Control apparatus and control method thereof

Abstract

To perform highly accurate position control of a universal head using a motor.SOLUTION: A control device that drives a movable part using a motor includes a first reception unit that receives absolute position information of an output shaft that is a rotation shaft of the movable part, a second reception unit that receives relative position information of a motor shaft that is a rotation shaft of the motor, a generation unit that generates correction data corresponding to a plurality of positions of the output shaft based on the absolute position information and the relative position information, a setting unit that sets a coordinate origin of the relative position information based on the absolute position information, and a drive signal generation unit that generates a drive signal for the motor using the relative position information based on the coordinate origin. The setting means sets the coordinate origin on the basis of corrected position information obtained by correcting the absolute position information on the basis of the correction data.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a technology for controlling the position of a camera platform using a motor. [Background technology]

[0002] Remote cameras that can remotely control the shooting direction in the pan / tilt direction are being used. Furthermore, the applications of remote cameras are expanding to a wide range of applications, from surveillance cameras to video production. High-precision pan and tilt position control is required in video production. Patent Document 1 proposes a method for reducing pan / tilt position deviation by moving to a home position and resetting a step counter. Patent Document 2 proposes a method for eliminating linearity deviation, which is an issue when using a potentiometer as a position detection method, by also using a pulse encoder. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4599273 [Patent Document 2] Japanese Patent Application Publication No. 7-230031 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in Patent Document 1, to correct a positional deviation of the camera platform, the camera must first move to the home position and reset the step counter. This can result in unintended movement of the camera platform. Furthermore, there is the problem that the pan and tilt positions must be reset. Furthermore, in Patent Document 2, there is the problem that potentiometers generally have low resolution, making it impossible to achieve position detection accuracy higher than the resolution.

[0005] The present invention has been made in view of the above-mentioned problems, and aims to provide a technique that enables highly accurate position control of a camera platform using a motor. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems, the control device according to the present invention has the following configuration. That is, the control device that drives a moving part using a motor includes: a first receiving means for receiving absolute position information of an output shaft which is a rotation shaft of the movable part; a second receiving means for receiving relative position information of a motor shaft, which is a rotation shaft of the motor; a generating means for generating correction data corresponding to a plurality of positions of the output shaft based on the absolute position information and the relative position information; a setting means for setting the coordinate origin of the relative position information based on the absolute position information; a drive signal generating means for generating a drive signal for the motor using the relative position information based on the coordinate origin; Equipped with The setting means sets the coordinate origin based on corrected position information obtained by correcting the absolute position information based on the correction data. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a technique that enables highly accurate position control of a camera platform using a motor. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 2 is a diagram illustrating a configuration of a remote camera. [Figure 2] FIG. 10 is a diagram illustrating an initialization process of a motor encoder. [Figure 3] 10A and 10B are diagrams illustrating a linearity deviation of an output shaft encoder. [Figure 4] 10A and 10B are diagrams illustrating processing by a tilt (pan) correction unit. [Figure 5]10 is a flowchart showing the processing of a tilt (pan) correction unit. [Figure 6] 10A and 10B are diagrams illustrating averaging processing in a small section in a tilt (pan) correction unit. [Figure 7] 10 is a flowchart showing the processing of a tilt (pan) setting unit. [Figure 8] FIG. 10 is a diagram illustrating linear interpolation in a tilt (pan) setting unit. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the scope of the invention claimed. Although multiple features are described in the embodiments, not all of these multiple features are necessarily essential to the invention, and multiple features may be combined arbitrarily. Furthermore, in the accompanying drawings, the same reference numerals are used to designate the same or similar components, and redundant explanations will be omitted.

[0010] (First embodiment) A first embodiment of a control device according to the present invention will be described below by taking as an example a remote camera whose shooting direction can be changed in the pan / tilt direction.

[0011] <Device configuration> 1 is a diagram showing a schematic configuration of a remote camera 100. The remote camera 100 includes a camera head 110, camera head supports 120 and 130, a turntable 140, a bottom case 150, and a microcomputer processing unit 160 that performs pan / tilt drive control.

[0012] Camera head 110, which is an imaging device, is composed of a lens unit 111 and a charge-coupled device (CCD) sensor 112. The output of CCD sensor 112 is converted into a video signal via correlated double sampler (CDS) / automatic gain control (AGC) circuit 113 and signal processing unit 114, and is output to image display unit 115, which is externally connected.

[0013] Camera head support section 120 also serves as a drive section that drives camera head 110 in the tilt direction. A motor 122 (tilt drive motor) is driven by a motor drive signal generated by motor driver 121. A motor gear (gear) 123 is provided on the motor shaft of motor 122, and when motor 122 rotates, a drive gear 124 that meshes with motor gear 123 rotates. As a result, the rotation shaft of drive gear 124 serves as an output shaft to drive camera head 110 in the tilt direction.

[0014] Motor encoder 125 generates a pulse signal in response to the rotation of the motor shaft of motor 122. Here, it is assumed that motor encoder 125 is an incremental type encoder (relative value encoder). On the other hand, output shaft encoder 126 detects the position (phase angle) of drive gear 124, which is the rotation shaft (output shaft) of camera head 110 in the tilt direction. Here, an absolute type encoder (absolute value encoder) is used as the output shaft encoder.

[0015] Absolute value encoders include potentiometers with a simple structure and optical or magnetic linear encoders that obtain absolute values ​​with high precision by combining multiple periodic signals. While any of these encoders can be used to implement this embodiment, the following describes an optical linear encoder that obtains absolute values ​​by combining sine wave signals with three different periods—upper, middle, and lower. The sine wave signals are two-phase signals (sinusoidal (sinusoidal) and cosine (cosine)) with a 90° phase shift. Therefore, these signals are converted into angle information by arctangent (ATAN (sinusoidal) / cosine (cosine)) conversion, and the three types of angle information—upper, middle, and lower—are combined to obtain absolute position information (phase angle).

[0016] The bottom case 150 also serves as a drive unit that drives the camera head 110 in the pan direction. A motor 152 (pan drive motor) is driven by a motor drive signal generated by a motor driver 151. A motor gear 153 is provided on the motor shaft of the motor 152, and when the motor 152 rotates, the rotation is transmitted to a drive gear 154 that meshes with the motor gear 153. As a result, the rotation shaft of the drive gear 154 serves as an output shaft to drive the turntable 140 in the pan direction.

[0017] Motor encoder 155 generates a pulse signal in response to the rotation of motor 152. Output shaft encoder 156 detects the position (phase angle) of drive gear 154, which is the rotation shaft (output shaft) in the pan direction of camera head 110. Here, an absolute value encoder is used, similar to motor encoder 125 for tilt.

[0018] The microcomputer processing unit 160 includes a control block 170 for tilt position control and a control block 180 for pan position control. A pan / tilt (PT) controller 190 is an externally connected control device that outputs commands to the microcomputer processing unit 160 specifying target positions in the pan and tilt directions in accordance with instructions input by an operator. The microcomputer processing unit 160 is assumed to be configured using an application specific integrated circuit (ASIC), but some or all of its functions may be implemented by software. In this case, the microcomputer processing unit 160 includes, as components, a central processing unit (CPU), random access memory (RAM), and read-only memory (ROM) that stores programs.

[0019] First, the processing of the control block 170 that controls the tilt direction will be described. As the camera head 110 moves in the tilt direction, a detection signal is output from the output shaft encoder 126. The detection signal is received and quantized by an analog / digital (A / D) converter 171, and position information in the tilt direction (phase angle of the output shaft) is calculated by a tilt calculation unit 172. The position information in the tilt direction is calculated using a conversion coefficient k tilt The conversion coefficient k is multiplied and output. tiltis calculated as the ratio of the resolution of the motor encoder 125 to the resolution of the output shaft encoder 126 when the camera head (=tilt output shaft) rotates by a unit angle.

[0020] On the other hand, the pulse signal output from the motor encoder 125 is received and counted by a tilt measurement unit 173, and the relative position information (rotation angle) of the motor 122 is calculated from the count number. The coordinate origin of the rotation position of the motor is set via a tilt correction unit 174 and a tilt setting unit 175. The process of setting the origin coordinate will be described later. A tilt control unit 176 compares the target position instructed by the pan / tilt controller 190 with the rotation position of the motor 122 measured by the tilt measurement unit 173 to generate a motor drive signal and output it to the motor driver 121.

[0021] Next, the processing of the control block 180 that controls the pan direction will be described. As the camera head 110 moves in the pan direction, a detection signal is output from the output shaft encoder 156. The detection signal is received and quantized by an A / D converter 181, and position information in the pan direction (phase angle of the output shaft) is calculated by a pan calculation unit 182. The position information in the pan direction is calculated using a conversion coefficient k pan The conversion coefficient k is multiplied and output. pan is calculated as the ratio of the resolution of the motor encoder 155 to the resolution of the output shaft encoder 156 when the camera head (=pan output shaft) rotates by a unit angle.

[0022] Meanwhile, the pulse signal output from motor encoder 155 is received and counted by pan measurement unit 183, and the rotation angle of motor 152 is calculated from the count number. The coordinate origin of the rotation position of the motor is set via pan correction unit 184 and pan setting unit 185. The process of setting the origin coordinate will be described later. Pan control unit 186 compares the target position instructed by pan / tilt controller 190 with the rotation position of motor 152 measured by pan measurement unit 183, generates a drive signal for the motor, and outputs it to motor driver 151.

[0023] <Motor rotation position coordinate setting> Next, we will explain how to set the coordinates of the motor rotation position. Note that since the processing for the tilt direction and pan direction is similar, we will explain the tilt direction below and omit the explanation for the pan direction. Note that in Figures 2 to 7, differences in the pan direction are written in parentheses.

[0024] FIG. 2 is a diagram illustrating the concept of motor encoder initialization processing. Initialization processing is processing for setting the coordinate origin of the motor encoder based on the output value of the output shaft encoder. While FIG. 2 shows the encoder detection values ​​of the output shaft and motor in the tilt direction, the same applies to the pan direction. In FIG. 2, the horizontal axis represents the tilt position (phase angle) and the vertical axis represents the encoder detection value.

[0025] A solid line 201 indicates the characteristics of the output shaft encoder. For example, when the remote camera 100 is powered on with its orientation at tilt position P, the tilt calculation unit 172 outputs tilt direction position information 202 corresponding to tilt position P. Meanwhile, the tilt measurement unit 173 is a relative value counter that measures pulse signals. Therefore, when the power is turned on, the counter value is set to "0" as indicated by initial value 204. Therefore, in the initialization process indicated by arrow 205, the coordinate origin of the motor encoder is set to the position information calculated by the tilt calculation unit 172. Once the coordinate origin is set, the motor encoder 203 measures position information (position coordinates) in the same coordinate system as the output shaft encoder 201, as indicated by characteristic 203 (converted position information) converted into an absolute position in accordance with the rotation angle (movement of the tilt position). Note that, for the sake of explanation, the characteristics 201 and 203 are depicted shifted in FIG. 2.

[0026] However, it is generally known that the absolute position information (phase angle) obtained by an absolute value encoder has a linearity deviation (error). That is, in this embodiment, an absolute value encoder is used as the output shaft encoder, so that the detected value of the output shaft encoder has a linearity deviation.

[0027] FIG. 3 is a diagram illustrating the linearity deviation of the output shaft encoder. Curve 301 shows the output characteristics of the output shaft encoder with deviation. In this case, when the power is turned on at tilt position P, the output of position information in the tilt direction is point 302-1. If the above-mentioned initialization process is performed at this position, the characteristics of the motor encoder in response to the movement of the tilt position will be as shown in characteristic 303-1. On the other hand, when the power is turned on at tilt position Q, the output of position information in the tilt direction is point 302-2. If the above-mentioned initialization process is performed at this position, the characteristics of the motor encoder in response to the movement of the tilt position will be as shown in characteristic 303-2.

[0028] Therefore, the coordinates of the motor encoder will be shifted depending on the position in the tilt direction at the time the power is turned on. As a result, a position shift will occur in the shot function (a function that sets the camera attitude to a preset position). For example, when the power is turned on at point P and the motor encoder position is preset to point 331, if the power is turned off once and then turned on again at point Q and the shot function is used to move to the preset position, a shot position shift 332 will occur due to the shift in the motor encoder.

[0029] Therefore, in the first embodiment, the tilt correction unit 174 (and the pan correction unit 184) calculates correction data, and the tilt setting unit 175 (and the pan setting unit 185) corrects the motor coordinates using the correction data. This corrects the deviation of the absolute value in the output shaft encoder, making it possible to set the shot position with high precision.

[0030] <Device Operation> The method of calculating the correction data will be described below with reference to Figures 4 and 5. Note that the processing for the tilt direction and the pan direction is similar, so the following description will focus on the tilt direction.

[0031] 4 is a diagram illustrating the calculation process of correction data in the tilt (pan) correction unit. The calculation process of the correction data is performed when the remote camera is installed and / or prior to shooting, for example, in an operation mode such as an adjustment mode in the remote camera 100.

[0032] In the adjustment mode, the tilt correction unit 174 calculates linearity deviation correction data 411 and stores it as a correction table (for example, a look-up table (LUT)). As shown in the figure, the correction data 411 is calculated as a difference between an output shaft encoder characteristic 401 and a motor encoder characteristic 403 for a plurality of small sections (a plurality of phase angle sections in the output shaft).

[0033] 5 is a flowchart showing the processing of the tilt (pan) correction unit, which is executed when, for example, the user selects operation in the adjustment mode.

[0034] In S501, the tilt correction unit 174 sets position information obtained from the output shaft encoder in the tilt direction to AbsEnc. This position information is set as a temporary coordinate origin for MotEnc, which is the position information of the motor encoder. In addition, various parameters SumDiff, n, and s are cleared to zero. SumDiff is the cumulative error, n is the number of sampling counts in one small section, and s is the number of counts in the processed small section. In S502, the tilt correction unit 174 drives the tilt motor to move the tilt direction of the camera head 110 toward the bottom end. In S503, the tilt correction unit 174 drives the tilt motor to start moving the tilt direction of the camera head 110 toward the top end at a constant speed.

[0035] In S504, the tilt correction unit 174 samples the correction data. For data sampling, the position information of the output shaft encoder is set to AbsEnc, and the position information of the motor encoder is set to MotEnc. Furthermore, the difference between the two is set to diff, and diff is added to SumDiff. In S505, the tilt correction unit 174 determines whether the tilt direction of the camera head 110 has moved from the small interval sampled in S504 (entered the next small interval). If it has not moved, the process returns to S504; if it has moved to the next small interval, the process proceeds to S506.

[0036] In S506, the tilt correction unit 174 calculates the average value of the multiple diffs obtained in the small section. In S507, the tilt correction unit 174 stores the average value calculated in S506 in a correction table (LUT) in association with AbsEnc as correction data for the small section s.

[0037] In S508, the tilt correction unit 174 determines whether or not the tilt direction of the camera head 110 has reached the upper end. If the upper end has not been reached, the process returns to S504, and if the upper end has been reached, the process ends.

[0038] FIG. 6 illustrates the averaging process (S506) for small intervals in the tilt (pan) correction unit. As described above, the output shaft encoder obtains angle information by performing an arctangent transform on a sine wave signal with three periods—upper, middle, and lower. Therefore, if the sine wave signal is distorted, a periodic fluctuation (ripple) like that shown in curve 601 occurs in the angle information obtained corresponding to the tilt position. This periodic fluctuation is difficult to correct because its shape and phase change with environmental changes. Therefore, small intervals equivalent to N times the ripple period (N is a natural number) are determined, multiple differences (diffs) are calculated for each small interval, and the average value 603 of the multiple differences is stored as correction data for the corresponding small interval (representative position). The narrower the phase angle range of each small interval, the more correction data can be set for that small interval. Therefore, the phase angle range of each small interval is set to correspond to one ripple period.

[0039] Next, referring to FIGS. 7 and 8, the setting of the coordinate origin of the motor encoder when the power is turned on will be described.

[0040] FIG. 7 is a flowchart showing the processing of the tilt (pan) setting unit. This processing is executed, for example, when the power is turned on.

[0041] In S701, the tilt setting unit 175 sets the position information obtained from the output shaft encoder in the tilt direction to AbsDet.

[0042] In S702, the tilt setting unit 175 compares AbsEnc(s) corresponding to the small section s in the correction table with AbsDet. If AbsDet ≦ AbsEnc(s), the process proceeds to S704; otherwise, in S703, s is incremented and the focused small section is moved. By this processing, the small section s that satisfies AbsEnc(s - 1) < AbsDet ≦ AbsEnc(s) is specified.

[0043] In S704, the tilt setting unit 175 calculates the correction value 806 corresponding to the tilt position of AbsDet. Here, it is assumed that linear interpolation is performed, but the correction value 806 may be calculated by other known interpolation methods.

[0044] FIG. 8 is a diagram for explaining linear interpolation in the tilt (pan) setting unit. As described above, the small section s specified in S702 satisfies AbsEnc(s - 1) < AbsDet ≦ AbsEnc(s). Also, as described above, the correction data stores AbsEnc(s) and Diff(s) corresponding to the small section s. Therefore, the correction value 806 corresponding to AbsDet is calculated by linear interpolation using Diff(s - 1) and Diff(s).

[0045] In S705, the tilt setting unit 175 corrects AbsDet using the correction value 806 and sets it to MotDet. In S706, the tilt setting unit 175 executes setting (initialization processing) of the coordinate origin of the motor encoder using the corrected position information MotDet (corrected position information).

[0046] As described above, according to the first embodiment, a correction table is derived based on the difference (deviation) between the detection value of the absolute value encoder of the output shaft and the detection value of the motor encoder of the motor shaft. Then, when setting the coordinate origin of the motor encoder (initialization processing), the detection value (AbsDet) of the output shaft encoder is corrected by referring to the correction table. This enables initialization processing with reduced influence of linearity deviation in the absolute value encoder. This enables highly accurate position control of the pan head using a motor.

[0047] In the first embodiment described above, the position (phase angle) control of the motor used in the pan / tilt head of the remote camera has been described. However, the present invention can also be applied to any other device / system that uses a motor to control the position of a moving part and that uses a relative value encoder and an absolute value encoder in combination.

[0048] The disclosure of this specification includes the following control device, control method, and program. (Item 1) A control device that drives a moving part using a motor, a first receiving means for receiving absolute position information of an output shaft which is a rotation shaft of the movable part; a second receiving means for receiving relative position information of a motor shaft, which is a rotation shaft of the motor; a generating means for generating correction data corresponding to a plurality of positions of the output shaft based on the absolute position information and the relative position information; a setting means for setting the coordinate origin of the relative position information based on the absolute position information; a drive signal generating means for generating a drive signal for the motor using the relative position information based on the coordinate origin; Equipped with The setting means sets the coordinate origin based on corrected position information obtained by correcting the absolute position information based on the correction data. A control device characterized by: (Item 2) the first receiving means receives the absolute position information from a first encoder that detects a phase angle of the output shaft; The second receiving means receives the relative position information from a second encoder that detects the rotation angle of the motor shaft. 2. The control device according to item 1, (Item 3) a conversion means for converting the relative position information into converted position information in the position coordinates of the output shaft; The generating means generates the correction data based on the difference between the absolute position information and the converted position information. 3. The control device according to item 2, (Item 4) a motor gear coupled to the motor shaft and a drive gear coupled to the output shaft meshing with each other, thereby transmitting rotation of the motor shaft to rotation of the output shaft; The conversion means converts the relative position information into the converted position information based on a ratio of the resolution of the first encoder to the resolution of the second encoder when the output shaft rotates by a unit angle. 4. The control device according to item 3, (Item 5) each of the plurality of positions is a representative position of each of a plurality of phase angle intervals of the output shaft; The generating means calculates a plurality of the differences for each of the plurality of phase angle sections, and generates an average value of the calculated differences as correction data corresponding to the representative position of the corresponding phase angle section. 5. The control device according to item 3 or 4. (Item 6) the absolute position information output from the first encoder periodically varies in response to a change in the absolute position of the output shaft; The phase angle interval is determined based on the period of the fluctuation. 6. The control device according to item 5, (Item 7) The phase angle interval is an interval corresponding to one period of the fluctuation. 7. The control device according to item 6, (Item 8) the movable part is an imaging device, The motor is a pan drive motor or a tilt drive motor for changing the shooting direction of the imaging device. 8. The control device according to any one of items 1 to 7, (Item 9) A control method for a control device that drives a moving part using a motor, comprising: a first receiving step of receiving absolute position information of an output shaft which is a rotation shaft of the movable part; a second receiving step of receiving relative position information of a motor shaft that is a rotation shaft of the motor; a generating step of generating correction data corresponding to a plurality of positions of the output shaft based on the absolute position information and the relative position information; a setting step of setting a coordinate origin of the relative position information based on the absolute position information; a drive signal generating step of generating a drive signal for the motor using the relative position information based on the coordinate origin; Including, In the setting step, the coordinate origin is set based on corrected position information obtained by correcting the absolute position information based on the correction data. A control method comprising: (Item 10) A program for causing a computer to execute the control method described in item 9.

[0049] (Other Examples) The present invention can also be realized by supplying a program that realizes one or more functions of the above-described embodiments to a system or device via a network or a storage medium, and having one or more processors in the computer of the system or device read and execute the program.The present invention can also be realized by a circuit (e.g., ASIC) that realizes one or more functions.

[0050] The invention is not limited to the above-described embodiments, and various changes and modifications can be made without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention. [Explanation of symbols]

[0051] 100 remote camera; 110 camera head; 120, 130 camera head support; 140 turntable; 150 bottom case; 122, 152 motor; 125, 155 motor encoder; 126, 156 output shaft encoder; 174 tilt correction unit; 175 tilt setting unit; 176 tilt control unit; 184 pan correction unit; 185 pan setting unit; 186 pan control unit

Claims

1. A control device that drives a moving part using a motor, a first receiving means for receiving absolute position information of an output shaft which is a rotation shaft of the movable part; a second receiving means for receiving relative position information of a motor shaft, which is a rotation shaft of the motor; a generating means for generating correction data corresponding to a plurality of positions of the output shaft based on the absolute position information and the relative position information; a setting means for setting the coordinate origin of the relative position information based on the absolute position information; a drive signal generating means for generating a drive signal for the motor using the relative position information based on the coordinate origin; Equipped with The setting means sets the coordinate origin based on corrected position information obtained by correcting the absolute position information based on the correction data. A control device characterized by:

2. the first receiving means receives the absolute position information from a first encoder that detects a phase angle of the output shaft; The second receiving means receives the relative position information from a second encoder that detects the rotation angle of the motor shaft.

2. The control device according to claim 1.

3. a conversion means for converting the relative position information into converted position information in the position coordinates of the output shaft; The generating means generates the correction data based on the difference between the absolute position information and the converted position information.

3. The control device according to claim 2.

4. a motor gear coupled to the motor shaft and a drive gear coupled to the output shaft meshing with each other, thereby transmitting rotation of the motor shaft to rotation of the output shaft; The conversion means converts the relative position information into the converted position information based on a ratio of the resolution of the first encoder to the resolution of the second encoder when the output shaft rotates by a unit angle.

4. The control device according to claim 3.

5. each of the plurality of positions is a representative position of each of a plurality of phase angle intervals of the output shaft; The generating means calculates a plurality of the differences for each of the plurality of phase angle sections, and generates an average value of the calculated differences as correction data corresponding to the representative position of the corresponding phase angle section.

4. The control device according to claim 3.

6. the absolute position information output from the first encoder periodically varies in response to a change in the absolute position of the output shaft; The phase angle interval is determined based on the period of the fluctuation.

6. The control device according to claim 5.

7. The phase angle interval is an interval corresponding to one period of the fluctuation.

7. The control device according to claim 6.

8. the movable part is an imaging device, The motor is a pan drive motor or a tilt drive motor for changing the shooting direction of the imaging device.

2. The control device according to claim 1.

9. A control method for a control device that drives a moving part using a motor, comprising: a first receiving step of receiving absolute position information of an output shaft which is a rotation shaft of the movable part; a second receiving step of receiving relative position information of a motor shaft that is a rotation shaft of the motor; a generating step of generating correction data corresponding to a plurality of positions of the output shaft based on the absolute position information and the relative position information; a setting step of setting a coordinate origin of the relative position information based on the absolute position information; a drive signal generating step of generating a drive signal for the motor using the relative position information based on the coordinate origin; Including, In the setting step, the coordinate origin is set based on corrected position information obtained by correcting the absolute position information based on the correction data. A control method comprising:

10. A program for causing a computer to execute the control method according to claim 9.

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