Research Of Flexible Gyro Digital Control Loop Key Technologies

The flexible gyro is an electromechanical gyroscope,which is used widely in the guided munitions,combat vehicles,UAV and other weapon equipment whose volume and cost have a strict limit.In the traditional flexible gyroscope closed-loop control circuit,the demodulation,notch filter,decoupling,compensator,and low-pass filter are realized by analog circuit.But analog circuit has various obvious disadvantages.For example,when the external environment changes sharply or gyro strenuous exercise,the parameters of the gyro control circuit formed by the analog circuit will change,and the performance of analog components in the analog circuit will gradually decline with aging,and thus the measurement error of flexible gyroscope will deteriorate;It is difficult to realize complex control algorithm by the gyro analog control circuit,and the gyro control loop based on classical control algorithm is generally difficult to meet some of the special requirements of the carrier.The analog circuit has a lot of discrete components,large size,complex structure,poor reliability.In order to overcome various disadvantages of analog control circuit,the digital control technology is used to digitize the flexible gyro closed-loop control circuit and complete flexible gyroscope closed-loop control.The digital circuit loop based on DSP can greatly improve the measurement accuracy and reliability of the flexible gyroscope.In other to achieve digital measurement and control of the flexible gyro.First,the working theory of the flexible gyro is studied deeply.Based on the principle of gyroscope dynamics and kinematics analysis,the flexible gyroscope and its open-loop transfer function and closed-loop transfer function are established.The flexible gyro digital control circuit is composed of band-pass filter,conversion circuit,power amplifier circuit,digital signal processing circuit,gyro secondary power supply circuit and gyro signal output circuit.Among them,the band-pass filter circuit can filter the noise voltage except the modulation signal voltage we want.Power amplifier OPA544 can drive the flexible gyro torquer.Digital signal processing circuit using TI floating-point TMS320F28335 as the core control chip can achieve the gyro signal phase-sensitive demodulation,low-pass filter,notch,correction,angular rate output and other functions.All of functions are implemented by TMS320F28335 software.When designing the correction controller of the control loop,it is designed by using the lead correction and the fuzzy adaptive PID control.And through the simulation analysis by Matlab,it is proved that the fuzzy adaptive PID controller has better control performance compared with the traditional lead correction controller.Finally,we had tested all digital control loop of the flexible gyro,which showed that the intended function of the control loop had been achieved and the technical indicators met the system requirements.