JPH03134872A - Information recording and reproducing device - Google Patents

Abstract

PURPOSE:To reach an objective track within the minimum time by using the maximum value of a driving power supply voltage by detecting the absolute velocity of a head from the eccentric velocity of a track and relative velocity between the head and the information track. CONSTITUTION:A relative velocity detection part 11 detects the relative velocity between a head 3 and the track. The position of the objective track is generated as an absolute position and defined as a target absolute position signal 20 by adding an eccentric amount, which is forecasted by an eccentric amount forecasting block 18, and an access position. Next, when a target velocity signal 29 is generated by a target velocity generating block 22 while using a target position in an absolute position level and the position of the head, the target velocity of equal deceleration not to include disturbance caused by eccentricity. Thus, even in disk with the large eccentric amount, the performance of a voice coil motor for driving the head can be led out at the maximum.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an information recording and reproducing apparatus that performs recording and reproducing using an eccentric rotating information medium and improving the method of accessing a desired track.

[Prior Art] FIG. 3 schematically shows a hard disk device or an optical disk device as a conventional information recording/reproducing device.

In the figure, a disk 1 serving as a rotating information medium for storing information is rotated by a motor 2. As shown in FIG.

Information tracks are formed on the disk 1 in a concentric or spiral manner.

Particularly in the case of an optical disc, since the disc 1 is replaceable, there is a misalignment between the rotation center of the motor 2 and the track center of the disc 1, and the track position fluctuates due to eccentricity caused by the rotation of the motor 2. For this reason, the head 3 needs to perform an operation that follows this.

Furthermore, in order to access any track on the disk 1, the head 3 needs to move in the radial direction of the disk. This access and the above-mentioned tracking operation are realized by moving the head 3 using the voice coil motor 4.

Conventionally, the configuration shown in FIG. 6 has been used to access any track.

When a target track is designated by an access position command from a host computer or a controller (not shown), a distance difference between the current position of the head and the target track is calculated. A necessary target speed for the head is generated in accordance with this distance difference, and the head 3 is moved by controlling the speed to the target speed using the voice coil motor 4 while detecting the speed of the head 3 with a speed detector.

The target speed is, for example, as shown in Fig. 7(a) (because the target position is reached by a set uniform deceleration, the target speed generator shown in Fig. 6 has the characteristics shown in Fig. 7(b)). Become.

In addition, position detectors or speed detectors are designed to improve detection accuracy and reduce costs by using tracking error signals generated when a head crosses a track.

[Problems to be Solved by the Invention] However, in the above-mentioned conventional example, since the track crossing signal of the disk is used for position detection, the relative position or relative speed between the head and the track is detected. In the case of a disk, there is a large error in the absolute position or velocity of the head, making it impossible to expect ideal head operation.

Therefore, a margin is required to withstand eccentricity and disturbances, and there is a problem in that it is not possible to reach the target track in the minimum time using the maximum value of the drive power supply voltage, and it is not possible to bring out the limits of the performance.

[Means and effects for solving the problems] In order to solve the above-mentioned problems, the present invention records or reproduces information on a rotating information medium having a plurality of concentric or spiral information tracks. The apparatus includes: a head for recording or reproducing information on the medium; a head moving means for moving the head in a direction substantially perpendicular to the information 1-rack; and an eccentric velocity measurement for measuring the eccentric velocity of the information 1-rack. means for detecting a relative speed between the head and the information track; and a relative speed detecting means for detecting a relative speed between the head and the information track; and a relative speed detecting means for detecting a relative speed between the head and the information track; Absolute speed detection means for detecting the absolute speed of the head; and control means for controlling the head moving means based on the detected absolute speed to access the head to a desired information track. The present invention provides an information recording and reproducing device for recording and reproducing information.

The control means further includes: relative position detection means for detecting a relative position between the head and the information track; eccentricity measurement means for measuring the eccentricity of the information track; and the relative position detection means and the eccentricity. absolute position detection means for detecting the absolute position of the head from the output of the measurement means; means for outputting a target speed of the head based on the detected absolute position; and detection with the absolute speed detection means. The object of the present invention is to solve the above problem by providing an information recording/reproducing apparatus characterized by comprising means for feeding back the difference between the absolute speed determined by the head and the target speed to the head moving means.

According to the present invention, the target speed of head movement can be set based on absolute speed or absolute position, and the head can be driven while predicting errors due to eccentricity in advance.

[Embodiment] FIG. 1 is a block diagram of the first embodiment of the present invention.
This will be explained below with reference to the schematic diagram of the conventional example shown in the figure.

In FIG. 1, reference numeral 5 denotes a rotary encoder attached to the motor 2 shown in FIG. 3, which outputs a rotation synchronization pulse 6.

A head 3 records or reproduces information on the disk 1 as a rotating recording medium, and outputs a tracking error signal 7 indicating a deviation from a track on the disk. This ) racking error signal 7 becomes a sine wave with a repetitive track pitch as the track traverses.

8 is an eccentricity measurement block, 9 is an eccentricity speed measurement block,
10 is a relative position detection block, 11 is a relative velocity detection block, and 8 to 11 process the l/racking error signal 7 and output necessary information.

Reference numeral 12 denotes an eccentricity storage block, which stores the eccentricity measured by the eccentricity measuring block 8 at the timing of the rotation synchronization pulse 6, and sometimes the rotation in FIG. This is a block diagram, and will be described below with reference to the schematic diagram of the conventional example shown in FIG.

In FIG. 1, 5 is a rotary encoder attached to the motor 2 in FIG. 3 and outputs a rotation synchronizing pulse 6.

A head 3 records or reproduces information on the disk 1 as a rotating recording medium, and outputs an I/racking error signal 7 indicating a deviation from a track on the disk. This tracking error signal 7 becomes a sine wave with a repetitive track pitch as the track traverses.

8 is an eccentricity measurement block, 9 is an eccentricity speed measurement block,
10 is a relative position detection block, 11 is a relative velocity detection block, and 8 to 11 process the dragging error signal 7 and output necessary information.

Reference numeral 12 denotes an eccentricity storage block which stores the eccentricity measured by the eccentricity measurement block 8 at the timing of the rotation synchronization pulse 6, and outputs it at the rotation synchronization pulse timing 6 at certain times.

Reference numeral 13 denotes an eccentric speed storage block which stores the eccentric speed measured by the eccentric speed measurement block 9 at the timing of the rotation synchronization pulse 6, and outputs data at the rotation synchronization pulse timing 6 at certain times.

Reference numeral 14 denotes an access position command pointer, in which a command for the access position of a desired information track, such as "10001-rack °", is inputted by a command from a host computer or controller (not shown).

15 is an absolute position signal that is the sum of the output of the relative position detection block 10 and the output of the eccentricity storage block 12;
26 is an addition means (absolute position detection means) for calculating this sum.
It is. Similarly, 16 is an absolute speed signal which is the sum of the outputs of the eccentric speed storage block 13 and the relative speed detection block E1, and 28 is an addition means (absolute speed detection means) for calculating this sum.

17 is a moving distance signal obtained by taking the difference between the access position command 14 and the absolute position signal 15.

18 is an eccentricity prediction block that predicts the amount of eccentricity after movement using the movement distance signal 17 and the output of the eccentricity storage block 12; 19 is an eccentricity prediction block that uses the movement distance signal 17 and the output of the eccentricity speed storage block 13 to An eccentricity speed prediction block 20 predicts the subsequent eccentricity speed; 20 is an access position command 14 and an eccentricity amount prediction block 18;
The predicted target absolute position signal 21 is the sum of the output of the predicted target absolute position signal 2o and the absolute position signal 1 of the predicted target absolute position signal 2o.
22 is a target speed generation block that receives the absolute movement distance signal 21 and generates the target speed of the head. 23 is a prediction obtained by adding the output signals of the eccentric speed prediction block 19 and the target speed generation block. The target speed signal 24 is the absolute speed signal 1 from the predicted target absolute speed signal 23.
25 is a driver for driving the voice coil motor 4.

The operation of this embodiment having the above configuration will be described below.

First, the disk 1 is rotated by a motor 2 (not shown in FIG. 3). If the disc 1 is an optical disc, focus servo is applied.

In this state, with the voice coil motor 4 stopped, the eccentricity measurement block 8 and the eccentricity speed measurement block 9 use the tracking error signal output from the head 3.
Each outputs the amount of eccentricity and eccentricity speed. These eccentricity amounts and eccentric speeds are stored in an eccentricity storage block 12 and an eccentricity speed storage block 13 in synchronization with the rotation of the disk.

The storage blocks 12, 1.3 then only output data.

Figure 4 shows a graph of eccentricity and eccentricity speed. Both become sine waves synchronized with the disk rotation period as shown in the figure.

By the way, the relative position detector 1o and the relative speed detector 11 are as follows.
This does not mean that the absolute position or absolute speed of the head 3 is detected, but the relative position with respect to the track or similar relative speed ((absolute position) - (1 position due to eccentricity)). .

Therefore, the absolute position signal 15 is generated by adding the relative position signal 31 and the amount of eccentricity, and similarly, the absolute velocity is also generated by adding the relative speed signal 32 and the eccentric speed.

When the access position command 14 is manually input, the apparatus of the present invention first calculates the distance between the target access position and the current head position, that is, the absolute position signal 15 that takes into account the amount of eccentricity.

If the distance difference is large, the access time will be long; if the distance difference is small, the access time will be short.

Furthermore, since the optimal speed pattern is set in advance, the time required for access can be easily predicted. For example, the time required to access 5 mm is 15
m5 can be predicted.

In addition, the number of rotations of the disk was 300 Orpm, and one cycle was 20 m.
5, in FIG. 4, if access is started at point a, it is possible to predict the position due to eccentricity and the speed due to eccentricity at point b after 15 m5. Therefore, using this prediction signal, the absolute position and absolute velocity at the end of access are made to match the target track and eccentric velocity, respectively, thereby achieving a smooth transition to the tracking state.

The eccentricity prediction block 18 generates a target track position as an absolute position by adding the predicted eccentricity and the access position, and uses this as a predicted target absolute position signal 20.
shall be.

Next, a target speed signal 29 is generated by the target speed generation block 22 using the target position at the absolute position level and the position of the head. As a result, the target speed signal becomes a constant deceleration target speed that does not include disturbance due to eccentricity.

Furthermore, in order to calculate the speed difference between the head and the track at the time of reaching the target track, an eccentric speed prediction value is added to the target speed.

FIG. 5 shows the eccentric speed and target speed signal in the present invention.

In FIG. 5, ■1 indicates the target speed that does not take eccentricity into account when accessing from point a to point b shown in FIG. By adding Vb with an offset, V
It is possible to obtain a target speed of ++Vb in consideration of eccentricity.

Similarly, V 2 + v x is the target velocity when accessing position X, taking into account the eccentricity.

In addition, as a second embodiment, as shown in FIG. 2, the eccentricity measurement block 8, the eccentricity storage block 12, and the eccentricity prediction block 18 in FIG. It is also possible to output the predicted target absolute speed 23 by adding the target speed according to the position difference between the position and the relative position, and based on this, the head is driven in consideration of the influence of eccentricity. be able to.

[Effects of the Invention] As explained above, head speed control that eliminates disturbances caused by eccentricity makes it possible to maximize the performance of the head-driving voice coil motor, even for disks with large eccentricity, and achieve maximum drive. High-speed access using voltage becomes possible.

In addition, since the drive is performed while anticipating positional errors due to eccentricity,
It is possible to quickly set the track, and it is possible to drive the head in an ideal manner.

[Brief explanation of the drawing]

FIG. 1 shows a first embodiment of an information recording/reproducing device implementing the present invention.
block diagram. FIG. 2 shows a second embodiment of an information recording/reproducing device implementing the present invention.
block diagram. FIG. 3 is a schematic diagram of the information recording/reproducing device. FIG. 4 is an explanatory diagram of track eccentricity. FIG. 5 is an explanatory diagram of a target speed signal according to the present invention. FIG. 6 is a block diagram of a conventional example. FIG. 7 is an explanatory diagram of the target speed signal. ]...Disk, 2...Motor, 3...Head, 4...Voice coil motor, 5 5...Rotary encoder, 8...Eccentricity measurement block, 9...Eccentricity speed measurement Blocks 10... Relative position detection block, 11... Relative speed detection block, 12... Eccentricity storage block, 13... Eccentricity speed storage block, 14... Access position command, 18... Eccentricity amount prediction block, 19... Eccentricity speed prediction block, 22... Target speed generation block. 6

Claims (2)

[Claims] (1) A device for recording or reproducing information on a rotating information medium having a plurality of concentric or spiral information tracks, comprising: a head for recording or reproducing information on the medium; and a head for recording or reproducing information on the medium; head moving means for moving in a direction substantially perpendicular to the information track; eccentric speed measuring means for measuring the eccentric speed of the information track; relative speed detecting means for detecting the relative speed between the head and the information track; absolute speed detecting means for detecting the absolute speed of the head from the eccentric speed measured by the speed measuring means and the relative speed detected by the relative speed detecting means; and moving the head based on the detected absolute speed. An information recording/reproducing apparatus comprising: control means for controlling the head to access a desired information track. (2) The control means includes: relative position detection means for detecting the relative position between the head and the information track; eccentricity measurement means for measuring the eccentricity of the information track; the relative position detection means and the eccentricity. absolute position detection means for detecting the absolute position of the head from the output of the quantity measurement means; means for outputting a target speed of the head based on the detected absolute position; and the absolute speed detection means, 2. The information recording and reproducing apparatus according to claim 1, further comprising means for feeding back the difference between the detected absolute speed and the target speed to the head moving means.