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:
Dec. 30, 1997
Filed:
May. 22, 1996
Tien D Doan, Peoria, IL (US);
Caterpillar Inc., Peoria, IL (US);
Abstract
A method and apparatus for controlling the oscillatory motion of a test device by using amplitude and DC offset feedback for control purposes. The force applied to the test device is monitored by a load sensor and compared to a preset desired amplitude load setpoint to determine the positive peak amplitude of a sinusoidal control signal. The DC offset feedback is monitored by sampling the value of a displacement feedback signal a number of times for each cycle of movement. The values of the samples are averaged to determine a calculated DC offset. The calculated DC offset is compared to a desired DC offset, which is determined from a preset desired displacement setpoint. The difference between the calculated DC offset and the desired DC offset is then used to control the load applied to the test device to maintain the desired oscillatory movement.