JPH03260973A - Head positioning device - Google Patents

Abstract

PURPOSE:To realize the precise positioning of a head corresponding to the change of temperature by detecting the temperature of a head supporting means, where the head is mounted, with the aid of a temperature detection means and moving the head supporting means with the aid of a positioning means based on the detected temperature. CONSTITUTION:A positional information read circuit 32 reads the positional information of a servo disk 10 and a demodulation circuit 33 outputs it as a position signal. Next, a sense signal generation circuit 34 corrects the position signal by a circuit constant which is converted to an optimum with respect to the change of the temperature and generates a sense signal where abnormal amplitude does not appear. A servo signal output circuit 35 precisely detects the present position of the servo head 11 based on the sense signal and outputs a servo signal. A servo amplifier 13 amplifies the servo signal and supplies a servo current to a voice coil motor 14. Then, the head 11 is positioned. Thus, the precise positioning of the head corresponding to the change of the temperature is realized.

Description

[Detailed Description of the Invention] [Summary] To provide a head positioning device for positioning the head by moving a head support means to which the head is attached, so that stable head positioning can be performed at all times against temperature changes. In the head positioning device as described above, temperature detection means for detecting the temperature of the head support means and positioning means for moving the head support means based on the temperature detected by the temperature detection means are provided. Configure.

[Industrial application field]

The present invention relates to a head positioning device that positions a head by moving a head support means to which a head is attached.

[Conventional technology]

Conventional head positioning is performed as shown in FIG. 4 in, for example, magnetic disk drives. That is, the servo head 11 reads position information from the servo surface of the servo disk 10, and based on this position information, the head positioning circuit 12 outputs a servo signal to control the drive of the voice coil motor (hereinafter referred to as VCM) 14. . At this time, the seek operation control section 12a first demodulates a position signal (position signal) indicating the position of the head on the track from the position information, corrects this position signal based on circuit constants described later, and corrects the position signal as shown in FIG. 5(a). ) Create a sense signal as shown in When the servo head 11 is on track, the sense signal is 0 [Vl, as shown in FIG. It shows the number. Further, this circuit constant is indicated by a resistance value or a voltage value, and conventionally, the constant setting section 12b, which adjusts the variable resistance, is manually changed only once in accordance with the weight, size, inertia, etc. of the carriage. The value was set to such a value that no abnormal amplitude or overshoot appears in the sense signal. The head positioning circuit 12 detects the current position of the head from this sense signal and outputs the servo signal until the head reaches the target position.

Then, the servo amplifier 13 amplifies this servo signal and supplies it as a servo current to the VCM 14, thereby driving the VCM 14. When the VCM 14 is driven, the carriage 15 to which the RAD 11 and other heads are attached moves to the servo.
Each head is positioned at an arbitrary track on each surface of each magnetic disk.

Note that in the past, there was a method of automatically adjusting the circuit constants using a digital-to-analog converter (hereinafter referred to as DAC) 12b' as shown in FIG. 6 instead of the constant setting section 12b having a variable resistance. . This is done by starting a timer (not shown) when the power to the magnetic disk device is turned on.
The position information reproduced from each point on the servo disk by the servo controller 11 is DA'd every predetermined time by this timer.
C12b', and while switching the inputs, each sense signal is generated, and the circuit constants that give the best sense signal condition are automatically set.

[Problem to be solved by the invention]

By the way, in such a conventional positioning device,
Since we did not do anything to change the above circuit constants in response to temperature changes, if the playback characteristics of the servo head changed due to temperature changes or the access arm was thermally deformed (expansion and contraction), as shown in Figure 5. Although the sense signal was normal as shown in (b), overshoot or abnormal amplitude sometimes appeared at the end of the sense signal as shown in (c) of the same figure. Then, the servo head is positioned on the adjacent track, or jumps over that track to correctly position it on the target track (seek operation).
Off-track will occur.

For this reason, in the constant setting section 12b having a variable resistance, for example, the circuit constants are adjusted after off-track occurs, and even in the case of automatic adjustment by the DAC 12b', the DAC operates only at predetermined intervals, so temperature changes occur during that time. Conventionally, it is not possible to correct abnormalities such as overshoot in the waveform of the sense signal due to a change in the temperature of the carriage.

SUMMARY OF THE INVENTION An object of the present invention is to provide a head positioning device that can always perform stable head positioning against temperature changes.

[Means to solve the problem]

Means for solving the above problems in the present invention is a head positioning device that positions a head by moving a head support means 1 to which a head is attached, as shown in FIG. The head supporting means 1 is provided with a temperature detecting means 2 for detecting the temperature of 1, and a positioning means 3 for moving the head supporting means 1 based on the temperature detected by the temperature detecting means 2.

[Effect]

According to the present invention, the temperature detection means 2 detects the temperature of the head support means 1, and the positioning means 3 controls the positioning of the magnetic head based on the temperature detected by the temperature detection means 2. Therefore, even if the reproduction characteristics of the head attached to the head support means 1 change due to temperature changes, or the head support means 1 undergoes thermal deformation (expansion and contraction),
The positioning means 3 moves the head support means 1 according to the temperature, and can position the head at a target position.

〔Example〕

Embodiments of the head positioning device according to the present invention will be described below with reference to the drawings.

FIG. 2 is a block diagram showing the configuration of the head positioning device of this embodiment, and FIG. 3 is a diagram showing an example of a constant setting section and a circulator of this embodiment. Incidentally, in this embodiment, the same parts as the conventional one are given the same numbers and explained.

In FIG. 2, the positioning device of this embodiment includes a servo head 11 that reads position information from the servo surface of a servo disk 10, a carriage 15 as head support means that supports the servo head 11, and a voice coil that moves the carriage 15. A motor (hereinafter referred to as VCM) 14,
A servo amplifier 13 supplies a servo current to the VCM 14, a servo amplifier 31 serves as a temperature detection means for detecting the temperature of the carriage 15, and a head positioning circuit 21 sends a servo signal to the servo amplifier 13. In addition, VC
M14, servo amplifier 13, and head positioning circuit 2
1 constitutes the positioning means of the present invention.

First, the carriage 15 of this embodiment shown in the figure has an access arm 15a to which the servo head 11 is attached, and a vertical shaft 15b that supports the access arm 15a and is movable by the drive of the VCM 14.

Further, the servo star 31 of this embodiment shown in the figure is attached to the vertical shaft 15b of the carriage 15, and the access arm 1
5a and the servo head 11, and the resistance value changes almost linearly with respect to temperature changes.

Furthermore, in the same figure, the head positioning circuit 22 of this embodiment is shown.
a seek operation control section 21a that feeds back the position information read by the servo head 11 and the circuit constant set by the constant setting section 21b, and outputs a servo signal based on these to control the seek operation of the head; A constant setting section 21 that sets a circuit constant from the resistance value of the thermistor 31 and sends this circuit constant to the seek operation control section 21a.
It consists of b.

The seek operation control unit 21a includes a position information reading circuit 32 that performs waveform shaping such as amplification and slewing on the position information read by the servo controller 11, and a position information reading circuit 32 that performs waveform shaping such as amplification and slewing on the position information read by the servo controller 11, and a position information reading circuit 32 that performs waveform shaping such as amplification and slewing. A demodulation circuit 33 demodulates the position signal, a sense signal generation circuit 34 generates a sense signal indicating the movement state of the servo head 11 using this position signal and a circuit constant from the constant setting section 21b, and a sense signal generation circuit 34 generates a sense signal indicating the movement state of the servo head 11 from this sense signal. It has a servo signal output circuit 35 that determines the position of the head 11 on the magnetic disk and outputs a servo signal until the current position reaches the target position.

Further, the constant setting section 21b obtains a resistance value according to the temperature of the servo head 11 and carriage 15 from the servo star 31 as shown in FIG. 3, and sets a circuit constant when creating a sense signal from this resistance value. It is something to do. In other words, when the resistance value of the circstar 31 changes due to a temperature change, the combined resistance value of the circstar 31 and the resistor 32 provided in parallel with it changes, and the component of this combined resistance and the resistor 33 is changed. The pressure ratio changes, and the circuit constants mentioned above are changed. Therefore, the values of the resistors 32 and 33 are set so that the change in voltage value due to this voltage division ratio changes optimally in accordance with temperature changes. Next, the operation of this embodiment will be explained. First, when positioning the head, a disk control circuit (not shown) such as an MPU sends a control signal such as a seek operation start signal and a target track address signal to the head positioning circuit 21 as shown in FIG. be done. Then, the seek operation control section 21a sends a servo signal to the servo amplifier 13 based on this control signal, causes the servo amplifier 13 to supply a servo current to the VCM 14, and moves the carriage 15. At the same time, the seek operation control section 21a causes the servo head 11 to feed back the position information read from the servo disk 10.

In the seek operation control section 21a, a position information reading circuit 32 first performs waveform shaping such as amplification and shuffling on this position information, and a demodulation circuit 33 demodulates this position information and outputs it as a position signal.

Then, the sense signal creation circuit 34 corrects this position signal using the circuit constant from the constant setting 6Blb to create a sense signal in which abnormal amplitude such as overshoot does not appear. At this time, the circuit 31 detects the temperature of the vertical shaft 15b of the carriage 15 and constantly sends a resistance value corresponding to the temperature to the constant setting section 2xb, so that the circuit The combined resistance of the star 31 and the resistor 32 changes, the voltage division ratio between the combined resistance and the resistor 33 changes, and the voltage value applied across the star 31 or the resistor 32 changes to an optimal value corresponding to temperature changes. Therefore, sense signal generation circuit 3
4, by using circuit constants that are optimally converted with respect to temperature changes, it is possible to create a sense signal that does not exhibit abnormal amplitude due to temperature changes.

Then, the servo signal output circuit 35 is the sense signal generation circuit 3
The current position of the servo controller 11 is accurately detected from this sense signal, which has been optimally corrected according to the temperature change in step 4, until this position becomes the target position according to the address signal sent from the disk control circuit. Outputs servo signals.

Then, the servo amplifier 13 amplifies this servo signal and
Since servo current is supplied to CM14, servo head 1
1 can be accurately positioned.

Therefore, according to this embodiment, the thermistor 31 always detects the temperature of the carriage 15, and the seek operation control section 21a corrects the sense signal based on the temperature so that waveform distortion such as overshoot or abnormal amplitude does not occur. Then, the current correct position of the servo head is detected from this sense signal and a servo signal 1 is output. For this reason, for example, the reproduction characteristics of the servo head 11 may change due to temperature changes, or the servo head 11 may change due to temperature changes.
Even if the access arm 15b to which the head is attached is thermally deformed (expanded or contracted) due to temperature changes, accurate head positioning, that is, seek operation is always possible.

In this embodiment, the thermistor 31 is used as a temperature detection means.
was provided on the vertical axis 15b of the carriage 15, but
In the present invention, the circuster 31 as a temperature detection means may be provided on the access arm to which the servo head is attached. Furthermore, in this embodiment, the circuit constant of the constant setting unit 21b is changed by the thermistor 31, and the circuit constant is constantly fed back to the sense signal generation circuit 34. However, in the present invention, for example, the sense signal generation circuit 34 The detected sense signal may be compared with a tolerance value, and the circuit constant may be fed back from the constant setting section 21b only when an abnormal waveform such as an overshoot exceeding the tolerance value appears. Further, in this embodiment, as shown in FIG. 3, the constant setting unit 21b is configured to use the resistance value from the thermistor 31, but in the present invention, a different circuit is configured using the thermistor 31. Alternatively, the circuit may be constructed using an element that detects temperature by another method and converts it into resistance or voltage without using a circstar.

〔Effect of the invention〕

As explained above, according to the present invention, the temperature detection means detects the temperature of the head support means to which the head is attached,
A positioning means moves the head support means based on the temperature. Therefore, even if, for example, the playback characteristics of the head change due to temperature changes, or the head support means undergoes thermal deformation (expansion, contraction, etc.) due to temperature changes, it is possible to always accurately position the head in accordance with the temperature changes. Become.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the principle of the present invention, FIG. 2 is a block diagram showing the configuration of an embodiment of a head positioning device according to the present invention, and FIG. 3 is an example of a constant setting section and a circstar of the present embodiment. 4 is a diagram showing a conventional example, FIG. 5 is a diagram showing a waveform of a sense signal according to a conventional example, and FIG. 6 is a diagram showing another example of a conventional head positioning circuit. 1.15 Head support means (carriage) 2.31
...Temperature detection means (thermistor) 3.13, 14.
21...Positioning means (servo amplifier, voice coil motor, head positioning circuit)

Claims (1)

[Claims] A head positioning device that positions a head by moving a head support means (1) to which a head is attached, comprising: temperature detection means (2) for detecting the temperature of the head support means (1); A head positioning device comprising: positioning means (3) for moving the head support means (1) based on the temperature detected by the temperature detection means (2).