A method for controlling an optical pickup head of an optical processing apparatus is provided. A first lead-lag compensator is disabled and a second lead-lag compensator is enabled when the optical pickup head switches from a following mode to a seeking mode. Then, an initial operating factor of the second lead-lag compensator is determined according to a last input value and a last output value of the first lead-lag compensator. An initial kick force of the actuator in the seeking mode is calculated by realizing the last input value and the last output value of the first lead-lag compensator immediately before the first lead-lag compensator is disabled. Finally, the optical pickup head is actuated to perform a seeking operation with the initial kick force.
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13. A method for determining an initial kick force for moving an optical pickup head upon said optical pickup head is switched from a following mode to a seeking mode, said method comprising steps of:
disabling a first compensation operation applied to said following mode and enabling a second compensation operation applied to said seeking mode;
determining an output value of said second compensation operation according to an output value of said first compensation operation; and
determining said initial kick force in response to said output value of said second compensation operation.
0. 16. A method for controlling a pickup head of an optical processing apparatus, comprising:
disabling a first compensator of the optical processing apparatus and enabling a second compensator of the optical processing apparatus when the optical pickup head switches from a first operating mode to a second operating mode;
determining an initial operating factor of the second compensator based on an initial output value of a lag compensator of the second compensator; and
calculating an initial kick force to actuate the pickup head in the second operating mode, wherein the initial output value correlates to an output of a lag compensator of the first compensator.
0. 24. An optical processing apparatus, comprising:
a pickup head configured to access information from an optical medium;
an actuator configured to operate the pickup head in a following mode or a seeking mode;
a first compensator configured to control the actuator when the pickup head operates in the following mode; and
a second compensator configured to control the actuator when the pickup head operates in the seeking mode, wherein when the pickup head switches from the following mode to the seeking mode, the optical processing apparatus provides the actuator an initial kick force corresponding to an initial output value of a lag compensator of the second compensator, and wherein the initial output value correlates to a final input value and a final output value of a lag compensator of the first compensator.
0. 19. A method for controlling an optical pickup head of an optical processing apparatus upon switching from a first operating mode to a second operating mode, the optical processing apparatus comprising a first compensator, a second compensator, and an actuator for moving the optical pickup head in either the first operating mode or the second operating mode, the method comprising:
disabling the first compensator and enabling the second compensator; and
determining an initial kick force of the actuator to operate the optical pickup head in the second operating mode, wherein the initial kick force corresponds to an initial output value of a lag compensator of the second compensator, and wherein the initial output value correlates to a final input value and a final output value of a lag compensator of the first compensator.
8. A method for controlling an optical pickup head of on optical processing apparatus upon switching from a following mode to a seeking mode, said optical processing apparatus further comprising a first compensator with a first gain, a second compensator with a second gain higher than said first gain, and an actuator for moving said optical pickup head in either said following mode or said seeking mode, and said method comprising steps of:
disabling said first compensator, and enabling said second compensator; and
determining an initial kick force of said actuator for moving said optical pickup head at the moment that said seeking mode is entered according to an initial output value of a lag compensator of said second compensator, which correlates to last input and output values of a lag compensator of said first compensator before said lag compensator of said first compensator is disabled.
1. A method for controlling an optical pickup head of an optical processing apparatus, said optical pickup head being actuated by an actuator of said optical processing apparatus in either following mode or a seeking mode, said method comprising steps of:
disabling a first compensator of said optical processing apparatus with a first gain and enabling a second compensator of said optical processing apparatus with a second gain higher than said first gain when said optical pickup head switches from said following mode to said seeking mode;
determining an initial operating factor of said second compensator according to a last input value and a last output value of said first compensator, which are realized immediately before said first compensator is disabled in order to calculate an initial kick force of said actuator in said seeking mode; and
actuating said optical pickup head to perform a seeking operation with said initial kick force.
2. The method according to
3. The method according to
4. The method according to
5. The method according to
a(nseek)=k1×b(nseek)+k2×X(ntrack)+k3×Y(ntrack) where
b(nseek) is an input value of said lag compensator of said second lead-lag compensator,
X(ntrack) and Y(ntrack) are said last input and said last output values of a lag compensator of said first lead-lag compensator, respectively, and
k1, k2 and k3 are coefficients.
6. The method according to
7. The method according to
9. The method according to
10. The method according to
a(nseek)=k1×b(nseek)+k2×X(ntrack)+k3×Y(ntrack) where
X(ntrack) and Y(ntrack) are said last input and said last output values of said lag compensator of said first compensator realized immediately before said lag compensator of said first compensator is disabled, respectively,
b(nseek) is an initial input value of said lag compensator of said second lead-lag compensator, and
k1, k2 and k3 are coefficients.
11. The method according to
12. The method according to
14. The method according to
15. The method according to
0. 17. The method according to
0. 18. The method according to
0. 20. The method according to
0. 21. The method according to
0. 22. The method according to
0. 23. The method according to
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For example, the optical processing apparatus includes an optical pickup apparatus selected from one of a compact disk-read only memory (CD-ROM) drive and a digital versatile disk-read only memory (DVD-ROM) drive. And, the optical processing apparatus includes an optical recording apparatus selected from a group consisting of a compact disk-recordable (CD-R) drive, a compact disk-rewritable (CD-RW) drive, a digital versatile disk-recordable (DVD-R) drive, a digital versatile disk-rewritable (DVD-RW) drive and a digital versatile disk-random access memory (DVD-RAM) drive.
According to another aspect of the present invention, there is provided a method for controlling an optical pickup head of an optical processing apparatus upon switching from a following mode to a seeking mode. The optical processing apparatus further comprises a first compensator with a first gain, a second compensator with a second gain higher than the first gain, and an actuator for moving the optical pickup head in either the following mode or the seeking mode. The method comprises steps of disabling the first compensator and enabling the second compensator, and determining an initial kick force of the actuator for moving the optical pickup head at the moment that the seeking mode is entered according to an operating factor of the first compensator before the first compensator is disabled.
In an embodiment, the initial kick force is determined in response to an initial output values of a lag compensator of the second lead-lag compensator, and the initial output value correlates to last input and output values of a lag compensator of the first lead-lag compensator realized immediately before the lag compensator of the first lead-lag compensator is disabled.
According to another aspect of the present invention, there is provided a method for determining an initial kick force for moving an optical pickup head upon the optical pickup head is switched from a following mode to a seeking mode. The method includes steps of disabling a first compensation operation applied to the following mode and enabling a second compensation operation applied to the seeking mode, determining on output value of the second compensation operation according to an output value of the first compensation operation, and determining the initial kick force in response to the output value of the second compensation operation.
The above objects and advantages of the present invention will become more readily apparent to those ordinarily skilled in the art after reviewing the following detailed description and accompanying drawings, in which:
FIG. 3(a) schematically illustrates some positions of the optical pickup head occurring relative to track 1 of an optical disk in a following mode;
FIG. 3(b) is a schematic waveform diagram illustrating a tracking error signal TE in a following mode;
FIG. 3(c) is a schematically waveform diagram illustrating a tracking output signal TRO in a following mode; and
In order to overcome the problems in the prior art, a method for controlling an optical pickup head is developed. The method is now illustrated based on a tracking control system of FIG. 2. The first lead-lag compensator 231 with a relatively low gain is selected for determining the kick force of the actuator 24 when the optical pickup head 20 is in a following mode. In contrast, the second lead-lag compensator 232 with a relative high gain is selected when the optical pickup head 20 is in a seeking mode.
The method for controlling the optical pickup head 20 of an optical processing apparatus, for example a compact disk-read only memory (CD-ROM) drive or a digital versatile disk-read only memory (DVD-ROM) drive, will be described as follows with reference to FIG. 4.
When the optical pickup head 20 switches from a following mode to a seeking mode, the first lead-lug compensator 231 is disabled and the second lead-lag compensator 232 is enabled, as indicated in Step 41. Meanwhile, the last input value and the last output value of the first lead-lag compensator 231 in the following mode is loaded into the second lead-lag compensator 232 to realize an initial output value according to a predetermined formula, as indicated in Steps 42 and 43. Then, in Step 44, an initial kick force of the actuator 24 in the seeking mode is determined according to the initial output value. The optical pickup head 20 is then moved by the actuator 24 under the initial kick force. Further, the motion-related information of the optical pickup head 20 in response to the kick force is provided to the pre-amplifier 21 so as to realize the tracking error signal TE. During the seeking mode, the velocity error signal Verr is produced by the velocity profile generator 25 according to the frequency variation level of the tracking error signal TE, as indicated in Step 45. The second lead-lag compensator 232 thus determines an updated output value according to the velocity error signal Verr and the predetermined formula, as indicated in Step 46. Therefore, an updated kick force of the actuator 24 is determined according to the updated output value, as indicated in Step 44. The kick force is being updated by keeping on monitoring the position of the optical pickup head relative to the optical disk.
In an embodiment, the output values of the first lag compensator 2312 and the second lag compensator 2322 are calculated by the following equations (1) and (2), respectively:
Y(m)=k1×X(m)+k2×X(m−1)+k3×Y(m−1) (1)
a(n)=k1×b(n)+k2×b(n−1)+k3×a(n−1) (2)
where
It is assumed that the last input and the last output values of the first lag compensator 2312 obtained immediately before the following mode changes to the seeking mode are X(ntrack) and Y(ntrack), respectively, and the initial input and output values of the second lag compensator 2322 are a(nseek) and b(nseek), respectively. Thus,
Y(ntrack)=k1×X(ntrack)+k2×X(ntrack−1)+k3×Y(ntrack−1) (3); and
a(nseek)=k1×b(nseek)+k2×b(nseek−1)+k3×a(nseek−1) (4)
In accordance with the present invention, the last input and the last output values X(ntrack) and Y(ntrack) of the first lag compensator 2312 are incorporated into the equation (4) to substitute for the values b(nseek−1) and a(nseek−1), respectively, and the value b(nseek) is a preset value. Therefore, when the optical pickup head 20 is switched to the seeking mode, the output value a(nseek) of the second lag compensator 2322 is obtained by the following equation:
a(nseek)=k1×b(nseek)+k2×X(ntrack)+k3×Y(ntrack) (6)
Therefore, the second lead-lag compensator 232 incorporates therein the operational factors of the first lead-lag compensator 231.
According to the present invention, at the moment the following mode changes to the seeking mode, the power required for moving the optical pickup head from different positions around a starting track to the target track will be properly determined by referring to the operating factors of the previous compensator used in the following mode.
Since the last input and the last output values X(ntrack) and Y(ntrack) of the first lag compensator 2312 are utilized for determining the initial operating factors of the second lead-lag compensator 232, the initial kick force of the actuator 24 provided for the optical pickup head 20 at the beginning of a seeking mode can be precisely calculated according to the initial output value or the second lead-lag compensator 232. Such appropriate initial kick force is advantageous for performing an effective seeking operation, especially a short seeking operation.
The present invention is illustrated by referring to an optical pickup apparatus such as a compact disk-read only memory (CD-ROM) drive or a digital versatile disk-read only memory (DVD-ROM) drive. Nevertheless, the present invention can be applied to an optical recording apparatus, for example, a compact disk-recordable (CD-R) drive, a compact disk-rewritable (CD-RW) drive, a digital versatile disk-recordable (DVD-R) drive, a digital versatile disk-rewritable (DVD-RW) drive and a digital versatile disk-random access memory (DVD-RAM) drive.
While the invention has been described in terms of what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention needs not be limited to the disclosed embodiments. On the contrary, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims which are to be accorded with the broadest interpretation so as to encompass all such modifications and similar structures.
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