JP2010035385A - Motor drive controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress gear jitter signals generated by a gear section decelerating the rotation of a motor at a small value, at a high speed. <P>SOLUTION: A rotation driving section 1 drives the rotation of the motor 3. A decelerating gear section 5 decelerates the rotation of the motor 3. A detecting section 11 detects a pulse signal corresponding to the revolving speed of the motor 3, the pulse signal of an exponent number of 2 at each adjacent tooth in the decelerating gear section 5. A rotation control section 13 detects the revolving speed of the motor and a gear-jitter period, on the basis of the pulse signal from the detecting section 11. The rotation control section 13 subtracts an individual pulse-signal timing and a speed value, with a timing delayed from the pulse-signal timing by N/2; successively integrates the subtracted values; and controls the rotation driving section 1 by a rotation control signal obtained, by dividing the integral signal by the number of integrations. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a motor drive control device, and more particularly, to an improvement of a motor drive control device suitable for use in an image forming apparatus such as a multi function peripheral (MFP).

  In an image forming apparatus, image data is converted into laser light and irradiated to a photosensitive rotating body that is an image carrier, a toner image is formed on a latent image formed on the surface of the rotating body, and this is transferred to paper. A configuration for fixing is common.

  Therefore, the image forming apparatus includes a plurality of motors for rotating the rotating body and the polygon mirror for scanning and irradiating the rotating body with laser light.

  In addition, these motors need to be driven to rotate at a desired stable rotational speed from the viewpoint of ensuring good image formation.

  2. Description of the Related Art Conventionally, a motor drive control device that controls driving of these motors connects a reduction gear unit 5 to a rotor shaft of a DC (direct current) brushless motor 3 that is driven to rotate by a drive signal from a rotation drive unit 1, as shown in FIG. The rotary encoder 7 having a large number of radial slits is arranged on the rotation shaft of the reduction gear unit 5, and the rotation speed of the brushless motor 3 is controlled by the sensor 9 by the transmitted light from the slits of the rotary encoder 7 by the rotation of the brushless motor 3. It has a feedback control system configuration that controls the rotation of the brushless motor 3 with a drive signal that is detected and calculated by the rotation drive unit 1 so that the rotation speed becomes a predetermined set speed.

  In the figure, the illustration of the brushless motor 3, the reduction gear unit 5, and the rotary encoder 7 is simplified.

  However, in such a motor drive control device, when a high-resolution rotary encoder 7 having a large number of accurate slits is used and a feedback control gain is increased, gear jitter (speed unevenness due to gear meshing of the reduction gear unit 5 is obtained. ) Becomes obvious as a noise component, and this makes the feedback control system easily saturated.

  On the other hand, since the frequency of the gear jitter can be calculated from the rotational speed of the brushless motor 3 (rotary encoder 7) and the number of teeth of the reduction gear unit 5, a notch filter (not shown) including a comb filter and an integrator is used. Thus, it is possible to cut gear jitter.

For example, Japanese Patent Application Laid-Open No. 2007-232986 (Patent Document 1) proposes a speed control device for an image forming apparatus.
JP 2007-232986 A

  However, as described above, the configuration in which the gear jitter component is cut using the notch filter including the comb filter and the integrator requires a divider in addition to the comb filter and the integrator as the notch filter, and processing of this division operation is performed. There is a difficulty in that the calculation time is long and control delay is likely to occur, and proper rotation control is likely to be hindered.

  Therefore, as a result of intensive studies on gear jitter generated mainly due to the reduction gear unit 5, the present inventor completed the present invention by paying attention to the fact that gear jitter within a predetermined period is close to a sine wave having a fixed period. It was.

  The present invention has been made to solve such a problem, and it is possible to reduce the influence of gear jitter caused by the rotation of the motor, to increase the speed of the arithmetic processing, and to hardly cause a control delay. An object is to provide a drive control device.

  In order to solve such a problem, a motor drive control device according to the present invention includes a motor, a rotation drive unit that calculates a drive signal and outputs the calculated drive signal to the motor, and rotates the motor. A speed reduction gear portion that decelerates and a pulse signal as a speed signal corresponding to the rotational speed of the motor, and a power of 2 for each adjacent tooth in the speed reduction gear portion (N = 2n, n = 1, 2) 3) detecting unit for detecting the pulse signals set in units, and detecting the rotation speed based on the pulse signals from the detection unit, the speed value at the timing of each pulse signal, and each timing Is subtracted from the speed value at the timing delayed by N / 2, and the power is sequentially integrated with the subtraction signal, and based on the rotation control signal obtained by dividing the integration signal by the number of integrations. Rotation drive And includes a rotation control unit, the controlling the operation of the drive signal.

  In the motor drive control device of the present invention, the rotation control unit may be configured to bit-divide the integral signal by bit shift by the power value.

  In the motor drive control device of the present invention, the rotation control unit may obtain the rotation control signal from the pulse signal detected in a predetermined fixed period.

In the motor drive control device of the present invention, when the detection unit sets the high-order cycle related to the gear jitter cycle as the k-th cycle, the N pieces are “2 ^{n− (k−1)} (where n> k)”. A configuration for detecting the above-described pulse signal selected in (1) is also possible.

  In the motor drive control device of the present invention, a configuration in which the motor is a DC brushless motor is also possible.

  In such a motor drive control device according to the present invention, the rotation drive unit rotates the motor, decelerates and rotates through the reduction gear unit, and the detection unit outputs a pulse as a speed signal corresponding to the rotation speed of the motor. This signal is a power of 2 (N = 2n) pulse signals detected between adjacent teeth in the reduction gear unit, and the rotation control unit determines the rotation speed of the motor based on the detected pulse signal. Detecting, subtracting each pulse signal timing and each speed value of each timing delayed by N / 2 from each timing, sequentially integrating the subtraction signal by its power, and integrating the integration signal A rotation control signal obtained by dividing by the number of integrations is output, and the motor is driven to rotate by the rotation drive unit based on this rotation control signal. It can suppress the effects of jitter, easily processing even faster for suppressing the influence of Giajitta.

  In the motor drive control device according to the present invention, the configuration in which the rotation control unit bit-divides the integral signal by a power value and divides it has the advantage that the division process is extremely simple and speeded up.

  In the motor drive control device of the present invention, in the configuration in which the rotation control unit obtains the rotation control signal from the pulse signal detected in a predetermined fixed period, the influence of the gear jitter is reliably and accurately suppressed, and the desired stability Motor rotation control is possible.

In the motor drive control device of the present invention, when the high-order cycle related to the gear jitter cycle is the k-th cycle, the detection unit determines that the N pieces are “2 ^{n− (k−1)} (where n> k)”. In the configuration for detecting the pulse signal selected in (4), it is possible to suppress the influence of higher-order gear jitter.

  The motor drive control device of the present invention is particularly useful in a configuration in which the motor is a DC brushless motor.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected to the part which is common in a conventional structure.

  FIG. 1 is a schematic block diagram showing an embodiment of a motor drive control device according to the present invention.

  In FIG. 1, a brushless motor 3 is a conventionally known DC (direct current) motor having a stator portion and a rotor portion, and rotates by switching energization of, for example, a three-phase drive signal applied to the drive coil from the rotary drive portion 1. . Since the brushless motor 3 is not a main part of the present invention, detailed description and illustration are omitted.

  As shown in FIG. 2, the brushless motor 3 is connected to the rotor shaft 3 a so that teeth 5 b of a disk-shaped reduction gear portion 5 having a larger diameter engage with the rotor shaft 3 a, and the brushless motor 3 is connected by the reduction gear portion 5. The rotational speed decelerated from the high speed rotational speed is obtained on the rotating shaft 5a.

  The reduction ratio is determined by the ratio between the number of teeth 3 b formed on the outer periphery of the rotor shaft 3 a and the number of teeth 5 b formed on the outer periphery of the reduction gear unit 5.

  The rotation center 5a of the disk-shaped rotary encoder 7 is fixed to the rotation shaft 5a of the reduction gear unit 5, and the rotary encoder 7 rotates at a rotation speed reduced by the reduction gear unit 5 from the brushless motor 3. Yes.

  The rotary encoder 7 is formed with a plurality of slits 7a having the same shape radially formed from the center of rotation in the vicinity of the peripheral edge thereof, and these are arranged at equal intervals in the circumferential direction. In FIG. 2, the rotary encoder 7 is shown only partially including the slit 7a.

  The number of slits 7a formed through the rotary encoder 7 is a power of "2" (N = 2n, where n is an integer) in relation to the distance between adjacent teeth 5b (gear grooves) in the reduction gear unit 5. n = 1, 2, 3,...), for example, 4, 8, 16, and 32. That is, in the rotary encoder 7, when the number of slits 7a is P and the number of teeth 5b is Z, the relationship is P = Z × 2n.

  In the present invention, the number of slits 7a is one of the characteristics in relation to each adjacent tooth 5b (gear groove).

  Returning to FIG. 1, a sensor 9 made up of a light emitting element and a light receiving element is disposed on the peripheral edge of the rotary encoder 7 so as to sandwich the rotary encoder 7 with a slight gap therebetween. In FIG. 1, only one of the light emitting element and the light receiving element is shown as the sensor 9 for easy understanding.

  Therefore, the light emitted from the light emitting element is repeatedly shielded by the rotational movement of the slit 7 a caused by the rotation of the rotary encoder 7, and an electrical pulse signal based on repeated light reception by the light receiving element is output from the sensor 9. .

  When the rotational speed of the rotary encoder 7 is high, the rotational angle per unit time of the rotating shaft 5a of the brushless motor 3 is large. On the other hand, when the rotational speed is slow, the rotational angle is small. A pulse signal whose interval or individual pulse width is changed is detected by the sensor 9.

  That is, an optical detection unit 11 that detects a pulse signal as a speed signal corresponding to the rotation speed of the brushless motor 3 is formed by the rotary encoder 7 and the sensor 9. The rotation control unit 13 is included in the detection unit 11. It is connected.

  It is also possible to use a magnetic detection unit that arranges a magnet in the rotary encoder 7 and detects its magnetic pole.

  The rotation control unit 13 converts and detects the rotation speed of the brushless motor 3 as a digital signal based on the pulse signal from the sensor 9 (detection unit 11), and calculates the speed value at the timing of each pulse signal and the respective timings. The speed value at the timing delayed by N / 2 is subtracted, the subtraction signal is sequentially integrated with its power (N), and the rotation control signal obtained by dividing the integration signal by the number of integrations is detected and rotated. It has a function of outputting as a number and is connected to the rotation drive unit 1. Details of the rotation control unit 13 will be described later.

  The rotational drive unit 1 forms an operational rotational speed by, for example, calculating PID (proportional, integral, differential) so that a deviation between the rotational speed detected by the rotational control signal and a predetermined set rotational speed is small. The PWM pulse signal having a pulse width according to the function is applied to the brushless motor 3 as a drive signal.

  The rotation control unit 13 described above has a function of detecting the rotation speed of the brushless motor 3 and, as shown in FIG. 3, includes a filter unit 13a, an integrator 13b, and a divider 13c.

  The filter unit 13a has a function of subtracting a speed value at a timing delayed by N / 2 from each timing from a speed value at the timing of each pulse signal.

  The above-mentioned gear jitter is likely to be mixed in the rotation speed signal, but in general, the gear jitter (unevenness of rotation) is noise caused by the gear, so if the gear tooth configuration is known, the frequency of the gear jitter is 2 It is known in advance that it is N-th power (N is a positive integer).

  Therefore, for example, as shown in FIG. 4, the speed signal value “Z” at the timing P1 of the maximum point of each pulse signal at the rotational speed between the adjacent teeth 5b (gear groove) and the timings P1 to 8 When viewed from the intermediate level between the maximum value and the minimum value, the timing P2 point speed signal value “ZN” at the lowest point delayed by one can be canceled by subtracting the other from one.

  FIG. 4 is a virtual analog display of the rotational speed of the brushless motor 3 based on the pulse signal in a state where no gear jitter is on.

  The integrator 13b in FIG. 3 sequentially integrates the subtraction signal “Z” output from the filter unit 13a and the next subtraction signal “Z−1” by a power multiplier (N), and supplies the integration value to the divider 13c. It has a function to output.

  The divider 13c has a function of outputting a rotation control signal obtained by dividing the integration signal by the number of integrations (N), and “bit shift calculation” is performed as a division process.

  In the “bit shift operation”, when a value is represented by a bit in binary number, if it is shifted S bits to the left, 2S times the original value, and if it is shifted S bits to the right, 2-S times the original value is obtained. This calculation method corresponds to the latter processing in the present invention.

  Although not shown, the rotation driving unit 1 and the rotation control unit 13 described above are formed from a microcomputer having a CPU, a ROM, a RAM, and the like that store an operation program for operating the CPU.

  Next, the operation of the motor drive control device of the present invention described above will be briefly described.

  As an example, the case where the number of slits 7a of the rotary encoder 7 is set to “24”, that is, 16 in relation to the distance between adjacent teeth 5b (gear grooves) of the reduction gear unit 5 will be described.

  The brushless motor 3 is activated and rotated by the application of a drive signal switched and energized from the rotary drive unit 1, and the rotary encoder 7 is decelerated and rotated through the reduction gear unit 5 connected to the rotor shaft 3 a of the brushless motor 3.

  When the rotary encoder 7 rotates, a pulse signal as a speed signal corresponding to the rotation speed of the brushless motor 3 is output from the detection unit 11 to the rotation control unit 13 due to the rotation displacement of the numerous slits 7 a formed through the rotary encoder 7. .

  The filter unit 13a of the rotation control unit 13 subtracts the speed value at the timing of each pulse signal and the speed value at a timing delayed by 16/2, that is, eight from each timing, and calculates the increase / decrease value thereof. Canceled value is obtained.

  Subsequently, in the integrator 13b, the subtraction signal “Z” output from the filter unit 13a and the next timing subtraction signal “Z-1” are sequentially integrated. In the divider 13c, the integration signal is integrated (16). Is divided by a 4-digit “bit shift operation”, and the value is output to the rotation drive unit 1 as a speed control signal.

  In the rotation drive unit 1, an operation rotation signal is formed by performing PID control calculation so that a deviation between a detected rotation speed based on the rotation control signal and a predetermined set rotation speed is small, and a PWM pulse having a pulse width corresponding to the operation rotation speed A signal is applied to the brushless motor 3 as a drive signal to control rotation.

  As described above, in the present invention, the rotation drive unit 1 and the rotation control unit 13 are constituted by a microcomputer centered on a CPU. Therefore, the main operation will be described from the viewpoint of an operation program as shown in FIG. .

  In FIG. 5, when the program starts, in step S1, the rotation control unit 13 performs processing for starting the acquisition of rotational speed information and proceeds to step S2. In step S2, has the rotation control unit 13 interrupted the rotary encoder 7? It is determined whether or not the gear jitter information acquisition period has arrived.

  If no interruption occurs and step S2 is NO, the process waits until an interruption occurs and step S2 becomes YES. If step S2 becomes YES, the rotation control unit 13 obtains information on the rotation speed in step S3. Stop processing. Through the processes in steps S1 to S3, the rotation control unit 13 acquires rotation speed data in a fixed manner.

  In the subsequent step S4, the rotation control unit 13 generates and processes speed information (rotation control signal). In step S5, the rotation driving unit 1 controls and calculates the operation rotation number based on the rotation control signal. In step S6, the rotation driving unit. 1 generates a PWM drive signal, outputs it to the brushless motor 3, returns to step S1, and thereafter repeats these steps.

  As described above, in the motor drive control device of the present invention, the DC brushless motor 3, the rotation drive unit 1 that calculates the drive signal, outputs the drive signal to the brushless motor 3, and rotates and drives the rotation of the brushless motor 3. The speed reduction gear unit 5 that decelerates the motor and a pulse signal as a speed signal corresponding to the rotational speed of the brushless motor 3, and a power of 2 (N = 2n) for every adjacent tooth in the speed reduction gear unit 5 The detection unit 11 that detects the pulse signal set to 1 and the rotational speed of the brushless motor 33 is detected based on the pulse signal from the detection unit 11, and the speed value at the timing of each pulse signal and the respective timings It is obtained by subtracting the speed value at the timing delayed by N / 2, sequentially integrating the subtraction signal with a power (N), and dividing the integration signal by the number of integrations. A rotation control unit 13 for controlling the operation of the drive signal from the rotary drive unit 1 in a converter control signal, which comprises a.

  Therefore, it is possible to cancel the gear jitter caused by decelerating the rotational speed of the brushless motor 3 to suppress the influence of noise, and it is possible to use a bit shift operation as a division process performed in the process. Since it is possible, it becomes extremely high-speed arithmetic processing, and it becomes difficult to cause a control delay.

  In particular, in the DC brushless motor 3, it is possible to cancel the gear jitter component and keep the influence small in the process of stably controlling the rotation speed by feedback control based on the detected rotation speed of the brushless motor 3. It is.

  In addition, since the rotation control unit 13 can acquire a speed signal fixedly for a predetermined period, for example, between adjacent teeth 5b in the reduction gear unit 5, it is possible to reliably and accurately suppress the gear jitter. It is.

  In the present invention, the detection unit 11 that detects a pulse signal as a speed signal corresponding to the rotation speed of the brushless motor 3 is not limited to the configuration including the rotary encoder 7 having the slit 7a and the sensor 9, but a reduction gear. The present invention can be implemented as long as the configuration is such that a pulse signal set to a power of 2 (N = 2n, n = 1, 2, 3,...) For each adjacent tooth in the unit 5 is detected as a speed signal.

  Incidentally, the gear jitter caused by the reduction operation of the reduction gear unit 5 described above includes not only the above-described primary component but also k-order (multiplication, high-order) components, for example, high-order components such as secondary components and tertiary components. It is thought that it occurs.

In such a case, in the present invention, when the higher-order period related to the gear jitter period is the k-order period and the k-order component is filtered by the filter unit 13a, the setting in the detection unit 11 is set to N = 2N = 2 ^{n− ( k-1)} (where n> k) is adopted, the canceling operation for the specific multiplication period can be performed by adopting a configuration in which the detection unit 11 detects the pulse signal selected.

  Furthermore, the motor drive control device of the present invention can be implemented in a motor drive control device such as a copying machine, a facsimile machine, or a multifunction machine.

It is a schematic block diagram which shows embodiment of the motor drive control apparatus which concerns on this invention. It is a figure explaining the main structures of the motor drive control apparatus of FIG. It is a block diagram explaining the rotation control part in this invention. It is a figure explaining operation | movement of the motor drive control apparatus of FIG. It is a flowchart explaining operation | movement of the motor drive control apparatus of FIG. It is a block diagram explaining the conventional motor drive control apparatus.

Explanation of symbols

1 Rotation drive 3 Motor (Brushless motor)
3a Rotor shaft 3b, 5b Teeth 5 Reduction gear 5a Rotating shaft 7 Encoder (Rotary encoder, Detection unit)
7a Slit (detector)
9 Sensor (Detector)
11 Detection Unit 13 Rotation Control Unit 13a Filter Unit (Rotation Control Unit)
13b Integrator (rotation control unit)
13c Divider (rotation control unit)

Claims (5)

A motor,
A rotation drive unit that calculates a drive signal and outputs it to the motor to rotate it;
A reduction gear portion for reducing the rotation of the motor;
It is a pulse signal as a speed signal corresponding to the rotational speed of the motor, and is set to a power of 2 (N = 2n, n = 1, 2, 3,...) For every adjacent teeth in the reduction gear unit. Detecting the detected pulse signal;
The rotational speed of the motor is detected based on the pulse signal from the detector, and the speed value at the timing of each of the pulse signals is subtracted from the speed value at the timing delayed by N / 2 from each timing. A rotation control unit that sequentially integrates the subtraction signal with the power and controls the calculation of the drive signal of the rotation drive unit based on a rotation control signal obtained by dividing the integration signal by the number of integrations;
A motor drive control device comprising: The motor drive control device according to claim 1, wherein the rotation control unit performs the power bit shift on the integration signal and performs the division. The motor drive control device according to claim 1, wherein the rotation control unit obtains the rotation control signal from the pulse signal detected in a predetermined fixed period. The detection unit detects the pulse signal in which the N pieces are selected as “2 ^{n− (k−1)} (where n> k)”, where the higher order period related to the gear jitter period is a kth period. The motor drive control apparatus of any one of Claims 1-3. The motor drive control device according to claim 1, wherein the motor is a direct current brushless motor.

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