What is claimed:
1. A disk apparatus, comprising:
a head for moving to an arbitrary track position of a disk medium;
a positional signal detection unit for detecting a positional signal according to the dislocation amount of said head from a predetermined reference position of the track on the medium;
a feedback control unit for computing a control signal for moving said head from said positional signal so that said dislocation amount is controlled to zero;
a drive unit for driving said head based on said control signal; and
a learning control unit for obtaining an unknown function for one disk rotation along with the periodic disturbance to memory which is comprised of N number of memory cells by a learning algorithm as an approximate function which is approximated by the height allocated to each time block when the time required for one rotation of said disk medium is divided by N;
wherein said learning control unit
samples a signal which follows said positional signal according to said learning algorithm at a sampling period which is less than the time obtained by dividing the time required for one rotation of said medium by N,
updates said one or more memory cells corresponding to said sampling time synchronizing with said sampling period according to said signal value,
reads the values of two memory cells located at the cell positions corresponding to said output time at an output period which is less than the time obtained by dividing the time required for one rotation of said medium by N, and
interpolates the values of said both memory cells based on said output time to generate a periodic disturbance compensation signal.
2. The disk apparatus according to claim 1, wherein said learning algorithm of said learning control unit is for calculating the memory cell value after an update by multiplying said sampled signal by a predetermined or variable gain and adding the computed result to the memory cell value before update.
3. The disk apparatus according to claim 1, wherein said learning control unit reads the values of the two memory cells associated at an advanced time moved forward for a predetermined amount of time from the update target memory cell, and performs interpolating processing for the values of the two memory cells by said learning algorithm, so as to generate a periodic disturbance compensation signal corresponded to said advanced time.
4. The disk apparatus according to claim 1, wherein said learning control unit samples a signal which follows said positional signal, selects two memory cells corresponding to said sampling time, and updates the values of the memory cells by the learning algorithm so as to learn said unknown function.
5. The disk apparatus according to claim 4, wherein said learning algorithm of said learning control unit changes the update gains for the two memory cells to be the update target according to said sampling time and adjusts the update balance between the two memory cells when the two memory cells are updated.
6. The disk apparatus according to claim 1, wherein said learning control unit samples a signal which follows said positional signal, updates a value of one of said memory cells, which is allocated to a time close to said sampling time, by the learning algorithm, so as to learn said unknown function.
7. The disk apparatus according to claim 1, wherein said learning control unit performs learning control at a timing immediately after inserting said medium into the apparatus, and performs feed-forward control for removing a periodic disturbance by outputting the learning result at tracking control after learning.
8. The disk apparatus according to claim 7, wherein said learning control unit performs feed-forward control for removing a periodic disturbance by outputting the learning result at track jump and at seek control after learning.
9. The disk apparatus according to claim 1, wherein said learning control unit executes an operation to obtain an approximate function for each location at a plurality of locations in the disk radius direction when said approximate function is obtained, and selects and feed-forwards the approximate function to be used according to the position in the radius direction at that time when feed-forward is performed after said learning.
10. The disk apparatus according to claim 9, wherein said learning control unit applies the learning algorithm using already existent approximate function data as initial values if the approximate function already obtained at another location exists when the approximate function is obtained at a plurality of locations.
11. The disk apparatus according to claim 1, wherein said head has a carriage mounted with an objective lens which freely moves in the direction crossing the tracks of the medium such that focus can be freely controlled,
and said head has a fine and a coarse control integrated structure which allows both tracking control for the optical beam to follow the track and seek control for the optical beam to move to an arbitrary track position by moving said carriage.
12. A track-following control method of a disk apparatus, comprising;
a step of detecting a positional signal according to the dislocation amount of a head which moves to an arbitrary track position of a disk medium, from a predetermined position of the track on said disk medium;
a feedback control step of computing a control signal for moving said head from said positional signal so that said dislocation amount is controlled to zero;
a step of driving a drive section for driving said head based on said control signal; and
a learning control step,
said learning control step comprising the steps of;
sampling a signal which follows said positional signal at a sampling period which is less than the time obtained by dividing the time required for one rotation of the medium by N;
updating said one or more memory cells corresponding to said sampling time synchronizing with said sampling period according to said signal value;
reading the values of two memory cells located at the cell positions corresponding to said output time at an output period which is less than the time obtained by dividing the time required for one rotation of the medium by N; and
interpolating the values of both memory cells based on said output time so as to generate a periodic disturbance compensation signal.
13. The track-following control method for a disk apparatus according to claim 12, wherein said learning control step is for sampling a signal which follows said positional signal and updating the values of said two memory cells corresponding to said sampling time so as to learn said unknown function.
14. The track-following control method for a disk apparatus according to claim 12, wherein said learning control step is for sampling a signal which follows said positional signal and updating the value of said memory cell close to said sampling time so as to learn said unknown function.
15. The track-following control method for a disk apparatus according to claim 12, wherein said learning control step is for controlling learning at a timing immediately after inserting said medium into the unit, and performing feed-forward control for removing a periodic disturbance by outputting the learning result at tracking control after learning.
16. The track-following control method of a disk apparatus according to claim 15, wherein said learning control step performs feed-forward control for removing a periodic disturbance by outputting the learning result at track jump and at seek control after learning.
17. The track-following control method for a disk apparatus according to claim 12, wherein said learning control step is for executing an operation to obtain an approximate function for each location at a plurality of locations in the disk radius direction when said approximate function is obtained, and selecting and feed-forwarding the approximate function to be used according to the position in the radius direction at that time when feed-forward is performed after said learning.
18. The track-following control method for a disk apparatus according to claim 12, wherein said update step of said learning control step is a step for calculating the memory cell value after an update by multiplying said sampled signal by a predetermined or variable gain and adding the computed result to the memory cell value before update.
19. The track-following control method for a disk apparatus according to claim 12, wherein said learning control step comprises a step for reading the values of the two memory cells associated at an advanced time for a predetermined amount of time from the update target memory cell, and performing interpolating processing for the values of the two memory cells, so as to generate a periodic disturbance compensation signal corresponded to said advanced time.
20. The track-following control method for a disk apparatus according to claim 12, wherein said learning step comprises a step for changing the update gains for the two memory cells to be the update target according to said sampling time and adjusting the update balance between the two memory cells when the two memory cells are updated.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. An angular velocity sensor comprising:
an oscillating element including a drive electrode, a monitor electrode and a detecting electrode;
a drive circuit having an output side connected with the drive electrode of the oscillating element;
a detecting circuit having an input side connected with the detecting electrode of the oscillating element;
a monitor circuit having an input side connected with the monitor electrode of the oscillating element;
a rectifying circuit for rectifying an output signal of the monitor circuit;
a smoothing circuit for smoothing an output signal of the rectifying circuit to obtain a smoothed signal; and
an oscillation control circuit adapted to be fed with the output signal of the monitor circuit and to have a gain controlled with an output signal of the smoothing circuit, the oscillation control circuit inputting its output signal to the drive circuit,
wherein the smoothing circuit includes:
a first switch having an input terminal connected with the output side of the rectifying circuit;
a first capacitor having a first terminal connected with an output terminal of the first switch;
a second switch having an input terminal connected with the output terminal of the first switch and an output terminal connected with an input side of the oscillation control circuit;
a first reference voltage connected with a second terminal of the first capacitor;
a second capacitor having a first terminal connected with the output terminal of the second switch and a second terminal connected with the first reference voltage; and
control signal feeding means for feeding a signal to control the ONOFF of the first switch and the second switch.
2. The angular velocity sensor of claim 1, wherein the control signal feeding means receives, as a source signal, the output signal of the monitor circuit.
3. The angular velocity sensor of claim 1, wherein the control signal feeding means receives, as a source signal, the output signal of the drive circuit.
4. The angular velocity sensor of claim 1, wherein the control signal feeding means receives, as a source signal, the output signal of the oscillation control circuit.
5. The angular velocity sensor of claim 1, wherein the control signal feeding means receives, as a source signal, an output signal of an oscillating circuit.
6. The angular velocity sensor of claim 1, wherein the control signal feeding means receives, as a source signal, an AC signal applied from signal generating means outside of the sensor.
7. An automobile comprising: a body; a plurality of tires for supporting the body; and a brake system provided for each tire, wherein the brake system is fed with a detected output from an angular velocity sensor of any of claims 1 to 6.
8. An automobile comprising: the body; at least one seat disposed in the body; and an airbag system disposed near the seat, wherein the airbag system is fed with a detected output from an angular velocity sensor of any of claims 1 to 6.