Thermal gradient compensator for fluid rotor gyroscopic apparatus
AssigneeSperry Corporation
InventorWillis G. Wing
Life of this patent
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Abstract
A fluid sphere gyroscope is used as the north-seeking sensing element in a gyrocompass. A sensor responsive to angular deviation of the gyroscope from the horizontal provides a tilt signal which is used to energize heating elements located along the independent spin axis of a rotating fluid mass. Application of a thermal gradient along the spin axis of the fluid mass causes a controlled precession of the gyroscope, thereby compensating for bias and acceleration sensitive drift errors and precessing the gyroscope about a vertical axis in a controlled manner. Rotary transformers permit inductive coupling of the heating elements to the tilt signal and to a power source with minimal disturbing torques.
Claims17
In a gyroscopic apparatus comprising a housing, a fluid mass, means for containing said fluid mass within said housing, drive means for spinning said containing means about an axis thereof, thereby also spinning said fluid mass about a fluid axis, and means communicating with said fluid mass for detecting an angular difference between said spin axis of said fluid and said spin axis of said containing means, the improvement comprising:
- means for providing a tilt signal representative of an angular difference between said spin axis of said containing means and an essentially horizontal axis;
- and
- means responsive to said tilt signal for heating said fluid mass to provide a predetermined thermal gradient along said fluid spin axis.
A gyrocompass comprising:
- a mechanical suspension including a support rotatable about an approximately vertical compass axis;
- a gyroscope pivoted on said support for rotation about an approximately horizontal tilt axis;
- a motor driven fluid gyroscopic mass contained within said gyroscope for rotation about a spin axis perpendicular to said approximately horizontal tilt axis;
- and
- a torque precession system including drive means about said approximately vertical axis and said approximately horizontal tilt axis;
- wherein said torque precession system further comprises means responsive to an inclination of said gyroscope about said tilt axis for heating said fluid mass to a predetermined thermal gradient along said spin axis and for inducing a corrective precession about said approximately vertical compass axis.
A method for reducing operating errors in a gyrocompass having a fluid sphere gyroscope with an approximately horizontal spin axis, comprising:
- sensing the precession rate of said gyroscope about said approximately horizontal tilt axis;
- sensing the precession rate of said gyroscope about an approximately vertical azimuth axis;
- sensing the angular deviation of said gyroscope from the horizontal;
- introducing a torque about said tilt axis responsive to said precession rate about said approximately vertical azimuth axis in a direction so as to reduce said precession rate;
- introducing a torque about said azimuth axis responsive to said precession rate about said tilt axis so as to reduce said precession rate, also responsive to said angular deviation, and
- compensating for a precession of said gyroscope about any acceleration normal to said spin axis by introducing a thermal mass unbalance in said fluid along said spin axis, responsive to said angular deviation, so as to cause precession about said approximately vertical axis until said deviation is substantially reduced to zero.
Dependencies are inferred from the claim text.