Showing papers on "Inductive sensor published in 1971"

Accelerometer for measuring angular accelerations

Abstract: An angular accelerometer comprises a rotor rotatably supported in a stator by air bearings. An inductive sensor is mounted on the stator and arranged to detect displacement of the rotor from a datum relative to the stator. A torquer, comprising two coils connected in a circuit so that the currents through the coils can be varied differentially, is also mounted on the stator. The sensor and torquer are disposed transversely of a cooperating ferromagnetic bar which extends transversely on the rotor. The sensor includes two coils and has an associated source of oscillating flux so arranged that the reluctance between the source and the two coils is varied differentially when the rotor is displaced. The sensor coils are connected through a differential amplifier and a phase-sensitive detector to the torquer. The current in the torquer coils is varied differentially in response to variations of the signal from the phase-sensitive detector to produce a torque on the rotor proportional to the angular acceleration of the stator to maintain the rotor substantially in its datum position. An output provides a signal proportional to the torque to indicate the angular acceleration. The spacing between the torquer and the ferromagnetic bar is much greater than the spacing between the sensor and the bar so that there is substantially no change of reluctance between the torquer coils and the bar on a change of angular acceleration of the stator.