A drive system of a gas turbine engine includes a first drive shaft and a second drive shaft operable to rotate within the gas turbine engine, a first sensor operable to detect rotation of the first drive shaft, a second sensor operable to detect rotation of the second drive shaft, and a processing system coupled to the first sensor and the second sensor. The processing system is operable to determine a timing variation based on output of the first sensor and output of the second sensor, determine a torsional deflection between the first drive shaft and the second drive shaft based on the timing variation, and detect a health status of the drive system based on the torsional deflection.

A drive system of a gas turbine engine includes a first drive shaft and a second drive shaft operable to rotate within the gas turbine engine, a first sensor operable to detect rotation of the first drive shaft, a second sensor operable to detect rotation of the second drive shaft, and a processing system coupled to the first sensor and the second sensor. The processing system is operable to determine a timing variation based on output of the first sensor and output of the second sensor, determine a torsional deflection between the first drive shaft and the second drive shaft based on the timing variation, and detect a health status of the drive system based on the torsional deflection.

A method includes receiving data characterizing time-dependent lateral vibration of a shaft of a machine, the lateral vibration indicative of motion of at least a portion of the shaft perpendicular to a first direction. The lateral vibration is detected by a first sensor located at a first predetermined location on the shaft. The method further includes, receiving data characterizing time-dependent torsional vibration of the shaft, the torsional vibration indicative of rotation of the shaft around the first direction. The torsional vibration is detected by a second sensor located at a second predetermined location on the shaft. The method also includes calculating a coherence of the data characterizing time-dependent lateral vibration and the data characterizing time-dependent torsional vibration. The method further includes identifying, based on the coherence, a first frequency value in the frequency domain indicative of coupling between the time-dependent lateral vibration and the time-dependent torsional vibration.

A hardened inductive device and systems and methods for protecting the inductive device from impact is provided. The inductive device is hardened with protective coating and/or an armor steel housing. The hardened inductive device is protected from impact by an object such as a bullet and leakage of dielectric fluid is prevented. Acoustic and vibration sensors are provided to detect the presence and impact, respectively, of an object in relation to the inductive device housing. The measurements of the acoustic and vibration sensors are compared to thresholds for sending alarms to the network control center and initiating shut-down and other sequences to protect the active part. The acoustic sensor results are utilized to determine the location of origin of the projectile.

A hardened inductive device and systems and methods for protecting the inductive device from impact is provided. The inductive device is hardened with protective coating and/or an armor steel housing. The hardened inductive device is protected from impact by an object such as a bullet and leakage of dielectric fluid is prevented. Acoustic and vibration sensors are provided to detect the presence and impact, respectively, of an object in relation to the inductive device housing. The measurements of the acoustic and vibration sensors are compared to thresholds for sending alarms to the network control center and initiating shut-down and other sequences to protect the active part. The acoustic sensor results are utilized to determine the location of origin of the projectile.

The present invention relates to a method for estimating a speed (v) of movement of a wheeled vehicle, wherein a frequency trajectory (?.sub.t) representative of the speed (v) of a wheel (RO) of the vehicle (VE) in a filtered spectrogram (S(f.sub.t, t)) is estimated (E5) as follows: a probability (p.sub.Zt|?t) of observation of the trajectory (ft) is estimated (E51) on the basis of a computed amplitude of the filtered spectrogram (S(f.sub.t, t)), an a posteriori observation law (p.sub.Zt|?t) proportional to the product of the probability (p.sub.?) and of the probability (p.sub.?|Z) is estimated (E52), the trajectory (ft) is estimated (E53) on the basis of the law (p.sub.?|Z), and the speed (v) of movement of the wheel of the vehicle is estimated (E6) on the basis of the trajectory (?.sub.t).

The present invention relates to a method for estimating a speed (v) of movement of a wheeled vehicle, wherein a frequency trajectory (?.sub.t) representative of the speed (v) of a wheel (RO) of the vehicle (VE) in a filtered spectrogram (S(f.sub.t, t)) is estimated (E5) as follows: a probability (p.sub.Zt|?t) of observation of the trajectory (ft) is estimated (E51) on the basis of a computed amplitude of the filtered spectrogram (S(f.sub.t, t)), an a posteriori observation law (p.sub.Zt|?t) proportional to the product of the probability (p.sub.?) and of the probability (p.sub.?|Z) is estimated (E52), the trajectory (ft) is estimated (E53) on the basis of the law (p.sub.?|Z), and the speed (v) of movement of the wheel of the vehicle is estimated (E6) on the basis of the trajectory (?.sub.t).

Embodiments of the invention relate to a thrust stand and a method of measuring thrust. Embodiments of the invention pertain to a method of calibrating a thrust stand. Embodiments of the subject thrust stand can incorporate a passive eddy current based damper. Specific embodiments of the passive eddy current based damper can function without contact with the balance arm. Further specific embodiments of the passive eddy current based damper can be used in a vacuum. Embodiments can utilize signal analysis techniques to identify and reduce noise. A logarithmic decrement method can be used to calibrate the thrust stand. Force measurements can be made with embodiments of the subject thrust stand for a standard macroscale dielectric barrier discharge (DBD) plasma actuator and/or other thrust producing devices.

Embodiments of the invention relate to a thrust stand and a method of measuring thrust. Embodiments of the invention pertain to a method of calibrating a thrust stand. Embodiments of the subject thrust stand can incorporate a passive eddy current based damper. Specific embodiments of the passive eddy current based damper can function without contact with the balance arm. Further specific embodiments of the passive eddy current based damper can be used in a vacuum. Embodiments can utilize signal analysis techniques to identify and reduce noise. A logarithmic decrement method can be used to calibrate the thrust stand. Force measurements can be made with embodiments of the subject thrust stand for a standard macroscale dielectric barrier discharge (DBD) plasma actuator and/or other thrust producing devices.

An abnormality detection device includes a vibration measurement value acquisition unit configured to acquire a measurement value of vibration of a rotation shaft, which is measured by each of shaft vibration sensors provided to be spaced apart in a diameter direction of the rotation shaft with respect to an outer circumferential surface of the rotation shaft at positions spaced apart in a shaft direction of the rotation shaft, for each rotation angle of the rotation shaft, a vibration vector calculation unit configured to calculate a vibration vector indicating a rotation angle at which a vibration of the rotation shaft is a maximum and a magnitude of the vibration on the basis of the measurement value of the vibration, and an estimation unit configured to estimate an abnormality occurrence position in the shaft direction of the rotation shaft on the basis of a time change in the vibration vector.