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. 09, 1999
Filed:
Jan. 23, 1997
Hiroaki Takeuchi, Tenri, JP;
Tohru Okuda, Nara, JP;
Sharp Kabushiki Kaisha, Osaka, JP;
Abstract
An actuator moves a signal reproducing element based on an applied control input. An error detector detects a difference in relative position between a desired track and the signal reproducing element. A drive circuit computes the input valuable applied to the actuator based on an output from the error detector and applies it to an adder. On the other hand, the actuator simulation circuit for electrically simulating the characteristics of the actuator estimates the position of the actuator from the control input. Furthermore, a target follow-up estimator estimates a track bend based on outputs from the actuator simulation circuit and the error detector and are fed forward to the adder via a feedforward gain. The Adder applies the computed control input to the actuator. As a result, a control system which offers an improved precision over a wide band can be achieved while maintaining the stability.