Complete decoupling rebalance loop design of a micromachined electrostatically suspended gyroscope

A micromachined electrostatically suspended gyroscope(MESG)based on UV-LIGA microfabrication process was introduced.By close-loop control,the suspended rotor is kept in null position and through the torque rebalance loop,in which the output control voltages reflects the input angular velocity,a dual-axis input angular velocity can be measured simultaneously.First,the system model of MESG was established by dynamic analysis based on the torque analysis.Then,the rebalance loop under ideal condition is designed using modern control technique.The performance of the designed decoupling rebalance loop was compared with that of conventional proportional integral differential(PID)rebalance loop combined with the compensation loop.In order to realize the decoupling of the output voltages,a compensated decoupling matrix and its difference equation were presented and realized by a digital decoupling method employing digital signal processor(DSP).It was confirmed that the controller could realize the complete decoupling and improve the performance of the gyroscope,which includes merits of fast response speed,low overshoot and good dynamic performance,as the simulation results shown.At last,the circuit and digital realization scheme were given.

Deformation Analysis and Optimization on Hollow Spherical Rotor in Electrostactically Suspended Gyroscope

Non-spherical of rotor was described with solution method. Electrostatically suspended gyroscope＇s hollow spherical rotor＇s structure was presented. The simulative analysis of static deformation, dynamic deformation and synthesize deformation of rotor under different working conditions using the finite element software were carried out. Its deformation law and volume were obtained. The structural parameters of the rotor were optimized. The value of pressure required when the rotor was machined was calculated. The analysis has important theoretical reference value to the design for hollow spherical rotor in electrostatically suspended gyroscope.

COMBINATION OF DISTRIBUTED KALMAN FILTER AND BP NEURAL NETWORK FOR ESG BIAS MODEL IDENTIFICATION

By combining the distributed Kalman filter （DKF） with the back propagation neural network （BPNN）,a novel method is proposed to identify the bias of electrostatic suspended gyroscope （ESG）. Firstly,the data sets of multi-measurements of the same ESG in different noise environments are ＂mapped＂ into a sensor network,and DKF with embedded consensus filters is then used to preprocess the data sets. After transforming the preprocessed results into the trained input and the desired output of neural network,BPNN with the learning rate and the momentum term is further utilized to identify the ESG bias. As demonstrated in the experiment,the proposed approach is effective for the model identification of the ESG bias.

A New Fine Damping Method for Solid ESG Rotor

For the electrostatically suspended gyro （ESG） with solid rotor, because the equatorial photoelectric sensor won＇t sense the equatorial marking line and output the correct damping control information when the nutation angle is small, the active damping with equatorial marking line will bring considerable error. The passive damping method by applying strong DC magnetic field requires too much time. So an active damping method by longitude marking lines is proposed to fulfill the fine damping for solid ESG rotor. The shape of rotor marking lines and the principle of fine damping are introduced. The simulation results prove that this fine damping method can effectively solve the problem of damping error introduced by active damping with equatorial marking line. The estimating resuits for damping time indicate that the fine damping time is less than 10 percent of passive damping time.

Research on the Electrostatic Torques in the MUM-ESG

A research on the electrostatic torques in the electrostatically suspended gyroscope (ESG) that uses the mass-unbalance modulation (MUM) scheme (MUM-ESG) to sense the direction of the rotor's spinning axis is presented here. Spherical harmonic functions are used to describe the asphericity of the rotor and the electrodes. Rotational matrix theory in quantum mechanics is utilized to transform the description of the rotor's asphericity from the rotor-fixed frame into the cavity-fixed frame. And the principle of the virtual displacement is applied to find out the electrostatic torques acting on the rotor. Analytical expressions of the electrostatic torques indicate that there are only three kinds of factors need to be considered when looking for the electrostatic torques in the MUM-ESG. The factors are the asphericity of the rotor, the eccentric rotation of the rotor, and the coupling between the rotor's translational displacement and asphericity. An intuitionistic explanation for the electrostatic torque that comes of the rotor's eccentric rotation is presented also. The effects of these conclusions should be tested and verified in the future experiments and applications.