JP2011125073A - Motor drive control device and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor drive control device and method that can reduce a speed ripple, while keeping the repeatability of positional information of a mover in a motor drive position. <P>SOLUTION: The motor drive control device has an ellipse computer which computes an elliptical parameter showing an ellipse that is approximate to a Lissajous's curve based on two sine wave signals with shifted phases which are output from the mover in the motor drive position, a corrector which corrects the two sine wave signals so that an ellipse shown by an elliptical parameter may be a perfect circle, a converter which converts the Lissajous's curve based on the two corrected sine wave signals into speed information that shows the moving speed of the mover, and a control unit which controls the motor driver based on the speed information. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a control technology for a motor drive device.

  2. Description of the Related Art Conventionally, in a motor drive device having a stator and a mover, a technique using a SIN signal and a COS signal obtained from a resolver is known as a technique for detecting position information of the mover. In this technique, the accuracy of the position signal depends on the degree of approximation of the Lissajous circle based on the SIN and COS signals. Therefore, the position and velocity accuracy of the moving element depends on the sine and cosine signals obtained from the resolver being maintained in a sine and cosine relationship, and that these signals are stable in waveform.

  When the position information described above is applied to a planar motor, it is particularly difficult to maintain its accuracy. Here, the planar motor will be described. FIG. 12 is a diagram showing a conventional planar motor. As shown in FIG. 12, the planar motor 9 includes a platen 91 as a stator and a slider 92 as a mover. The slider 92 has a plurality of magnetic poles, and each of the platen 91 and the plurality of magnetic poles of the slider 92 has grooves and teeth in a direction perpendicular to the moving direction of the slider 92. In this planar motor 9, the distance from one tooth to the next tooth, that is, the distance between the teeth and the adjacent groove is called the pitch, and the distance from the tooth of the platen 91 to the tooth of the slider 92 is called the gap. . In such a flat motor 9, the pitch of the teeth of the platen 91 depends on the machining accuracy, surface roughness, warpage, and the like.

JP 2006-112862 A JP 2006-112859 A JP 2006-90741 A JP 2006-90738 A

  From the above, when the pitch of the teeth of the platen 91 varies depending on the location, there arises a problem that the signal from the resolver is affected by the influence. Since the slider 92 is controlled based on a signal from the resolver, depending on the position of the slider 92 on the platen 91, the Lissajous has a waveform including elliptical properties and harmonics. This means that a ripple (speed ripple) occurs in the speed information based on the position information. In addition, when the position information is corrected in real time in order to reduce the speed ripple described above, there is a problem that the reproducibility of the position information is reduced. This is because the correction value differs depending on the operation direction immediately before the slider 92 stops.

  The present invention has been made to solve the above-described problems, and a motor drive control device and a motor drive capable of reducing speed ripple while maintaining the reproducibility of the position information of the mover of the motor drive device. An object is to provide a control method.

In order to solve the above-described problem, one aspect of the present invention is an ellipse that calculates an ellipse parameter indicating an ellipse that approximates a Lissajous curve based on two sinusoidal signals out of phase output from a moving element in a motor drive device. A calculating unit; a correcting unit that corrects the two sinusoidal signals so that the ellipse indicated by the ellipse parameter is a perfect circle; and a Lissajous curve based on the two corrected sinusoidal signals. A conversion unit that converts speed information indicating speed and a control unit that controls the motor drive device based on the speed information are provided.

  According to another aspect of the present invention, an ellipse parameter indicating an ellipse that approximates a Lissajous curve based on two sine wave signals that are out of phase output from a moving element in a motor drive device is calculated. The two sinusoidal signals are corrected so that the indicated ellipse is a perfect circle, a Lissajous curve based on the two corrected sinusoidal signals is converted into speed information indicating the moving speed of the moving element, and the speed information and The motor drive device is controlled based on the above.

  The speed ripple can be reduced while maintaining the reproducibility of the position information of the mover of the motor drive device.

It is a figure which shows the motor drive system which concerns on embodiment. It is a figure which shows the structure of a slider. It is a figure which shows the hardware constitutions of a control apparatus. It is a figure which shows the function structure of a control apparatus. It is a flowchart which shows operation | movement of a control apparatus. It is a figure which shows a Lissajous curve. It is a figure which shows an ellipse approximate expression. It is a figure which shows the expanded ellipse approximate expression. It is a figure which shows the matrix for calculating | requiring unknown AE. It is a figure which shows a displacement signal. It is a figure which shows the type | formula of a displacement signal. It is a figure which shows the conventional planar motor.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  First, the configuration of the motor drive system according to the present embodiment will be described. FIG. 1 is a diagram showing a configuration of a motor drive system according to the present embodiment.

  As shown in FIG. 1, a motor drive system 1 according to the present embodiment includes a planar motor 2 as a motor drive device, and a control device 3 (motor drive control device) that is connected to the planar motor 2 and controls the planar motor 2. ). The planar motor 2 includes a platen 21 as a stator and a slider 22 as a mover.

  Next, the configuration of the slider will be described. FIG. 2 is a diagram illustrating the configuration of the slider.

  As shown in FIG. 2, the slider 22 includes a plurality of salient poles 221 around which coils are wound, and a resolver 222 as an encoder. The resolver 222 excites the coil of the salient pole 221 with SIN-phase and COS-phase AC signals, and outputs displacement information indicating the SIN signal and the COS signal based on this to the control device 3. The slider 22 includes a power amplifier (not shown). This power amplifier amplifies a control signal based on the control information sent from the control device 3 and transmits it to the slider 22 as a drive signal.

  Next, the hardware configuration and functional configuration of the control device will be described. FIG. 3 is a diagram illustrating a hardware configuration of the control apparatus. FIG. 4 is a diagram illustrating a functional configuration of the control device.

  As shown in FIG. 3, the control device 3 includes, as hardware, an external I / F 33 that mediates transmission / reception of information with a CPU (Central Processing Unit) 31, a memory 32, and a slider 22. As shown in FIG. 4, the control device 3 functions as a displacement information acquisition unit 41, a Lissajous calculation unit 42, a correction unit 43 (ellipse calculation unit, correction unit), a speed conversion unit 44 (conversion unit), a position. A conversion unit 45 and a control unit 46 are provided. These functions are realized by the cooperation of the CPU 31 and the memory 32.

  The displacement information acquisition unit 41 acquires displacement information indicating measured values of the SIN signal and the COS signal as two signals shifted in phase from the resolver 222 via the external I / F 33. The Lissajous calculation unit 42 performs a Lissajous calculation based on the displacement information acquired by the displacement information acquisition unit 41. The correction unit 43 corrects the SIN signal and the COS signal based on an ellipse that approximates the Lissajous curve calculated by the Lissajous calculation. The speed conversion unit 44 converts the Lissajous curve based on the SIN signal and the COS signal corrected by the correction unit 43 into speed information. The position conversion unit 45 converts the Lissajous curve calculated by the Lissajous calculation into position information. The control unit 46 sends control information based on the speed information converted by the speed conversion unit 44 and the position information converted by the position conversion unit 45 to the slider 22 via the external I / F 33.

  Next, the operation of the control device will be described. FIG. 5 is a flowchart showing the operation of the control device. FIG. 6 is a diagram showing a Lissajous curve. FIG. 7 is a diagram showing an ellipse approximation formula. FIG. 8 is a diagram showing the developed ellipse approximation formula. FIG. 9 is a diagram illustrating a matrix for obtaining A to E. FIG. 10 is a diagram showing a displacement signal. FIG. 11 is a diagram showing an equation of the displacement signal.

  First, the displacement information acquisition unit 41 acquires displacement information from the resolver 222 (S101).

  Next, the Lissajous calculating unit 42 calculates a Lissajous curve ab 'as shown in FIG. 6 based on the displacement information acquired by the displacement information acquiring unit 41 (S102). In FIG. 6, the horizontal axis indicates the SIN signal output, and the vertical axis indicates the COS signal output. The Lissajous curve ab represents a Lissajous curve that is a perfect circle as a correction target, and the Lissajous curve ab 'represents a Lissajous curve based on displacement information.

  Next, the position conversion unit 45 converts the Lissajous curve calculated by the Lissajous calculation unit 42 into a phase, that is, position information (S103).

Next, the correction unit 43 calculates a coefficient using an elliptic approximation (S104). Hereinafter, a specific calculation method of this coefficient will be described. First, as shown in FIG. 6, the center of the ellipse is (X ₀ , Y ₀ ), the length in the horizontal axis direction is c, the length in the vertical axis direction is d, and the counterclockwise rotation with respect to the horizontal axis intersecting the center When the inclination of the direction is θ, the ellipse approximation formula is as shown in FIG. If this elliptical approximate expression is developed and the unknown part is replaced with variables A, B, C, D, and E, the expression becomes as shown in FIG.

In order to obtain values of A to E that minimize the sum of the squares of this equation, partial differentiation is performed with A to E, and the equation is as shown in FIG. 9 when represented by a matrix for obtaining A to E. . A to E can be obtained by substituting each of the actually measured values in the displacement information for X and Y in the equation shown in FIG. In the present embodiment, A = 0.578878, B = 2.777778, C = −0.
05788, D = −0.55556, E = −0.94207.

Next, the correction unit 43 calculates an OFFSET (X ₀ , Y ₀ ), an amplitude ratio (d / c), and a phase difference (θ) of the ellipse as the Lissajous curve ab ′ based on the coefficients (S105). In this embodiment, it is assumed that OFFSET is 0.1, phase difference is 0.174533, and amplitude ratio is 0.6. In this case, the displacement signal has waveforms a and b ′ as shown in FIG. In FIG. 10, a represents a SIN signal, and b and b ′ represent COS signals. Here, a and b indicate ideal displacement signals. Here, the ideal displacement signal indicates a SIN signal or a COS signal having a perfect circle like the Lissajous curve ab in FIG. 6 when the Lissajous calculation is executed. Further, b ′ represents a COS signal in the present embodiment. Here, b ′ is a COS signal that is distorted due to deformation, crossing or the like of the platen 21. For ease of explanation, it is assumed that the SIN signal according to the present embodiment is not distorted. These are shown by the equations as shown in FIG.

Next, the correction unit 43 corrects the displacement signal based on the calculated OFFSET (X ₀ , Y ₀ ), amplitude ratio (d / c), and phase difference (θ) (S106). In this embodiment, since only the COS signal is distorted, by correcting the COS signal based on OFFSET (X ₀ , Y ₀ ), amplitude ratio (d / c), and phase difference (θ), A Lissajous curve ab ′ for drawing an ellipse shown in FIG. 6 becomes a Lissajous curve ab for drawing a perfect circle.

  Next, the speed conversion unit k44 converts the Lissajous curve ab corrected by the correction unit 43 into phase information (S107), and further converts it into speed information (S108).

  Next, the control unit 46 feedback-controls the planar motor 2 by outputting control information to the slider 22 based on the target value indicating the control target, position information, and speed information (S109).

  As described above, velocity ripple can be reduced while ensuring position reproducibility by performing ellipse correction so that an ellipse becomes a perfect circle only on a displacement signal based on velocity information. In the present embodiment, the motor drive device is a flat motor, but the present invention can also be applied to a rotary motor.

  DESCRIPTION OF SYMBOLS 1 Motor drive system, 2 Planar motor, 3 Motor drive control apparatus, 21 Platen, 22 Slider, 221 Salient pole, 222 Resolver, 31 CPU, 32 Memory, 33 External I / F, 41 Displacement information acquisition part, 42 Lissajous calculation part , 43 Correction unit, 44 Speed conversion unit, 45 Position conversion unit, 46 Control unit.

Claims (4)

An ellipse calculator that calculates an ellipse parameter indicating an ellipse that approximates a Lissajous curve based on two sinusoidal signals out of phase output from a mover in a motor drive device;
A correction unit that corrects the two sinusoidal signals so that the ellipse indicated by the ellipse parameter is a perfect circle;
A converter that converts a Lissajous curve based on the two corrected sinusoidal signals into speed information indicating the moving speed of the moving element;
A motor drive control device comprising: a control unit that controls the motor drive device based on the speed information.   The motor drive control device according to claim 1, wherein the motor drive device is a planar motor.   An ellipse parameter indicating an ellipse that approximates a Lissajous curve based on two sinusoidal signals out of phase output from a mover in a motor drive device is calculated, and the ellipse indicated by the ellipse parameter is a perfect circle Two sine wave signals are corrected, a Lissajous curve based on the two corrected sine wave signals is converted into speed information indicating the moving speed of the moving element, and the motor drive device is controlled based on the speed information. Motor drive control method.   The motor drive control method according to claim 3, wherein the motor drive device is a planar motor.

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