Position calibration device, position calibration method, and position calibration program

Abstract

To provide a position calibration device etc., capable of efficiently calibrating the position of a dancer roller.SOLUTION: A calibration device 10 for a dancer roller 243 which can move in a direction of an added thrust and applies tension to an object of conveyance in a direction opposite to the thrust comprises: a calibration start signal generation part 181 which generates a calibration start signal before the dancer roller 243 is moved to at least one of an upper end 243A and a lower end 243B of a movable range of the dancer roller 243 in the direction of the thrust; and an end position information recording part 19 which detects that the dancer roller 243 is moved to at least one of the upper end 243A and lower end 243B and records information on a position of the dancer roller.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a dancer roller position calibration device and the like. [Background technology]

[0002] Known conveying devices for conveying linear conveyed objects such as strings and wires, or planar conveyed objects such as paper and cloth, use dancer rollers to apply tension to the conveyed objects. The dancer rollers in Patent Document 1 are movable in the direction of the thrust applied by the spring, and come to rest at a position where the thrust from the spring and the tension from the conveyed object are balanced. The resting position of the dancer rollers, which indicates the tension of the conveyed object, is measured by a position sensor.

[0003] Before using the dancer rollers, their positions are calibrated so that the position sensors can measure the positions of the dancer rollers, i.e., the tension of the transported object, with high accuracy. Specifically, an operator manually moves the dancer rollers to both ends of their range of motion and records the position information in the position sensors. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-176080 Summary of the Invention [Problem to be solved by the invention]

[0005] In conventional calibration of the dancer roller positions, an operator had to manually move the dancer rollers to both ends of their range of motion, and then use strong force to hold the heavy dancer rollers in a fixed position until the position sensor successfully recorded the position information. To ensure safety and calibration accuracy, multiple people were often required to work together, which was not necessarily a highly efficient process.

[0006] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a position calibration device or the like that can efficiently calibrate the positions of dancer rollers. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems, one aspect of the present invention provides a position calibration device for dancer rollers that are movable in the direction of an applied thrust and that apply a tension to a transported workpiece in the opposite direction to the thrust, and includes: a calibration start signal generating unit that generates a calibration start signal before moving the dancer rollers to at least one end of their movable ranges in the thrust direction; and an end position information recording unit that detects that the dancer rollers have been moved to one end, and records the position information of the dancer rollers.

[0008] In this embodiment, a calibration start signal is generated before the dancer rollers are moved manually or otherwise to one end of their movable range, and when the dancer rollers are subsequently moved manually or otherwise to one end, position information is automatically recorded, thereby eliminating the need to continue manually holding the heavy dancer rollers in a fixed position as in the conventional method.

[0009] Another aspect of the present invention is a position calibration method for dancer rollers that are movable in the direction of an applied thrust and that apply a tension to a transported workpiece in the opposite direction to the thrust, the method comprising: a calibration start signal generating step of generating a calibration start signal before moving the dancer rollers to at least one end of their movable range in the thrust direction; and an end position information recording step of detecting that the dancer rollers have been moved to one end and recording position information thereof.

[0010] Any combination of the above components and any conversion of these expressions into methods, devices, systems, recording media, computer programs, etc. are also encompassed by the present invention. [Effects of the Invention]

[0011] According to the present invention, the positions of the dancer rollers can be calibrated efficiently. [Brief explanation of the drawings]

[0012] [Figure 1] 1 shows a schematic configuration of a transport control device. [Figure 2] FIG. 10 is a functional block diagram of a dancer roller position calibration device. [Figure 3] FIG. 10 is a functional block diagram of a dancer roller position calibration device. [Figure 4] FIG. 10 is a functional block diagram of a dancer roller position calibration device. [Figure 5] 10 shows the position calibration process of the dancer rollers performed by the position calibration device over time. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, a mode for carrying out the present invention (hereinafter also referred to as an embodiment) will be described in detail with reference to the drawings. In the description and / or drawings, identical or equivalent components, members, processes, etc. will be assigned the same reference numerals, and redundant explanations will be omitted. The scale and shape of each part shown in the drawings are set for convenience to simplify the explanation, and should not be interpreted as limiting unless otherwise specified. The embodiment is an example and does not limit the scope of the present invention in any way. All features and combinations thereof described in the embodiment are not necessarily essential to the present invention.

[0014] FIG. 1 is a schematic diagram showing the configuration of a conveyance control device 1 that controls the conveyance operation of a conveyance device 2 that conveys a conveyed object 3. The conveyed object 3 can be, for example, a linear object such as a string or wire, or a planar object such as paper, cloth, film, foil, or rubber. In this embodiment, a roll-to-roll type conveyance device 2 that conveys a planar substrate as the conveyed object 3 in a conveyance direction (the left-right direction in FIG. 1) will be described. The conveyance device 2 may be part of a device that applies any processing to the conveyed object, such as a coater or applicator that applies a coating to the conveyed object, a printer that prints on the conveyed object, or a stretching device that applies tension to the conveyed object to stretch it.

[0015] The conveying device 2 includes a conveying roller group 20 and a dancer 24. The conveying roller group 20 includes a plurality of conveying rollers as a plurality of conveying sections that convey the conveyed object 3. In the example of FIG. 1, the conveying roller group 20 includes three conveying roller pairs arranged in series along the conveying direction of the conveyed object 3. The plurality of conveying rollers are adjacent to each other in the conveying direction. Each conveying roller pair includes a driving roller 211-213 that is rotationally driven by each of the driving sections 111-113 described below, and a driven roller 221-223 that rotates in conjunction with the driving roller 211-213 while sandwiching the conveyed object 3 between the driving roller 211-213. The three conveying roller pairs 211 / 221-213 / 223, the three driving sections 111-113, and the three speed control sections 121-123 provided in the conveying control device 1 corresponding to each of them can be configured similarly to one another. Therefore, the following will explain the first conveying roller pair 211 / 221, the first driving unit 111, and the first speed control unit 121, and will omit redundant explanations of the other conveying roller pairs 212 / 222, 213 / 223, the other driving units 112, 113, and the other speed control units 122, 123. Note that the number of conveying roller pairs provided in the conveying roller group 20 may be any number (any integer greater than or equal to 1).

[0016] The drive roller 211 and the driven roller 221 are transport rollers that serve as a form of a transport unit that transports the transported object 3, and are rotatable around a rotation axis that is perpendicular to the transport direction (the left-right direction in FIG. 1) (the direction perpendicular to the plane of FIG. 1). The drive roller 211 is driven to rotate by a drive unit 111, such as a motor, in response to a rotation speed command generated by a speed control unit 121. When the transport direction of the transported object 3 in FIG. 1 is rightward, the drive roller 211 is driven to rotate clockwise by the drive unit 111, and the driven roller 221 rotates counterclockwise in conjunction with the drive roller 211. By individually driving and rotating the drive rollers 211-213 that make up the transport roller group 20 by the drive units 111-113 of the transport control device 1, the speed and tension of each part of the transported object 3 can be precisely controlled, thereby optimizing the transport operation of the transported object 3 by the transport device 2 and the processing by various devices to which the transport device 2 is installed.

[0017] The dancers 24 are provided upstream (left side in FIG. 1) and downstream (right side in FIG. 1) in the conveying direction of the conveying roller group 20, so as to sandwich the conveying roller group 20 from both sides in the conveying direction. The two dancers 24 shown in the figure can be configured similarly, so only the dancer 24 on the left side will be described.

[0018] The dancer 24 applies tension in the conveying direction to the transported object 3. The dancer 24 includes a pair of rollers 241, 242 provided on the transport path of the transported object 3 (the path in the left-right direction along which the transported object 3 extends in FIG. 1), and a dancer roller 243 provided between the pair of rollers 241, 242 at a position deviated from the transport path of the transported object 3. The dancer roller is also called a dancer roll.

[0019] The dancer rollers 243 are provided so as to be movable between upper ends 243A and lower ends 243B in a direction perpendicular to the conveyance path of the transported object 3 (the up-down direction in FIG. 1). The air cylinder 244, which serves as a thrust applying unit, generates a thrust that urges or pressurizes the dancer rollers 243 in a direction away from the conveyance path of the transported object 3 (downward in FIG. 1). This thrust is based on the air pressure of the air cylinder 244, which is connected to the dancer rollers 243 via a piston rod or a connecting rod. The air pressure of the air cylinder 244 is generated by a thrust control unit 17, which is composed of an electro-pneumatic regulator or the like that electrically controls the air pressure. A substantially constant voltage is generally applied to the electro-pneumatic regulator (thrust control unit 17), and the air pressure of the air cylinder 244, i.e., the thrust of the dancer rollers 243, is controlled to be substantially constant. It should be noted that instead of the air cylinder 244, a thrust applying unit that applies thrust to the dancer rollers 243 based on another principle (for example, a linear motor that applies thrust to the dancer rollers 243 based on electricity) may be provided.

[0020] The dancer rollers 243, which are biased or pressurized downward by the thrust from the air cylinder 244, apply tension to the transported object 3 by pulling the transported object 3 in a direction away from the transport path. At this time, the downward thrust received by the dancer rollers 243 from the air cylinder 244 and the upward tension received by the transported object 3 are balanced. As described above, the downward thrust received by the dancer rollers 243 from the air cylinder 244 is generally maintained or controlled to be approximately constant, so the vertical position of the dancer rollers 243 represents the tension of the transported object 3. Typically, by controlling the tension of the transported object 3, the vertical position of the dancer rollers 243 is controlled to be approximately midway between the upper end 243A and the lower end 243B.

[0021] The position of the dancer rollers 243 in the thrust direction (the vertical direction in FIG. 1 ) is detected as an electric signal by the position detection unit 245 or a position sensor, and is provided to the subtractor 14 of the conveyance control device 1. In addition, the subtractor 14 receives a position command for the dancer rollers 243 in the thrust direction, which is generated by the position command generation unit 13 of the conveyance control device 1. As described above, the position of the dancer rollers 243 approximately corresponds to the tension of the conveyance object 3, and therefore the position command for the dancer rollers 243 generated by the position command generation unit 13 approximately corresponds to the tension command for the conveyance object 3. The speed control unit 15 of the conveyance control device 1 generates a speed command for reducing the deviation of the position of the dancer rollers 243 or the tension of the conveyance object 3, which is provided by the subtractor 14. This speed command is a command for the conveyance speed of the conveyance object 3, and more specifically, a command for the rotational speed of the drive roller 251, which will be described below.

[0022] The drive unit 16 of the conveyance control device 1 drives and rotates the drive roller 251, which is provided immediately after the dancer 24, in response to a speed command provided by the speed control unit 15. The drive roller 251 is a conveyance roller that can rotate around a rotation axis perpendicular to the conveyance direction of the conveyed object 3. When the drive roller 251 is driven and rotated clockwise in FIG. 1, the driven roller 252 rotates counterclockwise in conjunction with the drive roller 251. In addition, a drive roller 231 similar to the drive roller 251 and a driven roller 232 similar to the driven roller 252 are also provided immediately before the dancer 24. The drive roller 231 is driven and rotated at a constant rotation speed, for example, by a drive unit (not shown). In contrast, the rotation speed of the drive roller 251 is adaptively controlled in response to deviations in position and / or tension. In this way, the drive roller 251 and the driven roller 252 convey the conveyed object 3 sandwiched between them, while applying a desired tension to the conveyed object 3 in accordance with the position command of the dancer roller 243 generated by the position command generating unit 13, i.e., the tension command of the conveyed object 3. In the example of Fig. 1, two dancers 24 are provided immediately before and after the group of conveying rollers 20 in the conveying direction, so that the tension of the conveyed object 3 at the entrance portion (left end in Fig. 1) and exit portion (right end in Fig. 1) of the group of conveying rollers 20 can be controlled to a desired value.

[0023] Before use, the positions of the dancer rollers 243 are calibrated so that the position detection unit 245 can measure the positions of the dancer rollers 243, i.e., the tension of the transported load 3, with high accuracy. Specifically, an operator manually moves the dancer rollers 243 to the upper end 243A and the lower end 243B, which are the ends of the range of motion in the thrust direction (the vertical direction in FIG. 1 ), and the position information for each end is detected and recorded by the position detection unit 245 for calibration. In conventional calibration of the dancer rollers 243, after manually moving the dancer rollers 243 to the ends 243A and 243B of the range of motion, the operator must continue to hold the heavy dancer rollers 243 in a fixed position with great force until the position information is successfully recorded by the position detection unit 245. To ensure safety and calibration accuracy, multiple people are often required to work together, which is not necessarily a highly efficient method. The position calibration device 10 of this embodiment, described below, allows the position of the dancer rollers 243 to be calibrated efficiently.

[0024] 2 is a functional block diagram of the position calibration device 10 for the dancer roller 243. The position calibration device 10 includes the thrust control unit 17, the calibration start signal generating unit 181, the calibration end signal generating unit 182, and the end position information recording unit 19. These functional blocks are realized by the cooperation of hardware resources such as the computer's central processing unit, memory, input devices, output devices, and peripheral devices connected to the computer, as well as software executed using these resources. Regardless of the type of computer or its installation location, each of the above functional blocks may be realized by the hardware resources of a single computer or by combining hardware resources distributed across multiple computers.

[0025] The configuration and operation of the dancer 24 in this figure are the same as those in Figure 1, but a piston rod 246 and a connecting rod 247 are additionally shown in this figure. The piston rod 246 is connected to a piston (not shown) that is provided movably in the thrust direction (up and down direction in Figure 2) within an air cylinder 244. The piston is urged upward together with the piston rod 246 by air pressure generated by the thrust control unit 17. In this way, an upward thrust F is generated on the piston and piston rod 246.

[0026] The upper end of the piston rod 246 is connected to the left end of the connecting rod 247. The right end of the connecting rod 247 is connected to the dancer roller 243. The connecting rod 247 is rotatably fixed by a fulcrum O provided at approximately the center in its longitudinal direction (the left-right direction in FIG. 2 ). An upward thrust F that the left end of the connecting rod 247 receives from the upper end of the piston rod 246 becomes a torque that rotates the connecting rod 247 in the clockwise direction around the fulcrum O. As a result, a downward thrust proportional to the upward thrust F at the left end is applied to the dancer roller 243 connected to the right end of the connecting rod 247.

[0027] As shown in Fig. 3, the upper end 243A abuts against and stops the connecting rod 247 that has rotated counterclockwise around the fulcrum O, thereby determining the upper end in the thrust direction of the dancer rollers 243. As shown in Fig. 4, the lower end 243B abuts against and stops the connecting rod 247 that has rotated clockwise around the fulcrum O, thereby determining the lower end in the thrust direction of the dancer rollers 243. For convenience, below, the upper end of the movable range of the dancer rollers 243 will also be referred to as the upper end 243A, and the lower end of the movable range of the dancer rollers 243 will also be referred to as the lower end 243B.

[0028] The calibration start signal generating unit 181 generates a calibration start signal before moving the dancer rollers 243 to at least one of the upper end 243A and the lower end 243B of the movable range in the thrust direction during position calibration of the dancer rollers 243. Note that the movement of the dancer rollers 243 to the upper end 243A and / or the lower end 243B during position calibration of the dancer rollers 243 may be performed manually by an operator, or may be performed using thrust generated by the thrust control unit 17 and the air cylinder 244 in addition to or instead of manual force, or may be performed using driving force generated by another driving device such as a linear motor that can drive at least one of the piston, the piston rod 246, the connecting rod 247, and the dancer rollers 243 in the thrust direction in addition to or instead of manual force.

[0029] When the dancer rollers 243 are moved in the direction opposite to the thrust (upward in FIG. 3 ), as shown in FIG. 3 , the thrust control unit 17 reduces the thrust of the air cylinder 244 in response to the calibration start signal generated by the calibration start signal generation unit 181. For example, the thrust control unit 17 reduces the thrust of the air cylinder 244 to zero in response to the calibration start signal. This reduces the force required by the operator to move the dancer rollers 243 to the upper end 243A, thereby improving work safety and efficiency. Note that if the thrust control unit 17 and the air cylinder 244 can apply a thrust to the piston and piston rod 246 in the direction opposite to the thrust F in FIG. 2 (downward in FIG. 3 ), or if another driving device such as a linear motor can drive the dancer rollers 243 to the upper end 243A, the movement of the dancer rollers 243 to the upper end 243A during position calibration, and ultimately the entire position calibration process, can be automated without the intervention of the operator.

[0030] When the dancer rollers 243 are moved in the thrust direction (downward in FIG. 4) as shown in FIG. 4, the thrust control unit 17 increases the thrust F by the air cylinder 244 in response to the calibration start signal generated by the calibration start signal generation unit 181. This reduces the force required by the operator to move the dancer rollers 243 to the lower end 243B, thereby improving the safety and efficiency of the work. Note that if the thrust control unit 17 and the air cylinder 244 can apply to the piston and piston rod 246 a thrust F large enough to drive the dancer rollers 243 to the lower end 243B, or if another driving device such as a linear motor can drive the dancer rollers 243 to the lower end 243B, then the movement of the dancer rollers 243 to the lower end 243B during position calibration, and ultimately the entire position calibration process, can be automated without the intervention of the operator.

[0031] The end position information recording unit 19 detects that the dancer rollers 243 have been moved to the upper end 243A (FIG. 3) or the lower end 243B (FIG. 4) after the calibration start signal generating unit 181 has generated the calibration start signal, and detects and records the respective position information using the position detecting unit 245 for calibration. For example, the end position information recording unit 19 records the position information of the dancer rollers 243 that is closest to the upper end 243A (FIG. 3) or the lower end 243B (FIG. 4) among the position information of the dancer rollers 243 measured by the position detecting unit 245 continuously or intermittently multiple times after the calibration start signal generating unit 181 has generated the calibration start signal. The end position information recording unit 19 does not need to record the position information of the upper end 243A and the lower end 243B of the dancer roller 243 in real time. It is also possible to temporarily store a series of position information groups in the vicinity of the upper end 243A and the lower end 243B acquired by the position detection unit 245 in a buffer or the like, and later select and record the information closest to the upper end 243A or the lower end 243B.

[0032] The calibration end signal generating unit 182 generates a calibration end signal after the end position information recording unit 19 detects that the dancer rollers 243 have been moved to the upper end 243A or the lower end 243B. As will be specifically shown in Fig. 5 (described later), the position information of the dancer rollers 243 continuously acquired by the position detecting unit 245 takes extreme values ​​or maximum absolute values ​​at the upper end 243A and the lower end 243B. Therefore, the end position information recording unit 19 can detect that the dancer rollers 243 have been moved to the upper end 243A or the lower end 243B based on the transition of the position information including the extreme values. Here, since it is sufficient for the end position information recording unit 19 to detect the extreme values ​​of the position information of the dancer rollers 243, it is no longer necessary to manually hold the heavy dancer rollers 243 in a fixed position (the upper end 243A or the lower end 243B) as in the conventional method, thereby improving the safety and efficiency of the work.

[0033] 3, when the calibration end signal generating unit 182 generates a calibration end signal after reducing the thrust by the air cylinder 244 in response to the calibration start signal, the thrust control unit 17 stops reducing the thrust by the air cylinder 244 in response to the calibration end signal (for example, returns to the thrust before the reduction). Similarly, when the calibration end signal generating unit 182 generates a calibration end signal after increasing the thrust F by the air cylinder 244 in response to the calibration start signal as shown in FIG. 4, the thrust control unit 17 stops increasing the thrust F by the air cylinder 244 in response to the calibration end signal (for example, returns to the thrust before the increase).

[0034] FIG. 5 shows the time course of the position calibration process of the dancer rollers 243 performed by the position calibration device 10. In the initial state, the dancer rollers 243 are in the "center" position as shown in FIG. 2, and the thrust F of the air cylinder 244 is at the "normal" level. In this state, the calibration start signal generating unit 181 generates an upper limit position calibration start signal to start the upper limit position calibration of the dancer rollers 243. Upon receiving the upper limit position calibration start signal, the thrust control unit 17 reduces the thrust of the air cylinder 244. Then, as shown in FIG. 3, the dancer rollers 243 are moved to the upper end 243A by the operator's manual force or the like. At this time, as shown in "Dancer Roller Position" in FIG. 5, the position information of the dancer rollers 243 continuously acquired by the position detecting unit 245 reaches a local maximum value or a maximum value at the upper end 243A. After confirming this local maximum value or maximum value on a screen or the like, the operator causes the calibration end signal generating unit 182 to generate an upper limit position calibration end signal to end the upper limit position calibration of the dancer rollers 243. The end position information recording unit 19, which has autonomously detected the maximum or local maximum value, may cause the calibration end signal generating unit 182 to generate the upper limit position calibration end signal without the intervention of an operator. Upon receiving the upper limit position calibration end signal, the thrust control unit 17 returns the thrust by the air cylinder 244 from the "reduced" level to the "normal" level.

[0035] Next, the calibration start signal generating unit 181 generates a lower limit position calibration start signal to start the lower limit position calibration of the dancer rollers 243. Upon receiving the lower limit position calibration start signal, the thrust control unit 17 increases the thrust force of the air cylinder 244. Then, as shown in FIG. 4, the dancer rollers 243 are moved to the lower end 243B by the operator's manual force or the like. At this time, as shown in "Dancer Roller Position" in FIG. 5, the position information of the dancer rollers 243 continuously acquired by the position detecting unit 245 becomes a minimum value or a lowest value at the lower end 243B. After confirming this minimum value or a lowest value on a screen or the like, the operator causes the calibration end signal generating unit 182 to generate a lower limit position calibration end signal to end the lower limit position calibration of the dancer rollers 243. The end position information recording unit 19, which autonomously detects the minimum value or a lowest value, may also cause the calibration end signal generating unit 182 to generate the lower limit position calibration end signal without the operator's intervention. Upon receiving the lower limit position calibration end signal, the thrust control unit 17 returns the thrust by the air cylinder 244 from the "increased" level to the "normal" level.

[0036] Simultaneously with or after the above processing, the end position information recording unit 19 searches for and selects position information of the upper end 243A of the dancer roller 243, which corresponds to the maximum or maximum value of the "dancer roller position", from the group of position information continuously acquired by the position detection unit 245, and records this for upper limit position calibration, and searches for and selects position information of the lower end 243B of the dancer roller 243, which corresponds to the minimum or minimum value of the "dancer roller position", from the group of position information continuously acquired by the position detection unit 245, and records this for lower limit position calibration.

[0037] The present invention has been described above based on the embodiments. Various modifications are possible to the combinations of the components and processes in the exemplary embodiments, and it will be obvious to those skilled in the art that such modifications are included within the scope of the present invention.

[0038] The configuration, operation, and function of each device and method described in the embodiments can be realized by hardware resources, software resources, or a combination of hardware and software resources. Examples of hardware resources include processors, ROMs, RAMs, and various integrated circuits. Examples of software resources include operating systems, applications, and other programs. [Explanation of symbols]

[0039] 1 conveyance control device, 2 conveyance device, 3 conveyed object, 10 position calibration device, 13 position command generation unit, 14 subtractor, 15 speed control unit, 16 drive unit, 17 thrust control unit, 19 end position information recording unit, 24 dancer, 181 calibration start signal generation unit, 182 calibration end signal generation unit, 243 dancer roller, 243A upper end, 243B lower end, 244 air cylinder, 245 position detection unit.

Claims

1. A position calibration device for a dancer roller that is movable in the direction of an applied thrust and to which a tension force in the opposite direction to the thrust force is applied from a transported object, a calibration start signal generating unit that generates a calibration start signal before moving the dancer rollers to at least one end of a movable range of the dancer rollers in the direction of the thrust; an end position information recording unit that detects that the dancer rollers have been moved to the one end and records the position information; A position calibration device comprising:

2. 2. The position calibration device according to claim 1, wherein the end position information recording unit records the position information of the dancer roller closest to the one end among the position information of the dancer rollers measured a plurality of times after the calibration start signal is generated.

3. 3. The position calibration device according to claim 2, wherein the end position information recording unit records information on the dancer rollers that is closest to the one end among information on the positions of the dancer rollers that are continuously measured after the calibration start signal is generated.

4. 4. The position calibration device according to claim 1, further comprising a calibration end signal generating unit that generates a calibration end signal after the end position information recording unit detects that the dancer roller has been moved to the one end.

5. the calibration start signal generating unit generates a calibration start signal before moving the dancer rollers to the other end of the movable range, the end position information recording unit detects that the dancer rollers have been moved to the other end, and records the position information.

5. A position calibration device according to claim 1.

6. 6. The position calibration device according to claim 1, further comprising a thrust control unit that increases the thrust in response to the calibration start signal when the dancer roller is moved in the direction of the thrust.

7. 7. The position calibration device according to claim 1, further comprising a thrust control unit that reduces the thrust in response to the calibration start signal when the dancer roller is moved in a direction opposite to the thrust.

8. 8. The position calibration device according to claim 1, wherein the thrust is based on air pressure of an air cylinder connected to the dancer roller.

9. A method for calibrating the position of a dancer roller that is movable in the direction of an applied thrust and to which a tension force in the opposite direction to the thrust force is applied from a carried object, comprising: a calibration start signal generating step of generating a calibration start signal before moving the dancer rollers to at least one end of a range of motion of the dancer rollers in the direction of the thrust; an end position information recording step of detecting that the dancer rollers have been moved to the one end and recording the position information; A position calibration method comprising:

10. A method for calibrating the position of a dancer roller that is movable in the direction of an applied thrust and to which a tension force in the opposite direction to the thrust force is applied from a carried object, comprising: a calibration start signal generating step of generating a calibration start signal before moving the dancer rollers to at least one end of a range of motion of the dancer rollers in the direction of the thrust; an end position information recording step of detecting that the dancer rollers have been moved to the one end and recording the position information; A position calibration program that causes a computer to execute the following.

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