Research And Design On Accelerometer Temperature Control System

The accelerometer is one of the core component of inertial navigation system,its performance directly affects the precision of navigation and guidance of the whole system.But the measurement accuracy of the accelerometer isn't only closely related to the structure design,technology craft,production materials and so on,but also to working environment,especially the environmental temperature.The change of temperature can cause the ther mal expansion and shrinkage of components and the variation of physical parameters of materials which is mainly reflected in its scale factor and zero drift.Therefore,it is of great significance to analyze the influence mechanism of the working environment temperature on the output precision of the accelerometer and to study how to improve the performance of the accelerometer on this basis.Thus this paper takes quartz flexible accelerometer as the research object and enhances the precision of temperature control as the goal to design the temperature control system that will ensure the output precision of the accelerometer and improve the performance of the inertial navigation system.First of all,this paper qualitatively analyzes the influence mechanism of the working environment temperature on the output precision of the accelerometer and the advantages and disadvantages of the current solution,and adopts the method of “temperature control” based on this.Then analyzing from the five angles of improving the accuracy of the temperature detection,building the hardware structure of the reasonable temperature control system,identifying the fine model of the controlled object,and adopting the appropriate temperature control strategy and temperature control algorithm,this paper puts forward the overall design scheme of high precision temperature control system.Secondly,the wheatstone bridge composed of the PT100 type platinum resistor is directly drived by the sinusoidal AC source,and the accelerometer temperature signal is detected based on the orthogonal vector phase-locked phase sensitive detection algorithm to make up the defect of the weak DC signal detection.Then using the DC driving mode replaces the PWM driving model to heat the accelerometer's working environment and independent high temperature hardware protection circuit is designed.Meanwhlie,the peripheral hardware circuit and Labview virtual instrument are configured with Aduc7026 precision microcontroller as the core,which is conveninet for system debugging.Then the ANSYS thermal analysis of accelerometer material and structure is conducted to guide the effective layout of the the temperature control element.Finally,based on the step response method and the Labview measured data,the second order fine mathematical model of the controlled object is established by using the least square method and the particle swarm optimization algrithm.Then this paper on that model designs a segmented multi-mode control strategy based on Fuzzy-PID algorithm and GPC prediction algorithm to achieve the high precision control of the accelerometer temperature,and makes compensation and correction according to the actual effect.The simulation results of the temperature control system show that using the system is not only able to achieve the good control effect on nonlinear temperature object with large inertia and parameter time-varying delay,but also has the characteristics of fast response speed,stable output and better adaption to the changes of the working environment temperature.Then the adjustment time of five to eight minutes and the temperature control accuracy of ±0.1? for the accelerometer temperature control system are satisfied.So utilizing the method of high precision “temperature control” is an effective way to ensure the output performance of the accelerometer.