JP4702526B2 - Angular position detection apparatus and method - Google Patents

Description

  The present invention relates to an angular position detection apparatus and method, and is suitable for application to an angular position detection apparatus used in, for example, a direct drive motor.

  Conventionally, there is a direct drive motor as a motor that directly drives a load without using a speed reducer. The direct drive motor is capable of positioning without backlash and lost motion with high accuracy, and is therefore used in various applications such as an index table for an NC machine tool, a transfer device, and a robot arm for an assembly device. In recent years, with the diversification of applications of direct drive motors, it is desired to develop a direct drive motor that enables positioning with higher precision and smaller size.

  As an angle detection device used to detect the rotation angle of the rotation shaft of such a direct drive motor, a combination of a monopolar resolver and a multipolar resolver is known. In this type of angle detection device, the mechanical misalignment or the like of the monopolar resolver is likely to affect the absolute accuracy, and it is difficult to improve the absolute accuracy especially when trying to reduce the size by reducing the diameter. On the other hand, if an attempt is made to increase the resolution by increasing the number of poles of the multipolar resolver, the single pole resolver is required to have an accuracy equal to or less than one pole of the multipolar resolver, so that the error tolerance becomes small. Therefore, with this type of angle detection device, it is difficult to achieve both high resolution and absolute measurement.

  As one method for solving such a problem, conventionally, an output error of a monopolar resolver is previously measured based on the output of a multipolar resolver, and an output error of the monopolar resolver is corrected based on the measurement result. A method has been proposed in which a correction amount is calculated and stored, and the output of the monopolar resolver is corrected using the stored correction amount when the actual angle detection device is used (see Patent Document 1). . According to this method, it is possible to construct an angular position detection device that can achieve both high resolution and absolute measurement with a simple device configuration.

  Here, the correction amount acquisition method in this method is performed according to the following procedure. 1) First, turn on the servo of the direct drive motor (that is, start supplying drive current to the direct drive motor), and set the direct drive motor to the reference position of the multipolar resolver (position where the detection angle is “0”). Position. 2) After that, in order to stop the vibration generated when the drive current is supplied, the servo of the direct motor is turned off (that is, the supply of the drive current to the direct drive motor is stopped), and the output of the unipolar resolver at this time is To detect. Then, an error is detected between the position of the direct drive motor positioned using the multipolar resolver and the position detected by the monopolar resolver at that time.

3) Next, the servo of the direct drive motor is turned on again. 4) Thereafter, the direct drive motor is positioned at the next correction amount measurement point based on the output of the multipolar resolver. 5) Then, the above steps 2) to 4) are repeated. At this time, in step 2), an average of the error detected at the current measurement point and the error detected at the previous measurement point is calculated and stored as a correction amount at the current measurement point.
Japanese Patent Laying-Open No. 2005-062098

  However, in this method, for example, when the direct drive motor is a motor with a magnet, the rotor rotates under the influence of the cogging torque when the servo of the direct drive motor is turned off in the above step 2). May cause the position detected by deviating from the position to be detected.

  As a result, in step 2), there is a difference in rotation due to cogging between the position of the direct drive motor positioned using the multipolar resolver and the position detected by the monopolar resolver at that time, and the measurement point However, the position detection error of the single pole resolver based on the output of the multipolar resolver cannot be obtained accurately, and a highly reliable correction amount cannot be obtained. This means that even if the output of the unipolar resolver is corrected using such a correction amount, accurate correction cannot be performed, and the reliability of the angular position detection device itself is lowered.

  If the reliability of the angular position detection device is low in this way, the accuracy of the index table of an NC machine tool driven by this direct drive motor, the transported material transported by the transport device, the robot arm of the assembly device, etc. There is a problem in that it cannot be located at a well-designated position, causing a problem.

  The present invention has been made in consideration of the above points, and intends to propose a highly reliable angular position detection device and a correction amount detection method capable of improving the reliability of the angular position detection device.

In order to solve such a problem, the present invention provides an angle detection device that detects a rotation angle of a rotation shaft of a motor that generates cogging torque, and outputs a signal corresponding to the rotation angle position of the rotation shaft of the motor. A plurality of resolvers having different numbers of poles and an output error of a resolver on the small pole side with respect to an output on the majority pole side of the plurality of resolvers, for each predetermined measurement point, A correction amount acquisition unit that acquires a correction amount for each measurement point based on a measurement result, a storage unit that stores the acquired correction amount, and a corresponding stored in the storage unit for each measurement point based on the correction amount, wherein a correcting means for correcting the output of the low pole side of the resolver, each of said measurement point, when each off servo of the motor, before Wherein the rotary shaft is a rotary angle position which does not rotate.

  As a result, in this angle detection device, when measuring the output error of the resolver on the small pole side based on the output on the multipole side, the rotating shaft is affected by the coking torque even when the motor servo is turned off. Since it does not rotate, an accurate correction amount at each measurement point can be acquired. Therefore, it is possible to accurately correct the output of the resolver on the small pole side based on this correction amount.

The angle detection method of the present invention is configured to output a signal corresponding to the rotation angle position of the rotation shaft of the motor in the angle detection method of detecting the rotation angle of the rotation shaft of the motor that generates cogging torque. The output error of the resolver on the minor pole side with respect to the output on the majority pole side among the plurality of resolvers having different pole numbers is measured for each predetermined measurement point, and the measurement point based on the measurement result The first step of acquiring and storing the correction amount for each and the corresponding correction amount stored in the storage means for each measurement point, and correcting the output of the resolver on the low pole side And each measurement point is a rotation angle position where the rotation shaft does not rotate when the servo of the motor is turned off .

  As a result, according to this angle detection method, when measuring the output error of the resolver on the small pole side with respect to the output on the multiple pole side, the rotating shaft is not affected by the coking torque even when the motor servo is turned off. Since there is no rotation due to the influence, an accurate correction amount at each measurement point can be acquired. Therefore, it is possible to accurately correct the output of the resolver on the small pole side based on this correction amount.

  According to the present invention, the output of the resolver on the small pole side can be corrected with high accuracy, and a highly reliable angle detection device and method can be realized.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

(1) Motor system configuration according to the present embodiment FIG. 1 is a sectional view of a direct drive motor according to the present embodiment. As shown in the figure, in the direct drive motor 10, a rotary shaft 12 is rotatably supported via a bearing 13 fixed to the outer peripheral side surface of a hollow cylindrical inner housing 11. The rotary shaft 12 is configured as a hollow cylindrical body so that the inner housing 11 can be overlaid therein.

  The rotating shaft 12 has a cylindrical wall thickness that changes in an uneven shape, and accommodates the indoor space 1 for accommodating the monopolar resolver 20 and the multipolar resolver 30 in the gap with the inner housing 11, and the motor unit 16. An indoor space 2 is defined. These indoor spaces 1 and 2 are separated by a bearing 13 and are separated by a certain distance so that the leakage magnetic flux from the motor unit 16 does not reach the indoor space 1. When the bearing 13 or the like is not interposed between the indoor spaces 1 and 2 and both are close to each other, it is desirable to provide a shielding member so that the leakage magnetic flux from the motor unit 16 does not reach the indoor space 1. .

  The motor unit 16 is an outer rotor type PM motor including a rotor 14 and a stator 15. The rotor 14 is formed of a permanent magnet having N poles and S poles fixed alternately along the circumferential direction on the inner wall of the rotating shaft 12. The stator 15 is a motor core formed by laminating a plurality of thin iron plates, and is fixed to the outer wall of the inner housing 11 so as to face the rotor 14 with a minute air gap. Here, an outer rotor type PM motor is illustrated as the motor unit 16, but an inner rotor type PM motor may be employed.

  On the other hand, the monopolar resolver 20 includes an annular resolver rotor 21 fixed to the inner peripheral surface of the rotating shaft 12 and a resolver stator 22 fixed to the outer peripheral wall of the inner housing 11 so as to face the resolver rotor 21. It is prepared for. Similarly, the multipolar resolver 30 includes an annular resolver rotor 31 fixed to the inner peripheral surface of the rotating shaft 12, and a resolver stator 32 fixed to the outer wall of the inner housing 11 so as to face the resolver rotor 31. Configured.

  The monopolar resolver 20 and the multipolar resolver 30 are fixed with a minute gap in the indoor space 1 so as to have a two-stage stacked structure via a rotor spacer 18 and a stator spacer 19. That is, the rotor spacer 18 is interposed between the resolver rotors 21 and 31 fixed to the inner peripheral wall of the rotating shaft 12 by a plurality of bolts 18a, while being fixed to the outer peripheral wall of the inner housing 11 by the bolts 19a. A stator spacer 19 is interposed between the resolver stators 22 and 32.

  The inner housing 11 and the rotating shaft 12 that define the indoor space 1, and the rotor spacer 18 and the stator spacer 19 that are mounted in the indoor space 1 are preferably made of nonmagnetic materials. By configuring these members that define the indoor space 1 with a non-magnetic material, the leakage magnetic flux from the motor unit 16 can be configured not to reach the indoor space 1.

FIG. 2 is a plan view of the monopolar resolver 20. As shown in the figure, in the single pole resolver 20, the reluctance of the gap between the resolver rotor 21 and the resolver stator 22 varies depending on the rotational angle position of the resolver rotor 21, and the fundamental wave component of the reluctance change by one revolution of the resolver rotor 21. Is a three-phase VR resolver configured to have one cycle. That is, the outer diameter center and inner diameter center of the resolver stator 22 and the outer diameter center of the resolver rotor 21 coincide with the rotation center O ₁ of the direct drive motor, but the inner diameter center O ₂ of the resolver rotor 21 is relative to the rotation center O _1. Therefore, the thickness of the resolver rotor 21 in the radial direction is continuously changed so as to be eccentric by Δx.

On the outer periphery of the resolver stator 22, a total of 18 stator poles 23 constituting an A phase, a B phase, and a C phase at 120 degree intervals are projected in an outer tooth shape at equal intervals. A coil bobbin 24 around which stator coils C _{1 to} C ₁₈ are wound is mounted on each stator pole 23. The material of the coil bobbin 24 is not particularly limited as long as it is a non-magnetic material having appropriate elasticity. For example, styrene resin, polycarbonate resin, polyphenylene ether resin, nylon, polybutylene terephthalate resin, etc. If it is a thermoplastic resin, injection molding is easy.

When an excitation signal is applied to the common terminals of the stator coils C _{1 to} C _18, the phase of the stator coils C _{1 to} C ₁₈ of A phase, B phase, and C phase is 120 degrees during one revolution of the resolver rotor 21. One cycle of current signals that are shifted from each other are output. The absolute rotation angle position can be detected by the monopolar resolver signal output from the monopolar resolver 20.

FIG. 3 is a connection diagram of the stator coils C _{1 to} C ₁₈ wound around the stator pole 23 of the single pole resolver 20. The excitation signal to the common terminal COM is applied, A-phase, B-phase and C-phase stator coil C ₁ -C ₆ constituting _{a, C 7 ~C 12, C 13} ~C 18 each current signal flowing through the detection It is converted into a voltage signal by a current / voltage converter 41a composed of resistors R ₁ , R ₂ and R ₃ . This voltage signal is supplied as a unipolar resolver signal (ABS signal) to a 3 / 2-phase converter 42a described later.

  FIG. 4 is a plan view of the multipolar resolver 30. As shown in the figure, in the multipolar resolver 30, the inner diameter center O of the resolver rotor 31 coincides with the inner diameter center O of the resolver stator 32, and the reluctance of the gap between the resolver rotor 31 and the resolver stator 32 is the resolver rotor 31. The fundamental wave component of the reluctance change is a plurality of cycles in one rotation of the resolver rotor 31. A total of 160 pole teeth 35 are formed on the inner peripheral surface of the resolver rotor 31 so as to protrude in an inner tooth shape at equal intervals in the radial direction. A total of 48 stator poles 33 are protruded in the outer peripheral surface of the resolver stator 32 in a radially outward direction at equal intervals so that the A phase, the B phase, and the C phase are shifted by an electrical angle of 120 degrees. Two pole piece teeth 34 project from the tip of each stator pole 33.

Stator coils C _{a to} C _c are wound around the respective stator poles 33. When excitation signals are supplied to the common lines of the stator coils C _{a to} C _c , 160 cycles of AC signals are output for each phase while the resolver rotor 31 rotates once. The relative rotation angle position can be detected by the multipolar resolver signal output from the multipolar resolver 30.

FIG. 5 is a connection diagram of the respective stator coils C _{a to} C _c wound around the stator pole 33 of the multipolar resolver 30. When an excitation signal is applied to the common terminal COM, the resolver signals flowing through the stator coils C _a , C _b , and C _c constituting the A phase, the B phase, and the C phase are detected by the detection resistors R _a , R _b , and R _{c, respectively.} Is converted into a voltage signal by a current / voltage converter 41b. This voltage signal is supplied as a multipolar resolver signal (INC signal) to a 3 / 2-phase converter 42b described later.

  The number of stator poles 32 may be a multiple of the number of phases (3 in this example), and is not limited to 48. In this example, 160 pole teeth 35 are formed, but the number of pole teeth 35 is not limited to 160. In the above description, the stator poles of the single-pole resolver 20 and the multi-pole resolver 30 are external teeth, and the resolver rotor is disposed outside the resolver stator. It is good also as a structure which is set as a tooth | gear and a resolver rotor is distribute | arranged inside a resolver stator. Further, the number of phases of the resolver signal is not limited to the three-phase resolver, and a two-phase resolver, a four-phase resolver, a six-phase resolver, or the like can be used.

  FIG. 6 is a block diagram showing the angular position detection device of this embodiment. The angular position detection device includes a monopolar resolver 20 and a multipolar resolver 30 incorporated in the direct drive motor 10 and a part of a drive unit 60 that controls them. The drive unit 60 supplies an excitation signal to one of the single-pole resolver 20 and the multi-pole resolver 30, takes in the resolver signal, outputs a digital angle signal φ, and a rotation angle position signal from the digital angle signal φ. And a CPU 61 that supplies power to the direct drive motor 10 via a power amplifier 62. The drive unit 60, the monopolar resolver 20, and the multipolar resolver 30 are connected by a resolver cable 71, and the unit 60 and the motor unit 16 are connected by a motor cable 72.

  The servo driver 50 amplifies the excitation signal output from the transmitter 51 to an appropriate signal level by the amplifier 52, and supplies the excitation signal to the common terminal COM of the unipolar resolver 20 and the multipolar resolver 30.

  The current signal output from the unipolar resolver 20 is converted into an ABS signal by the current / voltage converter 41a, and then converted into a two-phase signal (sin signal, cos signal) by the 3 / 2-phase converter 42a. 43.

  Here, if the transmission angular frequency of the transmitter 51 is ω and the higher-order components are ignored, the resolver signal of each phase obtained by the current / voltage converter 41a is as shown in the following equations (1) to (3). It becomes. Here, for convenience of explanation, a case where the phases of the B phase and the C phase are respectively delayed by 120 degrees with respect to the A phase is illustrated. Further, the two-phase signals obtained by the 3 / 2-phase converter 42a are shown in the equations (4) to (5). In equation (5), sqr (x) is a function that returns the square root of the argument x.

(Equation 1)
φA = (A ₁ + A ₂ sin θ) · sin ωt (1)
(Equation 2)
φB = {B ₁ + B ₂ sin (θ−2π / 3)} · sin ωt (2)
(Equation 3)
φC = {C ₁ + C ₂ sin (θ−4π / 3)} · sin ωt (3)
(Equation 4)
sin signal = φA− (φB + φC) / 2 (4)
(Equation 5)
cos signal = sqr (3/4) · (φB−φC) (5)

  On the other hand, the excitation signal is also supplied to the multipolar resolver 30. The current signal output from the multipolar resolver 30 is converted into an INC signal by the current / voltage converter 41b, and then converted into a two-phase signal (sin signal, cos signal) by the 3 / 2-phase converter 42b. It is supplied to the switch 43.

  The analog switch 43 is a switch element that is switched and controlled by an ABS / INC switching signal from the CPU 61, and selectively passes either one of a two-phase ABS signal and a two-phase INC signal, and a position detection circuit (RDC). 44.

  The phase shifter 45 delays the phase of the excitation signal output from the transmitter 51, and synchronizes with the phase of the carrier signal of the sin signal and cos signal of the ABS signal or INC signal converted into two phases. Is supplied to the position detection circuit 44. The position detection circuit 44 digitizes the two-phase signal supplied from the analog switch 43 and outputs a digital angle signal φ to the CPU 61. The position detection circuit 44 outputs an analog speed signal after synchronous rectification based on the oscillation angular frequency of the transmitter 51. The correction amount storage memory 63 includes a storage device such as a flash ROM, and stores a correction amount described later.

  In the above description, a configuration using a three-phase resolver as the monopolar resolver 20 is illustrated, but the present invention is not limited to this, and a six-phase resolver can also be used as the monopolar resolver 20. When using a 6-phase resolver, the following equations (6) to (11) are used instead of the above equations (1) to (3) as the resolver signal, so as shown in FIG. A subtractor 46a may be interposed between the current / voltage converter 41a and the 3 / 2-phase converter 42a. The subtractor 46a calculates the difference dA, dB, dC of the resolver signal of each phase and converts the 6-phase resolver signal into a 3-phase resolver signal of the expressions (12) to (14). The three-phase resolver signal of the same formula is converted into a two-phase signal by the 3/2 phase converter 42a.

(Equation 6)
φA + = (A ₁ + A ₂ sin θ) · sin ωt (6)
(Equation 7)
φA − = (A ₁ + A ₂ sin (θ−π)) · sin ωt (7)
(Equation 8)
φB + = {B ₁ + B ₂ sin (θ−2π / 3)} · sin ωt (8)
(Equation 9)
φB − = {B ₁ + B ₂ sin (θ−2π / 3−π)} · sin ωt (9)
(Equation 10)
φC + = {C ₁ + C ₂ sin (θ−4π / 3)} · sin ωt (10)
(Equation 11)
φC − = {C ₁ + C ₂ sin (θ−4π / 3−π)} · sin ωt (11)
(Equation 12)
dA = 2A ₂ sin θ · sin ωt (12)
(Equation 13)
dB = 2B ₂ sin (θ-2π / 3) · sin ωt (13)
(Equation 14)
dC = 2C ₂ sin (θ-4π / 3) · sinωt (14)

  Furthermore, for example, when other types of resolvers such as a two-phase resolver and a four-phase resolver are used, the configuration of the detection circuit unit 40 may be appropriately changed according to each case.

  In the above description, the excitation signal is supplied to both the monopolar resolver 20 and the multipolar resolver 30, but the present invention is not limited to this, and the excitation signal is not limited to the monopolar resolver 20. Alternatively, the magnetic interference between the resolvers may be prevented by selectively switching so as to be supplied to any of the multipolar resolvers 30.

FIG. 8 shows a digitally converted resolver signal. When a 12-bit converter is used as the position detection circuit 44, the two-phase ABS signal is converted into a digital angle signal φ of 4096 (= 2 ¹² ) pulses per revolution of the resolver rotor as shown in FIG. Is done. That is, the ABS signal becomes a digital value counted up from 0 to 4095 while the single pole resolver 20 makes one rotation. On the other hand, the two-phase INC signal is converted into a digital angle signal φ of 4096 × 160 (total number of pole teeth 35) = 655360 pulses per revolution of the resolver rotor, as shown in FIG. That is, the INC signal is a digital value in which the count up from 0 to 4095 is repeated 160 times while the multipolar resolver 30 makes one rotation.

  In the figure, the offset value is a deviation from one of the fundamental components of 160 periods of the INC signal when the rotation angle corresponding to the starting point of the fundamental component of the ABS signal is 0 degree. Is the value of.

The CPU 61 takes in these digital angle signals φ and calculates the rotational angle position of the direct drive motor 10. The value of the digital angle signal φ converted from the two-phase ABS signal to the digital signal by the position detection circuit 44 is abs, and the value of the digital angle signal φ converted from the two-phase INC signal to the digital signal by the position detection circuit 44 , Inc, the rotational angle position can be obtained by the calculation of equation (15). When a correction amount described later is stored in the correction amount storage memory 63, the corrected value is used as the value of abs.
(Equation 15)
abs × 160 + (2048−inc) + offset value (15)

  The CPU 61 outputs a rotation angle position signal so as to supply power to the direct drive motor 10 via the power amplifier 62.

  In order to obtain the digital angle signal φ from the resolver signal, it is not always necessary to process it with hardware (3/2 phase converter, position detection circuit, etc.). A digital angle signal φ may be obtained by information processing.

(2) Correction amount calculation processing and correction processing according to the present embodiment Next, the correction amount calculation processing stored in the correction amount storage memory 63 and the output correction processing of the unipolar resolver 20 based thereon will be described. The correction amount calculation process is a process performed for each direct drive motor 10 before the direct drive motor 10 is shipped. The correction process for the output of the monopolar resolver 20 is performed when the direct drive motor 10 is used thereafter. This is a process to be performed.

  First, the principle of the correction amount calculation process will be described. The location where the cogging torque is generated in the direct drive motor 10 is determined by the positional relationship between the rotor 14 (rotor magnet) of the motor unit 16 and the slots on the stator 15 side. For example, the angle at which the rotor 14 (rotor magnet) rotates by one pole pair (one S pole and one N pole) with respect to a phase with a slot having three phases of UVW is 360 degrees of the motor electrical angle. In this case, as shown in FIG. 9, fluctuations in cogging torque occur at six locations within the range of 0 to 360 degrees of the motor electrical angle. This means that there are six stable positions for every 360 degrees of motor electrical angle.

  Therefore, if the output of the unipolar resolver 20 is measured aiming at a stable position of cogging (hereinafter referred to as a cogging stable position), even when the servo of the motor unit 16 is turned off, the influence of the cogging torque is applied. It is possible to prevent the rotation shaft 12 of the direct drive motor 10 from rotating, and as a result, the adverse effect due to cogging when acquiring the correction amount for correcting the output of the single pole resolver 20 can be effectively prevented. The output error of the polar resolver 20 can be detected with high accuracy.

  In the following description, it is assumed that the motor unit 16 is a three-phase motor with 11 pole pairs (22 poles including S pole and N pole). Therefore, in the case of the direct drive motor 10 (motor unit 16) according to the present embodiment, there are six cogging stable positions within the range of 0 to 360 degrees of the motor electrical angle shown in FIG. Within the range of 0 to 360 degrees, there are 66 cogging stable positions that are 11 times as large. That is, in this direct drive motor 10, there is a stable cogging position every 5.45 (= 360/66) mechanical angles.

  Therefore, in the present embodiment, the output error of the unipolar resolver 20 is measured every 5.45 degrees, and the correction amount of the output of the unipolar resolver 20 at these measurement points (each cogging stable position) is sequentially obtained. To do.

  FIG. 11 shows a series of processing procedures of the CPU 61 relating to such correction amount acquisition processing. When detecting that the power is turned on in step S1, the CPU 61 reads the value abs of the digital angle signal φ based on the output of the monopolar resolver 20 in the subsequent step S2. When the output of the monopolar resolver 20 is read, the process proceeds to step S3, and a rotation command to the position closest to the position where the position signal abs of the monopolar resolver 20 is 0 and no cogging torque is generated is given to the power amplifier 62. The motor 72 is rotated. Since such a position can be determined by design, it can be given to the CPU 61 in advance. If this position is designed to be the cogging stable position of the motor 72, the subsequent measurement can be facilitated.

  Next, the process proceeds to error measurement processing after step S4. Specifically, the rotor of the motor is rotated by 5.45 degrees, and the output error of the monopolar resolver 20 with respect to the output of the multipolar resolver 30 at each position is measured. In the example of FIG. 11, first, in step S5, the CPU 61 gives a rotation command signal of 5.45 degrees to the power amplifier 62, and rotates the motor 72 to the next cogging stable position. The positioning at that time is performed based on the value inc of the digital angle signal φ based on the output of the multipolar resolver 30, whereby positioning close to the true value is possible.

  In the subsequent step SP6, the CPU 61 reads the position signal abs of the monopolar resolver 20 at the position after rotation. In step S7, the difference from the true value is calculated and set as the error E of the unipolar resolver 20. Next, in step S8, correction amount data is created based on the error of the unipolar resolver. Specifically, an average value of the error E (n) of the unipolar resolver in the n-th measurement and the error E (n−1) of the unipolar resolver in the previous measurement is calculated and used as the correction amount.

  Furthermore, the CPU 61 stores the created correction amount data in the correction amount storage memory 63 in step S9. After that, the CPU 61 repeats the above operation, and when the positioning, measurement, and creation of correction amount data for one round (in this embodiment, 66 locations) are completed (step S10: YES), the series of processing ends. .

  FIG. 12 is a flowchart describing the position detection processing routine of the CPU 61. The absolute position is corrected according to the correction amount data calculated and stored by the above processing.

  That is, when the CPU 61 detects that the power is turned on in step S11, the CPU 61 takes in the output of the monopolar resolver 20 at that position in the subsequent step S12. Specifically, the excitation signal output from the transmitter 51 is supplied to the monopolar resolver 20, and the reluctance corresponding to the rotation angle position is supplied to the detection circuit unit 40 as a current signal. In the detection circuit unit 40, the current signal is converted into a voltage signal by the current / voltage converter 41 a, converted into a two-phase signal by the 3 / 2-phase converter 42 a, and supplied to the analog switch 43. The CPU 61 outputs an ABS / INC switching signal so as to select a two-phase ABS signal as a signal to pass through the analog switch 43. The two-phase ABS signal passes through the analog switch 43, is converted into a digital signal by the RDC 44, and is supplied to the CPU 61 as a digital angle signal φ. The CPU 61 acquires the value of the digital angle signal φ as abs.

  Next, in step S13, the CPU 61 reads the correction amount data from the correction amount storage memory 63 and corrects the absolute position data based on the correction amount. That is, if the correction amount is positive, the correction amount is subtracted from the value abs of the digital angle signal based on the unipolar resolver.

  And CPU61 takes in the output of the multipolar resolver 30 in the following step S14. Specifically, the excitation signal output from the transmitter 51 is supplied to the multipolar resolver 30, and the reluctance corresponding to the rotation angle position is supplied to the detection circuit unit 40 as a current signal. In the detection circuit unit 40, the current signal is converted into a voltage signal by the current / voltage converter 41 b, converted into a two-phase signal by the 3 / 2-phase converter 42 b, and supplied to the analog switch 43. The CPU 61 outputs an ABS / INC switching signal so as to select a two-phase INC signal as a signal to pass through the analog switch 43. The two-phase INC signal passes through the analog switch 43, is converted into a digital signal by the RDC 44, and is supplied to the CPU 61 as a digital angle signal φ. The CPU 61 acquires the value of the digital angle signal φ as inc.

  With the above processing, the absolute position immediately after the power is turned on can be obtained accurately. The absolute position is information necessary only immediately after the power is turned on, and the subsequent driving is driving using inc, that is, the position signal of the multipolar resolver. Then, when the CPU 61 detects that the power is turned off (step S15), the processing procedure ends.

  As described above, in this embodiment, the output error of the unipolar resolver 30 is measured at the cogging stable position, and the correction amount is calculated based on the measurement result. Therefore, the servo for the motor unit 16 is turned off. Even in this case, the rotating shaft 12 of the direct drive motor 10 does not rotate due to the influence of the cogging torque, and the correction amount for correcting the output of the unipolar resolver 20 by preventing the bad influence caused by cogging in advance and effectively. Data with high accuracy can be obtained as data. Therefore, in the motor system according to the present embodiment, the output of the unipolar resolver 30 can be accurately corrected based on this correction amount.

  In the motor system according to the present invention, since the output of the monopolar resolver 20 is corrected, absolute correction can be performed by its own system function without using an external reference as disclosed in, for example, Japanese Patent Publication No. 8-1388. As a result, the absolute function can be realized with high accuracy with a simple configuration, and both ultra-high resolution and the absolute function can be achieved. In addition, the tolerance of mechanical errors during assembly is increased, and the manufacturing process can be simplified.

  Further, correction by the end user is possible, and replacement such as when a failure occurs in the driver or the like can be handled by performing the processing described above with reference to FIG. Furthermore, even when an excessive impact is applied and the absolute accuracy deteriorates, it is not necessary to replace the entire motor, so that correction on the spot is possible.

(3) Other Embodiments In the above-described embodiment, the configuration including the unipolar resolver 20 and the multipolar resolver 30 is exemplified as the low-polarity resolver and multipolar resolver incorporated in the direct drive motor 10. The present invention is not limited to this, and can be applied to a case where any different type of resolver is incorporated in the direct drive motor 10.

  In the above-described embodiment, the case where the correction amount data for correcting the output of the monopolar resolver 20 is obtained every 5.45 degrees is described. However, the present invention is not limited to this. The output of the unipolar resolver 20 is output at every multiple angle of 5.45 degrees where cogging torque is generated, for example, every 10.9 degrees which is twice 5.45 degrees or every 16.35 degrees which is three times 5.45 degrees. Correction amount data for correction may be acquired.

  Further, in the above-described embodiment, the case where the present invention is applied to a resolver device that detects a rotation angle has been described. However, the present invention is not limited to this and can be applied to a linear motor. .

  The present invention can be widely applied to angular position detection devices used for other PM motors in addition to angular position detection devices used for direct drive motors.

It is sectional drawing which shows the structure of the direct drive motor by this Embodiment. It is a top view which shows the structure of a monopolar resolver. It is a connection diagram of the status coil of a monopolar resolver. It is a top view which shows the structure of a multipolar resolver. It is a connection diagram of the status coil of a multipolar resolver. It is a block diagram which shows the structure of the drive unit in an angular position detection apparatus. It is a block diagram which shows the hardware constitutions of a detection circuit part. It is a wave form diagram which shows the waveform of the resolver signal after digital conversion. It is a conceptual diagram with which it uses for description of a cogging torque. It is a conceptual diagram which shows the relationship between a position detection coordinate and a motor coordinate. It is a flowchart which shows the correction amount calculation processing procedure. It is a flowchart which shows a position detection process procedure.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Direct drive motor, 20 ... Single pole resolver, 30 ... Multi-pole resolver, 40 ... Detection circuit part, 41 ... Current / voltage converter, 42 ... 3/2 phase converter, 43 ... Analog switch 44... Position detection circuit 50... Servo driver 60... Drive unit 61.

Claims (4)

In the angle detection device that detects the rotation angle of the rotating shaft of the motor that generates the cogging torque,
A plurality of resolvers each configured to output a signal corresponding to a rotational angle position of the rotating shaft of the motor, and having a different number of poles;
The output error of the resolver on the minor pole side with respect to the output on the majority pole side among the plurality of resolvers is measured for each predetermined measurement point, and the correction amount for each measurement point is acquired based on the measurement result Correction amount acquisition means;
Storage means for storing the acquired correction amount;
Correction means for correcting the output of the resolver on the low pole side based on the corresponding correction amount stored in the storage means for each measurement point;
Each said measurement point is
Each of the angle detection devices is a rotation angle position where the rotation shaft does not rotate when the servo of the motor is turned off . The angle detection device according to claim 1, wherein the reference position of the resolver on the small pole side is set to the rotation angle position where the rotation shaft does not rotate when the servo of the motor is turned off . In an angle detection method for detecting the rotation angle of the rotating shaft of a motor that generates cogging torque,
Each of the plurality of resolvers having different pole numbers is configured to output a signal corresponding to the rotational angle position of the rotating shaft of the motor. A first step of measuring an output error for each predetermined measurement point and acquiring and storing a correction amount for each measurement point based on the measurement result;
A second step of correcting the output of the resolver on the low pole side based on the corresponding correction amount stored in the storage means for each measurement point;
Each said measurement point is
An angle detection method , wherein each of the rotation axes is a rotation angle position where the rotation shaft does not rotate when the servo of the motor is turned off . The angle detection method according to claim 3, wherein the reference position of the resolver on the small pole side is set to the rotation angle position where the rotation shaft does not rotate when the servo of the motor is turned off .

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