The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 29, 1994
Filed:
Sep. 23, 1991
Richard J Hellinga, Sagamihara, JP;
Masakazu Nakazato, Sagamihara, JP;
Yoichi Shimoura, Sagamihara, JP;
Hideki Yamagata, Sagamihara, JP;
Kayaba Kogyo Kabushiki Kaisha, Tokyo, JP;
Abstract
A magnetic scale formed by arranging a non-magnetic material at a predetermined pitch in the direction of motion of a piston rod, and a pair of magnetic sensors which output two sine waves with a phase difference of 90.degree. corresponding to the pitch of said magnetic scale, are provided. The peak voltages of the sensor output at each pitch of the magnetic scale are updated and stored. Center voltages are computed from the peak voltages at each pitch, and a coarse displacement is computed based on the result of comparing the center voltages and sensor outputs. Correction coefficients of the sensor outputs are computed from the peak voltages and center voltages, and the sensor outputs are compensated based on these correction coefficients. A fine displacement is then computed by an inverse trigonometric function from the two corrected signals, and a displacement signal is output by adding the coarse displacement to the fine displacement.