Micro-electro-mechanical sensor with force feedback loop

An integrated micro-electro-mechanical gyroscope, comprising:

• a microstructure having a first mass which is free to oscillate along a first axis;
• a driving device coupled to said first mass for maintaining said first mass in oscillation at a resonance frequency;
• and
• inertial sensor means mechanically coupled to said first mass so as to be fixedly drawn by said first mass along said first axis and have an axis of detection perpendicular to said first axis, said inertial sensor means including
• a second mass movable with respect to a rest position along said
• axis of detection, and a displacement-detecting means for detecting a displacement of said second mass along said axis of detection, said displacement-detecting means having a force feedback loop supplying electrostatic forces tending to restore said second mass to said rest position in response to the displacement of said mass along said axis of detection, said force feedback loop being an analog feedback loop.

A method for determining characteristics of a rotating system, comprising the steps of:

• maintaining a first mass in oscillation at a resonance frequency along a first axis;
• coupling a second mass to the first mass via a mechanical means;
• determining feedback voltages via an analog force feedback loop, the analog force feedback loop acting on the second mass, comprising the steps of
• receiving reading currents indicative of a velocity of the second mass along a second axis,
• converting the reading currents to reading voltages, the reading voltages indicative of a displacement of the second mass relative to a rest position along the second axis, and
• filtering the reading voltages to generate the feedback voltages;
• and
• applying the feedback voltages to the second mass, the feedback voltages tending to restore the second mass to the rest position.

An integrated micro-electro-mechanical gyroscope, comprising:

• means for maintaining a first mass in oscillation at a resonance frequency along a first axis;
• means for mechanically coupling a second mass to the first mass;
• means for determining feedback voltages via an analog force feedback loop, the analog force feedback loop acting on the second mass, including
• means for receiving reading currents indicative of a velocity of the second mass along a second axis,
• means for converting the reading currents to reading voltages, the reading voltages indicative of a displacement of the second mass relative to a rest position along the second axis, and
• means for filtering the reading voltages to generate the feedback voltages;
• and
• means for applying the feedback voltages to the second mass, the feedback voltages tending to restore the second mass to the rest position.