Double Closed-loop Control Circuit of Micromachined Gyroscope

Abstract

The invention discloses a double-closed-loop control circuit of a micromechanical gyroscope and belongs to the field of guide or control devices based on a Coriolis effect. The circuit is used for closed-loop control of driving and detection modes of the micromechanical gyroscope. A simplified self-oscillation closed-loop control circuit based on automatic gain control (AGC) is employed for the driving mode of the circuit, and the frequency stability and amplitude stability of the micromechanical gyroscope in the driving mode can be effectively improved; and a six-order continuous band-pass Sigma Delta M closed-loop control circuit for the detection mode has six-order noise reshaping capacity, and the signal to noise ratio (SNR), linearity and zero-bias stability of a system detection signal can be improved. The double-closed-loop control circuit of the micromechanical gyroscope is easy to control and simple, the accuracy of a system is improved, the SNR of the system is high, and the system is self-adaptively adjusted and high in stability.

Description

technical field [0001] The invention relates to a circuit respectively used for closed-loop control of a micromechanical gyroscope drive mode and a detection mode, and belongs to the field of guidance or control devices utilizing the Coriolis effect. Background technique [0002] For micromechanical gyroscopes, the closed-loop driving mode of the driving mode can effectively improve the stability of the driving mode vibration, and the vibration frequency f x and amplitude a x Locked at a certain value; Yang Bo et al. from Southeast University proposed a decoupled closed-loop drive scheme in the paper "Research on an Improved High-precision Silicon Micro Gyroscope Closed-loop Drive Scheme", and its principle block diagram refers to figure 1 . The driving direction of micromachined gyroscope 1 outputs displacement signal x(t)=a x · sin(ω x t+φ), where ω x =2πf x ; After the pre-detector 2 outputs the voltage signal u(t), it is divided into two circuits: the amplitude cont...

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Problems solved by technology

However, this system does not consider the influence of the frequency and amplitude stability of the micro-mechanical gyroscope driving mode on the performance; at the same time, due to the parasitic capacitance generated by some processing techniques during the micro-machining process, the driving signal in the driving mode is easy to pass through the parasitic Capacitive coupling to the detection mode affects the detection of the signal; the pulse width density modulated digital signal b(t) output in the system needs to be consistent with the drive signal V d (t) Do further demodulation and filtering to get the final angular velocity signal Ω(t)

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