Caterpillar Inc.

Eric F Lee

John W Crayton

Denny E Morgan

Dennis L Schumacher

Kenneth Lee Stratton

Karl W Kleimenhagen

Howard J Chizeck

Gangadhar Jayaraman

The present invention is directed toward estimating certain operating parameters of an earth moving machine. Advantageously, the present invention utilizes a Kalman filter to estimate the pitch, pitch rate and ground speed of the earth moving machine as a function of the sensed pitch and ground speed signals. By estimating the pitch and ground speed, the present invention overcomes the prior problems of sensing signal noise and bias. The present invention overcomes these problems by combining pitch, pitch rate and ground speed, and determining an estimate of pitch and ground speed by using a sensor measurement model, machine process model and Kalman filter update equations.

Method and apparatus for determining pitch and ground speed of an earth

A piston position sensing system in which tabulated resonance width related information is stored in a form correlated with piston travel so that measured resonance width information can be compared with the stored information in determining piston position and compensation for the velocity of the piston is provided by correction for a time difference in serial sensing between the initial and the following extremes of a resonance signal as the piston moves. the compensation is developed from velocity information identified through previous and current processing cycles which assures reliability in detection of the subsequently sensed portion of the resonance signal envelope and enhanced sensitivity and accuracy through automatic application incrementally in a dynamic gain adjustment of the sensing system.

Hydraulic cylinder piston position sensing with compensation for piston

Dynamic gain adjustment in hydraulic piston position sensing that continuously accommodates for changes in signal level is provided by attenuating the gain of the sensing system through a comparison of a measured value with a stored value at each piston position.

Dynamic gain adjustment in electromagnetic wave hydraulic cylinder

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Peoria Heights, IL, United States of America

Eric F Lee