Free rotor gas-bearing gyroscope having electro-magnetic rotor restraint and acceleration output signal and method of operating a gyroscope

摘要

A two degree-of-freedom, free-rotor, gas-bearing gyroscope having greatly reduced sensitivity to acceleration-induced and other disturbances. An electromagnetic forcer (42) acts on the rotor (22) to keep the axial component of bearing deflection negligible. Closed-loop control circuitry for energizing the axial forcer responds to a linear displacement signal. The circuitry also provides an output signal proportional to the component of acceleration along the spin axis. This signal may be used to replace an accelerometer output signal in navigation equipment. In addition to being functional during normal operation, the control functions during start-up and shut-down to center the rotor over the support ball (16). The functions of forcer and torquer are combined in a single structure. A dual motor arrangement (32, 34, 36, 38, 40) and a dual forcer-torquer arrangement provide cancellation of bias variations due to housing, shaft, and bearing deflections. The ball support shaft (18) has larger diameter and the gas fill pressure is lower than would be feasible in the absence of the electromagnetic axial forcing.