Research On The Drive Technology Of Ball-disk Rotor Micro Gyroscope

Gyroscope is a kind of sensor which can accurately measure the angular motion of objects.It is widely used in aviation,spaceflight,resource exploration and weapon guidance.The gyroscope based on MEMS(Micro-Electro Mechanical Systems)has the advantages of small size,lightweight and low power consumption,and has been widely used in the fields of consumer electronics and tactical weapons.The vibratory gyroscope works on the principle of reciprocating motion,which leads to the low linear velocity of the mass,and the performance of the device is limited.In recent years,it is desirable to increase the linear velocity of the mass through the development of rotor micro gyroscope to improve the performance of the device.However,since the rotational stability of the rotor is quite difficult to control,its performance is not so good as vibratory gyroscope.To solve this problem,a new rotor gyroscope based on liquid-suspension is proposed by us.The device has the characteristics of small size,lightweight,low cost,and is expected to achieve higher accuracy.Since the structure and the working principle of this device are quite different from the ones of the existing rotor gyroscope.The existing theoretical models have been unable to support the design and optimization of new device.In this paper,the theoretical analysis and optimization of the new device 's rotational driving system are carried out,and the high-speed and stable driving of the device is realized and verified by experiments.The structure of ball-disk rotor gyroscope is proposed and its working principle is expounded.The magnetic field distribution of the device is analyzed according to the Maxwell's electromagnetic theory,and the driving model of the new device is established.On the basis of this,the length of the air gap and the width of the stator outer ring are optimized.The analytical relationship among the gyro driving torque,the driving current and the rotational position of the rotor is obtained by the Maxwell tensor method combining with the driving model.The driving model is validated by experiment,which provides a theoretical basis for the design and optimization of gyroscope's drive system.A high-speed and stable electromagnetic drive method for ball-disk rotor gyroscope is proposed.By studying the moment balance relationship of the micro gyroscope during steady-state rotation,combined with the analysis of the magnetic circuit and the optimization of the driving system structure and driving strategy,the problem that the driving torque of the traditional rotor micro gyroscope is too small is solved.In addition,the source of electromagnetic torque fluctuation during the operation is analyzed,and the mechanical structure and driving strategy are optimized,reducing the electromagnetic torque fluctuation.The high-speed and stable drive of the rotor micro gyroscope is achieved.A low power drive and a quick start method for ball-disk rotor micro gyroscope are presented.Based on Maxwell's electromagnetic theory,the instantaneous rotation position of the rotor can be determined through the back-EMF signal generated during the operation.According to the position of the rotor,the angular acceleration of the starting process and the driving hysteresis angle during the steady-state operation are dynamically set to achieve the adaptive acceleration and the power consumption control.This method can effectively shorten the start-up time of the device and reduce the steady-state power consumption of the device.Based on the above studies,the realization and performance-test of the ball-disk rotor micro gyroscope are carried out to verify the correctness of the driving model and the effectiveness of the driving method.Test results show that,the speed control error is less than 0.03‰.When the rotational speed is 10000 rpm,after the optimization of the driving method,the device's steady-state power consumption is reduced by 89.86%,and the total power consumption is lower than 0.5W.The device's acceleration time is reduced by 34.00% and its start-up time is less than 3.25 s.The sensitivity,linearity and bias stability of the device are 98.3mV/(°/s),0.85% FS and 0.5°/h respectively.If the processing accuracy of the mechanical parts and the performance of the magnetic circuit are improved,the device's performance can be further improved.