Self calibrating linear position sensor
AssigneeInternational Business Machines Corporation
InventorMichael Philip Goldowsky
Life of this patent
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Abstract
A rotor is disposed coaxially in a tubular housing and spaced therefrom to define a gap for receiving a fluid. An ultrasonic transducer is mounted at one end of the housing in alignment with a target at a corresponding end of the rotor. Ultrasonic pulses are bounced off the target for measuring linear position thereof based on the speed of sound in the fluid and round trip pulse time between the transducer and target. The speed of sound in the fluid between the transducer and target is self-calibrated.
Claims23
An apparatus comprising:
- a tubular housing;
- a rotor disposed coaxially in said housing and spaced radially inwardly therefrom to define a gap therebetween for receiving a fluid, and including a target at one end thereof;
- an ultrasonic transducer mounted at a first end of said housing in alignment with said target for bouncing ultrasonic pulses thereoff for measuring linear position thereof based on the speed of sound in said fluid and the round trip pulse time between said transducer and target;
- and
- means for calibrating said speed of sound in said fluid from a predetermined calibration dimension between said transducer and target.
A method of measuring linear position of a rotor disposed inside a housing in a fluid comprising:
- bouncing from said housing ultrasonic pulses off a target at a first end of said rotor and through said fluid for measuring linear position of said target in said housing based on the product of speed of sound in said fluid and round trip times of said bounced pulses along a pulse path between said housing and target;
- and
- calibrating said speed of sound in said fluid from a predetermined calibration dimension along said pulse path.
Dependencies are inferred from the claim text.