Methods and systems for calibrating an engine having a rotating shaft are provided. Readings from a plurality of speed sensors provided in one of a plurality of configurations about the shaft are obtained over a plurality of rotations of the shaft, the readings indicative of the passage of position markers and associated with a first precision level. A parameter indicative of relative spacing between the plurality of speed sensors is determined by applying a statistical algorithm to the readings, the parameter being associated with a second precision level higher than the first precision level. The parameter is compared to reference parameters associated with the plurality of configurations to identify an actual speed sensor configuration from amongst the plurality of configurations. The engine is calibrated based on the actual speed sensor configuration.

A system of a machine includes a waveguide system and a radio frequency transceiver/detector coupled to the waveguide system and configured to emit a calibration signal in the waveguide system to establish a reference baseline between the radio frequency transceiver/detector and a calibration plane associated with an aperture of the waveguide system, emit a measurement signal in the waveguide system to transmit a radio frequency signal from the radio frequency transceiver/detector out of the aperture of the waveguide system, and detect a reflection of the measurement signal at the radio frequency transceiver/detector based on an interaction between the measurement signal and a component of the machine. A measurement result of the reflection of the measurement signal can be adjusted with respect to a reflection of the calibration signal.

Disclosed is a method for calibrating at least one gap sensor, the at least one gap sensor being provided on a magnetic bearing supporting a floating body in a non-contact manner by an electromagnetic force, the at least one gap sensor being configured to detect a gap between the floating body and a reference object that serves as a positional reference for position control of the floating body. The method includes: constructing a transformation formula for transforming an output of the at least one gap sensor into the gap using three or more constraints that are set as conditions for associating the gap with the output of the at least one gap sensor.

Systems and methods for measuring a clearance between a rotating machine component and a sensor unit are disclosed. In some aspects, a system includes a sensor unit oriented to detect the rotating machine component as the rotating machine component rotates past the sensor unit, the sensor unit including at least a first sensing element and a second sensing element spaced apart from the first sensing element. The system includes a sensor processing unit in electrical communication with the sensor unit. The sensor processing unit is configured for receiving a first waveform from the first sensing element; receiving a second waveform from the second sensing element; and determining, based on a comparison between the first waveform and the second waveform, a distance between the blade tip and the sensor unit.

Methods and apparatus for real-time clearance assessment using a pressure measurement are disclosed. An example method includes determining a first and a second static pressure measurement at a first measurement location and a second measurement location, respectively, relative to the blade tip clearance, determining a normalized pressure measurement using the first and second static pressure measurements, generating a conversion curve to correlate the normalized pressure measurement with a clearance measurement, wherein the conversion curve is developed for the turbine engine during testing at a plurality of operating conditions, and adjusting active clearance control of the blade tip clearance based on the conversion curve.

A method for calibrating a position sensor of a variable vane assembly for a gas turbine engine includes positioning an actuator member in at least one predetermined position, determining a first measured position of the actuator member in the at least one predetermined position with a first channel of a position sensor, determining a second measured position of the actuator member in the at least one predetermined position with a second channel of a position sensor, determining a measured position difference between the first measured position and the second measured position, and calibrating the second channel of the position sensor by adjusting the second measured position by the measured position difference to determine a second calibrated position.

Based upon a measured first resistance, a first delta curve is selected. Based upon a measured second resistance, a second delta curve is selected. A first fuel valve position (FVP) is received from a first position sensor, and the first FVP is applied to the first delta curve to obtain a first offset. A second FVP is received from a second position sensor, and the second FVP is applied to second delta curve to obtain a second offset. The first offset is applied to the first measured FVP to obtain the first compensated FVP and the second offset is applied to the second measured FVP to obtain the second compensated FVP. The first compensated FVP and the second compensated FVP are correlated to obtain a final compensated FVP, which is applied to a desired fuel valve position,

Methods and apparatus for real-time clearance assessment using a pressure measurement are disclosed. An example method includes determining a first and a second static pressure measurement at a first measurement location and a second measurement location, respectively, relative to the blade tip clearance, determining a normalized pressure measurement using the first and second static pressure measurements, generating a conversion curve to correlate the normalized pressure measurement with a clearance measurement, wherein the conversion curve is developed for the turbine engine during testing at a plurality of operating conditions, and adjusting active clearance control of the blade tip clearance based on the conversion curve.

Methods and apparatus for real-time clearance assessment using a pressure measurement are disclosed. An example method includes determining a first and a second static pressure measurement at a first measurement location and a second measurement location, respectively, relative to the blade tip clearance, determining a normalized pressure measurement using the first and second static pressure measurements, generating a conversion curve to correlate the normalized pressure measurement with a clearance measurement, and adjusting active clearance control of the blade tip clearance based on a comparison of real-time in-flight pressure measurements to the conversion curve.

Methods and apparatus for real-time clearance assessment using a pressure measurement are disclosed. An example method includes determining a first and a second static pressure measurement at a first measurement location and a second measurement location, respectively, relative to the blade tip clearance, determining a normalized pressure measurement using the first and second static pressure measurements, generating a conversion curve to correlate the normalized pressure measurement with a clearance measurement, and adjusting active clearance control of the blade tip clearance based on a comparison of real-time in-flight pressure measurements to the conversion curve.