Feedback mechanism for rate gyroscopes

A mechanical rate gyroscope, comprising:

• a mechanical sensor including a base, a mass, a first segmented drive system configured to cause the mass to vibrate relative to the base, a displacement sensor configured to measure deflection of the mass caused by a Coriolis force generated in response to an applied angular rate, and a transverse segmented drive system configured to generate a feedback force to cancel the Coriolis force;
• and
• control circuitry configured to receive the measure of deflection and provide at least one feedback signal based on the measure of deflection to the transverse drive system for generating the feedback force,
• wherein the first drive system includes a plurality of segments operatively coupled to the mass and the transverse drive system includes at least one segment operatively coupled to the mass,
• wherein the control circuitry is configured to receive at least one sense signal provided by the displacement sensor and having a magnitude proportional to a magnitude of deflection, and to generate an error signal representative of a time average of a difference between the Coriolis force and the feedback force using the sense signal, and
• wherein the error signal comprises a pulse repetition frequency proportional to the applied angular rate.

A mechanical rate gyroscope, comprising:

• a mechanical sensor including a base, a mass, a first segmented drive system configured to cause the mass to vibrate relative to the base, a displacement sensor configured to measure deflection of the mass caused by a Coriolis force generated in response to an applied angular rate, and a transverse segmented drive system configured to generate a feedback force to cancel the Coriolis force;
• and
• control circuitry configured to receive the measure of deflection and provide at least one feedback signal based on the measure of deflection to the transverse drive system for generating the feedback force,
• wherein the first drive system includes a plurality of segments operatively coupled to the mass and the transverse drive system includes at least one segment operatively coupled to the mass,
• wherein the at least one feedback signal comprises at least one cycle of a drive signal provided to the first drive system for causing the mass to vibrate relative to the base.

A mechanical sensor, comprising:

• a base;
• a mass;
• a suspension system configured to couple the mass to the base;
• a first segmented drive system including a first number Nd of segments operatively coupled to the mass, the first drive system being configured to generate a drive force Fd to cause the mass to vibrate relative to the base;
• a displacement sensor configured to measure a deflection of the mass caused by a Coriolis force;
• and
• a transverse segmented drive system including a second number Nf of segments operatively coupled to the mass, the segments of the transverse drive system being substantially similar to and transversely oriented relative to the segments of the first drive system, the transverse drive system being configured to generate a feedback force Ff to cancel the deflection of the mass,
• wherein the segments of the first drive system and the segments of the transverse drive system are arranged to cause fringe fields associated with the respective drive systems to substantially match, and
• wherein Fd/Ff is proportional to Nd/Nf.

A method of operating a mechanical rate gyroscope including a mechanical sensor and control circuitry, the mechanical sensor having a base, a mass, a first drive system, a displacement sensor, and a transverse drive system, the method comprising the steps of:

• generating a drive force Fd to cause the mass to vibrate relative to the base by the first drive system, the first drive system having a first number Nd of segments operatively coupled to the mass;
• measuring a deflection of the mass caused by a Coriolis force generated in response to an applied angular rate by the displacement sensor;
• generating a feedback force Ff to cancel the Coriolis force by the transverse drive system, the transverse drive system having a second number Nf of segments operatively coupled to the mass, the segments of the transverse drive system being substantially similar to and transversely oriented relative to the segments of the first drive system, the segments of the first drive system and the segments of the transverse drive system being arranged to cause fringe fields associated with the respective drive systems to substantially match, and Fd/Ff being proportional to Nd/Nf;
• and
• receiving the measure of deflection and providing at least one feedback signal based on the measure of deflection to the transverse drive system for generating the feedback force Ff by the control circuitry.