TW539933B - Controller for optical scanner - Google Patents

Abstract

A controller for an optical scanner (1) includes a mirror angle detecting unit (17a, 17b, 17c, 17d) for detecting an angle of a mirror, a rotation axis angle detecting unit (16, 35) for detecting an angle of the axis, a current detecting unit (27, 31) for detecting a current supplied to a motor (13), and a torsional vibration stabilizing compensation unit (33) for stabilizing a torsional vibration of the axis, thereby a value (42) subjected to a proportional compensation (25) and a differential compensation (32) by using a rotation axis angle detected value (22) and a value (33a) from the torsional vibration stabilizing compensation unit (33) are negatively fed back to a value obtained by integrally compensating for a deviation (23) between the angle desired value (21) and a mirror angle detection value (17e) to determine a current value (29) to be supplied to the motor.

Description

539933 Printed by the Consumers ’Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs A7 B7 V. Description of the invention (1) [Technical field to which the invention belongs]: The invention relates to an angle detection device, and it is decided to support the rotation axis around the rotation axis. Control device for the position of the mirror in the optical scanner. An optical scanning device used for laser marking and laser drilling of printed circuit boards. The built-in electric motor rotates the mirror mounted on the rotating shaft. By changing the angle of the mirror, the laser oscillator will be changed. The output laser light is irradiated to a predetermined position of the workpiece. [Advanced Technology]: Figure 12 shows the structure of the movable part in the optical scanning device. The mirror 11 is mounted on one end of the rotating shaft 12. The rotating shaft 12 is supported by the bearings 14 and 15 and the moving wire 圏 1 3 integrated with the rotating shaft 12 receives the driving torque (Torque) and rotates. Determined at the given location. Hereinafter, the mirror 11, the rotating shaft 12, and the moving coil 13, which rotate together, are collectively referred to as an optical scanner 1. In the optical scanner 1, an angle for detecting the rotation angle of the rotating shaft 12 which is omitted in the figure is set. Detection sensors, such as variable capacity type sensors. The variable-capacity type inductor is constructed by rotating a flat plate of a dielectric body mounted on a rotating shaft between two sets of fixed plates and rotating the shaft, and the angle of the rotating shaft is used as static electricity. Changes in capacity are detected by electrical signals. Regarding the technology of the variable capacity sensor, please refer to, for example, US Patent No. 3 5 7 2 8 2 and US Patent No. This paper is applicable to the Chinese National Standard (CNS) A4 specification (210X297 mm). (Please read the notes on the back before filling this page) -4-Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs 539933 A7 1 '___ B7 V. Description of Invention (2) Gazette No. 4864295 and Japanese Patent Application Laid-Open No. 7-55500 Bulletin. In addition, Japanese Unexamined Patent Publication No. 4-1 2 7 9 8 1 discloses that a laser for angle measurement is irradiated on a mirror, and the reflected light is detected by a linear sensor, and the angle of the mirror is feedback-controlled. Technology. Furthermore, Japanese Patent Application Laid-Open No. 6 3-1 4 7 1 3 8 discloses that a reflecting surface is formed on a part (mirror frame) in which a mirror is fixed to a rotation axis, and the light coming from the reflecting surface is detected by a light receiving element. A technique for determining the position of a mirror by reflecting the light of a light-emitting element. Figure 13 is a block diagram of the control of the optical scanner. In order to feed the angle detection signal 2 2 negatively to the angle target designated by the upper control device 値 signal 2 Γ, and set the deviation signal 2 3 in the normal state to 0, the deviation signal 2 3 is used to integrate the compensation circuit 2 4 Integrate. In addition, in order to maintain the stability of this servo mechanism, the angle detection signal 2 2 is input to the proportional compensation circuit 25 and the differential compensation circuit 26, and the sum of the output signals of these circuits is output from the output signal of the integral compensation circuit 24. Subtract and set to control input signal 2 7. The motor drive circuit 28 supplies a motor drive current 29 to the optical scanner 1 in proportion to the control input signal 27. The motor driving current 29 flows in the moving coil 13 and generates a driving torque in the moving coil 13 which is proportional to the current 値. In the case where a laser light is used to perform hole processing on a printed circuit board, in order to perform precise processing on a fine circuit diagram, it is necessary to reduce the error of the position determination of the laser light used for processing to about 10 A m or less. In addition, in order to reduce the processing time, it must be required to open the paper size after opening a hole. The Chinese paper standard (CNS) A4 size (210X297 mm) is applicable. -5- ^ Assemble. (Please read the back first Please pay attention to this page, please fill out this page) Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs 539933 A7 'B7 _____ V. Description of the invention (3) The speeding up of a hole-cutting operation, for example, opening at 1 00 per second In the case of 0 holes, it is necessary to reduce the moving time between holes to an average of 1 m S. The laser light has its energy distribution and is incident on the mirror 11 with a wide area. Therefore, in order to perform high-quality For the hole-cutting process, the mirror 11 is preferably larger (the area is wider). However, if the mirror 1 1 is enlarged, the torsional vibration and bending vibration of the rotating shaft 12 will become larger and hinder the mirror. Position-dependent high response capability. First, the effect of torsional vibration will be explained. As the mirror 1 1 becomes larger, the moment of inertia (Moment) around the rotation axis 12 also increases, so the rotation of the rotation axis 12 Of Spring The natural vibration number of the rotational vibration will also decrease. The primary mode of the torsional vibration is the torsional vibration with the smallest natural vibration number. There is a twisted node in the longitudinal direction of the rotation axis 12 and the two sides of this node are clamped to each other. The inverse phase is used to generate angular displacement. In addition, the 2nd mode of torsional vibration is torsional vibration with low natural vibration several times. There are 2 twisted nodes in the longitudinal direction of the rotation axis 12. The central part and the parts on both sides vibrate in an inverse phase. For example, when an angle detection sensor is arranged beside a mirror, a node of torsional vibration is placed between the angle detection sensor and the moving coil 13 In this case, in the above-mentioned servo mechanism, the vibration number component of the angle detection signal 22 becomes a positive feedback, resulting in unstable control. The height response determined by the mirror position will be g-force. Considering the suppression characteristics of low-frequency external interference, although the control bandwidth is the largest standard scale applicable to the Chinese National Standard (CNS) A4 specification (210X297 mm) I —; ------ ^ I ----: --- Order ------- AW (Please read the notes on the back before filling out this page) -6- Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs 539933 A7 B7 V. Invention Explanation (4) It is better to be as wide as possible, but the control bandwidth is limited due to the number of torsional vibrations. In addition, when the node of torsional vibration overlaps or is extremely close to the position of the sensor, it cannot be detected by the angle The sensor observes its vibration mode, so the stability of the control cannot be controlled, and the precision of the position determination of the laser light is reduced. Next, the effect of bending vibration will be described. The movable part of the optical scanner shown in Figure 12 It is preferable to maintain balance around the rotation axis 12. However, for example, if the left and right sides of the mirror receiving the driving torque of the moving coil 13 or the length of the mirror about the axis of the rotation axis 12 are uneven, the difference in quality will cause an uneven weight. And by the imbalanced inertial force of the weight accompanying the operation of the optical scanner 1, a bending vibration will be generated at the support points of the bearings 14 and 15 and the rotating shaft 12. As a result, the mirror vibrates in parallel or at right angles to the mirror surface. Generally, the optical scanner 1 does not include a sensor capable of detecting bending vibration of the rotating shaft 12 or an adjuster for offsetting bending vibration is added to the rotating shaft 12. In addition, in the feedback control of the above-mentioned servo mechanism, the bending vibration that has occurred cannot be attenuated. Therefore, the precision of the laser light position determination cannot be improved. [Invention]: The purpose of the present invention is to provide, not only reduce the torsional vibration and bending vibration generated on the rotating shaft on which the mirror is installed, and shorten the position determination time of the mirror, but also improve the precision of the position determination of the laser light. Control device for optical scanner. This paper size applies the Chinese National Standard (CNS) A4 specification (210 > < 297mm) I ^ „Order. (Please read the precautions on the back before filling this page) 539933 Printed by the Consumers’ Cooperative of Intellectual Property Bureau of the Ministry of Economic Affairs A7 B7 V. Description of the invention (5) In order to achieve the above object, the first feature of the present invention is that, based on the angle target 値 and the angle detection 値, a mirror that will be supported on the rotation axis is determined around the rotation axis. In the control device of the position optical scanner, a correction 値 for the torsional vibration of the rotation axis is added to the integral of the deviation between the angle target 値 and the angle detection 値. Thus, the torsional vibration of the rotation shaft can be reduced. In this case, the above-mentioned correction 値 can be used as an output of a transfer function up to r times (r is a positive integer) the angular velocity of the rotation shaft of the rotation shaft caused by the driving torque of the rotation shaft.値 Furthermore, the output 値 of the above-mentioned transfer function can be calculated from the current 値 supplied to the motor which generates the drive torque described above.値 and angle detection 値, the mirror that is supported on the rotation axis, and the control device of the optical scanner that determines its position around the rotation axis, not only the target track as a function of position time, but also from this target track and Based on the sum of the target speed and the target acceleration of the target orbit, a specific frequency number component is removed as the angle target 値. Thus, the bending vibration can be reduced. In this case, the above specific frequency number can be reduced The component is used as the natural vibration number component of the bending vibration of the rotary shaft, or as the natural vibration number component of the torsional vibration of the rotary shaft. A second feature of the present invention is based on the angle target 基于 and the angle detection 値, The control device of the optical scanner that determines the position of the mirror supported by the rotation axis around the rotation axis includes a mirror angle detection means that detects the angle of the mirror, and a paper that detects the angle of the rotation axis. Standards are applicable to Chinese National Standard (CNS) Α4 specification (210 × 297 mm) I ^ Order „(Please read first Note on the back, please fill in this page again) -8- 539933 • ω 1 • · · (Formula i) Printed by the Consumers ’Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs A7 B7 V. Description of the invention (6) Rotation axis angle detection method, and A current detection means for detecting a current supplied to a motor that rotates the above-mentioned rotating shaft, and a torsional vibration stabilization compensation means for stabilizing torsional vibration based on the above-mentioned current, and the rotation axis angle detection is used for proportionality After the compensation and differential compensation, and the above-mentioned torsional vibration stabilization compensation method, the negative feedback is fed back to the angle after the deviation of the angle target 角度 and the mirror angle detection 加以 are integrated and compensated, and the current supplied to the motor is determined 値. This can reduce the torsional vibration of the rotating shaft. [Implementation Mode of the Invention]: First, the principle of the present invention will be described with reference to FIGS. 12 and 13 again. The frequency response (self-compliance) from the driving torque received by the moving wire 圏 13 to the angular displacement of the moving coil 13 is expressed by the transfer function G (s) of the first formula.

G {s) = + X Here, s is a complex variable of Laplace transform, n is the η-th mode of torsional vibration (η is a positive integer), and Γ η is the attenuation coefficient of the η-th mode of torsional vibration K is the constant for the rigid body mode, and k η is the mode constant for the η-th mode of torsional vibration. Here, 'if you pay attention to a specific torsional vibration mode (rth-order mode)', the transfer function G r (s) shown in the second equation is that the driving torque is applied to the paper standard of China National Standard (CNS) A4 (210X297 mm) 11 -------- HI equipment ---- Ί .-- Order ------- (Please read the notes on the back before filling this page) -9- 539933 • ( (Equation 2)… (Equation 3) A7 · B7 V. Explanation of the invention (7) The transfer function until the angle change of the% r-order mode in the position of the moving coil 13 is displayed in H r (s) of Equation 3 The transfer function from the driving torque to the angular displacement of the r-th mode in the position of the moving coil 13 is + 2ζτωΓΞ + ωΓ W Yang; because the transmission function H r (s) is shown to act on the driving torque Position response, so the mode constant kr is positive. Therefore, if the negative of the transfer function H r (s) is fed back to the control input signal 2 7, the controllable attenuation can be given to the r-th mode to stabilize the motor drive circuit 28 as the current control method. In this case, in general, since the driving torque of the moving coil 13 is proportional to the motor driving current 2 9, the driving torque of the moving wire 圏 13 can be obtained by measuring the motor driving current 29. The current detection signal corresponding to 値 of the motor drive current 29, for example, flows the motor drive current 29 to a current detection resistor with a small resistance 0 (0 · 1 to several Ω or less). The inter-voltage input to the differential input type subtraction circuit can be obtained as the output of the differential input type subtraction circuit. Hereinafter, the present invention will be described based on the illustrated embodiments. Fig. 1 is a control block diagram of the optical scanner of the present invention. The same or same function as the first and second pictures shown in Figure 12 are given the same paper size as the Chinese National Standard (CNS) A4 specification (21〇297 mm). I ^ Binding ^. (Please read the back first Please note this page, please fill in this page) Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs -10- Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs 539933 A7, B7 V. Description of Invention (8) Symbols and descriptions are omitted. The angle detection signal 2 2 is negatively fed back to the angle target 値 signal 21 to obtain the deviation signal 2 3, and the deviation signal 2 3 is integrated by the integral compensation circuit 2 4. In addition, in order to maintain the stability of this servo mechanism, the angle detection signal 2 2 is input to the proportional compensation circuit 25 and the angular velocity observation circuit 32 described later. In addition, a current detection signal 3 1 corresponding to the magnitude of the current supplied to the moving coil 13 is input to the angular velocity observation circuit 3 2 and the torsional vibration primary compensation circuit 3 3 and the torsional vibration secondary compensation circuit 3 4 described later. . The sum of the output signals of the proportional compensation circuit 25 and the angular velocity observation circuit 3 2 and the primary torsional vibration compensation circuit 3 3 and the secondary torsional vibration compensation circuit 3 4 is subtracted from the output signal of the integral compensation circuit 2 4. Go as a control input signal 2 7. The mirror angle command circuit 20 and the mirror vibration suppression factor 41 will be described in detail later. Next, the torsion r-time compensation circuit will be described. By measuring the frequency response of the mirror 11 actually, the natural vibration number and attenuation coefficient of r times can be known. In addition, a secondary filter (hereinafter referred to as a torsion r-th order compensation circuit) having a frequency response characteristic proportional to the same sign in Equation 3 can be constructed by an electronic circuit. Figure 2 shows the torsion r-time compensation circuit of the present invention, which is composed of three operational amplifiers 3 3 3 to 3 35, six resistors Roi-Roe, and two capacitors CQ1 and CQ2. The positive input terminals of the operational amplifiers 3 3 3 to 3 3 5 are grounded. The negative input terminal of the operational amplifier 3 3 3 is connected to the resistor R. i terminal and C. i terminal. The output terminals of the op amp 3 3 3 are connected to the original paper size of C 〇i. Applicable to China National Standard (CNS) A4 (210 X 297 mm) I ^ ^ Order (please read the precautions on the back before filling this page) -11-539933

S (Equation 4) A7 'B7 __ 5. Description of the invention (9) The terminal at the other end and the terminal at one end of R03. And R. The terminal at the other end of 3 is connected to the terminal at one end of R ◦ 2, R ◦ 4, c ◦ 2 and the negative-side input terminal of the operational amplifier 3 3 4. The output of the operational amplifier 3 3 4 is connected to the terminal of the other end of C ^ 2 and the terminal of the other end of R ◦ 4 and the terminal of one end of R ◦ 5. The negative input terminal of the operational amplifier 3 3 5 is connected to R. The terminal at the other end of 5 and the terminal at one end of R ^ 6. The output terminal of the computing amplifier 3 3 5 is connected to the terminal at the other end of R ◦ 6 and the terminal at the other end of R 0 1 and the terminal 3 3 2. The terminal at the other end of Ro2 is connected to terminal 3 31. In addition, R ◦ 2 is a variable resistor. In this circuit, if the resistor 値 R is made. If 5 is equal to the resistance 値 R Q 6, then the transfer function G c (s) from the input signal input to the terminal 3 3 1 to the output signal output from the terminal 3 3 2 is shown in the fourth formula. ^ 02 ^ 02 S + And if the resistance 値 Rqi, R〇3, R〇4 and the capacitance of the capacitor C01, the constant term of the denominator polynomial of Formula 4 and the constant term of the denominator polynomial of Formula 3 If the coefficients of the first term of the denominator polynomial of Formula 4 and the coefficients of the first term of the denominator polynomial of Formula 3 are set equal, then the natural vibration number and attenuation coefficient Γ r of this line are equal to the I · th order. Vibration mode. And if the current detection signal 3 1 is input to the terminal 3 3 1 ', then the output signal output from the terminal 3 3 2 uses the same symbol and the moving coil. The paper size applies the Chinese National Standard (CNS) A4 specification (210X297 mm) I — ^ ------ ^ Installation ---- „--- Order ------ (Please read the notes on the back before filling out this page) Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs- 12- 539933 Μ, B7 V. Description of the invention (The angular velocity of the r-order mode in the position of 1 3 is proportional. Therefore, the output signal from the terminal 3 3 2 is negatively fed back to the output of the integral compensation circuit 2 4 The signal can stabilize the vibration mode of the rth order, that is, reduce the vibration of the rth order. In this embodiment, since the resistance 値 R 0 2 and the natural vibration number and the attenuation coefficient are set independently from each other, it can be set. By setting the resistance 値 R.2 as a variable resistor, the amplitude of the output signal of the torsional vibration compensation circuit is adjusted. In addition, the control block diagram shown in Fig. 1 shows that the torsional vibration is set once. Compensation circuit 3 3 and torsional vibration secondary compensation circuit 3 4 'To stabilize the primary and secondary modes of torsional vibration, and to compensate for a larger number of vibration modes, a torsional vibration compensation circuit as shown in Figure 2 can be set in each mode By connecting these torsional vibration compensation circuits with the torsional vibration primary compensation circuit 33 and the torsional vibration secondary compensation circuit 34 in parallel, it is possible to stabilize the torsional vibration at a desired number of times. Next, regarding angular velocity observation The circuit 32 will be described. In the present invention, an angular velocity observation circuit 3 2 is provided instead of the differential compensation circuit 26 of FIG. 13 to estimate the angular velocity of the rigid body mode corresponding to the first term of the first equation. The obtained estimated signal is negatively fed back to the output signal of the integral compensation circuit 24, which can stabilize the servo system shown in Fig. 1. Fig. 3 shows the angular velocity observation circuit 32 of the present invention, which is composed of two Operational amplifiers 3 2 4, 3 2 5 and 6 resistors R ii ~ ri 6 This paper size is applicable to China National Standard (CNS) A4 specification (210X297 mm) ----- (Please read the back (Please fill in this page on the matters needing attention), printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs -13- printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs 539933 A7 B7 V. Description of Invention (11), and capacitor C! 1 The positive input terminal of the operational amplifier "3 2 4, 3 2 5 is grounded. The negative input terminal of the operational amplifier 3 2 4 is connected to the terminal of one of the resistors R 1 1 to R 1 3 and C 1 1 terminal. The other end of R 1 1 is connected to the terminal of terminals 3 2 1 and R 1 4, and the other end of R 1 2 is connected to terminal 3 2 2. The output terminal of the operational amplifier 3 2 4 is connected to the terminal at the other end of C! I, the terminal at the other end of R13, and the terminal at one end of Ris. The negative input terminal of the operational amplifier 3 2 5 is connected to the other terminal of R 1 4 and R i 5 and the terminal of one terminal of Rie. The output terminal of the operational amplifier 3 2 5 is connected to the terminal at the other end of R ^ 6 and the terminal 3 2 3. In this circuit, if the resistance 値 R 1 1, R 1 3, R 1 4, R 1 5 is set to satisfy the relationship of the fifth formula, then the signal input at the terminals 3 2 1 and 3 2 2 and The relationship between the signals output from terminals 3 2 3 is shown in Equation 6. l £ r-* · and " W 丨 4 ··: (Eq. 5)

Eo {s) = ~ R ^ 1 — (-exhaustion + ㈠ J +-S +-· _ · (Equation 6) 'Here, E ii (s) is the Laplace transform of the input signal 3 2 1, It is the signal after the sign inversion of the angle detection signal 2 2. In addition, E i 2 (s) is the Laplacian conversion of the input signal 3 2 2 'for the current. The paper standard applies Chinese National Standard (CNS) A4 Specifications (210X 297mm) --------- ^ Installation ---- ^-Order ------ (Please read the precautions on the back before filling this page) -14- 539933 A7 B7 V. Explanation of the invention (12) The detection signal 3 1. E ^ (s) is the Laplacian conversion of the input signal 3 2 3 and is the estimated signal of angular velocity. (Please read the precautions on the back before filling this page) Section 6 The first- and second-order transfer functions of the formula have a common denominator polynomial, and the constant term 1 / R 1 3 C ii is the frequency of the corner points of each transfer function. And corresponding to the first term of formula 6, And in the frequency region lower than the frequency of the corner point, the differential angular velocity estimation signal of the angle detection signal is mainly, in addition, it corresponds to the second term of formula 6 and the frequency of the corner point is In the high frequency area, the integral of the angle detection signal is the angular velocity estimation signal, so the angular velocity of the rigid body mode of the position in the moving coil 13 can be estimated with high precision. When the angle detection sensor is placed away from the position in the moving line 圏 13, the angle detection signal in the frequency region near the torsional vibration is deviated from the angular displacement in the position of the moving line 313. Therefore, In the case where the angle detection sensor is located away from the moving line 313, it is best to determine the capacitance of the resistor R13 and the capacitance C1 of the capacitor in such a way that the frequency of the corner point is lower than the one-time torsional vibration mode. 1 値. If this is done, the degree of torsional vibration of the angle detection signal can be reduced to a positive degree, so even if the servo bandwidth is extended to be wider than the conventional servo system, Ensuring the stability of the servo system. Next, the embodiment of suppressing the mirror vibration caused by the bending vibration of the rotating shaft will be described. Figure 4 is a block diagram of the mirror vibration suppression factor of the present invention shown in Figure 1. The target track 4 1 1 is the target trajectory of the rotation angle of the mirror 11 and the mirror vibration suppression factor 4 1 The angle target does not apply the Chinese National Standard (CNS) A4 specification (210X297 mm) -15- 539933 A7 B7 from this paper scale. 5. Description of the invention (13) The mirror angle command circuit 20 is supplied. Here, the target The orbit 4 1 1 is set to the shortest time orbit of the inertial body that uses the ama X shown in Equation 7 as the maximum acceleration and performs maximum acceleration and maximum deceleration in the same time. And L is the stroke that starts from time 0 and stops at time T μ. In this case, the time function a (t) of acceleration, the time function v (t) of velocity, and the time function X (t) of position are each expressed by Equation 8, Equation 9, and Equation 10.

4L aMAX (Equation 7) a 0: (/) = < MAX aMAX 0 (0 < / < 0.57 ^) (0 ^ < / < 7 ^) (Equation 8) a

bAAX% -t] Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs

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L-05aMAX {t -L {〇 < t < 〇5TM) (05TM < t < TM) · (V 0 (0 < / < 0 ^) Tj (05TM < i < TM) • (Equation 9) • (Equation 10) Not only the time function x (t) of the position is set to the target orbit 4 1 1 and the output of the differential factor 4 1 2 and the output of the second order differential factor 4 1 3 are used. The paper scale is applicable to the Chinese National Standard (CNS) A4 specification (210X297 mm) —.------ ^ equipment ----— order —----- (Please read the notes on the back before filling this page) 16- 539933 A7 __B7_ V. Invention Explanation (Μ) is added to the target orbit 4 1 1 and input to the notch filter (Notch

Filter). The output signal of the notch filter is used as the angle target signal. As a constant of the notch filter, the angular vibration number ω b is equal to the natural angular vibration number of the bending vibration of the rotating shaft 12. In addition, the constant Γ b of the denominator polynomial and the constant t bn of the numerator polynomial are set to C b> Γ bn. Here, the Laplace transform of the time function of the target orbit 4 1 1 is set to X (S), and if the Laplace transform of the angle target 値 signal 2 1 is set to R (s), X (s ) And R (s) have a relationship as shown in Equation 11, and the zero point of the molecular polynomial of the notch filter can remove the bending vibration component of the rotating shaft 12. (Please read the notes on the back before filling this page) S2 + ^ bnC〇bS + C〇l S2 + 2ζόω ^ + ωΙ 2ζ,

• S bucket) (Eq. 11) Therefore, once the angle target signal 2 1 is input to the feedback control system shown in Fig. 1, it is possible to suppress the mirror vibration accompanying the position-determining action. Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs In addition, although the notch filter has a phase delay determined by the coefficient of the denominator polynomial, the output of the target orbit 4 1 1 and the differential factor 4 1 2 and the second-order differential factor The output of 4 1 3 is added so that the denominator polynomial of the notch filter is cancelled. As a result, the phase delay from the target track 4 11 to the angle target signal 2 1 can be eliminated, and the delay in determining the position of the target track 4 11 can be reduced. As mentioned above, the bending vibration that has occurred can be controlled by feedback to reduce the paper size. Chinese paper standard (CNS) A4 (210X297 mm) -17 539933 A7 B7 V. Description of invention (15) (please first Read the notes on the back and fill in this page) Subtraction is extremely difficult, but in the present invention, 'because it is input through the feedback control system, that is, the angle target signal is generated by the mirror vibration suppression factor 4 1 2 1 'To prevent bending vibration of the rotating shaft 12' Therefore, it is possible to reduce the error of the laser light position determination of the mirror vibration. The Laplace transform of the target velocity which is the first-order derivative of the time function of the target orbit is set to V (s), and the Laplace transform of the target acceleration which is the second-order derivative of the time function of the target orbit is set to If A (s), then Equation 1 1 can be transformed into Equation 12. Κ {ή = X (s) + sX (s) + ^ rs2X (s) ^ X (s) + ^ V (s) + ^ A (s), J \ cob cob ①b • · * (Eq. 12) Economy The 5th figure printed by the Ministry of Intellectual Property Bureau's Consumer Cooperatives is a block diagram of the vibration control factor of the present invention, and is the figure implementing the 12th formula. In the figure, the gain factors 4 1 7 and 4 1 8 are the coefficients of the weights determined by the constants of the notch filter 4 1 4. If it has such a structure, it can be added by assigning weights to the target trajectory (Formula 10), the target speed (Formula 9), and the target acceleration (Formula 8), even if the notch filter cannot be realized 4 1 4 , Can also generate the mirror vibration suppression factor shown in Figure 4 and the equivalent angle target 値 signal 21. Here, the vibration suppression factors shown in Figs. 4 and 5 can be easily realized by a microprocessor. In this case, in the case where the feedback control system of FIG. 1 is analog control, the digital angle target signal is converted to an analog signal by a DA converter, and the present invention is applicable. Except for calculating the target trajectory, target speed and target acceleration, this paper size applies the Chinese National Standard (CNS) A4 specification (210X297 mm) — -18- 539933 A7 B7 V. Description of the invention (16) (Please read the back first Note: Please fill in this page again.) In addition to the calculation, you can also calculate these time series 値 in advance and store them in memory, and read out the stored data in order when the position is determined. In this case, if each target is normalized by the stroke L and memorized in the memory, the memory capacity can be reduced. In addition, it is also possible to set several kinds of action time T μ by the size of the stroke L. Furthermore, the target track is not limited to that represented by Formula 10 '. The target track can also be set to be equal to or greater than Notch filter 4 1 4 is a time waveform differentiated by the power of the denominator polynomial. In addition, if the angular vibration number ω b of the notch filter 4 1 4 is set to be equal to the natural angular vibration number of the torsional vibration of the movable part of the scanner, it is possible to reduce the torsion with a structure different from that of the torsional vibration compensation circuit described above. vibration. In this case, the servo mechanism is not limited to the servo mechanism shown in Fig. 1, but the conventional servo mechanism shown in Fig. 13 may also be used. Printed by the Intellectual Property Bureau's Consumer Cooperatives, Ministry of Economic Affairs. Figure 6 shows another embodiment of the control device of the optical scanner. In Fig. 6, in addition to the elements shown in Fig. 1, a mirror 11 and elements attached to the mirror 11 and a sensor angle detection circuit 3 5 are added. Through this, the angle detection signal 2 2 It is only supplied to the angular velocity observation circuit 32 and the proportional compensation circuit 25, and is different from the first figure in this point. The other structures are the same as those in FIG. 1, and detailed descriptions thereof are omitted here. Referring to Fig. 6, an angle sensor 16 for detecting an angle is arranged on the rotation axis 12 of the optical scanner 1. The mirror 11 includes a mirror surface that reflects laser light for processing, and a mirror surface 17a that is disposed on the surface of the mirror surface. With the mirror surface 1 7 This paper size is applicable to the Chinese National Standard (CNS) A4 specifications (2 Shu 297 mm) -19-539933 Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs A7 B7 V. Description of the invention (17) a, glowing The element 17 b and the light-receiving element 17 c are arranged. As the light-emitting element 17 b, for example, a semiconductor laser element, and as the light-receiving element 1 7 c, for example, a P S D (Position Sensitive Device) element can be used. Ο The following describes the signal flow and servo mechanism. The mirror angle detection signal 17e (voltage signal proportional to the angle of the mirror 11) output from the light receiving element 17C is amplified by the amplifier 17d, and is negatively fed back to the mirror angle The angle target 値 signal 21 output from the command circuit 20 is generated, and the deviation signal 23 is generated. In order to make the angle of the mirror 1 1 follow the angular target 値 that does not produce a normal deviation, the deviation signal 2 3 is integrated by an integral compensation circuit 24 to form a type 1 servo system. In addition, in order to ensure the stability of this servo mechanism, the angle detection signal 22 is input to the proportional compensation circuit 25 and the angular velocity observation circuit 32, and the sum of the output signals of these circuits and the torsional vibration stabilization compensation circuit 3 is input. The output signal 3 3 a of 3 is subtracted from the output signal of the integral compensation circuit 24 and used as the control input signal 27. The motor drive circuit 28 supplies a motor drive current 2 9 proportional to the control input signal 27 to the optical scanner 1. The motor driving current 2 9 flows into the moving line 圏 1 3, and a driving torque proportional to the current 产生 is generated in the moving line 圏 1 3. By doing so, the torsional vibration of the rotating shaft 12 can be reduced. Here, in the case where the motor driving circuit 28 is a current control mode, generally, because the driving torque of the moving coil 13 is proportional to the motor driving current 29, it can be obtained by measuring the motor driving current 29. It is known that the paper size is applicable to the Chinese National Standard (CNS) A4 specification (21〇 > < 297 mm) --------- ^ ΙΙΓ Packing ----: --- Order ------ -I (Please read the notes on the back before filling out this page) -20- 539933 Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs A7 B7 V. Description of the invention (18) The driving torque of the moving coil 13. The current detection signal 3 1 which is proportional to 値 of the motor drive current 2 9, for example, the motor drive current 2 9 flows to a current detection resistor with a small resistance 値 (0 · 1 to several Ω or less). The voltage between the terminals of the resistor is input to the differential input type subtraction circuit, which can be obtained as the output of the differential input type subtraction circuit. Then, a current detection signal 3 1 proportional to the magnitude of the motor drive current 29 is input to the angular velocity observation circuit 32 and the torsional vibration stabilization compensation circuit 33. The position of the rotating shaft 12 detected by the angle sensor is output as an angle detection signal 22 from the sensor angle detection circuit 35. Then, the angle detection signal 2 2 is input to the proportional compensation circuit 25 and the angular velocity observation circuit 32. Next, for the description of the torsional vibration stabilization compensation circuit 33, reference may be made to the description of the torsional vibration primary compensation circuit 33 of FIG. 1 already described. Next, based on a specific example of an optical scanner, the torsional vibration characteristics of the movable part and the stability of the servo mechanism will be described. Figure 7A and Figure 7B are examples of Bode line diagrams showing the relationship between the gain and phase of the frequency response from the motor current 29 to the angle detection signal 22. The upper paragraph is Gain, the lower stage is phase. In addition, Fig. 8A and Fig. 8B are examples of Bird's-line diagrams showing the relationship between the gain and phase with respect to the frequency response from the motor current 29 to the mirror angle detection signal 17e. The upper section is the gain. , The lower section is phase. Comparing Figure 7A and Figure 8A, the two papers are applicable to the Chinese paper standard (CNS) A4 (210X 297 mm) at 3.8 paper size. —1 ^ ------ # ^ 1 ----, ---- 1T ------ 0 (Please read the notes on the back before filling this page) -21-Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs 539933 A7 ___ B7_ V. Description of the invention ( 19) The frequency of k Η z torsional primary resonance, 10 k Η z torsional second resonance, and the frequency of 1 k Η ζ torsional third resonance are the same. In addition, in FIG. 7A, there is an antiresonance at 3 kH ζ, and in FIG. 8A, there is no antiresonance. As a knowledge of the vibrational system of the construction system, the same phase of the special mode can be obtained from the arrangement of the co-matrix and antiresonance in the Bird diagram. In the case of FIG. 7A, there is an antiresonance between the rigid body mode, the first resonance, and the second resonance, and there is no antiresonance between the second resonance and the third resonance. Therefore, in the case of an optical scanner, between the moving line 13 and the built-in angle sensor 16, the primary mode and secondary mode are in phase, and the tertiary mode is out of phase. On the other hand, in the case of FIG. 8A, there is no antiresonance between the rigid body mode and the first resonance, there is one antiresonance between the first resonance and the second resonance, and the second resonance and the third resonance exist. There is no antiresonance between the resonances. Therefore, in the case of an optical scanner, between the moving coil 13 and the mirror 11, the primary mode and secondary mode are out of phase, and the tertiary mode is in phase. And the servo mechanism shown in FIG. 6 is applied to the optical scanner 1 having such characteristics, that is, the proportional compensation circuit 25 and the angular velocity observation circuit 2 6 do not use the mirror angle detection 値 1 7 e, but by using In the low-order mode (1st mode and 2nd mode), the same phase angle detection signal 2 2 is used for proportional compensation and differential compensation, which can ensure the stability of the servo mechanism. In this case, the 3rd mode is also out of phase. To widen the servo bandwidth, it is necessary to apply stabilization compensation to this mode. In addition, even if the Chinese paper standard (CNS) A4 size (210X297 mm) is applied to the same paper size, I order (please read the precautions on the back before filling this page) -22-539933 A7 B7 V. Description of the invention (20 ) The phase mode does not cause the servo mechanism to be unstable, but it may become a factor that causes the residual vibration to reduce the precision of the position determination. Therefore, it is necessary to quickly compensate the attenuation of the vibration, and the current detection signal 3 1 can be used as The input torsional vibration stabilization compensation circuit 3 3 performs this compensation. Figures 9A and 9B show the relationship between the elapsed time from the start of the mirror to the stop and the position deviation. The diagram is enlarged in the vicinity of 0. Fig. 9A shows the case where the torsional vibration stabilization compensation circuit 33 of the present invention is set in the primary mode to the third mode, and Fig. 9B shows only the conventional integration. Compensation, proportional compensation, differential compensation (I-PD compensation). By setting the torsional vibration stabilization compensation circuit 3 3, in the case of the present invention, it becomes a stable transition. Answer, and reach about 0.8ms before 10 # m of the target position converted by laser irradiation position. On the other hand, in the past, because the 3rd mode (1 1 k Η z) is inverse phase, it is not The vibration is stable in this resonance frequency. In addition, in the present invention, because the mirror angle is fed back to the angle target 値 signal 2 1 and the integral compensation of the deviation signal 2 3 is performed, it can be made with high precision The laser irradiation position when the mirror is stopped is consistent with the target position. Next, the stability function of Nyquist is used to evaluate the stability function of the first-time transfer function in the servo mechanism of Fig. 6. Part 1 Figure 0 shows the design of a torsional vibration stabilization compensation circuit without any error in the natural vibration number. In the case of 3 3, the paper size including the primary mode is applicable to the Chinese National Standard (CNS) A4 specification (2 丨 〇 > < 297 mm) (Please read the notes on the back before filling out this page)

, T d Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs -23- 539933 A7 B7 _ V. Description of the invention (21) (Please read the precautions on the back before filling this page) Frequency of natural vibration (3 · 8kHz) Nyguist trace in the range of numbers (1kHz ~ 7 k Η z). The solid line is the case where the stabilization compensation for the primary mode is applied, and the dashed line is the case where the stabilization compensation is not performed for the primary mode in the past. In the case of no stabilization compensation, the trajectory proceeds from (1) to (2), then leaves the frame outside the figure and traces the clockwise circular trajectory, and then returns to the frame to reach (3). This circular trajectory means that the gain gradually increases near the first resonance. In addition, this trajectory is close to the stability discrimination point of coordinates (-1, 0), and its phase margin is very small. On the other hand, when the stabilization compensation is applied, the distance from the origin to the trajectory becomes smaller, and the phase margin and gain margin relative to the stability discrimination point become larger. Therefore, the compensation circuit without the error of the natural vibration number has the effect of increasing the stability of the servo system by suppressing the resonance peaks. Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs. When designing a torsional vibration stabilization compensation circuit 33, it is necessary to measure the natural vibration number of the vibration mode to be compensated. The natural vibration number of the vibration mode to be compensated can be obtained by measuring the frequency response shown in Fig. 7A. However, the accuracy of this measurement depends on the performance and resolution of the used analyzer (such as a servo analyzer), and it will necessarily include errors. In addition, the inherent vibration number of the optical scanner does not always remain fixed. It must also take into account changes caused by the heat generated by the motor. Those who can maintain the stability of control even with such errors and changes are more practical. In the following, the error of the frequency of torsional vibration and the structure of a stable servo mechanism will be described. This paper size applies Chinese National Standard (CNS) A4 specification (210 X 297 mm) 539933 A7 _ B7 V. Description of the invention (22) (Please read the precautions on the back before filling this page) Figure 1 1 The natural vibration number of the torsional vibration stabilization compensation circuit 3 3 is lower than the actual natural vibration number of the primary mode 3. 8 kHz to 5% (190 kHz) 3. 3. 61 kHz torsional vibration stabilization compensation circuit 3 3 to In this case, the Nyquist trajectory that includes the natural vibration number (3.8 k Η z) of the primary mode. The solid line is the case where the stabilization compensation is applied to the primary mode. When the stabilization mode is not performed in the primary mode (the same trajectory as the dotted line in Fig. 10). When the stabilization compensation is applied, the trajectory goes from (1) to (4) ', then leaves the frame outside the figure and traces the clockwise circular trajectory, and then returns to the frame to reach (5). The distance from the origin to the trajectory is not as large as in Figure 10, but compared with the case without stabilization compensation, it is closer to the phase near the first resonance, so the phase margin relative to the stability discrimination point becomes larger. As a result, the stability of the servo system can be increased. Printed by the Employees' Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs The reasons for increasing the stability of the servo system are as follows. In the natural vibration number, this compensation circuit advances the phase to a maximum of approximately 90 degrees in a frequency region lower than the natural vibration number, and advances in a high-frequency region to a phase of approximately 90 degrees. . Therefore, when the natural vibration number of the actual mode is relatively higher than the natural vibration number of the compensation circuit, the phase of the Nyquist trajectory progresses in the vicinity of the resonance point of this mode. Thus, the torsional vibration stabilization compensation circuit 33 can be used as a phase compensator with respect to resonance. In addition, by designing the natural vibration number of the compensation circuit to the actual measured value, the Chinese National Standard (CNS) A4 specification (21〇 × 297 mm) can be applied to the paper size of the paper. Printed by the Consumer Cooperative of the Property Bureau 539933 A7 B7 V. Description of the invention (2) The stable servo mechanism of the error and change of the number. In this example, since the primary mode is in phase, it is set to move the natural frequency of the compensation circuit to a low-frequency region and form a phase advance. When the reverse mode (such as the third mode) is stabilized, It is set to move the natural vibration number of the circuit to a high frequency region and form a phase delay. In addition, the difference between the number of vibrations and the positive and negative values is determined by the method of increasing the phase margin in accordance with the in-phase and out-of-phase modes. The magnitude of the gap 値 must be determined in such a way that the actual natural vibration number and the natural circuit vibration number of the compensation circuit do not reverse even if the assumed maximum error and variation occur. [Brief description of the drawing]: Figure 1 is a control block diagram of the optical scanner of the present invention. Fig. 2 is a continuation diagram of the torsion r-time compensation circuit of the present invention. FIG. 3 is a continuation diagram of the angular velocity observation circuit of the present invention. Figure 4 is a block diagram of the vibration control factor of the present invention. Figure 5 is another block diagram of the vibration control factor of the present invention. Fig. 6 is another control block diagram of the optical scanner of the present invention. FIG. 7A and FIG. 7B are examples of a Bode (B o d e) diagram showing the relationship between the gain and the phase of the frequency response from the motor current to the angle detection signal. Fig. 8A and Fig. 8B are examples of Bird diagrams showing the relationship between the gain and the phase of the frequency response from the motor current to the detection signal at the angle of the mirror. This paper size applies to Chinese National Standard (CNS) A4 specification (210X297 mm) I -------- ^-Packing ---- Ί .-- Order ------- J (Please read first Note on the back, please fill out this page) -26- 539933 A7 B7 V. Description of the invention (: 4) Figure 9A and 9B show the relationship between the elapsed time and position deviation from the start of the mirror to the stop. . Fig. 10 is a quiz (N y q u i s t) locus in the case where there is no error in the natural vibration number at all. Fig. 11 is the Nyquist trajectory when the natural vibration number is shifted to the actual vibration number of the primary mode. Fig. 12 is a structural diagram of a movable part in the optical scanner. Figure 13 is a control block diagram of the optical scanner. Comparison table of main components 1 Printed by the Consumer Cooperative of Intellectual Property Bureau of the Ministry of Economic Affairs 1 4, 1 5 1 6, 3 5 17a, 17b, 17c, 17d 1 7 e 2 0 2 1 2 2 2 3 2 4 2 5 Optical scanner Mirror rotation axis, moving coil bearing, rotation axis angle detection means, mirror angle detection means, mirror angle detection, mirror angle command circuit, angle target, signal angle detection, signal deviation, signal integral compensation circuit, proportional compensation circuit assembly, (Please read the note on the back first Please fill in this page again for this matter) This paper size applies Chinese National Standard (CNS) A4 specification (210X297mm) -27- 539933 A7 B7 V. Description of invention ("2 6 2 7 2 8 2 9 2 Employees of Intellectual Property Bureau, Ministry of Economic Affairs Printed by Consumer Cooperatives 321, 322, 323, 33 1, 332 324, 325, 333, 334, 335 3 4 3 5 4 1 4 11 4 12 4 13 4 14 4 1 7, 4 1 8 4 2 C 0 1, C 0 2, C 1 1 differential compensation circuit control input signal motor drive circuit motor drive current detection signal angular velocity observation circuit primary torsional vibration compensation circuit output signal terminal operational amplifier torsional vibration secondary compensation circuit Reactor angle detection circuit, mirror vibration suppression factor, target orbit differential factor, second-order differential factor, notch filter, gain factor correction, capacitors R01, R02, R03, R04, R05, R06, R11 , Rl2, Rl3, Rl4, Rl5, Rl resistance I ------- ^ install ----:-order ------- (Please read the precautions on the back before filling this page) The paper size Applicable to China National Standard (CNS) A4 specification (210X297 mm) -28-

Claims (1)

539933 A8 B8 C8 D8 々, patent application scope 1. A control device of an optical scanner, based on the angle target 値 and angle detection 値, will be supported on the mirror of the rotation axis, determine its position around the rotation axis, The correction 値 for the torsional vibration of the rotation axis is added to the integral 値 of the deviation between the angle target 上述 and the angle detection 値. 2 · For the control device of the optical scanner according to item 1 of the scope of patent application, wherein the above-mentioned correction 値 is used as the torsional vibration of the rotation shaft caused by the driving torque attached to the rotation shaft to r times The output of the transfer function 的 up to the angular velocity (r is a positive integer). 3. The control device of the optical scanner according to item 2 of the scope of patent application, wherein the output 値 of the above-mentioned transfer function is calculated from the electric current 供给 supplied to the motor which generates the above-mentioned driving torque. 4. A control device for an optical scanner, which is based on the angle target 角度 and the angle detection 値, and will be supported by the mirror on the rotation axis to determine its position around the rotation axis, and not only the target track as the position time The function also removes a specific frequency component from the sum of the target track and the target speed and target acceleration based on the target track as the angle target 角度. 5. The control device of the optical scanner according to item 4 of the scope of patent application, wherein the specific frequency number component is used as the natural vibration number component of the bending vibration of the rotation axis. 6. The control device of the optical scanner according to item 4 of the scope of patent application, wherein the specific frequency number component is used as the natural vibration number component of the torsional vibration of the rotary shaft. This paper size applies to China National Standard (CNS) A4 specification (210X297 mm). ---------- II (Please read the precautions on the back before filling this page),?! Intellectual Property Bureau of the Ministry of Economic Affairs Printed by the employee consumer cooperative -29- 539933 A8 B8 C8 D8 VI. Application for patent scope 7. A control device of optical scanner, based on the angle target 値 and angle detection 値, will be supported on the mirror of the rotation axis, as described above The position around the rotating shaft determines its position, and it has a mirror angle detecting means that detects the angle of the mirror, a rotating shaft angle detecting means that detects the angle of the rotating shaft, and a motor supplied to rotate the rotating shaft. The current detection method of the current 'and the torsional vibration stabilization compensation method that stabilizes the torsional vibration of the above-mentioned rotating shaft based on the above-mentioned current, and will use the angle detection of the rotating shaft to perform proportional compensation and differential compensation. And the above-mentioned torsional vibration stabilization compensation method, greedy feedback to the deviation of the angle target 上述 and the mirror angle detection 値 e 2 3 After adding the integral compensation, determine the current to be supplied to the motor. 8 _ For the control device of the optical scanner of item 7 of the patent application scope, wherein the above-mentioned mirror angle detection means is a light emitting element for measuring the angle of the mirror, and a mirror surface for measuring the light reflected from the light emitting element, and · and A light receiving element that receives light from the light emitting element reflected by the mirror surface. 9. The control device of the optical scanner according to item 7 of the scope of patent application, wherein the above-mentioned torsional vibration stabilization compensation means has a characteristic of increasing the phase margin of its primary transfer function in the vicinity of the number of torsional vibrations. 〇1 〇 For example, the control device of the optical scanner of the seventh patent application range, wherein the torsional vibration stabilization compensation means has a natural vibration number, and the difference between this vibration number and the torsional vibration number of the movable part of the scanner is set to torsion The maximum variation of the vibration number is more than 値. This paper size applies to China National Standard (CNS) A4 specification (210X297 mm) " -30- '——----— (Please read the precautions on the back before filling this page) Order the staff of the Intellectual Property Bureau of the Ministry of Economic Affairs Printed by Consumer Cooperatives