Controller Design Of High Precision Digital Closed-loop Fiber Optic Gyro

Since the first of the concept of fiber optic gyroscope (FOG) was emerged in 1976, fiber optic gyroscope have been paid more and more attention by many countries, especially the national military, for its significant advantages, flexible structure and attractive future. Compared with the traditional electromechanical gyroscope, by the use of multifunction phase modulator and other integrated optical technology, modularization and miniaturization make it easy for mass production. As broadband erbium-doped fiber light source technology, all-digital closed-loop processing technology and other key technology improves, high precision digital closed-loop fiber optic gyro will become the main instrument in inertial navigation applications. Because FOG is an angular rate sensor and its working environment may change dramatically, so, to ensure that the gyro can be work in a variety of environments, requiring high performance controller designed to improve the performance of fiber optic gyroscope and the controller can enable the FOG meet the important indicators when engineering and utility.Firstly, the research and development of fiber optic gyroscope is briefly described in this paper, this paper also introduced the types of optical gyroscope and analyzed the features when design interferometric fiber optic gyroscope (IFOG) structure.Secondly, after studied the principles of interferometric fiber optic gyroscope and error sources introduced by optical and electrical subsystems, the mathematical model of optical subsystem of FOG and the digital closed-loop transfer function are established in this paper. Based on the analysis of the models, digital controller is designed in this paper. This paper also put forward the methods of the calculation of performance parameters, and one example for calculate the performance parameters is gave in this paper.Thirdly, testing methods for dynamic characteristics of fiber optic gyroscope is analyzed here. The testing method bases on the equivalent input for dynamic characteristic of FOG also focused in this paper. This paper realizes establishment test stimulus for FOG by use of direct frequency synthesis technology and points out the feasibility and effectiveness of the technology.Finally, for optical subsystem and circuit processing subsystem and also considering the gyroscope as a whole, this paper designs the optical path control scheme and PID controller, in order to better suppress the vibration error, suppress vibration error control system is also designed here. Experimental results show that the controller meets the design requirements. This article also discusses the intelligent control technology in the application of fiber optic gyroscope and designs a fuzzy self-tuning PID controller preliminarily; simulation results show the controller can meet the design requirements.