination unit that determines whether or not the workpiece is located at the work position based on a detection result by the workpiece detection means after the work by the working unit is interrupted and before the work is resumed;
A working device comprising: The working device according to claim 1, further comprising an operation control unit that controls the operation of the transport unit and the working unit, and when the determination unit determines that the workpiece is not located at the work position, the operation control unit causes the transport unit to perform a repositioning operation to reposition the workpiece at the work position and then causes the working unit to resume work, and when the determination unit determines that the workpiece is located at the work position, the operation control unit causes the working unit to resume work without causing the transport unit to perform the repositioning operation. The work device according to claim 1 or 2, wherein the work detection means includes a plurality of optical sensors, and the determination unit determines whether the work is located at the work position based on whether there is a change in the detection results of the plurality of optical sensors between the time when the work is interrupted and the time when the work is resumed. 3. The work device according to claim 1 or 2, wherein the work detection means includes a plurality of optical sensors, and the judgment unit judges that the work is located at the work position if there is no change in the detection results of the plurality of optical sensors between the time when the work is interrupted and the time when the work is resumed, and judges that the work is not located at the work position if there is a change in the detection results of the plurality of optical sensors between the time when the work is interrupted and the time when the work is resumed. The working device according to claim 3 or 4, wherein the plurality of optical sensors include a leading edge detection sensor that detects the leading edge of the workpiece transported by the transport unit when the workpiece reaches the working position, and a trailing edge detection sensor that detects the trailing edge of the workpiece when the workpiece located at the working position moves downstream. A transport unit that transports the workpiece and positions it at a work position;
a working unit that performs an operation on the workpiece positioned at the work position by the transport unit;
a workpiece detection means for detecting the workpiece positioned by the transport unit;
a determination unit that determines whether or not the workpiece is located at the work position based on a detection result by the workpiece detection means after the work by the working unit is interrupted and before the work is resumed;
An operation control unit that controls the operation of the transport unit and the working unit,
The operation control unit includes:
When the judgment unit determines that the workpiece is not located at the work position, the transport unit performs a repositioning operation to reposition the workpiece at the work position and then the work unit resumes work, and when the judgment unit determines that the workpiece is located at the work position, the work system causes the work unit to resume work without having the transport unit perform the repositioning operation. A method for performing a work by a work device including a transport unit that transports a work and positions it at a work position, a work unit that performs a work on the work positioned at the work position by the transport unit, and a work detection means that detects the work positioned by the transport unit, comprising:
a determination step of determining whether or not the workpiece is located at the work position based on a detection result by the workpiece detection means after the work by the working unit is interrupted and before the work is resumed;
a work resumption step of, when it is determined in the determination step that the work is not located at the work position, having the transport unit perform a repositioning operation to reposition the work at the work position and then having the working unit resume work, and, when it is determined in the determination step that the work is located at the work position, having the working unit resume work without having the transport unit perform the repositioning operation;
Including working methods.

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