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Browse Prior Art Database

Adaptive Identification for Hard Disk File

IP.com Disclosure Number: IPCOM000036636D
Original Publication Date: 1989-Oct-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 3 page(s) / 67K

Publishing Venue

IBM

Related People

Kisaka, M: AUTHOR

Abstract

Disclosed is an algorithm for an adaptive identification of a gain of a motor control system, which eliminates the need for estimating external bios.

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Adaptive Identification for Hard Disk File

Disclosed is an algorithm for an adaptive identification of a gain of a motor control system, which eliminates the need for estimating external bios.

A block diagram of the motor control system is shown in Fig. 1. As illustrated in Fig. 1, a gain K depends on a torque constant and inertia, so this parameter is different in each motor. To get stable control, this parameter should be identified. But there is another unknown term Iext (Fig. 1): therefore, the previous identification algorithm requires estimation of Iext. The following algorithm eliminates the need for extimating Iext.

For the system shown in Fig. 1, the difference equation can be described as

(Image Omitted)

(n)= 2* (n-1) -2 r(n-2) +K*{2(1-q)2* (n-1)

+ (1+2q-2q2)*U(n-2) + q2*U(n-3) } +K*Iext

where:

(n) : rotational angle at n'th sample

U(n) : control input at n'th sample

K : (torque constant) *Ts2/(2*inertia)

Ts : Sample time

q : /Ts is delay time (Fig. 2)

Iext : external current

In the above equation Iext is an external bios current or bios force which can not be obtained directly, the previous identification algorithm requires estimation of Iext. For r(n), the difference equation is:

r(n-1) = 2* r(n-2) - r(n-3) + K*{ (1-q)2*U(n-2)

+ (1+2q-2q2)*U(n-3) + q2*U(n-4) } +

K*Iext

The term Iext is the same in both equations (1) and

(2).

By subtracting equation (2) from (1), the following equation can be obtained. r(n) - r(n-1) = 2*{r(n-1)-r(n-2)} - {r(n-2)-O(n-3)...