Hydraulic cylinder piston position sensing with compensation for piston velocity

Reference Number: N 01-03

Inventors: Crayton, John W.; Lee, Eric F.; Morgan, Denny; Schumacher, Dennis L.

Owner: NISTAC

USPTO Link: 5710514

Invention Summary

A piston position sensing system where tabulated resonance signal width parameter related information is stored in a form correlated with piston travel so that measured resonance signal width information as the piston travels can be compared with the stored information for determining piston position; and, compensation is provided for the effect of piston velocity in a hydraulic cylinder electromagnetic wave piston position sensing system, that employs identification of a width parameter of a resonance signal such as positive and negative slope intercepts of a resonance signal with respect to a reference level. The compensation is achieved by calculating velocity and then using the calculated velocity value to correct the position of the initial intercept of the resonance signal with a reference level.

The correction assures reliability in detection of the subsequently sensed slope of the resonance signal and enhanced sensitivity and accuracy through automatic application incrementally in a dynamic gain adjustment.