JP5736934B2 - Drive control apparatus, image forming apparatus, drive control method, and program - Google Patents

Description

  The present invention relates to a drive control technique for controlling the drive of an electric motor, and more particularly to a drive control technique for stabilizing the drive in an acceleration region of an electric motor that drives a unit that is detachably installed.

  In an image forming apparatus using an electrophotographic method such as a laser printer or a copying machine, an electrostatic latent image is formed on a photosensitive member by optical writing, and toner is attached to the electrostatic latent image to make a visible image. Thereafter, the toner image formed on the photosensitive member is transferred to a sheet, and a print image is formed on the sheet by applying heat and pressure.

  In a full-color image forming apparatus, a process of transferring (primary transfer) a plurality of toner images of different colors on an intermediate transfer member and then transferring (secondary transfer) the toner image on the intermediate transfer member to a sheet. There is a method of forming a final full-color image through the above.

  In general, each unit that performs processes such as primary transfer, secondary transfer, and fixing provided in an image forming apparatus is detachably provided for maintenance or the like. These attachment / detachment mechanisms have large backlash and other backlash due to the engagement of gears and couplings, and the unit itself has variable components such as spring components and friction components due to the use of low-rigidity shafts and blades. Have.

  For this reason, when each unit is detached and attached for maintenance or the like, the stress at each part may be once released, or there may be a large amount of play in the driving direction of the unit due to meshing of gears or the like. When the unit is driven in such a state, an encoder that detects the speed or the like of each unit may detect an abnormal speed due to an impact with which a gear, a coupling, or the like meshes.

  If an abnormal speed or the like caused by a nonlinear element such as the above-described fluctuation component occurs in the feedback control system of the drive device using the encoder, the control may become oscillating and unstable in some cases. Depending on the image forming apparatus, for example, when each unit is not driven at a predetermined speed within a specified time, there is a problem that it is determined that the apparatus is abnormal and an error is displayed.

  Even after the unit is detached and attached, once it is started, the backlash is reduced by the gear hitting in one direction, and the torsion of each part becomes a steady state. Therefore, it is conceivable that the drive control device is stabilized by feedforward (open loop) control without performing feedback (closed loop) control only when the motor is started.

  However, since compensation by feedback is not performed in this case, the start-up time varies greatly depending on the load state, or the transient response when switching from feedforward control to feedback control is not smooth (discontinuous) Problem).

  Therefore, for example, Patent Document 1 discloses a gain of a frequency for exciting vibration with respect to a torque command value to the electric motor in order to prevent generation of vibration due to low rigidity of a control target connected to the electric motor. Has disclosed a method for controlling an electric motor that performs filtering having both a characteristic for lowering the frequency and a characteristic for suppressing a gain at a higher frequency than the excitation frequency.

  According to the above control method, it is possible to automatically prevent the torque command value to the motor from becoming an excessive value, so that the vibration of the motor and the controlled object is always automatically suppressed regardless of the characteristics of the controlled object. can do.

  However, according to the method according to Patent Document 1, it is effective in preventing mechanical resonance caused by low rigidity of the controlled object, but an encoder or the like that detects the driving of the motor by a non-linear element such as backlash. If it is detected incorrectly, the control may become unstable.

  Therefore, in the present invention, at the time of starting the electric motor, even when the detection system such as the encoder is vibrated by the impact generated by the meshing of the gear such as the backlash of the mechanism, and the speed and position of the mechanism are erroneously detected, An object of the present invention is to provide a drive control device, an image forming apparatus, a drive control method, and a program in which a feedback control system becomes stable.

In view of the above problems, the present invention provides an electric motor, a transmission mechanism that transmits the output of the electric motor, a driven mechanism that is driven by the output of the electric motor by being connected to the transmission mechanism, the electric motor, Based on a detection unit that detects the speed or position of either the transmission mechanism unit or the driven mechanism unit, and a deviation value between the output value of the detection unit and the target value, a predetermined calculation is performed using a compensator. Yes and compensator calculating section, a motor drive unit for driving the motor based on the calculation result of the compensator calculating unit, said compensator that limits the value of the deviation to be input to the arithmetic unit deviation limiting section, the The compensator computing unit sets a predetermined integral value in the compensator when the driving direction of the electric motor based on the output of the compensator is different from the driving direction set in the electric motor, Set a predetermined value to the motor drive Characterized in that that.

  According to the embodiment of the present invention, non-linear factors such as backlash due to meshing of gears and couplings, fluctuation components due to torsion of shafts and blades of units to be attached and detached, etc., which cause the control of the drive mechanism to become unstable. Even a drive control device having the above can be accelerated with high accuracy in a short time to reach a steady state speed.

  In particular, even when a detection system such as an encoder misdetects the drive speed due to the nonlinear element described above, the startup time from the start of driving to the steady state does not vary, and control This makes it possible to start up by stable drive control without causing vibration.

1 is a diagram schematically illustrating an image forming apparatus according to an embodiment. FIG. 3 is a diagram illustrating a configuration of a secondary transfer unit and an intermediate transfer belt cleaning unit according to the embodiment. FIG. 4 is a diagram schematically illustrating a drive mechanism of a secondary transfer roller and an intermediate transfer belt cleaning roller according to the embodiment. The figure which shows the structural example of the feedback control system of the drive control apparatus which concerns on embodiment. The figure which shows the block diagram of the feedback control of a drive control apparatus The figure which shows the block diagram of the feedback control of the drive control apparatus which concerns on 1st Embodiment. The figure which shows the block diagram of the feedback control of the drive control apparatus which concerns on 3rd Embodiment. The figure explaining the filter calculation of the compensator concerning an embodiment The figure which shows the example of control of the integral gain which concerns on 2nd Embodiment The figure which shows the example of the drive control result of a drive control apparatus Diagram showing an example of unstable drive control due to nonlinear elements The figure which shows the example of the drive control result of the drive control apparatus which concerns on 1st Embodiment. The flowchart which shows the process example of the deviation limiting part which concerns on 1st Embodiment. The flowchart which shows the process example of the compensator calculating part which concerns on 2nd Embodiment. The flowchart which shows the process example of the acceleration determination part which concerns on 3rd Embodiment.

DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention (hereinafter referred to as “embodiments”) will be described in detail with reference to the drawings.
<Outline of image forming apparatus>
FIG. 1 shows a configuration of a color image forming apparatus 100 according to the present embodiment.

  The image forming apparatus 100 includes a developing unit including a photoreceptor 40, a charging device 18 that charges the photoreceptor 40, a developing device 61 that attaches toner to an electrostatic latent image formed on the charged photoreceptor 40, and the like. This is a so-called tandem type image forming apparatus having a plurality of colors for each color of yellow (Y), cyan (C), magenta (M), and black (K).

  The toner images formed on the photoconductors 40 of the developing portions of the respective colors are primarily transferred to the intermediate transfer belt 10 and are overlaid with colors, and are biased while the paper P is conveyed between the secondary transfer roller 23 and the opposing roller 24. Is secondarily transferred onto the paper P.

The paper P on which the color toner image is placed is further conveyed and applied with heat and pressure when passing through the fixing device 25, whereby the toner image is fixed on the paper P and discharged outside the apparatus.
<Outline of secondary transfer and intermediate transfer belt cleaning>
FIG. 2 shows a configuration example of the secondary transfer unit and the intermediate transfer belt cleaning unit according to the present embodiment.

  The secondary transfer unit includes a secondary transfer roller 23 and a secondary transfer counter roller 24. When the paper P is conveyed and passed between the two rollers 23 and 24, a toner image 101 on the intermediate transfer belt 10 is transferred to the paper P by applying a pressure and a potential difference.

  In the secondary transfer portion, the paper P is nipped and conveyed between the secondary transfer roller 23 and the intermediate transfer belt 10. For this reason, the rotational speed of the secondary transfer roller 23 is related to the transport speed of the paper P. If the rotational speed varies, the transport speed of the paper P also varies. A problem will occur. Accordingly, the drive control of the secondary transfer roller 23 needs to be performed with high accuracy in order to maintain the image quality.

  The toner adhering to the secondary transfer roller 23 is scraped off by the cleaning blade 111 and removed. The cleaning blade 111 is made of an elastic material such as rubber and is provided in contact with the secondary transfer roller 23. Therefore, when the drive starts after the secondary transfer roller 23 is detached, a factor that destabilizes the drive. It may become. The secondary transfer roller 23 may be cleaned as long as the adhered toner can be removed, and a cleaning brush or the like can be used.

  The toner that is not transferred to the paper P in the secondary transfer portion and remains on the intermediate transfer belt 10 is collected by the cleaning roller 22, and the intermediate transfer belt 10 from which the untransferred toner has been removed is used for the next image formation. The

The cleaning roller 22 of the intermediate transfer belt 10 can be constituted by a rubber roller, a brush roller, a sponge roller, or the like. In any case, the transfer residual toner adhering to the intermediate transfer belt 10 is collected, and the collected toner is conveyed to a waste toner bottle by a mechanism (not shown).
<Outline of secondary transfer drive mechanism>
FIG. 3 schematically shows a drive mechanism including the secondary transfer roller 23 and the cleaning roller 22 of the intermediate transfer belt 10 according to the present embodiment.

  The driving force of the motor 110 that is an electric motor is transmitted to the secondary transfer roller 23 and the cleaning roller 22 that are driven mechanisms via the transmission mechanism 107.

  The motor 110 may be a DC brushless motor or a DC brush motor, and is preferably a motor capable of feedback control.

  The secondary transfer roller 23 and the cleaning roller 22 are provided with an attachment / detachment mechanism 106 such as a coupling so that the attachment / detachment can be performed for maintenance of each unit. A unit including the secondary transfer roller 23 and the cleaning blade 111 and a unit including the cleaning roller 22 are provided so as to be detachable at portions indicated by dotted lines 102 and 103 in the drawing.

  Since the rotation speed of the secondary transfer roller 23 is related to the conveyance speed of the paper P, it affects the image quality. Therefore, feedback control is performed based on the position or speed using the encoder 109 which is a detection unit, and the drive is controlled with high accuracy.

  In the image forming apparatus 100 according to the present embodiment, the encoder 109 is provided in the gear after the first reduction in the transmission mechanism from the motor 110. The position where the encoder 109 serving as the detection unit is provided may be provided on the shaft of the motor 110, the shafts of the secondary transfer roller 23 and the cleaning roller 22 which are the driven mechanism unit 107, or the like.

  Since each unit such as the secondary transfer roller 23 is detachably provided for maintenance or the like, the unit can be separated from the motor 110 serving as a drive source, the transmission mechanism 107, and the encoder 109 detecting the drive. It is common.

  The encoder 109 includes a code wheel 108 with a slit and an encoder sensor 103 that optically reads the slit. In the present embodiment, the optical encoder 109 is used, but a magnetic encoder can also be used. Also, an analog type or a digital type can be used. Furthermore, a tachometer that detects a speed instead of a resolver or a position may be used.

The actual speed is detected by the encoder 109, such as a period counting method in which the interval between encoder pulses is measured with a reference clock, a method in which encoder pulses are counted with an up / down counter and calculated from the difference, a high-frequency encoder pulse with a low-pass filter, etc. Any method such as a smoothing method may be used.
<About feedback control system>
FIG. 5 shows an example of a block diagram of feedback control of a commonly used drive control device. Here, an example of a speed control system for controlling the speed is shown.

  The target speed and the actual speed detected by the encoder 109 are compared by the comparator 201, and a speed deviation is output. The speed deviation is subjected to a predetermined filter calculation by the compensator 202, and a motor voltage value or a current value is instructed to the motor driver 126 which is an electric motor driving unit.

  The motor 110 is driven by a motor driver 126 to drive the driven mechanism unit 203 such as the transmission mechanism unit 107 and the secondary transfer roller 23. The speed at the time of driving is detected by the encoder 109 attached to the transmission mechanism unit 107.

  The filter operation of the compensator 202 can be performed based on a classical control theory such as a proportional + integral compensator (PI filter), a proportional + integral + differential compensator (PID filter), a phase compensator, or the like. Further, it may be based on a modern control theory such as state feedback or a robust control theory such as H∞, and any type of compensator can be used.

  FIG. 8 is a diagram for explaining the filter operation of the compensator when a general PI filter is used.

  The PI filter is represented by a block diagram as shown in FIGS. 8A and 8B, and the response characteristic of the control system can be controlled by adjusting the proportional gain Kp and the integral gain Ki or Ki ′.

  The motor driver 126 may be any of PWM input, analog input, and numerical input, and the output format may be PWM output or analog output. Here, the voltage control type motor driver 126 will be described, but a current control type motor driver can also be used. In the case of the current control type, the current and the motor torque are proportional.

Further, in the case of the position control feedback system, the value detected and fed back becomes a value indicating the position by the encoder 109, and the compensator 202 is configured so as to match it, and the position of the position outside the control system shown in FIG. Only the feedback loop is attached, and the basic configuration is the same.
<Configuration of feedback control system of drive control device>
FIG. 4 shows a configuration example of a feedback control system of the drive control apparatus according to the present embodiment.

  The CPU 120 performs a sequence operation, various filter operations, and the like, and various CPU peripheral devices are connected by a bus 129.

  The ROM 121 stores a program used for calculation in the CPU 120.

  A RAM 122 is an external storage unit of the CPU 120 and stores variables for calculation.

  The period counter 123 measures the pulse interval of the encoder 109 using a reference clock, and the CPU 120 performs a reciprocal calculation of the result to calculate the speed.

  The PIO 124 is a digital port for input / output from a peripheral device, and is used for ON / OFF of the motor driver 126 and the like.

  The PWM oscillator 125 sets a PWM value corresponding to the motor voltage to the motor driver 126. In addition to the PWM oscillator 125, an analog output such as an AD converter can be used in the case of an analog input motor driver 126.

  The motor driver 126 detects the rotor position of the motor 110 with the hall outputs HU, HV, and HW, applies a voltage to the U-phase, V-phase, and W-phase coils to drive current, and drives the motor 110.

When the motor 110 is driven, the driven mechanism unit 203 is driven via the transmission mechanism unit 107. In this embodiment, the encoder 109 detects the speed at which the transmission mechanism unit 107 is driven.
<About drive control at startup>
FIG. 10 shows an example of the drive control result of the drive control device. The dotted line in the figure is the target speed, and the solid line is the actual speed detected by the encoder 109.

  As illustrated, when the motor 110 is started at time t0, the actual speed detected by the encoder 109 is rapidly increased by driving the motor 110 so as to follow the target speed. Subsequently, the motor 110 is accelerated, and the detected speed reaches the target speed at time t1 and is controlled so as to maintain the speed.

  If the mechanism unit is driven without any problem at the time of startup and no abnormal value is detected by the encoder 109, drive control along the target speed as shown in the figure can be performed.

  However, the drive mechanism shown in FIG. 3 includes many nonlinear elements. Nonlinear elements include, for example, backlash due to gear meshing and coupling, twisting of shafts such as the secondary transfer roller 23 and the cleaning roller 105, deformation of the cleaning blade 111 that cleans the secondary transfer roller 23, and the cleaning roller 105. For example, deformation of the surface brush may be mentioned. These non-linear elements affect the detection value of the encoder 109 when the motor 110 is started, and cause the control system to become unstable.

  For example, in a configuration in which a plurality of driven mechanism units 203 are driven from one motor 110 via the transmission mechanism unit 107, when the encoder 109 is provided in the transmission mechanism unit 107, it is easily affected by the above-described nonlinear elements.

  In the configuration of the present embodiment, when the secondary transfer roller 23 which is one of the driven mechanism portions 203 is temporarily removed for maintenance or the like and is reassembled after the adjustment operation, the gear of the transmission mechanism portion 107 is hit. The characteristic of the controlled object changes from that at the time of steady driving due to change or release of stress once. When activated in this state, the encoder 109 attached to the transmission mechanism 107 is vibrated by an impact caused by a gear backlash or the like, whereby an abnormal speed is detected, and the control may become unstable.

  In this case, the inertia of the mechanism portion driven by the motor 110 may change due to the attachment / detachment of the driven mechanism portion 203, and the control may become unstable. However, in this embodiment, since the deceleration mechanism is used, the inertia is used. It is considered that there is almost no influence on the drive control due to the change of.

  Next, FIG. 11 shows an example of a drive control result in the case of being affected by the above-described nonlinear element.

  After starting up at time t0 after the unit is detached, the encoder 109 detects a value that greatly exceeds the target speed at time t1.

  Since such a large speed change is integrated in the integrator of the compensator 202, a delay occurs in the subsequent response, and the oscillatory operation is repeated until the target speed is reached at time t2.

  If it takes time for the vibrational operation to converge, problems such as the case where it is determined that the device has failed to start up due to the occurrence of a device abnormality or the mechanism part is broken due to the vibrational operation occur. There is a case.

  Even if an abnormal value is detected by the encoder 109, it is considered that if the feedback control is not performed at the time of activation, the encoder 109 does not become unstable even after being influenced by the nonlinear element. However, depending on the size of the load, the startup time may vary, and a response delay may occur when switching to feedback control after startup.

Also, even if the compensator 202 designed so that the speed deviation is small (high control performance) during steady driving is used to stabilize the control, the control becomes oscillating or worst. In this case, the control system may be broken due to oscillation.
[First Embodiment]
FIG. 6 shows an example of a block diagram of feedback control of the drive control apparatus according to the first embodiment.

  In the drive control apparatus according to the first embodiment, in addition to the drive control apparatus shown in FIG. 5, a deviation limiting unit 204 is provided at the subsequent stage of the comparator 201 that compares the target speed and the actual speed detected by the encoder 109. Have. Moreover, it has the transmission mechanism part 107, and the driven mechanism part 203 is comprised so that it may be driven by the motor 110 via the transmission mechanism part 107. The compensator operation unit 205 performs a predetermined compensator operation using the compensator 202.

  FIG. 13 shows a flowchart of a processing example of the deviation limiting unit.

  First, it is determined whether or not the speed deviation obtained by the comparator 201 in step S1 is ± 100 mm / s. If the speed deviation is within ± 100 mm / s, the value of the speed deviation is input from the deviation limiting unit 204 to the compensator computing unit 205 as it is.

  If the speed deviation exceeds ± 100 mm / s, whether the speed deviation value is positive or negative is determined in step S2. If the value of the speed deviation is larger than +100 mm / s, the value of the speed deviation is limited to +100 mm / s in step S3 and input to the compensator computing unit 205.

  If the speed deviation value is smaller than −100 mm / s in step S <b> 2, the speed deviation value is limited to −100 mm / s and then input to the compensator computing unit 205.

  The above processing of the deviation limiting unit 204 can limit a large speed deviation caused by a nonlinear element of the mechanism unit, and a value integrated in the integrator of the compensator 202 in the compensator calculating unit 205 becomes small. Therefore, the time until the integrated value in the compensator 202 converges to a predetermined steady value can be shortened, and the response can be avoided from being vibrated.

  Note that the integral value of the integrator in the steady state is almost constant to compensate for the steady load. If the integrated value deviates greatly from this value, an overshoot occurs in which the actual speed exceeds the target speed, or the convergence time until the drive is stabilized becomes longer due to the vibration of the control.

  In the deviation limiting unit 204 according to the first embodiment, the value for limiting the speed deviation is set to ± 100 mm / s. However, the value may be limited within the range of the speed deviation that may occur in the normal acceleration region.

  FIG. 12 shows an example of the drive control result of the drive control apparatus according to the first embodiment. The dotted line is the target speed, and the solid line is the actual speed of the mechanism detected by the encoder 109.

  After starting at time t0, the mechanism is driven by the motor 110 along the target speed, but the encoder 109 detects a value that greatly exceeds the target speed at the time t1 due to nonlinear elements such as gear backlash. .

  However, the deviation limiting unit 204 performs processing to prevent the calculation in the compensator 202 from becoming unstable by limiting the value of the speed deviation obtained by the comparator 201. As a result, acceleration control is performed along the target speed without vibration of the control of the mechanism unit, the target speed is reached at time t2, and the speed is maintained.

As described above, according to the drive control apparatus according to the first embodiment, even when the influence of the nonlinear element is caused by the attachment or detachment of the mechanism unit, the deviation limiting unit 204 limits the speed deviation value. It is possible to prevent the control from becoming unstable and to realize stable drive control.
[Second Embodiment]
Next, control of the drive control apparatus according to the second embodiment will be described.

  In the drive control apparatus according to the second embodiment, in addition to the first embodiment, the compensator computing unit 205 performs the processing described below.

  FIG. 14 shows a flowchart of a processing example of the compensator computing unit 205. In the following description, the rotation of the motor 110 in the positive direction is CW, and the rotation in the negative direction is CCW.

  When the image forming apparatus 100 is activated and the driving of the secondary transfer roller 23 and the like is started, the compensator calculating unit 205 determines whether or not it is an acceleration region. The determination as to whether or not the vehicle is in the acceleration region may be made based on whether or not the speed detected by the encoder 109 has reached a certain value, or may be determined to be a certain time from the start of the acceleration region.

  If it is in the acceleration region, first, in step S11, the target rotation direction of the motor 110 is determined. If the rotation direction is CW, the driving direction of the motor driver 126 is set to CW in step S12. Subsequently, in step S13, the speed deviation limited from the deviation limiting unit 204 is input to the compensator calculating unit 205, the result calculated by the compensator 202 is determined, and the output of the compensator 202 is positive. In step S14, the output of the compensator 202 is set to the motor driver 126.

  If the output of the compensator 202 is different from the rotation direction of the motor 110 in step S13, the integral value of the integrator included in the compensator 202 is reset to a predetermined value in step S15. In the second embodiment, the predetermined value is 0. Next, a predetermined value is set in the motor driver 126 in step S16.

  Such setting of the integral value is a process for suppressing a delay in response due to integration of values in different directions by the integrator. Setting the predetermined value in the motor driver 126 is an oscillatory operation. This is a process to prevent.

  If the target rotation direction of the motor 110 is CCW in step S11, the drive direction of the motor driver 126 is set to CCW in step S17.

  Next, the result of the compensator calculation is determined based on the speed deviation limited from the deviation limiting unit 204 in step S18, and if the output of the compensator 202 is the same as the rotation direction of the motor 110, the step In S19, the output of the compensator 202 is set to the motor driver 126.

  If the output of the compensator 202 is different from the rotation direction of the motor 110 in step S18, a predetermined value is set as the integral value of the integrator included in the compensator 202 in step S20. Next, a predetermined value is set in the motor driver 126 in step S21. In the second embodiment, each predetermined value is 0.

  In the above processing, the predetermined value set to the integral value of the compensator 202 is set to 0. However, it may not be 0 as long as it is a value for improving the response, and the integral value in the steady state is set. May be.

  In addition, when the rotation direction of the motor 110 and the rotation direction of the output of the compensator 202 are different, a predetermined value set in the motor driver 126 is set to 0. However, if the drive system does not vibrate or oscillate, a non-zero value is set. It may be used.

  By performing the above-described processing in the compensator computing unit 205, even if the output of the compensator 202 is different from the driving direction of the motor 110, the driving direction of the motor 110 is fixed and the integral value in the compensator 202 is reset. By doing so, stable drive control can be realized at the time of startup.

  The operation of the compensator 202 will be described with reference to FIGS.

  Assuming that the filter operation of the compensator 202 is a PI filter, the operation in the compensator 202 is represented by a block diagram as shown in FIG.

  Here, the transfer function in FIG. 8A is expressed by Equation 1, the transfer function in FIG. 8B is expressed by Equation 2, and the proportional gain Ki and Ki ′ have a relationship of Ki = Kp × Ki ′. It shows the same characteristics.

K _PI = Kp + Ki / s (Formula 1)
K _PI = Kp (1 + Ki ′ / s) (Formula 2)
Here, as described above, when the compensator computing unit 205 determines that the motor 110 is in the acceleration region, for example, the proportional gain Kp in the equation is decreased, and the response frequency of the compensator 202 is decreased. Set. When the acceleration region of the motor 110 ends and becomes a steady region, control is performed so as to increase the response frequency by increasing the proportional gain Kp.

FIG. 9 shows an example of controlling the proportional gain Kp. In the acceleration region of the motor 110, the proportional gain Kp is set to Kp ₀ and the response frequency is set to be low. In the steady region, the proportional gain Kp is controlled to Kp ₁ which is larger than Kp ₀ and the response frequency is controlled to be high. .

For example, by setting the proportional gain Kp ₀ in the acceleration region to 1/10 of the proportional gain Kp ₁ in the steady region, the response frequency can be controlled to 5 Hz in the acceleration region and 50 Hz in the steady region.

  In the case of Equation 1, it is possible to control the response frequency of the compensator 202 by changing only the proportional gain Kp, but not only the proportional gain Kp but also the integral gain Ki in consideration of the stability of the control system. It is common to change at the same rate.

  When the compensator 202 in the second embodiment uses, for example, a PI filter, the integral value is reset to a predetermined value. However, when the compensator 202 is described by a state equation, the state quantity is set to a predetermined value. Will reset to the value.

  As described above, in the acceleration region of the motor 110, control is performed so as to lower the response frequency by lowering the proportional gain or the like of the compensator 202 in the compensator computing unit 205. By controlling in this way, it is possible to obtain a drive control device that can be started up with a stable feedback control system and little variation in the time to reach a steady state.

  As described above, in the drive control device according to the second embodiment, when the output of the compensator 202 is different from the drive direction of the motor 110 in the acceleration region of the motor 110, the drive direction of the motor 110 is fixed. The compensator operation unit 205 performs processing for resetting the integral value in the compensator 202. Also, control is performed to lower the response frequency by lowering the proportional gain of the compensator 202 and the like.

According to the drive control apparatus which concerns on 2nd Embodiment, a mechanism part can be stably drive-controlled by above-described control, and control with little dispersion | variation in start-up time can be performed.
[Third Embodiment]
FIG. 7 shows an example of a block diagram of feedback control of the drive control apparatus according to the third embodiment.

  The drive control device according to the third embodiment has a configuration in which the driven mechanism unit 203 is driven by the motor 110 via the transmission mechanism unit 107, and has the same configuration as the first and second embodiments, but acceleration determination The difference is that it has a portion 206.

  The acceleration determination unit 206 receives the target speed and the actual speed detected by the encoder 109, and determines whether or not the motor 110 is in the acceleration region.

  FIG. 15 shows a flowchart of a processing example of the acceleration determination unit 206.

  When the image forming apparatus 100 is activated and the motor 110 starts to be driven, the acceleration determination unit 206 first determines whether or not the speed profile detected by the encoder 109 has reached a steady value in step S31. Do.

  Whether or not the speed profile has reached a steady value is determined by whether or not the speed detected by the encoder 109 has become a constant value at a predetermined period.

  If it is determined that the speed profile has reached a steady value, the speed detected by the encoder in step S32 is within a predetermined range of the target value, for example, within a range of 300 mm / s ± 5%. Judge whether it is in or not. If the speed profile reaches a steady value in step S31 and it is determined in step S32 that it is within ± 5% of the target speed, it is determined in step S33 that it is in the acceleration region.

  If the condition of step S31 or step S32 is not satisfied, it is determined in step S34 that the region is the acceleration region.

  In the drive control apparatus according to the third embodiment, the acceleration determination unit 206 can accurately determine whether or not the motor 110 is in the acceleration region. Therefore, the value limited in the deviation limiting unit 204, the control of the response frequency in the compensator calculating unit 205, the control of the integral value and the value set in the motor driver 126, and the like are controlled by switching between the acceleration region and the steady region with high accuracy. It becomes possible.

  Therefore, after the driving of the secondary transfer roller 23 and the like reaches the steady region, the load applied to the processing can be reduced when driving in the steady region by setting so as not to perform unnecessary processing.

  Further, only when the secondary transfer roller 23 or the like is first activated after the unit is attached / detached, the deviation limit unit 204 limits the deviation value, resets the integral value of the compensator 202, and sets a predetermined value to the motor driver 126. Also, response frequency control, acceleration determination, and the like can be performed. By performing the process for stable driving only at the time of the first activation, and setting so as not to perform the above-described process after the stable driving is performed once, the load on the subsequent drive control can be reduced.

  In the drive control apparatus according to the first to third embodiments described above, the case of the speed control system has been described. However, if the position deviation is used instead of the speed deviation, the same configuration and processing are performed for the position control system. Thus, the drive can be stably controlled.

The image forming apparatus 100 has been described based on the configuration in which the motor 110 drives the secondary transfer roller 23 and the intermediate transfer belt cleaning roller 22 via the transmission mechanism 107. However, the driving of the photosensitive unit and the fixing unit is described. The present invention can be applied to control and other drive control devices that drive a mechanism using a motor.
<Summary>
According to the embodiment of the present invention, an abnormal value is detected by the encoder 109 after the start of driving due to non-linear factors such as gear meshing and shaft twisting after the secondary transfer roller 23 or the like as the driven mechanism is detached. Even in such a case, it is possible to realize a stable driving start-up without causing the control to become oscillating and unstable.

  It should be noted that the present invention is not limited to the configuration shown here, such as a combination with other elements in the configuration described in the above embodiment. These points can be changed without departing from the gist of the present invention, and can be appropriately determined according to the application form.

22 Cleaning roller (driven mechanism)
23 Secondary transfer roller (driven mechanism)
100 Image forming apparatus 107 Transmission mechanism unit 109 Encoder (detection unit)
110 Motor (electric motor)
126 Motor driver (motor drive unit)
202 Compensator 204 Deviation Limiting Unit 205 Compensator Computing Unit 206 Acceleration Determination Unit

Japanese Patent No. 4294344

Claims (6)

An electric motor,
A transmission mechanism for transmitting the output of the motor;
A driven mechanism that is driven by the output of the electric motor by connecting to the transmission mechanism;
A detector that detects the speed or position of any one of the electric motor, the transmission mechanism, or the driven mechanism;
Based on the deviation value between the output value of the detection unit and the target value, a compensator operation unit that performs a predetermined operation using a compensator;
An electric motor drive unit for driving the electric motor based on a calculation result of the compensator calculation unit;
Have a, a deviation limiting section that limits a value of the deviation to be input to the compensator calculating unit,
The compensator computing unit sets a predetermined integral value in the compensator when the drive direction of the motor based on the output of the compensator is different from the drive direction set in the motor, and drives the motor A drive control device characterized in that a predetermined value is set in the unit. The response frequency of the compensator in the acceleration region of the electric motor,
The drive control device according to claim 1 , wherein the drive control device is set to be lower than a response frequency in a steady region of the electric motor. An acceleration determination unit that determines that the speed or position profile detected by the detection unit becomes a steady value and the speed or position detected by the detection unit falls within a predetermined range as an acceleration region of the electric motor; The drive control apparatus according to claim 1 or 2 , wherein An image forming apparatus, comprising a drive controller according to any one of claims 1 to 3. An electric motor,
A transmission mechanism for transmitting the output of the motor;
A driven mechanism that is driven by the output of the electric motor by connecting to the transmission mechanism;
Based on the result of compensator calculation using a compensator, an electric motor drive unit that drives the electric motor,
A drive control method for a drive control device comprising:
A detection step of detecting the speed or position of any one of the electric motor, the transmission mechanism section, or the driven mechanism section;
A calculation step for performing the compensator calculation based on a deviation value between the detected output value and the target value;
Have a, and limiting step of limiting the value of the deviation to be input to the compensator operation,
The calculation step sets a predetermined integral value in the compensator when the driving direction of the electric motor based on the output of the compensator is different from the driving direction set in the electric motor. A drive control method characterized by setting a predetermined value . A program for causing a computer to execute the drive control method according to claim 5 .