Rotation control system and rotation control method

Abstract

To provide a rotation control system capable of detecting an abnormality due to a composite factor which may occur in a conveyance system or the like.SOLUTION: A rotation control system comprises: a rotating body in which one or more structures executing an operation on a workpiece are disposed on a peripheral edge, and the operation by the structure is periodically repeated by rotation; a rotating shaft which is disposed to rotate concentrically and integrally with the rotating body; a motor having a rotary encoder; a power transmission system which has two or more gears including a first gear attached to an output shaft of the motor and a second gear attached to the rotating shaft, and transmits an output of the motor to the rotating shaft; and a control unit which controls rotation of the motor based on an output signal of the rotary encoder, and acquires and outputs positional information of the rotating body based on the output signal. The control unit setts a period for resetting the positional information of the rotating body based on a movement amount of one rotation of the rotating body and a gear ratio of the two or more gears.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a rotation control system and a rotation control method. [Background technology]

[0002] In systems in which workpieces such as PET bottles, cans, and glass bottles to be filled with beverages are continuously transported by a conveyor, star wheels are sometimes used to transport the workpieces onto or off the conveyor (for example, Patent Document 1).

[0003] The star wheel is a wheel with pockets around its periphery for accommodating workpieces, and is placed near the conveyor so that it can rotate integrally with the rotating shaft that rotates around its central axis. The star wheel rotates when the power of a motor is transmitted to the rotating shaft via a gear, and the workpieces accommodated in the pockets move along a circular orbit concentric with the rotating shaft. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-227257 Summary of the Invention [Problem to be solved by the invention]

[0005] When rotating the star wheel, the rotation of the motor is controlled based on the encoder's output signal, thereby controlling the position and speed of the star wheel, in other words, the position and movement speed of the workpiece. Here, the star wheel position corresponds to the amount of movement when the star wheel rotates from a reference position. Furthermore, by correlating and monitoring various measurement information such as the star wheel speed, position deviation, and motor torque with the star wheel position information acquired based on the encoder's output signal, it is possible to detect the occurrence of mechanical abnormalities in the conveyance system (e.g., chipped teeth).

[0006] In conventional star wheel control, the position information of the star wheel is reset every time the star wheel rotates once, or sometimes the position information is reset every time the star wheel pocket moves by one pitch.

[0007] If the position information is reset every time the star wheel rotates, it is possible to detect at which position the star wheel (in other words, in which pocket) an abnormality is occurring by comparing the position information with various measurement information.

[0008] On the other hand, in a conveyance system, abnormalities can occur not only due to the star wheel itself, but also due to a combination of factors such as abnormalities in the gears that make up the power transmission system from the motor to the star wheel, the meshing of these gears, their positional relationship with the conveyor, etc. However, if the position information of the star wheel is reset at the above-mentioned cycle, it is not possible to detect abnormalities caused by such a combination of factors.

[0009] The present invention has been made in consideration of the above, and one of its objects is to provide a rotation control system and a rotation control method that can detect abnormalities caused by multiple factors that may occur in a conveyance system, etc. [Means for solving the problem]

[0010] A rotation control system according to one aspect of the present invention comprises a rotating body having one or more structures provided on its periphery for performing operations on a workpiece, the rotating body periodically repeating the operations of the structures as it rotates; a rotating shaft arranged to rotate concentrically and integrally with the rotating body; a motor provided with a rotary encoder; a power transmission system including two or more gears, including a first gear attached to the output shaft of the motor and a second gear attached to the rotating shaft, and configured to transmit the output of the motor to the rotating shaft; and a control unit configured to control the rotation of the motor based on the output signal of the rotary encoder and to acquire and output position information of the rotating body based on the output signal, wherein the control unit is configured to set the period for resetting the position information of the rotating body based on the amount of movement of the rotating body per rotation and the gear ratio of the two or more gears.

[0011] In the above rotation control system, the period may be set to a value obtained by multiplying the amount of movement of the rotating body per rotation by a common multiple of the gear ratios of the two or more gears when the gear ratios of the two or more gears are expressed as relatively prime integers, divided by the gear ratio of the second gear.

[0012] In the above rotation control system, the least common multiple of the gear ratios of the two or more gears may be used as the common multiple.

[0013] In the above rotation control system, the control unit may be further configured to acquire measurement information regarding the rotating body in association with the position information.

[0014] In the above rotation control system, the control unit may be further configured to detect an abnormality in the power transmission system based on position information of the rotating body.

[0015] The rotation control system may further include a conveyor configured to continuously transport workpieces, the rotating body being positioned near the conveyor so that operations can be performed on the workpieces on the conveyor, and the control unit may be further configured to set a period for resetting the position information based on the circumference of the conveyor.

[0016] In the above rotation control system, the period may be set to a value obtained by multiplying the circumferential length of the conveyor by a common multiple of the gear ratios of the two or more gears, when the gear ratios of the two or more gears are expressed as relatively prime integers, divided by the gear ratio of the second gear, for the amount of movement of the rotating body per rotation.

[0017] In the above rotation control system, the rotating body may be a star wheel having one or more pockets on its periphery for accommodating the workpiece, and the star wheel may be positioned near the conveyor so as to enable the workpiece to be transported out of the conveyor or to be transported into the conveyor.

[0018] A rotation control method according to one aspect of the present invention is a rotation control method applied to a rotation control system, the rotation control system comprising: a rotating body having one or more structures provided on its periphery that perform operations on a workpiece, the rotating body periodically repeating the operations of the structures as it rotates; a rotating shaft that is arranged to rotate concentrically and integrally with the rotating body; a motor having a rotary encoder; and a power transmission system that includes two or more gears, including a first gear attached to the output shaft of the motor and a second gear attached to the rotating shaft, and is configured to transmit the output of the motor to the rotating shaft, the rotation control method comprising the steps of: controlling the rotation of the motor based on an output signal of the rotary encoder; acquiring and outputting position information of the rotating body based on the output signal; and resetting the position information of the rotating body at a period calculated based on the amount of movement of the rotating body per rotation and the gear ratio of the two or more gears. [Effects of the Invention]

[0019] According to the present invention, it is possible to detect abnormalities caused by multiple factors that may occur in a transport system or the like. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a schematic diagram illustrating a transport system according to an embodiment of the present invention. [Figure 2] FIG. 2 is an enlarged view of the arrow X in FIG. [Figure 3] FIG. 2 is a block diagram illustrating the configuration and operation of a control unit. [Figure 4] 10 is a graph illustrating position information and speed information of a star wheel. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, a rotation control system according to an embodiment of the present invention will be described with reference to the drawings. Note that the present invention is not limited to these embodiments. In addition, in the description of each drawing, the same parts are designated by the same reference numerals.

[0022] The drawings referred to in the following description merely show the shapes, sizes, and positional relationships in a schematic manner to enable the understanding of the contents of the present invention. That is, the present invention is not limited to the shapes, sizes, and positional relationships exemplified in each drawing. Furthermore, there may be parts in which the dimensional relationships and ratios differ between the drawings.

[0023] (Conveyor system configuration) Fig. 1 is a schematic diagram showing a transfer system (rotation control system) according to an embodiment of the present invention, Fig. 2 is an enlarged view taken along the arrow X in Fig. 1.

[0024] As shown in Fig. 1, the conveying system 1 according to this embodiment is a system that continuously conveys workpieces 2 having cylindrical portions, such as PET bottles, cans, and glass bottles to be filled with beverages, using a conveyor 10. The conveying system 1 is provided with star wheels (rotating bodies) 20, 60 arranged near the conveyor 10 so that the workpieces 2 can be transported out of the conveyor 10 or can be transported into the conveyor 10. For example, the star wheel 60 is configured to transport the workpieces 2 from another conveyor 12 into the conveyor 10.

[0025] The star wheels 20 and 60 are wheels with pockets (structures) 20a and 60a for accommodating the workpieces 2 provided on their peripheries. In FIG. 1, the star wheel 20 has 16 pockets 20a and the star wheel 60 has 6 pockets 60a, but the number of pockets may be one or more. While the star wheels 20 and 60 rotate around their own rotation axes 21 and 61, the claws 20b and 60b protruding from the outer periphery engage with the workpieces 2, accommodating them in the pockets 20a and 60a, and moving the workpieces 2. The star wheels 20 and 60 shown in FIG. 1 differ in planar shape and the number of pockets 20a and 60a, but their structures, operations, and control methods are basically the same. Therefore, the star wheel 20 will be described in detail below.

[0026] As shown in Fig. 2, the conveyance system 1 includes a star wheel 20, a rotating shaft 21 that is concentric with and rotates integrally with the star wheel 20, a servo motor 30, a power transmission system 40 that is configured to transmit the output of the servo motor 30 to the rotating shaft 21 of the star wheel 20, and a control unit 50 that controls the operation of the conveyance system 1. Note that Fig. 2 shows a state in which the star wheel 20 is fixed to a turntable 22 that is integrated with the rotating shaft 21, but the turntable 22 is not essential. The turntable 22 can be provided as appropriate depending on the shape of the star wheel, the type of workpiece, the arrangement of the star wheel 20 in the conveyance system 1, etc.

[0027] The power transmission system 40 includes a motor-side gear (first gear) 41 attached to the output shaft 33 of the servo motor 30 and a wheel-side gear (second gear) 42 attached to the rotation shaft 21 of the star wheel 20. Here, in this embodiment, the power transmission system 40 is configured using two gears, the motor-side gear 41 and the wheel-side gear 42, but it is also possible to arrange one or more gears between the motor-side gear 41 and the wheel-side gear 42 and configure the power transmission system 40 using three or more gears.

[0028] In this embodiment, a servo motor 30 is used as a motor for driving the star wheel 20. The servo motor 30 is a motor in which a rotary encoder (hereinafter also simply referred to as encoder) 32 is provided on a motor 31, and rotates the motor 31 in accordance with a drive signal output from a control unit 50. The encoder 32 detects the amount of rotation (rotation angle) of the motor 31 and outputs a signal (pulse signal) corresponding to this amount of rotation to the control unit 50.

[0029] The motor used in the conveyance system 1 is not limited to the servo motor 30, as long as it is provided with a rotary encoder and can detect the amount of rotation of the motor. For example, a stepping motor with an encoder may be used.

[0030] The transport system 1 may further include an infrared sensor 14 for detecting the passage of the workpiece 2 and a camera 16 for monitoring the state of the workpiece 2.

[0031] The control unit 50 can be configured as a dedicated computer or a general-purpose computer loaded with a control program. The control unit 50 is configured to control the rotation of the motor 31 based on the output signal of the encoder 32, and to acquire and output position information of the star wheel 20 based on the output signal of the encoder 32. Here, the position of the star wheel 20 corresponds to the amount of movement when the star wheel 20 rotates from a reference position, and can be expressed as the rotation angle [degrees] from the reference position or the distance moved by a specific point on the wheel (arc length [mm]).

[0032] 3 is a block diagram illustrating the configuration and operation of the control unit 50. As shown in Fig. 3, the control unit 50 includes a setting unit 51 that sets various conditions in the conveyance system 1, a signal receiving unit 52 that receives output signals (pulse signals) from the encoder 32, a measurement information acquiring unit 53 that acquires measurement information about the motor 31 and the star wheel 20 based on the output signals, and an output unit 54 that outputs this measurement information. The measurement information acquired by the measurement information acquiring unit 53 includes position information (amount of movement from a reference position) of the motor 31 corresponding to the count of the pulse signals, information on the speed and torque of the motor 31 based on this position information, and position information and speed information of the star wheel 20 calculated from the position information of the motor 31 and the gear ratio.

[0033] The control unit 50 also includes a drive signal control unit 55 that controls a drive signal that drives the motor 31 , and a drive signal output unit 56 that outputs a drive signal to the motor 31 .

[0034] Furthermore, the control unit 50 may have an abnormality detection unit 57 that detects abnormalities in the power transmission system 40 based on the measurement information acquired by the measurement information acquisition unit 53. The abnormality detection unit 57 may acquire position information and speed information of the star wheel 20 from the measurement information acquisition unit 53, as well as measurement information output from the infrared sensor 14 and the camera 16, and associate this measurement information with the position information of the star wheel 20 to detect abnormalities in the power transmission system 40.

[0035] In addition, the control unit 50 may be connected to an input device (e.g., a keyboard or touch panel) for inputting various conditions to be applied to the conveying system 1, and a monitor (e.g., an LCD monitor) for displaying various information output from the output unit 54.

[0036] (Transport control method) Next, a conveyance control method (rotation control method) applied in the conveyance system 1 will be described with reference to Fig. 4. Fig. 4 is a graph illustrating the position information and speed information of the star wheel 20 output from the output unit 54. For comparison, the dashed line in Fig. 4 illustrates the position information of the star wheel output in general conveyance control.

[0037] First, the setting unit 51 sets the gear ratio in the power transmission system 40 based on information inputted by, for example, an input device. For example, in the configuration shown in Fig. 2, when the gear ratio of the wheel side gear 42 (driven side gear) to the motor side gear 41 (driving side gear) is expressed as an irreducible fraction b / a, the gear ratio is (Motor side gear):(Wheel side gear)=a:b It is set in the format where the values ​​a and b are mutually prime integers.

[0038] Next, the setting unit 51 sets a period P for resetting the position information of the star wheel 20 acquired by the measurement information acquisition unit 53.

[0039] In general transport control, the position information of the star wheel is reset every time the star wheel rotates once (that is, every 360°) (see the dashed line in FIG. 4).

[0040] In contrast to this, in this embodiment, the period P for resetting the position information of the star wheel 20 is set based on the movement amount of one rotation of the star wheel 20 and the gear ratio of two or more gears included in the power transmission system 40.

[0041] In detail, the period P for resetting the position information is set to a value obtained by multiplying the amount of movement per rotation of the star wheel 20 by a common multiple of the gear ratios of two or more gears, where the gear ratios of these two or more gears are expressed as relatively prime integers, divided by the gear ratio of the wheel side. In this case, the common multiple may be the least common multiple in order to shorten the reset period.

[0042] For example, as described above, if the gear ratio between the motor-side gear 41 and the wheel-side gear 42 is a:b (a and b are coprime), the least common multiple of the gear ratios a and b is a×b. Therefore, the period P for resetting the position information can be calculated using the following equation (1).

number

[0043] Here, when the pulse signal output from the encoder 32 is used as a reference, the movement amount per rotation of the star wheel can be expressed using the following equation (2).

number

[0044] Therefore, the period P for resetting the position information can also be calculated by the following equation (3).

number

[0045] Furthermore, the setting unit 51 sets the speed of the motor 31 for rotating the star wheel 20 at a predetermined speed, based on, for example, information input by an input device and the set gear ratio.

[0046] When the operation of the conveyance system 1 starts, the drive signal control unit 55 controls the drive signal so that the motor 31 rotates at a preset speed, and the drive signal output unit 56 outputs a drive signal to the motor 31 in accordance with this control. As a result, the output of the motor 31 is transmitted to the rotation shaft 21 of the star wheel 20 via the output shaft 33, the motor-side gear 41, and the wheel-side gear 42, and the star wheel 20 rotates.

[0047] On the other hand, the encoder 32 outputs a pulse signal corresponding to the rotation amount of the motor 31 to the control unit 50. The signal receiving unit 52 receives the pulse signal output from the encoder 32 and inputs it to the measurement information acquiring unit 53.

[0048] The measurement information acquiring unit 53 acquires various pieces of information regarding the position, speed, and torque of the motor 31 based on the pulse signal input from the signal receiving unit 52, and inputs this information to the drive signal control unit 55 to feedback control the motor 31. At this time, the measurement information acquiring unit 53 may reset the position information of the motor 31 at a period in which the motor 31 makes one rotation.

[0049] Furthermore, the measurement information acquiring unit 53 acquires the position information and speed information of the star wheel 20 based on the position information of the motor 31 (or the pulse signal input from the signal receiving unit 52). At this time, the measurement information acquiring unit 53 resets the position information of the star wheel 20 at the period P set in the setting unit 51.

[0050] The measurement information acquisition unit 53 outputs the position information and speed information of the star wheel 20 to the output unit 54. Fig. 4 shows an example in which the gear ratio between the motor-side gear 41 and the wheel-side gear 42 is 3:5, and the position information of the star wheel 20 is reset every three rotations of the star wheel 20. This is equivalent to the position information of the star wheel 20 being reset every five rotations of the motor 31 (see equation (3)).

[0051] The abnormality detection unit 57 monitors the position information acquired by the measurement information acquisition unit 53 and detects abnormalities in the power transmission system 40. For example, if a localized fluctuation is observed in a graph showing the time change in the position of the star wheel 20 as shown in Fig. 4, it can be assumed that an abnormality has occurred somewhere in the power transmission system 40.

[0052] As described above, according to this embodiment, the period P for resetting the position information of the star wheel 20 is set based on the movement amount per rotation of the star wheel 20 and the gear ratio between the motor-side gear 41 and the wheel-side gear 42, making it possible to detect abnormalities caused by multiple factors that may occur in the power transmission system 40. As an example, an abnormality that occurs only in a specific combination of teeth between the motor-side gear 41 and the wheel-side gear 42 that mesh with each other will be periodically displayed in the graph representing the position of the star wheel 20 (see the solid line in Figure 4). Therefore, by investigating the state of the power transmission system 40 at the position of the star wheel 20 where such an abnormality occurs, it is possible to identify the cause of the abnormality.

[0053] The above describes the case where the power transmission system 40 includes two gears, but the period P for resetting the position information of the star wheel 20 can be set in a similar manner even when the power transmission system 40 includes three or more gears.

[0054] For example, when constructing a power transmission system using three gears, namely, a motor-side gear, a wheel-side gear, and one intermediate gear placed between them, first reduce the gear ratios of these three gears to become relatively prime integers. (Motor side gear): (Intermediate gear): (Wheel side gear) = a:b:c In the above equation, the values ​​a, b, and c are relatively prime integers.

[0055] The least common multiple of the gear ratios a, b, and c is a × b × c. Therefore, the period P for resetting the position information can be calculated using the following equation (4).

number

[0056] Furthermore, when the pulse signal output from the encoder 32 is used as a reference, the movement amount per rotation of the star wheel can be expressed using the following equation (5).

number

[0057] Therefore, the period P for resetting the position information can also be calculated by the following equation (6).

number

[0058] Even if the number of gears is four or more, the period P for resetting the position information can be calculated by multiplying the movement amount of one rotation of the star wheel by the least common multiple (or common multiple) of the gear ratios divided by the gear ratio of the wheel-side gear.

[0059] (Variation) The reset cycle for the position information of the star wheel 20 may be determined by taking into consideration the circumferential length of the conveyor 10 in addition to the gear ratio of the gears constituting the power transmission system. Specifically, the reset cycle can be calculated by multiplying the circumferential length of the conveyor 10 by the least common multiple (or common multiple) of the gear ratios divided by the gear ratio of the wheel-side gear for the amount of movement of one rotation of the star wheel 20. In this case, it is also possible to detect abnormalities that occur when the star wheel 20 and the conveyor 10 are in a specific positional relationship.

[0060] In the above embodiment, a star wheel is used as an example of a rotating body, but the rotating body is not limited to a star wheel and may be any rotating body with a phase, that is, a rotating body having one or more structures on its periphery that perform an action on a workpiece and periodically repeating the action of the structures through rotation. Other examples of rotating bodies are given below. (1) Rotary knife The rotating body may be a rotary knife having one or more blades (structures) on its periphery for cutting the workpiece. For example, the rotary knife may be arranged near a conveyor that transports the workpiece, and may cut the workpiece on the conveyor while rotating with the blades on its periphery.

[0061] (2) Roll with processing pattern The rotating body may be a roll having one or more patterns (structures) on its periphery for processing the workpiece. For example, the roll may be arranged near a conveyor that transports the workpiece, and while rotating, it may perform an operation of processing the workpiece on the conveyor using the patterns on its periphery.

[0062] The present invention is not limited to the above-described embodiments and modifications, and can be embodied in various other forms without departing from the spirit of the present invention. For example, some components may be removed from all of the components shown in the embodiments and modifications, or the components shown in the above-described embodiments and modifications may be appropriately combined.

[0063] Note that part or all of the above-described embodiments can be described as, but are not limited to, the following supplementary notes. (Appendix 1) a rotating body having one or more structures provided on its periphery for performing an operation on a workpiece, the rotating body periodically repeating the operation of the structures by rotation; a rotating shaft provided concentrically with the rotating body and rotating integrally therewith; a motor provided with a rotary encoder; a power transmission system including two or more gears, including a first gear attached to an output shaft of the motor and a second gear attached to the rotating shaft, and configured to transmit the output of the motor to the rotating shaft; a control unit configured to control the rotation of the motor based on an output signal of the rotary encoder, and to obtain and output position information of the rotating body based on the output signal; Equipped with A rotation control system, wherein the control unit is configured to set a period for resetting the position information of the rotating body based on the amount of movement of the rotating body per rotation and the gear ratio of the two or more gears. (Appendix 2) The rotation control system described in Appendix 1, wherein the period is set to a value obtained by multiplying the amount of movement of one rotation of the rotating body by a common multiple of the gear ratios of the two or more gears, when the gear ratios of the two or more gears are expressed as relatively prime integers, divided by the gear ratio of the second gear. (Appendix 3) 3. The rotation control system of claim 2, wherein the common multiple is the least common multiple of the gear ratios of the two or more gears. (Appendix 4) 4. The rotation control system according to any one of appendixes 1 to 3, wherein the control unit is further configured to acquire measurement information about the rotating body in association with the position information. (Appendix 5) 4. The rotation control system according to any one of appendixes 1 to 3, wherein the control unit is further configured to detect an abnormality in the power transmission system based on position information of the rotating body. (Appendix 6) Further comprising a conveyor configured to continuously transport the workpiece; the rotating body is disposed near the conveyor so as to be able to perform an operation on a workpiece on the conveyor; 4. The rotation control system according to any one of claims 1 to 3, wherein the control unit is further configured to set a period for resetting the position information based on a circumferential length of the conveyor. (Appendix 7) The rotation control system of Appendix 6, wherein the period is set to a value obtained by multiplying the circumferential length of the conveyor by a common multiple of the gear ratios of the two or more gears, when the gear ratios of the two or more gears are expressed as relatively prime integers, divided by the gear ratio of the second gear, for the amount of movement of one rotation of the rotating body. (Appendix 8) the rotating body is a star wheel having one or more pockets formed on its periphery for accommodating the workpiece; 7. The rotation control system of claim 6, wherein the star wheel is disposed near the conveyor so as to be able to transport a workpiece from the conveyor or to be able to transport a workpiece to the conveyor. (Appendix 9) A rotation control method applied in a rotation control system, comprising: The rotation control system includes: a rotating body having one or more structures provided on its periphery for performing an operation on a workpiece, the rotating body periodically repeating the operation of the structures by rotation; a rotating shaft provided concentrically with the rotating body and rotating integrally therewith; a motor provided with a rotary encoder; a power transmission system including two or more gears, including a first gear attached to an output shaft of the motor and a second gear attached to the rotating shaft, and configured to transmit the output of the motor to the rotating shaft; Equipped with controlling the rotation of the motor based on the output signal of the rotary encoder; acquiring and outputting position information of the rotating body based on the output signal; resetting the position information of the rotating body at a period calculated based on the amount of movement of the rotating body per rotation and the gear ratios of the two or more gears; A rotation control method comprising: [Explanation of symbols]

[0064] 1...Transport system, 2...Workpiece, 10, 12...Conveyor, 14...Infrared sensor, 16...Camera, 20, 60...Star wheel, 20a, 60a...Pocket, 20b, 60b...Claw portion, 21, 61...Rotating shaft, 22...Turntable, 30...Servo motor, 31...Motor, 32...Encoder, 33...Output shaft, 40...Power transmission system, 41...Motor side gear, 42...Wheel side gear, 50...Control unit, 51...Setting unit, 52...Signal receiving unit, 53...Measurement information acquisition unit, 54...Output unit, 55...Drive signal control unit, 56...Drive signal output unit, 57...Abnormality detection unit

Claims

1. a rotating body having one or more structures provided on its periphery for performing an operation on a workpiece, the rotating body periodically repeating the operation of the structures by rotation; a rotating shaft provided concentrically with the rotating body and rotating integrally therewith; a motor provided with a rotary encoder; a power transmission system configured to transmit the output of the motor to the rotating shaft, the power transmission system including two or more gears including a first gear attached to the output shaft of the motor and a second gear attached to the rotating shaft; a control unit configured to control the rotation of the motor based on an output signal of the rotary encoder, and to obtain and output position information of the rotating body based on the output signal; Equipped with A rotation control system, wherein the control unit is configured to set a period for resetting the position information of the rotating body based on the amount of movement of the rotating body per rotation and the gear ratio of the two or more gears.

2. 2. The rotation control system according to claim 1, wherein the period is set to a value obtained by multiplying the amount of movement of one rotation of the rotating body by a common multiple of the gear ratios of the two or more gears, when the gear ratios of the two or more gears are expressed as relatively prime integers, divided by the gear ratio of the second gear.

3. The rotation control system according to claim 2 , wherein the least common multiple of the gear ratios of the two or more gears is used as the common multiple.

4. 4. The rotation control system according to claim 1, wherein the control unit is further configured to acquire measurement information about the rotating body in association with the position information.

5. 4. The rotation control system according to claim 1, wherein the control unit is further configured to detect an abnormality in the power transmission system based on position information of the rotating body.

6. Further comprising a conveyor configured to continuously transport the workpiece; the rotating body is disposed near the conveyor so as to be able to perform an operation on a workpiece on the conveyor; The rotation control system according to any one of claims 1 to 3, wherein the control unit is further configured to set a period for resetting the position information based on a circumferential length of the conveyor.

7. 7. The rotation control system of claim 6, wherein the period is set to a value obtained by multiplying a common multiple of the gear ratios of the two or more gears, when the gear ratios of the two or more gears are expressed as relatively prime integers, by the gear ratio of the second gear, for the amount of movement of one rotation of the rotating body, by the circumferential length of the conveyor.

8. the rotating body is a star wheel having one or more pockets formed on its periphery for accommodating the workpiece; The rotation control system according to claim 6 , wherein the star wheel is disposed near the conveyor so as to be able to carry out a workpiece from the conveyor or to be able to carry a workpiece into the conveyor.

9. A rotation control method applied in a rotation control system, comprising: The rotation control system includes: a rotating body having one or more structures provided on its periphery for performing an operation on a workpiece, the rotating body periodically repeating the operation of the structures by rotation; a rotating shaft provided concentrically with the rotating body and rotating integrally therewith; a motor provided with a rotary encoder; a power transmission system configured to transmit the output of the motor to the rotating shaft, the power transmission system including two or more gears including a first gear attached to the output shaft of the motor and a second gear attached to the rotating shaft; Equipped with controlling the rotation of the motor based on the output signal of the rotary encoder; acquiring and outputting position information of the rotating body based on the output signal; resetting the position information of the rotating body at a period calculated based on the amount of movement of the rotating body per rotation and the gear ratios of the two or more gears; A rotation control method comprising:

Images