JP2004274948A - Encoder for servomotor and encoder control method for servomotor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the cost of a circuit component by reducing the number of signal lines. <P>SOLUTION: In this encoder for an servomotor that outputs three-phase incremental signals (A, B and Z) and three-phase magnetic pole position detecting signals (U, V and W), the encoder comprises a D-A conversion output circuit 11 that converts the magnetic pole position detecting signal to an analogue signal having eight kinds of analogue voltage values correspondent with signal states of phases of the incremental signals and the position detecting signals. A CPU 6 converts the analogue signal to signal information composed of a three-bit digital signal that indicates the signal state of each phase of the magnetic pole position detecting signals based on a voltage value of the analogue signal. The magnetic pole position detecting signal is converted to the analogue signal, transmitted to a controller 2 by the single signal line 24, and inputted to the CPU 6 after being subjected to noise filtering by an interface circuit 12. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a servomotor encoder, and more particularly to a servomotor encoder that reduces the number of signal lines and a control method thereof.
[0002]
[Prior art]
Conventionally, an incremental encoder that outputs three-phase incremental signals (A, B, Z) and three-phase magnetic pole position detection signals (U, V, W) has been used for controlling a servomotor. The incremental signal (A, B, Z) is composed of a two-layer square wave signal (A, B) having a phase difference of 90 ° and a square wave output (Z) of the origin signal output at the origin position. You. The rotation direction, rotation speed, and rotation position of the motor are detected based on the incremental signal. That is, the rotation direction is detected based on which of the signals A and B is output first, and the rotation speed is detected based on the cycle of the A and B signals. Further, the reference position of the motor rotor is detected from the Z signal, and the A and B signals are integrated (or subtracted) from that point, thereby detecting the rotor rotational position.
[0003]
The magnetic pole position detection signals (U, V, W) are square wave output signals having a phase difference of 120 ° corresponding to the electrical angle. A three-phase magnetic pole position detection signal is output with the driving of the motor, and the magnetic pole position of the rotor is detected by a combination thereof. The coils on the stator side are appropriately switched and excited in accordance with the position of the magnetic poles to generate a rotating magnetic field around the rotor. As a result, the rotor continuously rotates and the motor is driven at a desired speed and direction.
[0004]
Conventionally, such an encoder employs a circuit configuration as shown in FIG. 10 for detecting each signal. FIG. 10 is a block diagram showing a circuit configuration of a conventional servo motor encoder. The servo motor encoder includes a motor unit 51 disposed on the motor side and a controller 52 disposed on the control device side. The motor unit 51 is provided with an encoder 53 and a line driver 54. The controller 52 is used for motor control, and includes a line receiver 55 and a CPU 56. For signal transmission between the line driver 54 and the line receiver 55, a differential balanced type such as RS-422, which is strong against noise, is used.
[0005]
The encoder 53 outputs an incremental signal output unit 57 that outputs three-phase incremental signals (A, B, Z) and a magnetic pole position detection signal output unit 58 that outputs three-phase magnetic pole position detection signals (U, V, W). It has. The incremental signal output unit 57 and the magnetic pole position detection signal output unit 58 are connected to driver units 59A, 59B, 59Z; 61U, 61V, 61W provided in the line driver 54, respectively.
[0006]
The driver sections 59A, 59B, 59Z of the line driver 54 are provided for each incremental signal. The input side of each driver section 59A and the like is connected to the corresponding incremental signal output section 57, and the output side is provided with a pair of output terminals 62A, 62B, 62Z. From the output terminals 62A, 62B, 62Z, incremental signals A, A bar, B, B bar, Z, Z bar having different phases are output, respectively. The incremental signals A and A bar are used for detecting the rotor position of the motor.
[0007]
Driver units 61U, 61V, 61W of the line driver 54 are also provided for each magnetic pole position detection signal. Each driver section 61U and the like are connected on the input side to a corresponding magnetic pole position detection signal output section 58, and are provided on the output side with a pair of output terminals 63U, 63V and 63W. From the output terminals 63U, 63V, 63W, magnetic pole position detection signals U, U bar, V, V bar, W, W bar having different phases are output, respectively.
[0008]
The line driver 54 is connected to a line receiver 55 via a signal line 64. The line receiver 55 is provided with receiver sections 65A, 65B, 65Z; 66U, 66V, 66W. The receiver units 65A, 65B, 65Z receive signals from the driver units 59A, 59B, 59Z of the line driver 54. The receiver units 66U, 66V, 66W receive signals from the driver units 61U, 61V, 61W of the line driver 54. The receiver section 65A and the like receive signals from the driver section 59A and the like and output an incremental signal (A, B, Z) and a magnetic pole position detection signal (U, V, W) to the CPU 56.
[0009]
Power supply lines 67 and 68 are further provided between the motor unit 51 and the controller 52. The power supply line 67 is used for + power supply (VCC), and the power supply line 68 is used for ground connection (GND). As a result, power is supplied to the encoder 53 and the line driver 54 of the motor unit 51.
[0010]
[Patent Document 1] JP-A-8-18455
[Problems to be solved by the invention]
However, since such a servo motor encoder has the above-described configuration, a total of 14 wires are used between the motor unit 51 and the controller 52 as shown in FIG. That is, twelve signal lines 64 ((A, B, Z; U, V, W) × 2) and two power supply lines 67 and 68 are provided. For this reason, the number of harness cores between the line driver 54 and the line receiver 55 increases, the number of parts and the number of assembling steps increase, and the product cost increases.
[0012]
SUMMARY OF THE INVENTION An object of the present invention is to reduce the number of signal lines and reduce the cost of circuit components by commonly using signal lines.
[0013]
[Means for Solving the Problems]
The servo motor encoder of the present invention is a servo motor encoder that outputs a three-phase incremental signal (A, B, Z) and a three-phase magnetic pole position detection signal (U, V, W). A D / A conversion output circuit for converting the magnetic pole position detection signal into an analog signal having a voltage value corresponding to the signal state of each phase of the magnetic pole position detection signal, and outputting the analog signal based on the voltage value of the analog signal And control means for converting the signal into signal information indicating the signal state of each phase of the magnetic pole position detection signal.
[0014]
In the servo motor encoder according to the present invention, since the three-phase magnetic pole position detection signals (U, V, W) are converted into analog signals and output, only one signal line related to the magnetic pole position detection signals needs to be provided. Becomes possible. Accordingly, it is possible to reduce the number of components in the encoder, reduce the number of components and the number of assembling steps, and reduce the cost of circuit components.
[0015]
In the servo motor encoder, the D / A conversion output circuit converts the signal state of each phase of the magnetic pole position detection signal into eight analog voltage values, and the control means converts the analog voltage value into a 3-bit digital value. It may be converted to a value.
[0016]
In the servo motor encoder, a line driver connected to the encoder between the encoder and the control unit and including a driver unit corresponding to each of the incremental signals; and a line driver connected to the line driver; A line receiver provided corresponding to the driver unit and provided with a receiver unit that outputs an incremental signal to the control unit may be provided.
[0017]
Further, in the servo motor encoder, an interface circuit for removing noise of an analog signal output from the D / A conversion output circuit is provided between the D / A conversion output circuit and the control means. Is also good. The noise filter processing by the interface circuit can suppress the influence of noise on the analog signal.
[0018]
On the other hand, a control method of a servo motor encoder according to the present invention includes an encoder that outputs a three-phase incremental signal (A, B, Z) and a three-phase magnetic pole position detection signal (U, V, W); A D / A conversion output circuit for converting the magnetic pole position detection signal into an analog signal having a voltage value corresponding to the signal state of each phase of the magnetic pole position detection signal, and outputting the analog signal based on the voltage value of the analog signal And control means for converting the magnetic pole position detection signal into signal information indicating the signal state of each phase of the magnetic pole position detection signal, wherein the control means comprises: An initial value of the electric angle of the servomotor is estimated based on a combination of the position detection signals.
[0019]
According to the servo motor encoder control method of the present invention, since the estimation of the rotor electrical angle is performed before starting the motor, the magnetic pole position detection signals (U, V, W) do not change, and the analog signals obtained therefrom are not changed. Also does not change. Therefore, it is not necessary to transmit the analog signal at high speed, and the magnetic pole position information can be transmitted without any problem even with the analog signal.
[0020]
In the servo motor encoder control method, after the estimation of the electric angle initial value, the electric angle of the servo motor may be corrected based on an origin signal (Z) in the incremental signal.
[0021]
In the method for controlling an encoder for a servo motor, the counter may be incremented or decremented using the incremental signal using the estimated initial value of the electrical angle as an origin, until the origin signal in the incremental signal is obtained. The electric angle of the motor may be estimated and calculated.
[0022]
Further, in the servo motor encoder control method, after the electric angle of the servo motor is corrected based on the origin signal, the servo motor may be driven and controlled based on the incremental signal.
[0023]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing a circuit configuration of a servo motor encoder according to an embodiment of the present invention. As shown in FIG. 1, the servo motor encoder includes a motor unit 1 arranged on the motor side and a controller 2 arranged on the control device side. The motor unit 1 is provided with a D / A conversion output circuit 11 in addition to the encoder 3 and the line driver 4. The controller 2 is provided with an interface circuit 12 in addition to the line receiver 5 and the CPU (control means) 6. The motor unit 1 and the controller 2 are connected via signal lines 16 and 24. For signal transmission between the line driver 4 and the line receiver 5, a differential balanced system such as RS-422 is used.
[0024]
The encoder 3 includes an incremental signal output unit 7 for outputting three-phase incremental signals (A, B, Z) and a magnetic pole position detection signal output unit 8 for outputting three-phase magnetic pole position detection signals (U, V, W). It has. The incremental signal output unit 7 is connected to the line driver 4, and the magnetic pole position detection signal output unit 8 is connected to the D / A conversion output circuit 11.
[0025]
Power supply lines 25 and 26 are further provided between the motor unit 1 and the controller 2. The power supply line 25 is used for + power supply (VCC), and the power supply line 26 is used for ground connection (GND). As a result, power is supplied to the encoder 3 and the line driver 4 of the motor unit 1 and the D / A conversion output circuit 11.
[0026]
The line driver 4 is provided with driver sections 13A, 13B and 13Z. The driver sections 13A, 13B, 13Z are connected to output terminals 14A, 14B, 14Z of each phase of the incremental signal output section 7, respectively. The driver sections 13A, 13B, 13Z are provided with a pair of output terminals 15A, 15B, 15Z. The signal A and the signal A bar are selectively output from the output terminal 15A, the signal B and the signal B bar are selectively output from the output terminal 15B, and the signal Z and the signal Z bar are selectively output from the output terminal 15Z.
[0027]
The line receiver 5 is provided with receiver sections 17A, 17B, and 17Z. The line receiver 5 is connected to the line driver 4 via a signal line 16, and the receiver units 17A, 17B, 17Z receive signals from the driver units 13A, 13B, 13Z of the line driver 4, respectively. The receiver 17A and the like receive signals from the driver 13A and the like, and output incremental signals (A, B, Z) to the CPU 6.
[0028]
The D / A conversion output circuit 11 converts the three-phase magnetic pole position detection signals (U, V, W) output from the magnetic pole position detection signal output unit 8 of the encoder 3 into analog signals (analog voltage values) and outputs the signals. I do. FIG. 2 is a block diagram showing the configuration of the D / A conversion output circuit 11. As shown in FIG. 2, the D / A conversion output circuit 11 is a resistance-ladder-type digital-to-analog converter, and converts a combination of magnetic pole position detection signals (U, V, W) into eight analog voltages. Output.
[0029]
The signals (U, V, W) output from the output terminals 18U, 18V, 18W of each phase of the magnetic pole position detection signal output unit 8 are C-MOS type buffer ICs (for example, 74HC04 type) 19U, 19V, Input to 19W. Subsequent to the buffer ICs 19U, 19V and 19W, resistors 21U, 21V and 21W are connected. Subsequent stages of the resistors 21U, 21V, 21W are grounded via the resistors 22U, 22V, 22W and connected to the operational amplifier 23. The operational amplifier 23 is connected as a voltage follower, and is supplied with power from VCC in a single power supply system. The output signal of the operational amplifier 23 is input to the interface circuit 12 of the controller 2 via the signal line 24.
[0030]
The interface circuit 12 is connected to the CPU 6, and is used as a noise filter. An analog signal output from the D / A conversion output circuit 11 is input to the CPU 6 via the interface circuit 12, and an A / D converter built in the CPU 6 outputs a 3-bit signal corresponding to the U, V, and W states. Is converted to a digital value. FIG. 3 is a table showing the relationship between the magnetic pole position detection signals (U, V, W) of the encoder 3 and the output signals of the D / A conversion output circuit 11, and FIG. It is a table | surface which shows the relationship with the 3-bit digital value (U, V, W) created based on it.
[0031]
As shown in FIG. 3, the magnetic pole position detection signals (U, V, W) of the encoder 3 are inverted (UB, VB, WB) by the buffer ICs 19U, 19V, 19W and input to the operational amplifier 23. At this time, the output voltage from the operational amplifier 23 changes from 0 (V) to 7/8 VCC (V) as shown in FIG. 3 according to the input signal. That is, the 3-bit combination of the magnetic pole position detection signal (U, V, W) is converted by the D / A conversion output circuit 11 into an analog signal having eight voltage values corresponding to the signal state of each phase.
[0032]
On the other hand, the CPU 6 converts the analog signal into a 3-bit digital value (signal information) indicating the signal state of each phase of the magnetic pole position detection signal based on the voltage value of the input analog signal. For example, when the input voltage is equal to or more than 11/16 VCC and less than 13/16 VCC, it is determined that (U, V, W) has a center value of 12/16 = 6/8 VCC, and the relationship of FIG. (U, V, W) = (0, 0, 1). Similarly, for example, in the case of 5/16 VCC or more to less than 7/16 VCC, (U, V, W) is (U, V, W) = (1, 0, 0) from the center value 6/16 = 3/8 VCC. ). When the voltage value is 13/16 VCC or more or 1/16 or less, (U, V, W) = (0, 0, 0) or (1, 1, 1), and cannot appear during motor operation. Since it is a combination of signals, it is determined to be abnormal (error).
[0033]
Next, the operation of the servo motor encoder will be described. FIG. 5 is a flowchart showing an operation at the time of starting in the encoder of FIG. Here, first, the magnetic pole position detection signals (U, V, W) are obtained, the current rotor electrical angle is estimated, and the value is stored in the RAM of the CPU 6 (step S1). The rotor electrical angle is estimated by a combination of three magnetic pole position detection signals (U, V, W). At this time, the aforementioned (U, V, V) converted from the analog voltage value of the D / A conversion output circuit 11 is used. W) values are used.
[0034]
6 is a time chart showing the relationship between the magnetic pole position detection signal and the rotor electrical angle when the rotor rotates counterclockwise, and FIG. 7 is a time chart showing the relationship between the magnetic pole position detection signal and the rotor electrical angle when the rotor rotates clockwise. 6 is a time chart showing the relationship of FIG. For example, when the analog voltage value is equal to or more than 3/16 VCC and less than 5/16 VCC, the (U, V, W) value is (1, 0, 1) as shown in FIG. In this case, looking at the position where the combination of U, V, W is (1, 0, 1) = "H, L, H" in FIG. It turns out that this is the case. Therefore, at this time, it is estimated that the rotor is located at the electrical angle of 30 ° of the center value, and the value is set as the initial value of the electrical angle, which is stored in the RAM. Similarly, when the analog voltage value is equal to or greater than 1/16 VCC and less than 3/16 VCC, the (U, V, W) value is (1, 1, 0), and the combination of U, V, W is "H, H, Since the position “L” is the case where the electrical angle is 120 ° to 180 °, the estimated initial value of the electrical angle is set to 150 ° at this time.
[0035]
Here, the magnetic pole position detection signals (U, V, W) can be obtained even when the motor is not rotating. Therefore, such estimation of the rotor electrical angle can be performed before the motor is started. Since the magnetic pole position detection signal (U, V, W) does not change when the motor stops, the analog signal obtained therefrom does not change. That is, high-speed transmission of U, V, and W signals is not required here, and information can be transmitted without any problem even with analog signals whose information transmission speed is generally inferior to digital signals. Although analog signals are easily affected by noise, noise can be reduced because the rotor electrical angle can be estimated when the motor is stopped, and noise filtering can be performed by the interface circuit 12 and the CPU 6, so that sufficient noise countermeasures are taken. It is possible.
[0036]
After the initial value of the electrical angle is set in this manner, the value of the electrical angle written in the RAM is written in the presettable counter with the origin (step S2). For example, in the above example, when the estimated initial value of the electrical angle is 30 °, a count value corresponding to that value is written to the presettable counter as the initial value.
[0037]
Signals A and B are input to the CPU 6 with the driving of the motor. FIG. 8 is a time chart showing the incremental signals (A, B, Z) when the rotor rotates counterclockwise, and FIG. 9 shows the incremental signals (A, B, Z) when the rotor rotates clockwise. It is a time chart. As shown in FIGS. 8 and 9, among the incremental signals, the signal A and the signal B are output in a state where the phases are shifted by 90 ° with the rotation of the rotor. On the other hand, the signal Z is output once per rotation of the rotor. The position where the signal Z is output is known in advance from the installation position of the magnetic detection element, and by obtaining the signal Z and counting the number of input pulses of the signals A and B, the rotation angle of the rotor can be detected. .
[0038]
When the signals A and B are input to the CPU 6, the presettable counter is incremented (at the time of counterclockwise rotation) or decremented (at the time of clockwise rotation) (step S3). At this time, the CPU 6 monitors whether a Z-phase incremental signal (origin signal) has been input (step S4). Until the Z signal is input, the count in step S3 is continued, the rotor rotation angle is estimated based on this value, and the coil excitation phase is controlled. When the error of the electrical angle is φ, the motor torque is a value multiplied by cos φ as compared with the case where there is no error of the electrical angle. For this reason, when φ = −30 ° to + 30 ° as in the above-described estimated value, cos φ ≧ (） 3) /2≒0.866, and the starting torque of the motor is reduced by a maximum of about 13.4%. Controlled.
[0039]
When the Z signal is input, the process proceeds to step S5, where the counter is reset. As described above, the rotor rotation angle at the time of inputting the Z signal is predetermined, and when this is input, the counter is reset to that angle because the rotor rotation angle is accurately grasped. Then, the process proceeds to step S6, and the motor is controlled by the accurate rotor position detection reset by the Z signal.
[0040]
Thus, the servo motor encoder converts the three-phase magnetic pole position detection signal (U, V, W) into an analog signal having eight values and outputs the analog signal. It becomes possible to cover with one. Therefore, as shown in FIG. 1, the wiring between the motor unit 1 and the controller 2 is reduced to nine (six digital signal lines 16, one analog signal line 24, and two power supply lines 25, 26). A servomotor encoder can be formed with a reduced configuration. By this line saving, the number of circuits between the line driver 4 and the line receiver 5 is reduced by half, and the number of wirings can be reduced by five even if the addition of the signal line 24 is included. Therefore, the number of harness cores between the motor unit 1 and the controller 2 can be reduced, and the number of parts and the number of assembly steps are reduced. In addition, since an inexpensive resistance ladder type converter can be used for the D / A conversion output circuit 11, the D / A conversion output circuit 11 and the interface circuit 12 are added. It becomes possible to plan.
[0041]
The present invention is not limited to the above embodiment, and it goes without saying that various modifications can be made without departing from the scope of the invention.
For example, in the above-described servo motor encoder, an ASIC (Application Specific IC: dedicated IC for specific use) may be used instead of the CPU 6. In the above-described embodiment, the counter is incremented at the time of counterclockwise rotation. However, the counter may be incremented at the time of clockwise rotation and decremented at the time of counterclockwise rotation. Furthermore, although a configuration using a resistor ladder type converter as the D / A conversion output circuit 11 has been described, other types of digital / analog converters can be used.
[0042]
【The invention's effect】
According to the servo motor encoder of the present invention, a D / A conversion output circuit that converts a magnetic pole position detection signal (U, V, W) into an analog signal having a voltage value corresponding to the signal state of each phase and outputs the analog signal And control means for converting this analog signal into signal information indicating the signal state of each phase of the magnetic pole position detection signal based on the voltage value thereof, so that one signal line for transmitting the magnetic pole position detection signal to the control means is provided. It can be covered by books. Accordingly, it is possible to reduce the number of components in the encoder, reduce the number of components and the number of assembling steps, and reduce the cost of circuit components.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a circuit configuration of a servo motor encoder according to an embodiment of the present invention.
FIG. 2 is a block diagram illustrating a configuration of a D / A conversion output circuit.
FIG. 3 is a table showing a relationship between a magnetic pole position detection signal (U, V, W) of an encoder and an output signal of a D / A conversion output circuit.
FIG. 4 is a table showing a relationship between an output signal of a D / A conversion output circuit and a 3-bit digital value (U, V, W) created based on the output signal.
FIG. 5 is a flowchart showing an operation at the time of starting in the encoder of FIG. 1;
FIG. 6 is a time chart illustrating a relationship between a magnetic pole position detection signal and a rotor electrical angle when the rotor rotates counterclockwise.
FIG. 7 is a time chart showing a relationship between a magnetic pole position detection signal and a rotor electrical angle when the rotor rotates clockwise.
FIG. 8 is a time chart showing incremental signals (A, B, Z) when the rotor rotates counterclockwise.
FIG. 9 is a time chart showing incremental signals (A, B, Z) when the rotor rotates clockwise.
FIG. 10 is a block diagram showing a circuit configuration of a conventional servo motor encoder.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Motor part 2 Controller 3 Encoder 4 Line driver 5 Line receiver 6 CPU
7 Incremental signal output unit 8 Magnetic pole position detection signal output unit 11 D / A conversion output circuit 12 Interface circuits 13A, 13B, 13Z Driver units 14A, 14B, 14Z Output terminals 15A, 15B, 15Z Output terminals 16 Digital signal lines 17A, 17B , 17Z Receiver unit 18U, 18V, 18W Output terminal 19U, 19V, 19W Buffer IC
21U, 21V, 21W Resistance 22U, 22V, 22W Resistance 23 Operational amplifier 24 Signal line 25 Power line 26 Power line 51 Motor unit 52 Controller 53 Encoder 54 Line driver 55 Line receiver 56 CPU
57 Incremental signal output unit 58 Magnetic pole position detection signal output unit 59A, 59B, 59Z Driver units 61U, 61V, 61W Driver units 62A, 62B, 62Z Output terminals 63U, 63V, 63W Output terminals 64 Signal lines 65A, 65B, 65Z Receiver unit 66U, 66V, 66W Receiver section 67 Power line 68 Power line

Claims (8)

A servo motor encoder for outputting three-phase incremental signals (A, B, Z) and three-phase magnetic pole position detection signals (U, V, W),
A D / A conversion output circuit that converts the magnetic pole position detection signal into an analog signal having a voltage value corresponding to a signal state of each phase of the magnetic pole position detection signal and outputs the analog signal;
Control means for converting the analog signal into signal information indicating a signal state of each phase of the magnetic pole position detection signal based on a voltage value of the analog signal. 2. The servo motor encoder according to claim 1, wherein the D / A conversion output circuit converts the signal state of each phase of the magnetic pole position detection signal into eight different analog voltage values, and the control unit controls the analog voltage value. An encoder for a servo motor, which converts a value into a 3-bit digital value. 3. The encoder for a servo motor according to claim 1, wherein a line driver is connected between the encoder and the control unit, the driver including a driver unit corresponding to each of the incremental signals, and connected to the line driver. And a line receiver provided corresponding to each of the driver units and having a receiver unit for outputting an incremental signal to the control unit. 4. The encoder for a servo motor according to claim 1, wherein a noise of an analog signal output from the D / A conversion output circuit is provided between the D / A conversion output circuit and the control unit. 5. An encoder for a servo motor, comprising an interface circuit for removing the noise. An encoder that outputs a three-phase incremental signal (A, B, Z) and a three-phase magnetic pole position detection signal (U, V, W); and an encoder that outputs the magnetic pole position detection signal to each phase of the magnetic pole position detection signal. A D / A conversion output circuit that converts and outputs an analog signal having a voltage value corresponding to the signal state, and indicates a signal state of each phase of the magnetic pole position detection signal based on the voltage value of the analog signal. A control method for a servo motor encoder comprising:
The control method of a servo motor encoder, wherein the control unit estimates an initial value of an electric angle of the servo motor based on a combination of the magnetic pole position detection signals before the start of the encoder. 6. The servo motor encoder control method according to claim 5, wherein after estimating the electric angle initial value, the electric angle of the servo motor is corrected based on an origin signal (Z) in the incremental signal. Control method of servo motor encoder. 7. The control method of a servo motor encoder according to claim 6, wherein the counter is incremented or decremented by using the incremental signal with the estimated initial value of the electrical angle as an origin until the origin signal in the incremental signal is obtained. A servo motor encoder control method, comprising estimating and calculating an electric angle of the servo motor. 8. The control method of a servo motor encoder according to claim 6, wherein the electric angle of the servo motor is corrected based on the origin signal, and then the servo motor is drive-controlled based on the incremental signal. To control the servo motor encoder.

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