Settling judgment method for position control device and position control device
View Patent ↗In a settling judgment method for judging whether an object is settled at a target position, a margin for settling judgment is expanded, and settling is judged accurately. As the settling judgment formula of the settling judgment block, both the position error and the added value of the position errors of a plurality of samples are used. Particularly for the vibration in the low frequency area, the margin for settling judgment increases. Therefore even if vibration exists in the low frequency area, judging as deviation from the settling judgment conditions by mistake can be decreased, and operations (e.g. read/write operation) can be continued.
1. A settling judgment method of judging settling of an object to a target position of a positioning control device which performs position control according to a position error between the target position and a current position, comprising:
a step of computing the position error for each sample;
a first computing step of computing a first judgment value from the position error for each of the samples;
a first judgment step of judging whether a sample count, in which the first judgment value becomes less than a first slice value continuously, has reached a first judgment sample count;
a second computing step of computing a second judgment value from added position errors of a plurality of samples for each of the samples;
a second judgment step of judging whether a sample count, in which said second judgment value becomes less than a second slice value continuously, has reached a second judgment sample count; and
a step of outputting AND of the judgment results of the first judgment step and the second judgment step as a settling judgment result,
wherein the second computing step comprises a step of computing the second judgment value by adding the absolute values of the position errors of the plurality of samples.
2. The settling judgment method for a positioning control device according to claim 1 ,
wherein the second judgment step comprises a step of judging whether the sample count has reached the second judgment sample count which is equal to or less than 5.
3. The settling judgment method for a positioning control device according to claim 2 ,
wherein the second computing step comprises a step of computing the second judgment value by the addition of the position errors of equal to or less than 4 samples.
4. The settling judgment method for a positioning control device according to claim 1 ,
wherein the first judgment step comprises a step of judging whether the sample count has reached the first judgment sample count which is equal to or less than 5.
5. The settling judgment method for a positioning control device according to claim 1 , further comprising:
a third computing step of computing a third judgment value from a difference between said position error of the current sample and the position error of the previous sample for each of the samples; and
a third judgment step of judging whether the sample count, in which the third judgment value becomes less than a third slice value continuously, has reached a third judgment sample count,
wherein the output step comprises a step of outputting AND of the judgment results of the first judgment step, the second judgment step and the third judgment step as a settling judgment result.
6. The settling judgment method for a positioning control device according to claim 1 ,
wherein the output step comprises a step of outputting the judgment result on whether the position of a head is settled at the target position on a disk.
7. A position control device, comprising:
a position control block for performing position control for an object according to a position error between a target position and a current position; and
a settling judgment block for computing a first judgment value from the position error for each sample, and judging whether a sample count, in which the first judgment value becomes less than a first slice value continuously, has reached a first judgment sample count,
wherein the settling judgment block computes a second judgment value from added position errors of a plurality of samples for each of the samples, judges whether a sample count, in which the second judgment value becomes less than a second slice value continuously, has reached a second judgment sample count, and outputs AND of the two judgment results as a settling judgment result,
wherein the settling judgment block computes the second judgment value by adding the absolute values of the position errors of the plurality of samples.
8. The position control device according to claim 7 , wherein the settling judgment block judges whether the sample count has reached the second judgment sample count which is equal to or less than 5.
9. The position control device according to claim 8 , wherein the settling judgment block computes the second judgment value by the addition of the position errors of equal to or less than 4 samples.
10. The position control device according to claim 7 , wherein the settling judgment block judges whether the sample count has reached the first judgment sample count which is equal to or less than 5.
11. The position control device according to claim 7 ,
wherein the settling judgment block computes a third judgment value from a difference between the position error of the current sample and the position error of the previous sample for each of the samples, judges whether the sample count, in which the third judgment value becomes less than a third slice value continuously, has reached a third judgment sample count, and outputs AND of the three judgment results as a settling judgment result.
12. The position control device according to claim 7 , wherein the settling judgment block outputs the judgment result on whether the position of a head is settled at the target position on a disk.
13. The position control device according to claim 12 , wherein the settling judgment block judges whether the head is settled in the position accuracy range of the target position.
14. The position control device according to claim 12 , wherein the settling judgment block judges whether the head during seek control of the head is settled at the target position.
15. The position control device according to claim 12 , wherein the settling judgment block judges whether the head is following up the target position.