Method for measuring a rotational angular velocity and/or an angular position

A method for measuring an angular velocity of a rotation and/or an angular position, about a sensitive axis of an axisymmetric vibratory gyroscope sensor (1), comprising the implementation, by means (11) for processing data from the axisymmetric vibratory gyroscope sensor (1), of steps of:

• (a) receiving, from an electromechanical coupling instrument (31) of a resonator (3) of the axisymmetric vibratory gyroscope sensor (1), a first detection signal regarding a vibration of said resonator (3) according to a primary resonance mode, and a second detection signal regarding a vibration of said resonator (3) according to a secondary resonance mode;
• each of the first and the second detection signal comprising an in-phase component and a phase-quadrature component;
• said resonator (3) being vibrated via said electromechanical coupling instrument (31) according to a first signal for exciting the primary resonance mode and a second signal for exciting the secondary resonance mode;
• (b) implementing at least four control loops, including:
• a first loop for controlling the vibration amplitude of the resonator (3) about the primary resonance mode axis, using a first regulator (R1);
• a second phase-locked loop generating in-phase and phase-quadrature reference harmonic signals of the primary mode and/or secondary mode, for separating said in-phase and phase-quadrature components of the detection signals, using a second regulator (R2);
• a third loop for compensating for the Coriolis forces which are due to said rotation of the resonator (3) and which excites a resonance mode perpendicular to the vibration, using a third regulator (R3);
• a fourth loop for controlling the quadrature of said resonance mode perpendicular to the resonator vibration, using a fourth regulator (R4);
• (c) estimating said angular velocity and/or said angular position, as a function of the regulator outputs;
• characterized in that the vibration is constrained by the first and second excitation signals to have an azimuthal angle θ in the orthogonal modal base of the primary and secondary modes, the first regulator (R1) is configured to minimize the difference between the in-phase component of the first detection signal and the product of a first coefficient C1 that is a function of the azimuthal angle θ and a setpoint vibration amplitude of the resonator (3), and the third regulator (R3) is configured to minimize the difference between the in-phase component of the second detection signal and the product of a second coefficient C2 that is a function of the azimuthal angle θ and said setpoint vibration amplitude of the resonator (3), the first loop being also a Coriolis force compensation loop and the third loop being also a loop for controlling the vibration amplitude of the resonator (3) about the secondary resonance mode axis, said method comprising a step of selecting an operating mode among at least
• one Whole Angle, WA, mode, in which a fifth control loop for controlling said azimuthal angle θ is implemented, said fifth control loop being included in said step (b) and providing a command adjusting the setpoints of the regulators (R1, R3) of the first and third loops, using a fifth regulator (R5) and
• one all-attitude Force-To-Rebalance, AA FTR, mode, in which said azimuthal angle θ has a value selected manually, whereas the fifth control loop is not implemented.

An axisymmetric vibratory gyroscope sensor (1) for measuring an angular velocity or a rotation about a sensitive axis, comprising:

• a resonator (3) having an electromechanical coupling instrument (31) for vibrating said resonator according to a first excitation signal coming from a primary resonance mode and a second excitation signal coming from a secondary resonance mode;
• and
• a data processing means (11) configured to:
• receive, from the electromechanical coupling instrument (31), a first detection signal regarding a vibration of said resonator (3) according to the primary resonance mode, and a second detection signal regarding a vibration of said resonator (3) according to the secondary resonance mode;
• each of the first and the second detection signal comprising an in-phase component and a phase-quadrature component;
• implement at least four control loops, including:
• a first loop for controlling the vibration amplitude of the resonator (3) about the primary resonance mode axis, using a first regulator (R1);
• a second phase-locked loop generating in-phase and phase-quadrature reference harmonic signals of the primary mode and/or secondary mode, for separating said in-phase and phase-quadrature components of the detection signals, using a second regulator (R2);
• a third loop for compensating for the Coriolis forces which are due to said rotation of the resonator (3) and which excite a resonance mode perpendicular to the vibration, using a third regulator (R3);
• a fourth loop for controlling the quadrature of said resonance mode perpendicular to the resonator vibration, using a fourth regulator (R4);
• estimate said angular velocity and/or the angular position as a function of the regulator outputs;
• characterized in that the vibration is constrained by the first and second excitation signals to have an azimuthal angle θ in the orthogonal modal base of the primary and secondary modes, the first regulator (R1) is configured to minimize the difference between the in-phase component of the first detection signal and the product of a first coefficient C1 that is a function of the azimuthal angle θ and a setpoint vibration amplitude of the resonator (3), and the third regulator (R3) is configured to minimize the difference between the in-phase component of the second detection signal and the product of a second coefficient C2 that is a function of the azimuthal angle θ and said setpoint vibration amplitude of the resonator (3), the first loop being also a Coriolis force compensation loop and the third loop being also a loop for controlling the vibration amplitude of the resonator (3) about the secondary resonance mode axis.