JP2948830B2 - Spindle motor control method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a control method of a spindle motor for driving a disk-shaped storage medium.

[Prior art] In recent years, portable small personal computers,
Japanese word processor devices have been put into practical use, and magnetic disk devices having larger storage capacities have been used as auxiliary storage devices incorporated in these devices, in addition to floppy disk devices that can exchange media. I have.

This magnetic disk device usually cannot replace the storage medium, but recently, a medium-replaceable type (removable type) capable of replacing the storage medium has been put to practical use.

Conventionally, in such a magnetic disk device, when the main unit is stopped, the magnetic head for recording / reproducing data on the storage medium is retracted to a reference position, and the rotation of the storage medium is stopped. Also, in the removable magnetic disk device, when replacing the medium, the magnetic head is retracted to the reference position and the rotation of the storage medium is stopped.

In this way, when the rotation of the storage medium is stopped, the drive current of the spindle motor that rotates the storage medium is interrupted, and if the rotation is stopped by the frictional force acting on the rotation system of the spindle motor, it is extremely difficult. This is not preferable because it takes a long time.

For this purpose, conventionally, a mechanical braking means has been provided as disclosed in Japanese Patent Application Laid-Open No. Sho 57-1814181 and Japanese Utility Model Application Laid-Open No. Sho 57-3340, or a motor as disclosed in Japanese Patent Application Laid-Open No. Sho 56-22254. There has been proposed an apparatus provided with an electric braking means for performing braking using the back electromotive force.

[Problems to be Solved by the Invention] However, among the conventional devices using mechanical braking means, since the frictional force is used, the elements of the braking means are worn and dust is generated. If the dust adheres to the storage medium, the magnetic head may be broken.

In addition, when the back electromotive force of the motor is used, if the number of revolutions becomes very small immediately before the motor stops, the back electromotive force cannot be sufficiently obtained, and a long time is required before the motor stops. Such a disadvantage occurs.

The present invention has been made in view of such circumstances, and has as its object to provide a spindle motor control method capable of stopping a spindle motor in a short time.

Means for Solving the Problems In the present invention, when braking from a rotating state to a stop state, the application of a forward rotation driving current is stopped to apply a reverse rotation driving current, and the rotation speed and rotation acceleration of a spindle motor are reduced. The required stop time and the required stop rotation amount required to detect and stop the rotation are calculated, and when either the required stop rotation amount or the rotation speed becomes smaller than a predetermined value, the required stop time is calculated from that time. The application of the reverse rotation drive current is stopped at the time when the elapsed time.

[Operation] Therefore, since the spindle motor is stopped by applying the reverse rotation drive current, no dust or the like is generated when the spindle motor is stopped, and the time required for the stop can be reduced.

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

 First, the principle of the present invention will be described.

Now, when the maximum reverse rotation driving current that can be applied is applied to the spindle motor rotating at the speed v ₀ and the spindle motor is decelerated,
The change in the speed v of the spindle motor is expressed by the following equation (I).

v = αt + v ₀ (I) where α represents the acceleration at the time of deceleration.

Assuming that a rotation angle sensor that generates a pulse signal PR every time the spindle motor rotates 1/4 is provided, the speed v is calculated by the following equation (II) from the pulse interval T of the pulse signal PR generated from the rotation angle sensor. ).

v = 0.25 / T (II) Accordingly, the acceleration α at the time of stopping is represented by the following equation (III).

Here, T _n and T _n−1 are pulse signals PR at a certain point in time.
, And the pulse interval of the pulse signal PR obtained immediately before.

On the other hand, at a certain point during deceleration, the predicted value of the required stop time required to stop is represented by the following equation (IV).

That is, while doing deceleration of the spindle motor, detects two pulse interval T _n-1, T _n consecutive, on the basis of their pulse interval T _n-1, T _n, spindle from that point It is possible to calculate a predicted value of a required stop time required until the motor stops.

That is, the required stop time can be predicted at any time during the deceleration operation of the spindle motor.

Now, for example, as shown in FIG. 1, when driving the spindle motor at a velocity v _0, the instruction is stopped at time t _0, thereby the reverse rotation drive current to the spindle motor at the time t ₀ Considering the application, in that case, the spindle motor is braked in a state where the back electromotive force acting on the spindle motor is superimposed on the power of the reverse rotation drive current, so that the speed v of the spindle motor is large and the back electromotive force is high. At time t ₀ large power, acceleration of deceleration increases.

Then, as the speed v of the spindle motor decreases, the back electromotive force decreases, so that the effect of the back electromotive force on the acceleration of deceleration decreases. When the speed v of the spindle motor decreases to a certain extent, the effect of the back electromotive force decreases. Can be ignored.

That is, the predicted value of the required stop time calculated by using the above-described method is the same as the predetermined value v _a
It can be handled effectively in the following range.

Accordingly, during the deceleration operation of the spindle motor, the speed v of the spindle motor is sequentially detected, and the speed is set to _a predetermined value v _a.
When the predicted value t of the required stop time is calculated at a time point smaller than that, the reverse rotation drive current applied to the spindle motor is stopped when the predicted value t has elapsed from that time point, so that the spindle motor is stopped. It can be stopped reliably.

Further, by applying the reverse rotation drive current even when the spindle motor is stopped, it is possible to prevent the disadvantage that the spindle motor rotates in the reverse direction.

FIG. 2 shows a spindle motor drive control device according to one embodiment of the present invention. This spindle motor drive control device is used, for example, to drive a spindle motor of a removable magnetic disk device.

In FIG. 1, a control unit 1 is for performing a control operation of the spindle motor drive control device, and forms a duty control signal DD corresponding to the magnitude of a drive current of a spindle motor 2 to generate a motor drive signal. In addition to the output to the unit 3, a rotation command signal DR indicating the rotation direction of the spindle motor 2 is formed and output to the motor drive circuit 4. The control unit 1 exchanges various information with a system control unit of a magnetic disk drive (not shown) to perform operations such as starting and stopping the spindle motor 2.

For example, as shown in FIG. 3, the motor drive signal generator 3 has a constant cycle Td and a positive logic pulse width Tw corresponding to the value of the duty control signal DD input from the controller 1. The motor drive signal PD is converted into a motor drive signal SA having a signal value corresponding to the duty through a filter circuit 5, and the motor drive signal SA is added to the motor drive circuit 4. Have been.

The motor drive circuit 4 applies a motor drive signal SA to the spindle motor 2 in a direction corresponding to the rotation command signal DR, whereby the spindle motor 2 moves in the direction specified by the rotation command signal DR. , Motor drive signal
It rotates at the number of rotations corresponding to the size of SA.

The rotation angle sensor 6 detects the rotation of the spindle motor 2 and forms a pulse signal PR each time the spindle motor 2 rotates 1/4. The pulse signal PR is applied to the pulse interval measuring unit 7.

The pulse interval measuring unit 7 measures the interval between rising edges of the pulse signal PR, and the measurement result is added to the control unit 1 as pulse interval data TM.

 FIG. 4 shows an example of the rotation angle sensor 6.

In this case, the rotor 2a of the spindle motor 2 is provided with eight poles of a magnet shaped like a fan, and the rotation angle sensor 6 includes a Hall element 6a that detects the magnetic field of the magnet,
A pulse signal PR is generated based on the output signal SH of the Hall element 6a.
Is formed from a pulse signal generation circuit 6b that forms

Therefore, when the rotor 2a of the spindle motor 2 rotates, as shown in FIGS. 5 (a), (b) and (c), the output signal SH of the Hall element 6a becomes a sine every time the rotor 2a rotates 90 degrees. The pulse signal generation circuit 6b changes one cycle in a wave form
Outputs a pulse signal PR having a predetermined pulse width in synchronization with the zero crossing point on the rising side of the output signal SH.

Thus, the pulse signal PR is output from the pulse signal generation circuit 6b every time the spindle motor 2 rotates 1/4.

With the above configuration, when the spindle motor 2 is stopped, the control unit 1 outputs the duty control signal DD corresponding to the duty 0, whereby the motor drive signal generation unit 3 outputs the duty 0, , The motor drive signal PD maintaining the logic L level is output, and the level 0 motor drive signal SA is output from the filter circuit 5, so that the spindle motor 2 does not rotate.

Then, when a start command is input from the system control unit, the control unit 1 outputs a rotation command signal DR in the normal rotation direction, and changes the duty from 0 to a predetermined value in a change mode related to a predetermined speed-up control. The duty control signal DD is changed so as to change.

At this time, the spindle motor 2 starts rotating, and the pulse signal PR starts to be output from the rotation angle sensor 6, whereby pulse interval data TM is obtained. On the basis of,
The rotation speed of the spindle motor 2 is monitored, and the duty control signal is set so that the change in the rotation speed becomes a predetermined mode.
The duty is changed by DD.

In this way, when the rotation speed of the spindle motor 2 increases to a predetermined value, thereafter, the pulse interval data is set so that the rotation speed of the spindle motor 2 becomes a constant value.
While monitoring the rotational speed of the spindle motor 2 by inputting the TM, the duty control signal DD is changed accordingly.

Next, when a stop command is issued from the system control unit, for example, when the operator instructs a medium exchange, the control unit 1 performs the processing shown in FIG.

That is, first, a rotation command signal DR indicating the reverse rotation is output, and a duty control signal DD indicating the 100% duty is output (process 101).

As a result, the motor drive signal generator 3
A motor drive signal PD of 100% is output, and a motor drive signal SA having a maximum value corresponding to the motor drive signal PD is added to the motor drive circuit 4, so that the motor drive circuit 4 drives the motor in the reverse direction in a maximum value. An electric current is applied to the spindle motor 2 so that the spindle motor 2 is braked.

The control unit 1 inputs the pulse interval data TM, substitutes the value into a variable R1 (process 102), and inputs the pulse interval input this time into a variable T _n-1 that holds the value of the previous pulse interval data TM. with substitutes the value of variable T _n which holds the value of the data TM, by substituting the value of variable R1 in the variable T _n (process 103), the variable T
Update the values of _n and the variable T _n-1 .

Then, by using the updated values of the variable _Tn and the variable _Tn-1 , the calculation of the above equation (IV) is executed, and the predicted value of the required stop time from that time to the stop of the spindle motor 2 is calculated. Is calculated (step 104), and the speed v of the spindle motor 2 at that time is calculated based on the following equation (V) (step 10).
Five).

v = 0.25 / T _n (V) Next, it is checked whether or not the speed v is equal to or lower than the predetermined value v _a (determination 106). If the result of the determination 106 is NO, the spindle motor 2 Since the speed has not sufficiently decreased, the process returns to the process 102, and the subsequent processes are repeated.

When the result of the determination 106 is YES, the speed of the spindle motor 2 is in a sufficiently reduced state, and in this state, the system waits until a time corresponding to the predicted value has elapsed from that point (process 107). 0% duty control signal DD
The value is set to a value corresponding to the duty (process 108), and the spindle motor 2 is stopped.

Thus, the spindle motor 2 is decelerated / stopped in a manner according to the control method described above.

When the stop of the spindle motor 2 is completed, the control unit 1 notifies the system control unit of the completion.

In the system control unit, for example, the lock of the inkjet button for ejecting the disk cartridge containing the magnetic disk is released, and the disk cartridge can be ejected.

By the way, in the above-described processing, when the speed v of the spindle motor 2 becomes equal to or less than the predetermined value v _a ,
Although a transition has been made to the standby state of the predicted value, this determination can be made based on the required stop rotation amount representing the rotation amount of the spindle motor 2 rotating from that point to the stop.

The required stop rotation amount R can be calculated by the following equation (VI).

FIG. 7 shows an example of a process executed by the control unit 1 when the control unit 1 is stopped.

That is, first, the rotation command signal DR indicating the reverse rotation is output, and the duty control signal DD indicating the 100% duty is output (processing 201), whereby the spindle motor 2 is braked in the same manner as described above. .

Control unit 1 inputs the pulse interval data TM assigns the value to the variable R1 (process 202), as well as substitutes the value of variable T _n to the variable T _n-1, the value of the variable R1 in the variable T _n (Process 203) to update the values of the variable _Tn and the variable _Tn-1 .

Then, by using the updated values of the variable _Tn and the variable _Tn-1 , the calculation of the above equation (IV) is executed, and the predicted value of the required stop time from that time to the stop of the spindle motor 2 is calculated. The required stop rotation amount R of the spindle motor 2 at that time is calculated based on the above formula (VI) (process 205).

Next, it is checked whether or not the required stop rotation amount R is equal to or less than a predetermined value RR (for example, 0.5) (decision 206). When the result of the decision 206 is NO, the speed of the spindle motor 2 is sufficiently reduced. Since there is no state, the process returns to the process 202 and the subsequent processes are repeated.

When the result of the judgment 206 becomes YES, the speed of the spindle motor 2 is in a sufficiently reduced state, and in that state, the process waits until a time corresponding to the predicted value has elapsed from that time (process 207). , Duty control signal DD
Is set to a value corresponding to 0% duty (processing 20
8) Stop the spindle motor 2.

As described above, according to the present embodiment, the speed and the acceleration of the spindle motor 2 are detected, and the predicted value t of the time required from that time to the stop of the spindle motor 2 is calculated. In a state where the speed is sufficiently reduced, the application of the drive current to the spindle motor 2 is stopped at the time when the motor is further rotated in the reverse direction by the predicted value t calculated at that time, so that the spindle motor 2 is appropriately stopped. ing.

Therefore, the spindle motor 2 can be stopped without using mechanical means, and the maximum value of the reverse rotation driving current is applied to the spindle motor 2 until the spindle motor 2 is stopped, so that the time required for stopping can be reduced. .

Further, since the stop processing is performed while directly monitoring the rotation speed of the spindle motor 2, the same processing can be used when the magnetic disk of the spindle motor 2 is mounted and when it is not mounted.

In the above-described embodiment, a Hall element for detecting a change in a magnetic field of a permanent magnet provided as a rotation angle sensor on a rotor of a spindle motor, and a pulse signal for generating a pulse signal based on a detection signal of the Hall element Although the generation circuit is used, the configuration of the rotation angle sensor is not limited to this.

Further, in the above-described embodiment, the predicted value of the required stop time of the spindle motor, the required stop rotation amount, and the like are calculated based on the pulse interval of the pulse signal output in synchronization with the rotation of the spindle motor. It is also possible to provide a sensor for detecting the rotational speed of the spindle motor, and calculate the predicted value of the required stop time and the required stop rotation amount based on the speed signal detected by the sensor.

[Effects of the Invention] As described above, according to the present invention, when stopped,
In addition to applying the reverse rotation drive current, the required stop time and the required stop rotation amount required for stopping by detecting the rotation speed and the rotation acceleration of the spindle motor are calculated, and either the required stop rotation amount or the rotation speed is calculated. When is smaller than a predetermined value, the application of the reverse rotation drive current is stopped when a required stop time has elapsed from that point, so that no dust or the like is generated at the stop, and the time required until the stop is completed. Is obtained.

[Brief description of the drawings]

FIG. 1 is a graph for explaining the principle of the present invention, and FIG.
5 is a block diagram showing a spindle motor drive control device according to an embodiment of the present invention. FIG. 3 is a waveform diagram showing an example of a motor drive signal. FIG. 4 is a block diagram showing an example of a rotation angle sensor. FIG. 6 is a waveform diagram for explaining the operation of the rotation angle sensor, FIG. 6 is a flowchart showing an example of a process at the time of stop, and FIG. 7 is a flowchart showing another example of a process at the time of stop. 1 ... control section, 2 ... spindle motor, 3 ... motor drive signal generation section, 4 ... motor drive circuit, 6 ... rotation angle sensor, 7 ... pulse interval measurement section.

Continued on the front page (72) Inventor Takehiro Fujihira 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Company (72) Inventor Hiroyasu Onishi 1-3-6 Nakamagome, Ota-ku, Tokyo Co., Ltd. Ricoh (56) References JP-A-59-32377 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H02P 3/00-3/26

Claims (2)

(57) [Claims] 1. A method of controlling a spindle motor for driving a disk-shaped storage medium, comprising: during braking from a rotating state to a stopped state, stopping application of a forward rotation driving current and applying a reverse rotation driving current;
The required stop time and the required stop rotation amount required to stop after detecting the rotation speed and the rotational acceleration of the spindle motor are calculated, and when the required stop rotation amount becomes smaller than a predetermined value, the required stop is performed from that time. A method for controlling a spindle motor, comprising: stopping application of a reverse rotation drive current after a lapse of time. 2. A method of controlling a spindle motor for driving a disk-shaped storage medium, comprising: during braking from a rotation state to a stop state, stopping application of a forward rotation drive current and applying a reverse rotation drive current;
The required stop time required to stop by detecting the rotation speed and the rotation acceleration of the spindle motor is calculated, and when the rotation speed becomes smaller than a predetermined value, a reverse is performed at the time when the required stop time has elapsed from that time. A method for controlling a spindle motor, wherein application of a rotation drive current is stopped.