Surface elevation measuring apparatus
AssigneeThe United States of America as represented by the Secretary of the Navy
InventorJohn C. McKechnie
Life of this patent
Estimating the term…
Abstract
A terrain probe for sensing the elevation of a terrain surface whose prof is being measured and followed. A two-phase induction motor will raise or lower the terrain probe in response to either an increase or decrease in the elevation of the terrain surface. A four arm bridge circuit, which has an arm enclosed within the terrain probe, in combination with a low frequency oscillator, a differential amplifier, and power amplifier generate a sinusoidal drive signal which controls the two-phase induction motor.
Claims16
A surface elevation measuring apparatus comprising in combination:
- terrain probing means for sensing the elevation of a terrain surface whose profile is being measured and followed;
- oscillating means, having first and second outputs for generating a sinusoidal reference signal having a predetermined frequency;
- bridge circuit means having a quartet of arms, with one of said arms being enclosed within said terrain probing means;
- and having a first input terminal connected to the first output of said oscillating means, a second input terminal connected to the second output of said oscillating means, a first output terminal, and a second output terminal for providing a first sinusoidal signal, having a fixed amplitude, and a second sinusoidal signal, having a variable amplitude, in response to said sinusoidal reference signal generated by said oscillating means;
- amplifier means having a first input connected to the first terminal output of said bridge circuit means, a second input connected to the second terminal output of said bridge circuit means, and an output for providing a sinusoidal drive signal whose amplitude is proportional to the difference between the amplitude of the first sinusoidal signal and the amplitude of the second sinusoidal signal provided by said bridge circuit means;
- and
- servo drive motor means having an input connected to the output of said amplifier, and a shift output effectively connected to said terrain probing means for raising or lowering said terrain probing means along a vertical axis above said terrain surface in response to the sinusoidal drive signal provided by said amplifier means.
A surface contour measuring apparatus, comprising in combination:
- a terrain probe;
- an electromagnetic coil enclosed within said terrain probe, and having first and second leads protruding from said terrain probe;
- a low frequency oscillator having a first output connected to the first lead of said electromagnetic coil and a second output for generating a sinusoidal reference signal having a predetermined frequency;
- a potentiometer having a fixed resistance, and a movable arm in slidable engagement therewith, with the fixed resistance of said potentiometer having a first input terminal effectively connected to the first output of said low frequency oscillator, and a second input terminal effectively connected to the second output of said low frequency oscillator, and the movable arm of said potentiometer having an output terminal;
- a reference coil having a first lead connected to the second lead of said electromagnetic coil and a second lead connected to the second output of said low frequency oscillator;
- a differential amplifier having a first input connected to the output terminal of the movable arm of said potentiometer, a second input connected to the second lead of said electromagnetic coil, and an output;
- a power amplifier having an input connected to the output of said differential amplifier;
- and
- a servo drive motor having an input connected to the output of said power amplifier, and a shaft output effectively connected to said terrain probe.
Dependencies are inferred from the claim text.