JPH0312877A - System for removing vibration of head carriage - Google Patents

Abstract

PURPOSE:To control remaining vibration at the stop time of a head carriage to a minimum by switching the value of a stop current which is caused to flow for holding a stop when a step motor stops to a lower one for prescribed time and absorbing the remaining vibration of the carriage even on a step motor-side. CONSTITUTION:A control means 14 moving a head to an instruction track position by the driving of the step motor 12 when a seek instruction is received, and a stop current switching means 16 switching the value of the stop current which is caused to flow for locking the stop when the stop motor 12 stops to the lower one are provided. The stop switching means 16 switches the stop current to the lower stop current value when the step motor 12 stops, returns the value to the original stop current value after prescribed time corresponding to the setting time of the remaining vibration of the head carriage 10 passes, stops and locks the head carriage 10. Thus, the remaining vibration when the head carriage 10 which moves by the step motor 12 stops can be kept to a minimum.

Description

[Detailed Description of the Invention] [Summary] The purpose of this invention is to minimize the residual vibration when the head carriage stops, regarding a vibration removal method for a head carriage in which a head carriage with a head mounted thereon is moved by a step motor in an optical disk device, etc. Then, when the step motor is stopped, the stop current value applied to keep the step motor stopped is switched to a lower current value for a predetermined period of time, so that residual vibrations of the carriage can be absorbed on the step motor side as well.

[Industrial Field of Application] The present invention relates to an information recording device such as an optical disk device,
The present invention relates to a head carriage residual vibration removal method for removing residual vibration when a head carriage carrying a head is moved by a step motor and stopped.

2. Description of the Related Art Optical disk devices, magneto-optical disk devices, and magnetic disk devices are widely used as storage devices using high-density storage media having a large number of information tracks.

In such information recording devices, a voice coil motor is usually used for the seek operation to move the head to the target track, but in recent years, voice coil motors have been developed with high magnetic efficiency and open-loop control, which can simplify the device configuration. It uses a step motor.

However, in head seek using a step motor, when the head carriage carrying the head is linearly driven by intermittent step rotation and stopped at the target track position, residual vibration remains in the head carriage. If the head optical system does not stabilize, stable track following operation (tracking control) cannot be started by the head optical system, and it is desirable to suppress residual vibration of the carriage as much as possible when the step motor stops in order to improve access time. .

[Prior Art] FIG. 7 is an explanatory diagram of a conventional optical disk device, in which a plurality of optical disks 2 are rotated at a constant speed by a spindle motor.
2, and heads 24 are provided on both sides of the optical disc 22. The head 24 is moved in the direction indicated by the arrow by a slider 26 to select one of the optical disks 22. The head 24 is mounted on a head carriage located below, and can be moved in the radial direction of the optical disk 24 as indicated by arrow B by driving a pulley 28 with a step motor.

FIG. 8 shows the head carriage 12 used in the optical disk device of FIG. 7, with a top view shown in FIG. 8(a) and a side view shown in FIG. 8(b).

In FIG. 8, the head carriage 10 is an L-shaped member, and a steel belt 32 with one end fixed to the right end with a screw 30 is wound around a pulley 28 connected to the output shaft of a step motor. The other end is fixed to the 1° corner of the head carriage with a screw 34. At the same time, a plate spring 36 is fixed by the screw 34, and a predetermined tension is applied by the plate spring 36 to prevent the steel belt 32 from bending. ing.

Therefore, by rotating the pulley 28 with the step motor, the head carriage 1o can be moved linearly in the pulley rotation direction.

[Problems to be Solved by the Invention] However, when the head carriage is moved by such a conventional step motor, an inertial load is applied to the leaf spring 36 when the carriage is started and stopped, causing vibration and causing the carriage to stop. If the subsequent settling time of the residual vibration becomes longer, there is a problem that not only does it have a negative effect on the access time, but also stable seek performance cannot be obtained.

The present invention has been made in view of such conventional problems, and an object of the present invention is to provide a head carriage vibration removal method that minimizes the residual vibration when the head carriage moved by a step motor stops. .

[Means to solve the problem] FIG. 1 is a diagram explaining the principle of the present invention.

First, the present invention moves the head mounted on the head carriage 10 onto the information track of a rotating storage medium using a step motor 2.
The target is information storage devices that are moved by

The head carriage vibration removal method of the present invention for such an information storage device includes a control means 14 for moving the head to a command track position by driving the step motor 2 when a seek command is received; A stop current switching means 16 is provided for switching the value of the stop current flowing for stop locking to a lower current value when the step motor 2 is stopped.

Further, the stop switching means 16 switches the stop current to a lower current value when the step motor 2 is stopped, and at the same time returns the stop current to the original stop current value after a predetermined time corresponding to the settling time of the residual vibration of the head carriage 12. The carriage 12 is stopped and locked.

[Function] According to the head carriage vibration removal method according to the present invention having such a configuration, by completely locking the step motor when the head carriage stops moving, all the vibrations of the head carriage part can be eliminated by the carriage alone. What we had to deal with was that by switching the stop current value of the step motor to a lower current value, the step motor would not be completely locked, and the vibration of the carriage part would be absorbed and attenuated by the step motor side as well. By further enhancing the damper effect, residual vibrations in the carriage section can be quickly damped and removed.

[Embodiment] FIG. 2 is a block diagram showing an embodiment of the present invention.

In FIG. 2, 10 is a head carriage on which the head is mounted, and as shown in FIG. 8, it is supported by fixing both ends of a steel belt 32 wound around a pulley 28. A leaf spring 36 is provided on one side to prevent deflection. steel belt 32
The pulley 28 that supported the seat carriage 10 via
is fixed to the output shaft of the step motor 12.

In this embodiment, the step motor 12 uses a step motor equipped with five coils of A phase, B phase, C phase, D phase, and E phase, and has a resolution of 0.9 degrees per step. The entire stroke of the head carriage 10 corresponds to 256 steps of the step motor 12.

For the step motor 12, the A phase drive circuit 18-1
．． B-phase drive circuit 18-2. C-phase drive circuit 18-3. A D-phase drive circuit 18-4 and an E-phase drive circuit 18-5 are provided. The A-phase to E-phase drive circuits 18-1 to 18-5 are driven by control signals from the MPU 14 as a control means. For example, taking the A-phase drive circuit 18-1 as an example, MP
From U14, a phase signal Pa that determines the direction of the current flowing through the A-phase coil, and current control signals Lal and La2 that specify the magnitude of the current flowing through the A-phase coil are received. This also applies to the remaining B-phase drive circuits 18-2 to E-phase drive circuits 18-5.

Further, a reference voltage (1) is commonly supplied to the A-phase to E-phase drive circuits 18-1 to 18-5.

Here, the current control signals Lal, La2~L from the MPU
el and Le2 are A-phase to E-phase drive circuits 18-1 to 18-5
The coil current value can be controlled individually for each phase, but by changing the reference voltage (1), the A-phase to E-phase drive circuit 18
The coil drive currents from -1 to 18-5 can be switched all at once.

The reference voltage ■1 is the transistor 20. Resistance R1゜R2,R
3, that is, in the present invention, the stop current switching circuit 16. That is, when the transistor 20 is off, the power supply voltage +5 volts is directly supplied as the reference voltage (1), but when the transistor 20 is turned on, the supply is switched to the reference voltage VR reduced to the voltage divided by the resistors R1 and R2.

When the MPU 14 as a control means receives a seek command, it calculates the address difference between the current track address and the track address according to the seek command, converts this address difference into the number of steps of the step motor 12, and drives the A-phase to E-phase. The head carriage 10 is moved linearly by driving the step motor 12 by 4-5 phase excitation by the circuits 18-1 to 18-5, and the head mounted on the head carriage 10 is moved to the commanded track address by the seek command. .

In addition to the basic seek operation control function by the MPU 14, in the present invention, when the step motor 12 is stopped moving, the MPU 14 turns on the transistor 200 of the stop current switching circuit 16 to drive the A-phase to E-phase. circuit 18
By lowering the reference voltage (1) for -1 to 18-5, a stop current switching function is provided that lowers the stop current flowing to stop and lock the motor 12 at step 0 to a lower current value. After this switching of the stop current is performed for a predetermined time based on the settling time of the residual vibration of the head carriage section, the transistor 20 of the stop current switching circuit 16 is turned off again to return to the original stop current and stop the step motor 12. It will lock. That is, when the step motor 12 is stopped, the step motor 12 is not completely locked, and the residual vibration generated in the head carriage is received and absorbed not only by the head carriage 10 but also by the step motor 12, thereby reducing the settling time of the damped vibration. This shortens the term.

Figure 3 shows the A-phase to E-phase drive circuit 1 shown in the embodiment of Figure 2.
8-1 to 18-5 are step motor drive circuit configuration diagrams showing Examples 8-1 to 18-5, and the A-phase drive circuit 18-1 is shown as a representative.

In FIG. 3, 42 is an output circuit section, which controls the current to the A-phase coil 44-1.

46 is a logic input section, into which the 1-phase signal Pa and current control signals Lal and La2 from the MPU 1.4 are input. 48 is a current detection section, which receives current control signals La1. Outputs a current control signal according to La2. A pulse generator 50 outputs a pulse signal whose on-duty is controlled according to the current detection signal from the current detector 48 to the output circuit 42.

To explain in more detail, the output circuit section 42 includes four transistors TRI, TR2, and TR3.

TR4 is provided by H-type bridge connection and constitutes an excitation circuit for the A-phase coil 44-1. transistor TR
Diodes D1 to D4 for suppressing spikes are connected in parallel to each of I to TR4, and transistors TRI and TR
Inverters II and 12 are provided at the bases of transistors TR3 and TR4, and three-manufactured NO
R circuits Nl and N2 are provided. Furthermore, a drive voltage Vm is supplied to the collector sides of the transistors TRI and TR2, and the emitters of the transistors TR3 and TR4 are commonly connected and connected to a current detection resistor rd.

The logic input section 46 receives the phase signal Pa from the MPU 14.
Schmitt trigger circuit ST for removing noise,
A delay circuit DL prevents a short-circuit state during phase switching of the transistors TRI to TR4 of the output circuit section 42, and an inverter 1 of the output circuit section 42 inverts the output of the delay circuit DL.
An inverter I5 is provided to output the signal to the NOR circuit N2.

Further, the other output of the delay circuit DL is directly connected to the output circuit section 42.
is connected to the inverter (2) and the NOR circuit N1.

Furthermore, the logic input section 46 receives current control signals Lal and L.
Four AND gates Al input a2.

A2. A3. A4 is provided. AND gate Al outputs high current level signal H8, AND gate 1A2 outputs medium current level signal MS, AND gate A3 outputs constant current level signal LS, and AND gate A4 outputs zero current level signal zS. Output. Current control signal L from MPU 14 for these four AND gates A1 to A4
al.

3 The output with respect to the current level of La2 is as shown in the following table.

Table-1 The current detection section 48 has three comparators C1, C2, C
3 is provided. Resistors r1, r2 . r3. Reference voltages Vrl, Vr2, Vr3 as divided voltages of r4
are respectively input, and the reference voltages Vrl to Vr3 are determined by the reference voltage (1) from the stop current switching circuit 16 shown in FIG.

Comparator C1 is activated only when high current level signal H8 is output from AND gate Al. Furthermore, comparator C2 is activated only when medium current level signal MS is output from AND gate A2. Furthermore, comparator C34 is activated only when low current level signal LS is output from AND gate A3. This comparator C1
The detection voltage Vs of the current detection resistor rd provided in the output circuit section 42 is input to the negative input of ~C3. Therefore, the comparators C1 to C3 act on the output of the pulse generator 50 when the voltage Vs detected by the current detection resistor rd exceeds the reference voltages Vrl to Vr3 in any one operating state based on the outputs of the AND gates A1 to A3. Outputs a trigger pulse to the stable multivibrator MMB.

When the monostable multivibrator MMB provided in the pulse generation circuit 50 receives a trigger pulse from one of the comparators C1 to C3, it produces a pulse output for a certain period of time determined by its time constant, and
Transistors TR3 and TR via OR circuits Nl and N2
Turn on 4.

That is, the transistor TR3 is driven by a pulse from the monostable multivibrator MMB by a trigger pulse from one of the comparators C1 to C3.

By controlling the on-duty of TR4, the A-phase coil 44 functions as a switching regulator.
-1 control of the drive current and low current control are performed. As a result, a constant current corresponding to the magnitude of the reference voltages Vrl to Vr3 for the comparators C1 to C3 is caused to flow through the A-phase coil 44-1. Therefore, if the reference voltage vR from the reference voltage switching circuit 16 is changed, the reference voltage Vr
Since l~Vr3 also decreases, this reference voltage Vrl~V
As r3 decreases, the drive current flowing through the A-phase coil 44-1 can also be decreased.

Figure 4 shows a second motor equipped with the step motor drive circuit shown in Figure 3.
FIG. 4 is a step motor drive waveform diagram showing 4-5 phase excitation drive of the step motor 12 by the A-phase drive circuit 18-1 to the E-phase drive circuit 18-5 shown in the figure.

In Fig. 4, first looking at the A phase drive, the clock CL
The phase signal Pa that determines the direction of the drive current repeats 1 every 10 clocks of K, and the times tO and tlO when this phase signal Pa changes.

Current control signals Lal and La26 are applied for one clock at timing t20. In this case, (La], L
a2) - (1, 1), which means that a high current Ih is specified.

As a result, +Ia is applied to the A-phase coil until time to.

0 from time tO to t1, and -Ia from time t1 to t10.

0 from time t10 to t11, +Ia from time tll to t20
Positive and negative drive currents Ia flow alternately so that.

On the other hand, for phase B, 2
A phase signal Pb shifted by a clock is applied, and current control signals Lbl and Lb2 of one clock are applied in synchronization with the rise and fall of this phase signal pb, causing the illustrated B-phase drive current Ib to flow.

The same applies to the C phase, D phase, and E phase, and only the drive currents Ic, Id, and Ie are shown for these phases. As a result, for example, four-phase excitation at times tO to t1, t
Driving is performed by 4-5 phase excitation in which 4-phase excitation and 5-phase excitation are alternately repeated so that the head position is moved one step at a time so that five-phase excitation occurs from 1 to t2.

FIG. 5 shows the stop current switching circuit 1 which is activated by the MPU 14 when the step motor 7 is stopped in the embodiment shown in FIG.
6 is a step motor drive waveform diagram when the transistor 20 of No. 6 is turned on and the stop current is switched to a lower current value. FIG.

In FIG. 5, until time tn, the step motor 12 is driven by 4-5 phase excitation in the same manner as in the drive waveform diagram of FIG. 4. When the target track address is reached at time tn and the step drive is stopped, in the conventional system, the rotation is locked by holding the A-phase to E-phase current at that time, but in the present invention, the MPU 14 turns on the transistor 20 of the stop current switching circuit 16, and by turning on the transistor 20, the A-phase to E-phase drive circuits 181 to 1
The reference voltage vR for 8-5 is lowered to a lower voltage, and the stop current is reduced by half, for example, as shown in FIG. For this reason, the step motor 12 placed in a stopped state is not completely locked in rotation, and the residual vibration of the head carriage is transmitted to the head carriage 10. The residual vibration of the carriage part is quickly damped by receiving the inertial vibration by the 8 rotor of the step motor 12 via the steel belt 32 and the pulley 28, and absorbing the inertial vibration on the step motor 12 side.
The settling time until damped vibration disappears can be shortened.

When a predetermined time T has elapsed from time tn, the MPU 14 turns off the transistor 20 of the stop current switching circuit 16 again, so that the reference voltage 1 for the A-phase to E-phase drive circuits 18-1 to 18-5 returns to the original voltage. , the A-phase to E-phase drive currents for the step motor 12 each recover to their steady current values, and the step motor 12 is fixedly held in a stopped and locked state.

FIG. 6 is an operational flow diagram showing control processing according to the embodiment of the present invention shown in FIG.

In FIG. 6, first, when a seek command is given to the MPU 14, the current address where the head is currently located is checked in step S2, and then the difference between the current address and the instruction address by the seek command is calculated in step S3. ,
Based on this address difference, the number of feed steps of the corresponding step motor 912 is calculated in step S4.

Next, in step S5, the feed amount, feed direction, and drive current are set, and in step S6, the step motor 12 4-5 is set.
Start driving by phase excitation. When the feed amount of the step motor 12 reaches the set feed amount in step S7, step S
The process proceeds to step S8 to stop the drive, and then the stop current value is lowered to a lower current value in step S9.

Next, in step SIO, it is checked whether or not a predetermined time T has elapsed since the drive was stopped, and when it is determined that time-up has occurred based on the elapse of the set time T, the process proceeds to step Sll, where the stop current is restored to the normal current value. The seek operation ends in step S12.

According to the method of the present invention in which the current value is lowered when the step motor drive is stopped to absorb and eliminate residual vibrations on the step motor side, as a result of experiments by the inventor of the present invention, the conventional drive stop takes 50 to 18 Qms. According to the present invention, it was confirmed that the settling time, which was about 5 to 50 ms, can be shortened to about 5 to 50 ms.

In addition, in the above embodiment, drive by 4-5 phase excitation of step motor 0 and 12 was taken as an example, but the present invention is not limited to this and may be applied as is to any suitable total number of coils. can do.

[Effects of the Invention] As explained above, according to the present invention, the residual vibration when the head carriage stops can be settled in a short time, and the shortening of the settling time shortens the access time and improves the seek performance. can do.

[Brief explanation of drawings]

Fig. 1 is a diagram explaining the principle of the present invention; Fig. 2 is a block diagram of an embodiment of the present invention; Fig. 3 is a block diagram of a step motor drive circuit of the present invention;
Figure 5 is a step motor drive waveform diagram; Figure 5 is a step motor drive waveform diagram when stopped; Figure 6 is an operation flow diagram of the present invention; Figure 7 is an explanatory diagram of a conventional optical disc device; Figure 8 is an optical disc drive diagram. Carriage explanatory diagram of the device; 1 Fig. 9 is an explanatory diagram of residual vibration. In the figure, 10: head carriage 12 step motor 14; control means (MPU) 16: stop current switching means (circuit) 18-1 to 18-5: A-phase to D-phase drive circuit 22: optical disk 24: head 26: Slider 28: Pulley 32 Steel belt 36: Leaf spring 42: Output circuit section 44-1: A phase coil 46 2 logic input section 48: Current detection section 50: Pulse generation section 2 -573- Toso - Moki

Claims (2)

[Claims] (1) In an information storage device in which a step motor (12) moves a head mounted on a head carriage (10) on an information track of a rotating storage medium, the step motor (12) is driven when a seek command is received. a control means (14) for moving the head to a commanded track position by: said control means (14) moving said step motor (12);
stop current switching means (1
6) A head carriage vibration removal method characterized by comprising: and; (2) The stop current switching means (16) returns the reduced stop current to the original current value after a predetermined period of time has passed since the drive of the step motor (12) is stopped, and sets the stop current to the stop lock state. The head carriage vibration removal method described in 1.