Position detecting device and method

Abstract

Provided is a position detecting device capable of stably detecting the position of a slider even if signals detected by a sensor of a module vary between sliders. A position detecting device (51) is used in a conveying device in which a plurality of sliders (4) move along a conveying path having at least one module (7). The position detecting device (51) comprises: a position scale (32a) provided on each slider (4); sensors (29) provided in the module (7) to detect the position scale (32a); a parameter detecting unit (54) that detects, for each slider (4), a parameter for adjusting a Lissajous figure obtained from an A-phase signal and a B-phase signal obtained by digitally converting signals output by the sensors (29); and a correcting unit (55) for correcting, for each slider (4), at least one of the A-phase signal and the B-phase signal on the basis of the parameter.

Description

Position detection device and method

[0001] The present invention relates to a position detection device and method used in a conveying device in which a plurality of sliders move along a conveying path.

[0002] A conveying device has been developed in which multiple sliders move along a conveying path (see Patent Document 1). The conveying path is configured by combining at least one module. The module is provided with multiple coils that serve as stators of a linear motor and a drive circuit that controls the power supplied to the multiple coils. The slider is provided with a permanent magnet that serves as a mover of the linear motor. When the power supplied to the multiple coils is controlled by the drive circuit and a moving magnetic field is generated in the multiple coils, the slider moves along the conveying path.

[0003] This conveying device is characterized by its superior flexibility compared to conventional belt conveyors. For example, unlike conventional belt conveyors, it does not require multiple sliders to be moved simultaneously; instead, multiple sliders can be moved and positioned individually. Furthermore, by appropriately rearranging the modules, it is possible to create an appropriate conveying path depending on the application. For this reason, this conveying device is used in a variety of applications (manufacturing, processing, packaging, etc.).

[0004] A position scale is provided on the slider to detect its position. A sensor that detects the slider position scale is provided on the module. The slider position is detected based on A-phase and B-phase signals that are digitally converted from the signal output by the sensor on the module. The slider is then servo-controlled so that the detected slider position follows the target position.

[0005] JP 2023-19218 A

[0006] However, in this conveyance device, signals detected by the module sensors (such as magnetic flux density detected by a magnetic sensor) vary from slider to slider due to various factors (such as manufacturing variations in the scale and variations in the processed dimensions of the slider). It is difficult to suppress these variations, and if the variations become too large, errors in detecting the slider position occur, making the device uncontrollable.

[0007] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a position detection device and method that can stably detect the position of a slider even if the signals detected by the module sensor vary from slider to slider.

[0008] In order to solve the above problem, one aspect of the present invention is a position detection device used in a conveying device in which a plurality of sliders move along a conveying path having at least one module, the position detection device comprising: a position scale provided on the slider; a sensor provided on the module and detecting the position scale; a parameter detection unit that detects, for each slider, parameters for adjusting a Lissajous figure obtained from A-phase signals and B-phase signals obtained by digitally converting signals output by the sensor; and a correction unit that corrects at least one of the A-phase signals or the B-phase signals for each slider based on the parameters.

[0009] Another aspect of the present invention is a position detection method used in a conveying device in which a plurality of sliders move along a conveying path having at least one module, the position detection method comprising the steps of: detecting a position scale provided on the slider using a sensor provided on the module; detecting parameters for each slider to adjust a Lissajous figure obtained from A-phase signals and B-phase signals obtained by digitally converting signals output by the sensor; and correcting at least one of the A-phase signals or the B-phase signals for each slider based on the parameters.

[0010] According to the present invention, even if the signals detected by the sensor of the module vary from slider to slider, the position of the slider can be detected stably.

[0011] 8(a) shows an ideally adjusted Lissajous figure, and FIG. 8(b) shows a Lissajous figure with a gain deviation. FIG. 8(b) is a diagram showing the transfer of a slider from a belt conveyor to a detachable module. FIG. 8(c) is a diagram showing the switching from open control to servo control of a module controller of a detachable module. FIG. 8(d) is a flowchart of a position detection method according to an embodiment of the present invention. FIG. 8(a) shows an ideally adjusted Lissajous figure, and FIG. 8(b) shows a Lissajous figure with a gain deviation. FIG. 8(c) is a diagram showing the transfer of a slider from a belt conveyor to a detachable module. FIG. 8(d) is a diagram showing the switching from open control to servo control of a module controller of a detachable module. FIG. 8(d) is a flowchart of a position detection method according to an embodiment of the present invention.

[0012] Hereinafter, a position detection device and method according to an embodiment of the present invention will be described with reference to the accompanying drawings. However, the position detection device and method according to the present invention can be embodied in various forms and are not limited to the embodiments described herein. The present embodiment is provided with the intention that those skilled in the art will be able to fully understand the invention by fully disclosing the specification. (Transportation device)

[0013] 1 is a schematic diagram of a conveying device 1. The conveying device 1 includes a conveying path 2 having a belt conveyor 6, a detachable module 7, and a plurality of linear modules 3. The linear modules 3 are linear and connected end to end. Actuators 5 that perform work are disposed near the linear modules 3. The positions of the linear modules 3 facing the actuators 5 are identified by unique position numbers A, B, C, and D.

[0014] To form a closed conveying path 2, a belt conveyor 6 and a removable module 7 are provided on the conveying path 2. For example, the removable module 7 on the left side receives the slider 4 from the belt conveyor 6, moves the received slider 4 in the axial direction of the removable module 7, and hands over the slider 4 to the linear module 3. The removable module 7 on the right side receives the slider 4 from the linear module 3, moves the received slider 4 in the axial direction of the removable module 7, and hands over the slider 4 to the belt conveyor 6. The belt conveyor 6 moves the slider 4 in the opposite direction to the linear module 3. This causes the slider 4 to circulate on the conveying path 2. Note that the conveying path 2 may be arranged in a horizontal plane and the slider 4 may circulate horizontally as shown in FIG. 1 , or the conveying path 2 may be arranged in a vertical plane and the slider 4 may circulate vertically.

[0015] The conveying device 1 is controlled by a centralized controller 8. The centralized controller 8 is a general-purpose PLC (Programmable Logic Controller), a personal computer, or the like. The centralized controller 8 includes a processor, a memory, and a communication interface. The memory includes a ROM and a RAM.

[0016] For example, the centralized controller 8 generates a target position command to move the slider 4 to position number A and sends it to the detachable module 7 and the module controller 24 of the linear module 3 (see FIG. 6 ) via the controller 9. When the slider 4 reaches point A, the module controller 24 of the linear module 3 sends a signal to the centralized controller 8 via the controller 9 indicating that the slider 4 has reached position number A. Upon receiving this signal, the centralized controller 8 sends a command to start work to the actuator controller 10. The actuator controller 10 is a PLC, a personal computer, or the like, and controls the actuators 5 to work. When the actuators 5 have finished working, the centralized controller 8 moves the slider 4 to position number B. When all the actuators 5 have finished working, the centralized controller 8 moves the slider 4 to the detachable module 7. The centralized controller 8 then controls the detachable module 7 and the belt conveyor 6 so that the slider 4 circulates.

[0017] The centralized controller 8 and the controllers 9 are connected by a communication link 12 such as DeviceNet, EtherCAT, or EtherNET / IP. The centralized controller 8 and the actuator controllers 10 are also connected by a similar communication link 13. The controller 9 and the module controllers 24 of the detachable modules 7 and linear modules 3 (see FIG. 6) are connected by a communication line 14 capable of synchronous communication such as RS485 or I2C. The module controllers 24 of the detachable modules 7 and linear modules 3 (see FIG. 6) are connected to each other by a communication line 15 capable of synchronous communication such as RS485 or I2C.

[0018] The controller 9 executes the configuration software 11 when the conveyance device 1 is started up. As a result, the memory 36 of the controller 9 (see FIG. 6) stores the machine coordinates (movement coordinates) corresponding to the unique position numbers A, B, C, and D. The memory 36 of the controller 9 also stores the speed, acceleration, jerk, etc. used when the module controllers 24 of the detachable module 7 and linear module 3 create the motion profile (speed curve) of the slider 4. (Linear module)

[0019] As shown in FIG. 2 , the linear module 3 includes a stator 20 having a plurality of coils 21. As shown in FIG. 4 , a plurality of stators 20 (four in this embodiment) are provided for one linear module 3. Each stator 20 includes a plurality of sets (two sets in this embodiment) of coils 21 for U, V, and W phases. Power is supplied to the stator 20 by a drive circuit 22. The drive circuit 22 is a power converter such as a PWM inverter, and is connected to a power line (not shown). The drive circuit 22 is controlled by a module controller 24. A plurality of drive circuits 22 (four in this embodiment) are provided for one module controller 24. The drive circuit 22 is disposed on a driver board 23 shown in FIG. 3 . The module controller 24 is also disposed on the driver board 23 shown in FIG. 3 .

[0020] As shown in Fig. 3, the linear module 3 includes a linear guide 25 that smoothly guides the linear movement of the slider 4. A rail 26 of the linear guide 25 is attached to a base 28 of the linear module 3. As shown in Fig. 5, a carriage 27 of the linear guide 25 is attached to the slider 4.

[0021] The linear module 3 is provided with a sensor for detecting the identification ID of the slider 4, a sensor for detecting the position of the slider 4, and a sensor for detecting the magnetic pole position of the slider 4. These sensors are collectively indicated by the reference numeral 29 in FIG. 3. In this embodiment, four sensors 29 are provided for each stator 20. The sensors 29 are magnetic sensors such as Hall sensors or magnetoresistive sensors. The sensors 29 are arranged on a sensor board 30. (Detachable Module)

[0022] As shown in Figure 1, the removable module 7 includes a linear module section 7a and an axial movement mechanism 7b that moves the linear module section 7a in the axial direction of the removable module 7. The configuration of the linear module section 7a is substantially the same as that of the linear module 3. The axial movement mechanism 7b is composed of a feed screw, a linear motor, etc. (Slider)

[0023] As shown in Figure 5, the slider 4 is equipped with a driving permanent magnet 31 that serves as the mover of the linear motor. The slider 4 is provided with an AB scale 32a as a position scale and an NS scale 32b as a magnetic pole position scale. The AB scale 32a and the NS scale 32b are magnetic scales and are parallel to each other. The magnetic pole pitch (NN distance) of the NS scale 32b is equal to the magnetic pole pitch of the driving permanent magnet 31. The magnetic pole pitch of the AB scale 32a is smaller than the magnetic pole pitch of the NS scale 32b. (Conveyance Device System)

[0024] 6 shows a configuration diagram of the conveyance device system. The conveyance device system includes a centralized controller 8, a controller 9, and a plurality of module controllers 24. As described above, the centralized controller 8 is a general-purpose PLC or the like. The controller 9 is a computer such as a personal computer. The controller 9 includes a processor 35, a memory 36, and a communication interface 37. The memory 36 includes a ROM and a RAM. The processor 35 executes a program stored in the memory 36. The controller 9 may be a microcomputer or an electric circuit such as an FPGA (Field Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit).

[0025] The centralized controller 8 and the controllers 9 are connected by a communication link 12 such as the above-mentioned DeviceNet. The controller 9 and the module controllers 24 are connected by a communication line 14 such as the above-mentioned RS485 or I2C. Adjacent module controllers 24 are also connected by a communication line 15 such as the above-mentioned RS485 or I2C.

[0026] The controller 9 converts the target position command (position number A, B, C, D) of the slider 4 received from the centralized controller 8 into a target position command (movement coordinates), and transmits the target position command (movement coordinates) to all module controllers 24.

[0027] The module controller 24 is a microcomputer. The module controller 24 controls the drive circuits 22 of the detachable module 7 and the linear module 3. The module controller 24 includes a processor 38, a memory 39, a communication interface 40, and an interface circuit 41. The memory 39 includes a ROM and a RAM. The module controller 24 may be a computer such as a personal computer, or an electric circuit such as an FPGA or ASIC.

[0028] All module controllers 24 receive a target position command for the slider 4 from the controller 9. The module controller 24 of the detachable module 7 or linear module 3 in which the slider 4 is present creates a motion profile (speed curve, etc.) of the slider 4 based on the received target position command, generates a movement command (position command and speed command, or position command), and controls the drive circuit 22. When the slider 4 transfers from one stator 20 to another stator 20, the module controller 24 switches the drive circuit 22. When the slider 4 transfers from the detachable module 7 to the linear module 3, the module controller 24 of the linear module 3 takes over the motion profile and controls the drive circuit 22 of the linear module 3. The same applies when the slider 4 transfers from one linear module 3 to another linear module 3.

[0029] The module controller 24 includes an interface circuit 41. The interface circuit 41 processes the output signal of the sensor 29 that detects the position of the slider 4 so that it can be feedback-controlled. The interface circuit 41 also processes the output signal of the current sensor 42 that detects the current in the stator 20 so that it can be feedback-controlled.

[0030] The processor 38 of the module controller 24 controls the position, speed, and current of the slider 4. That is, the processor 38 generates a speed command based on the deviation between the position command of the movement command and the current position detected by the sensor 29. Then, it generates a current command based on the deviation between the speed command and the current speed detected by the sensor 29. Then, it generates a voltage command based on the deviation between the current command and the current current detected by the current sensor 42. The drive circuit 22 converts DC power to AC power using switching elements based on the voltage command generated by the processor 38, and supplies the AC power to the stator 20. The magnetic pole position of the slider 4 detected by the sensor 29 is used to determine the phase of the three-phase AC power to be supplied to the stator 20. (Position Detection Device)

[0031] FIG. 7 is a block diagram of the position detection device 51. As shown in FIG. 7, the position detection device 51 includes an AB scale 32a provided on the slider 4, a sensor 29 provided on the removable module 7, an A / D conversion circuit 52, a position counter circuit 53, a parameter detection unit 54, a correction unit 55, and an interpolation processing unit 56. The A / D conversion circuit 52 and the position counter circuit 53 are provided on the sensor board 30 (see FIG. 3) of the removable module 7, and constitute the interface circuit 41 (see FIG. 6) of the module controller 24 of the removable module 7. The parameter detection unit 54, the correction unit 55, and the interpolation processing unit 56 are realized by the processor 38 (see FIG. 6) of the module controller 24 of the removable module 7 executing a program stored in the ROM of the memory 39.

[0032] The sensor 29 generates two sinusoidal A-phase and B-phase signals that are out of phase with each other in accordance with the amount of movement of the slider 4. The A / D conversion circuit 52 converts the sinusoidal A-phase and B-phase signals into digital values. S / H 61 is a sample-and-hold circuit, and A / D 62 is an analog-to-digital converter.

[0033] The position counter circuit 53 shapes the waveforms of the two sinusoidal A-phase and B-phase signals output from the sensor 29, converting them into square waves to determine the moving direction of the slider 4 and incrementing or decrementing the count value. The waveform shaping circuit 63 shapes the waveforms of the sinusoidal A-phase and B-phase signals, converting them into square waves. The pulse counter 64 determines the moving direction of the slider 4 from the square waves that are 90 degrees out of phase and output from the waveform shaping circuit 63 and increments or decrements the count value.

[0034] There is a processing limit to the magnetic pole pitch of the AB scale 32a. To measure intervals finer than the magnetic pole pitch of the AB scale 32a, it is necessary to interpolate the A-phase signal and the B-phase signal obtained by converting the signal output by the sensor 29 into digital form. Ideally, the A-phase signal and the B-phase signal should be cosine waves and sine waves that are 90 degrees out of phase with each other, and it is desirable that the Lissajous figure obtained from the A-phase signal and the B-phase signal be a circle whose center coincides with the origin, as shown in Figure 8(a). However, in reality, the amplitudes of the A-phase signal and the B-phase signal are not ideal, as shown in the following equations (1) and (2), and the Lissajous figure obtained from the A-phase signal and the B-phase signal becomes an ellipse, for example, as shown in Figure 8(b). X = K Ａ cosθ...(1) Y=K Ｂ sin θ ... (2) where K Ａ , K. Ｂ are the amplitudes of the A-phase signal and the B-phase signal.

[0035] The interpolation processing unit 56 calculates the interpolated signal θ using the following equation (3), so if the Lissajous figure deviates from an ideal circle, an error occurs in the interpolated signal θ. －１ (K Ａ sinθ / K Ｂ cosθ) ... (3)

[0036] The parameter detection unit 54 detects parameters for adjusting the Lissajous figure shown in Fig. 8(b) to the ideal Lissajous figure shown in Fig. 8(a). Specifically, the A-phase signal and B-phase signal as shown in the above equations (1) and (2) are output from the sensor 29 for each slider 4, and when these are converted into digital data and input to the parameter detection unit 54, the parameter detection unit 54 detects the amplitude K Ａ , K. Ｂ and the amplitude ratio (gain) K Ａ / K Ｂ The slider identification ID and gain are stored in the RAM of the memory 39.

[0037] The correction unit 55 multiplies the B-phase signal of equation (2) by the gain for each slider 4 based on the identification ID and gain of the slider 4, and obtains correction signals X' and Y' with equal amplitude as shown in equations (4) and (5). By correcting the B-phase signal for each slider 4 in this way, an ideal Lissajous figure can be obtained. X'=K Ａ cosθ...(4) Y'=(K Ａ / K Ｂ ) K Ｂ sinθ=K Ａ sin θ ... (5)

[0038] The interpolation processing unit 56 performs interpolation processing using the correction signals X' and Y', and calculates an interpolation signal θ', which is the position within one period of the sine wave, as shown in equation (6). θ'=tan －１ (Y' / X')=tan －１ (K Ａ sinθ / K Ａ cosθ) ... (6)

[0039] The processor 38 of the module controller 24 adds the interpolated signal θ' to the position data output from the position counter circuit 53. This makes it possible to calculate the position of the slider 4 from the sensors 29. The absolute positions of each sensor 29 from the mechanical origin are stored in advance in the memory 39. The processor 38 adds the position of the slider 4 from the sensors 29 to the absolute positions of the sensors 29. This makes it possible to calculate the absolute position of the slider 4. The absolute position (current position) of the slider 4 is used as a feedback signal.

[0040] In the above embodiment, the gain is used as a parameter for adjusting the Lissajous figure, but an offset value and a phase difference α may also be used as parameters. This is because, as shown in the following equations (7) and (8), not only the amplitudes of the A-phase signal and the B-phase signal but also the offset value and α may not be ideal. X=K Ａ cosθ+O Ａ ... (7) Y = K Ｂ cos(θ+α)+O Ｂ ...(8) Here, K Ａ , K. Ｂ are the amplitudes of the A-phase signal and B-phase signal, and O Ａ, O Ｂ is the offset value (DC component) of the A-phase signal and the B-phase signal, and α is the phase difference (α=90 degrees in the ideal state).

[0041] There are no particular limitations on how to calculate the gain, offset value, and phase difference α. For example, the gain and offset values ​​may be calculated from the values ​​when the A-phase signal and the B-phase signal cross zero, and the phase difference α may be calculated from the phase difference when X=Y.

[0042] 9 shows the transfer of the slider 4 from the belt conveyor 6 (another transport device) to the detachable module 7. The position detection device 51 is provided in the detachable module 7. The module controller 24 of the detachable module 7 transmits the identification ID and parameters of the slider 4 to the module controller 24 of the linear module 3 (another module). The module controller 24 of the linear module 3 stores the identification ID and parameters of the slider 4 in the RAM of the memory 39, corrects the A-phase signal and B-phase signal for each slider 4 based on the identification ID and parameters of the slider 4, and calculates the absolute position of the slider 4.

[0043] The module controller 24 of the detachable module 7 may transmit an increase or decrease value from a reference parameter as a parameter to the module controller 24 of the linear module 3 (another module). For example, if the gain detected by the module controller 24 of the detachable module 7 is 1.2, the increase or decrease value from the reference gain of 1.0, 0.2, may be transmitted to the module controller 24 of the linear module 3 (another module).

[0044] In addition, the module controller 24 of the detachable module 7 may transmit the identification ID of the slider 4 and the correction value associated with the correction unit 55 (for example, a correction value tabulated as the difference between the correction signals X', Y' and the pre-correction signals X, Y) to the module controller 24 of the linear module 3 (another module), or may transmit the identification ID of the slider 4, the parameters, and the correction value associated with the correction unit 55 to the module controller 24 of the linear module 3 (another module).

[0045] The position detector 51 detects parameters when the slider 4 transfers from the belt conveyor 6 to the detachable module 7, before the module controller 24 of the detachable module 7 switches from open control to servo control, as shown in FIG. 10 . The belt conveyor 6 is controlled by the centralized controller 8 to push the slider 4 into the detachable module 7. Once the belt conveyor 6 has pushed the slider 4 into the detachable module 7, the module controller 24 of the detachable module 7 performs DC excitation (open control) on the stator 20 to retract the slider 4 to a predetermined position in the detachable module 7. The position detector 51 detects parameters while the module controller 24 is performing open control. Once the slider 4 has retracted to a predetermined position in the detachable module 7, the module controller 24 switches from open control to servo control, and servo-controls the slider 4 using the corrected interpolation signal θ'. (Position Detection Method)

[0046] 11 is a flowchart showing the position detection method of this embodiment. As shown in FIG. 11, the sensor 29 of the detachable module 7 detects the identification ID of the slider 4 and the AB scale 32a (S1).

[0047] The module controller 24 of the detachable module 7 calculates parameters for adjusting the Lissajous figure obtained from the A-phase signal and the B-phase signal obtained by digitally converting the signal output by the sensor 29 for each slider 4 (S2).

[0048] The module controller 24 of the detachable module 7 corrects the A-phase signal and B-phase signal for each slider 4 based on the identification ID and parameters of the slider 4, calculates an interpolated signal θ', and calculates the absolute position of the slider 4 (S3).

[0049] The module controller 24 of the detachable module 7 transmits the identification ID and parameters of the slider 4 to the module controller 24 of the linear module 3 (S4). Similar to the module controller 24 of the detachable module 7, the module controller 24 of the linear module 3 corrects the A-phase signal and B-phase signal for each slider 4 based on the identification ID and parameters of the slider 4, calculates an interpolated signal θ', and calculates the absolute position of the slider 4. (Effect)

[0050] The effects of the position detection device and method of this embodiment will be described below.

[0051] A parameter for adjusting the Lissajous figure obtained from the A-phase signal and B-phase signal obtained by digitally converting the signal output by the sensor 29 is detected for each slider 4, and at least one of the A-phase signal and the B-phase signal is corrected for each slider 4 based on the parameter.Therefore, even if the signal detected by the sensor 29 varies for each slider 4, the position of the slider 4 can be detected stably.

[0052] The module controller 24 of the detachable module 7 transmits (1) the identification ID of the slider 4 and (2) the parameters and / or correction values ​​associated with the correction unit 55 to the module controller 24 of the linear module 3, so that the module controller 24 of the linear module 3 can correct the A-phase signal and B-phase signal with appropriate parameters and / or correct the position of the slider 4 without detecting the parameters.

[0053] Since the detection of the parameters by the position detection device 51 is performed before the open control is switched to the servo control when the slider 4 transfers from the belt conveyor 6 to the detachable module 7, the slider 4 can be servo-controlled based on the corrected A-phase signal and B-phase signal. Also, the calculation load on the processor 38 when calculating the parameters can be reduced.

[0054] Since the parameters include the amplitude ratio (gain) between the A-phase signal and the B-phase signal, the A-phase signal and the B-phase signal can be effectively corrected.

[0055] The present invention is not limited to the above-described embodiment, and can be embodied in other embodiments without departing from the spirit of the present invention.

[0056] For example, in the above embodiment, a closed transport path is formed by a belt conveyor, a detachable module, and multiple linear modules, but a closed transport path may be formed by multiple linear modules alone, or a branching or merging transport path may be formed. In this case, a position detection device may be provided on the linear module, and the position detection device may detect parameters for adjusting the Lissajous figure while the slider is moving on the linear module.

[0057] In the above embodiment, the module controller that detected the parameter transmitted the slider identification ID and the parameter to the other module controller, but the other module controller may also detect the parameter without transmitting the parameter.

[0058] In the above embodiment, the AB scale is a magnetic scale, but the AB scale may also be an optical encoder.

[0059] This specification is based on Japanese Patent Application No. 2024-027469, filed February 27, 2024, the entire contents of which are incorporated herein by reference.

[0060] REFERENCE SIGNS LIST 1... Conveying device 2... Conveying path 3... Linear module (module) 4... Slider 6... Belt conveyor (another conveying device) 7... Detachable module (module equipped with position detection device) 24... Module controller 29... Sensor 32a... AB scale (position scale) 51... Position detection device 54... Parameter detection unit 55... Correction unit

Claims

1. A position detection device used in a transport device in which multiple sliders move along a transport path having at least one module, comprising: a position scale provided on the slider; a sensor provided on the module for detecting the position scale; a parameter detection unit for detecting, for each slider, parameters for adjusting a Lissajous figure obtained from A-phase signals and B-phase signals obtained by digitally converting the signals output by the sensor; and a correction unit for correcting at least one of the A-phase signal or the B-phase signal for each slider based on the parameters.

2. A position detection device as described in claim 1, characterized in that each of multiple modules is equipped with a module controller, and the module controller of the module equipped with the position detection device transmits (1) the slider identification ID and (2) the parameter or / and the correction value associated with the correction unit to the module controller of the other module.

3. A position detection device as described in claim 1 or 2, characterized in that the detection of the parameters by the position detection device is performed before switching from open control to servo control when the slider is transferred from another conveying device to a module equipped with the position detection device.

4. A position detection device according to claim 1 or 2, wherein the parameters include an amplitude ratio between the A-phase signal and the B-phase signal.

5. A position detection method used in a conveying device in which multiple sliders move along a conveying path having at least one module, comprising the steps of: detecting a position scale provided on the slider using a sensor provided on the module; detecting parameters for each slider to adjust a Lissajous figure obtained from A-phase signals and B-phase signals obtained by digitally converting the signals output by the sensor; and correcting at least one of the A-phase signal or the B-phase signal for each slider based on the parameters.

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