公开(公告)号：JPH06147841A

公开(公告)日：1994-05-27

申请号：JP29700492

申请日：1992-11-06

Applicant: IBM JAPAN

Inventor： MORITA TETSUHARU ,  KUNO TEIJI ,  FUKUZAWA TADASHI ,  ISOGI KOUICHI ,  NODA HIROSHI

IPC: G01B9/02 ,  G01B11/14 ,  G01D1/02 ,  G11B21/21

Abstract: PURPOSE:To provide a floating amount measuring apparatus for head which exhibits high sensitivity through simple structure. CONSTITUTION:Light projected from a white light source 25 is introduced into a gap between a disc 23 and a head 21 where multiple reflection takes place. Light reflected on an opaque body, out of the disc 23 and the head 21, is polarized into at least three wavelength regions and introduced to different optical detecting means 35, 36, 37. An estimating unit 38 estimates floating amount of head from an output of the optical detecting means according to the method of least squares based on a function between disc head gap lengths predetermined for respective wavelength regions and the intensity of reflected light detected through the optical detecting means. Calculation is carried out in real time according to table lookup system or follow-up control system.

公开(公告)号：JPH06138906A

公开(公告)日：1994-05-20

申请号：JP26763292

申请日：1992-10-06

Applicant: IBM

Inventor： ISOGI KOUICHI ,  ONO HIROYUKI

IPC: G05B13/02 ,  G05B11/42 ,  G05B13/04 ,  G05B17/02 ,  G05D3/12

Abstract: PURPOSE: To prevent the number of bits required for calculation (a dynamic range) from being affected by the level of a target value. CONSTITUTION: The state parameter of a controlled system 30 is inputted to an inverse system 34 having characteristics inverse to an internal model 32, and the output of the inverse system 34 is inputted to the internal model 32. When the state parameter of the controlled system 30 can not be directly observed, a state estimator 40 is used. In such a case, the inverse system 34 receives the input / output of the controlled system 30 and supplies that output to the state estimator 40. In place of inputting the input of the controlled system 30 to the inverse system 34, the input of the internal model 32 can be inputted to the state estimator 40 as well.

公开(公告)号：JPH0765331A

公开(公告)日：1995-03-10

申请号：JP20530893

申请日：1993-08-19

Applicant: IBM

Inventor： FUKUZAWA TADASHI ,  KUNO TEIJI ,  MORITA TETSUHARU ,  ISOGI KOUICHI

IPC: G11B5/455 ,  G01B11/14 ,  G11B5/60 ,  G11B21/21 ,  G11B33/10

Abstract: PURPOSE: To promptly and accurately measure a floating height of a head by optimizing necessary coefficients of a theoretical formula based on a nonlinear regression algorithm when an interference optical intensity corresponding to the floating height of the head is measured by using a white lamp and a color CCD camera. CONSTITUTION: By using a white lamp, a color CCD camera calculates R, G, and B output vectors (y) corresponding to a floating height of a magnetic head by using mathematical models such as a polynomial coefficient vector (b) showing a slider profile, a floating height vector H, a function f (p, x), etc., and outputs them. In this case, a signal processing part operates similar arithmetic operations based on assumed refraction indices of each color and pseudo-vectors (b) according to the extinction coefficients, and a vector (p) of the function (f) is not adopted as a fixed value but is optimized by a processing of a method of least square according to a nonlinear regression algorithm so that a difference vector e between each output vector as the result of the arithmetic operation and the vector (y) becomes a minimum, and thus, it becomes possible to measure the floating height of the floating head quickly and precisely.