Robust six degree-of-freedom micromachined gyroscope with anti-phase drive scheme and method of operation of the same

An anti-phase six degree-of-freedom tuning fork gyroscope system comprising:

• a first three degree-of-freedom gyroscope subsystem;
• and
• a second three degree-of-freedom gyroscope subsystem,
• where the first and second gyroscope subsystems each comprise two proof masses mechanically coupled together and mechanically restrained in each gyroscope subsystem to form a two degree-of-freedom sense mode oscillator in each gyroscope subsystem, and each of the two proof masses mechanically restrained in the first and second gyroscope subsystems to function as a one degree-of-freedom drive mode oscillator so that the four proof masses function overall as a two degree-of-freedom drive mode oscillator having two primary resonance modes, namely an in-phase and anti-phase mode;
• drive means for driving the two degree-of-freedom drive mode oscillator in the anti-phase mode at an anti-phase resonant frequency, and
• where each of the two degree-of-freedom sense mode oscillators is characterized by a flat frequency response range and where the anti-phase resonant frequency is within the flat frequency response ranges of the sense mode oscillators where response gain and phase are stable.

A method of operating a gyroscope with six degrees of freedom comprising:

• driving a 1-DOF drive oscillator in each of a first and second three degree-of-freedom (3-DOF) gyroscope systems, which 1-DOF drive oscillators in the first and second 3-DOF systems are coupled with each other to collectively function as a 2-DOF coupled system and to provide a common anti-phase drive-mode resonant frequency at which the first and second 3-DOF subsystems oscillate in opposite directions to substantially reject common-mode stimuli,
• sensing a rate of angular rotation by means of a 2-DOF sense oscillator in each of a first and second three degree-of-freedom (3-DOF) gyroscope systems, each 2-DOF sense oscillator providing a flat range in its frequency response where the response gain and phase are stable to provide robustness to imperfections and environmental influences, and to provide matching of sense-mode amplitude and phase of the first and second 3-DOF subsystems;
• and
• decoupling the 1-DOF drive oscillator and the 2-DOF sense oscillator from each other and from a substrate in each of the first and second three degree-of-freedom (3-DOF) gyroscope systems.

A method of operating an anti-phase six degree-of-freedom tuning fork gyroscope system comprising:

• driving a first three degree-of-freedom gyroscope subsystem;
• and
• driving a second three degree-of-freedom gyroscope subsystem in an anti-phase mode with the first three degree-of-freedom gyroscope subsystem at an anti-phase resonant frequency;
• and
• sensing motion by means of the first and second three degree-of-freedom gyroscope subsystems in a flat frequency response range where the anti-phase resonant frequency is within the flat frequency response ranges where response gain and phase are stable.