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:
Jul. 17, 1990
Filed:
May. 16, 1988
Thomas E Hainsworth, Holland, MI (US);
F Nicholaas Spanhak, Jennison, MI (US);
Richard R Paske, Jr, Holland, MI (US);
Bell & Howell Company, Skokie, IL (US);
Abstract
A self-adapting signal detector is adapted to be used with a plurality of guidepath sensors for controlling an automatically guided vehicle. The circuitry detects the presence of a valid guidepath signal over a large dynamic range without the need to make threshold or gain adjustments. A background noise signal is detected as well as a signal from each of the guidepath sensors. The background noise signal is substracted from each sensor signal to define a plurality of difference signals. A maximum remainder signal is defined as the maximum difference signal. Each difference signal is then compared with a predetermined percentage of the maximum remainder signal. Those sensors whose signal level exceeds the predetermined percentage of the maximum remainder signal by a predetermined amount are defined to be a valid guide path signal. The maximum remainder signal is also compared with a predetermined percentage of the background noise signal to determine the signal-to-noise ratio. If the signal-to-noise ratio signal falls below a predetermined value, a signal is provided to stop the vehicle. In an alternate embodiment, the lesser of a predetermined percentage of the maximum remainder signal and a predetermined percentage of the background level is selected to define a reference signal. Those sensors whose signals exceeds the reference signal are defined to be a valid guidepath signal.