Research On Digital Closed-loop Driving Circuit Of Electromagnetic Driven Micro-machined Gyroscope

Micro-machined gyroscope is a new type of inertial sensor with the development of microelectromechanical system,which has many advantages,such as low cost,small size,low power consumption,high resistance to overload,integration and so on.It has been widely used in the fields of aerospace,industrial control,automotive applications and consumer electronics.When the mechanical structure of the micro-machined gyroscope is designed,the control and signal processing circuit is critical to achieve the performance of the gyroscope.Because the digital circuit has the advantages of anti-interference,programmability,easy to design and integration,we used digital signal processing circuit in the control of micro-machined gyroscope.In this paper,we focuses on the digital closed-loop driving circuit of micromachined gyroscope.The main research contents are as follows:（1）Firstly,we introduce the basic working principle of micro-machined gyroscope,and deduce the expressions of amplitude and phase of driving mode according to the dynamic model of micro-machined gyroscope.After that,the mechanical structure and electromagnetic driving principle of the electromagnetic driven micro-machined gyroscope are introduced,and the resonant frequency and Q value of the driving mode of the micro-machined gyroscope are tested,which lays a foundation for the design of the follow-up driving closed-loop circuit.（2）We introduce the components of phase-locked loop and automatic gain control circuits,and their mathematical model and working principle in detail.We also build the frequency control based on phase-locked loop and the amplitude control based on automatic gain control,and simulate the driving mode of electromagnetic driven micro-machined gyroscope in the Simulink simulations,verifying the correctness of closed-loop control.（3）Finally,the main algorithms of drive control loop are realized based on FPGA digital platform,including CORDIC algorithm,LMS adaptive filter algorithm and so on.The function of drive loop is simulated based on digital platform.After that,the driven hardware circuit is designed and verified,in which the analog interface circuit includes the design of electromagnetic drive circuit and drive detection signal circuit,verifying the circuit using Multisim software.Finally,the digital closed-loop drive circuit is tested,and the experimental results show that the gyroscope can work in the resonant mode,and the accuracy of response amplitude jitter can reach to 387.6ppm.