The Design And Implementation Of Stabilized Platform Based On MEMS Gyro

MEMS (micro-electro-mechanical system) is the 21st century high-tech frontier technology that integrated a variety of micro-machining technology and developed based on the application of the latest achievements of modern information technology. Currently, the micro-inertial sensors attract more and more attention in the field of inertial navigation all over the world and have been applied to the stability and targeting areas. In this paper,MEMS gyro was used as space angular rate sensor to research the dual-axis stable platform based on MEMS gyro. It implemented the real-time tracking function of inertial space stability of video equipment and the laser spot target.The main work of this paper is the signal processing, modeling, controller design and tracking algorithm design of MEMS gyro stable platform. The specific work of this thesis is as follows:(1) The design and implementation of stable platform system. Combined with the characteristics of the stable platform perturbation theory and MEMS, we selected the composition of the platform to program the overall platform design and composition, and gave specific implementations for stable tracking. Finally, we designed the hardware of the stable control system and the spot tracking system.(2) The analysis and filtering of MEMS sensor. Firstly, we conducted the calibration and the Allan variance analysis experiments for the MEMS sensors used. Then, combined the features of MEMS sensor and system requirements,we designed the gyro filtering algorithms.Finally, we used data fusion algorithm that based on Kalman Filtering to conduct MEMS gyro drift compensation.(3) Modeling and controller design for stable platform. Firstly, we modeled each aspect of stable platform and ultimately got the whole model of the platform. We obtained the accurate parameters of the motor frame through scanning the motor framework. We designed the rate loop and position loop controller based on system model. For the influence on the platform performance that may caused by friction factors, we designed the adaptive rate based on Stribeck model and conducted the simulation experiments. Finally, we gave the specific implementation process of platform control algorithm in the DSP controller.(4) Laser spot detection algorithm design and implementation. This paper describes the common filtering algorithm and laser spot position detection algorithm. And it also gives a single spot detection algorithm in the FPGA implementation process. The final completion of the real-time transmission of off-target information to the DSP control stabilizer was by adding of SOPC embedded devices. In addition, in order to facilitate debugging and observation,we expanded the video buffer circuit and DA circuit, and prepared a VGA display program.(5) Biaxial stable platform experiments. Combined with actual experiment and facilities,we performed isolation experiment for the final finished platform system: Pitch axis step response setting time was 0.08s without overshoot,the azimuth axis step response setting time was about 0.18s with a 11% overshoot, and the isolation was 5% by system testing. Then,combined with the infrared spot tracking system we designed, we carried out laser spot tracking experiment, and made up gyro rate constitutes closed loop and photoelectricity position closed-loop, completed the spot tracking experiment with the measured tracking accuracy within ±0.3°. Finally, we analyzed the results of the experiments, obtained the experimental results and gave recommendations for further improvement of the system.