Method for controlling optical pickup head upon switching from following mode to seeking mode

Abstract

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.

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  claim 1  wherein said initial kick force is used for actuating said optical pickup head before a velocity feedback control of said optical pickup head is entered. 
     
     
       3. The method according to  claim 2  wherein said initial operating factor of said second compensator is replaced by an updated operating value realized in response to a velocity error signal to adjust a kick force of said actuator under said velocity feedback control of said optical pickup head. 
     
     
       4. The method according to  claim 1  wherein said first compensator and said second compensator are lead-lag compensators. 
     
     
       5. The method according to  claim 4  wherein said initial operating factor of said second compensator is an output value a(nseek) of a lag compensator of said second lead-lag compensator, and
   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  
 k 1 , k 2  and k 3  are coefficients.  
 
     
     
       6. The method according to  claim 1  wherein said optical processing apparatus includes an optical pickup apparatus selected from one of a compact disk-read only memory (CD-ROM) drive or a digital versatile disk-read only memory (DVD-ROM) drive. 
     
     
       7. The method according to  claim 1  wherein said optical processing apparatus includes an optical recording apparatus selected from one 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, or a digital versatile disk-random access memory (DVD-RAM) drive. 
     
     
       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.  
 
     
     
       9. The method according to  claim 8  wherein said first compensator and said second compensator are lead-lag compensators. 
     
     
       10. The method according to  claim 9  wherein said initial output value a(nseek) of said lag compensator of said second lead-lag compensator is calculated by the following equation:
   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  
 k 1 , k 2  and k 3  are coefficients.  
 
     
     
       11. The method according to  claim 8  wherein said optical processing apparatus includes an optical pickup apparatus selected from one of a compact disk-read only memory (CD-ROM) drive or a digital versatile disk-read only memory (DVD-ROM) drive. 
     
     
       12. The method according to  claim 8  wherein said optical processing apparatus includes an optical recording apparatus selected from one 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, or a digital versatile disk-random access memory (DVD-RAM) drive. 
     
     
       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.  
 
     
     
       14. The method according to  claim 13  wherein said first and said second compensation operations are performed by respective lead-lag compensators. 
     
     
       15. The method according to  claim 14  wherein said first and said second compensation operations are performed by respective lag compensators of said lead-lag compensators. 
     
     
       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.     
     
     
       17. The method according to  claim 16 , wherein a second gain value associated with the second compensator is greater than a first gain value associated with the first compensator. 
     
     
       18. The method according to  claim 16 , wherein the optical pickup head utilizes the initial kick force to perform a seeking operation of the optical processing apparatus. 
     
     
       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.     
     
     
       20. The method according to  claim 19 , wherein a second gain value associated with the second compensator is greater than a first gain value associated with the first compensator. 
     
     
       21. The method according to  claim 19 , wherein the first operating mode includes a following mode of the optical processing apparatus. 
     
     
       22. The method according to  claim 19 , wherein the second operating mode includes a seeking mode of the optical processing apparatus. 
     
     
       23. The method according to  claim 19 , wherein the optical pickup head utilizes the initial kick force to function according to the second operating mode of the optical processing apparatus. 
     
     
       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.