Research On Fast Steering Mirror Based On Compliant Mechanism

The Fast Steering Mirror(FSM)is a mirror device that accurately controls the direction of the beam between the target and the receiver,with advantages of high bandwidth,high precision,no backlash,no friction,no noise and compact structure,which has been widely used in aerial photoelectric imaging system,tracking precision equipment,telescopes and space laser communication.As early as the 1980 s,the study of Fast Steering Mirror technology was carried out in foreign countries.Its key technologies and related products have become increasingly mature.But because the fast steering mirror is mainly used in aviation,aerospace and other military fields,western countries have imposed a technical blockade on China.Therefore,in order to break through the technical barrier and enhance the comprehensive strength of our country,it is important to study the fast steering mirror system deeply.As one of the key parts of the fast steering mirror,the performance of the compliant mechanism directly determines the overall index of the fast steering mirror system.In this paper,the flexure hinges of compliant mechanism are studied in depth.Then the flexure hinge mathematical model developed in this paper is used to design a two-axis rotating compliant mechanism for a fast steering mirror.Then the design of a high precision,high bandwidth fast steering mirror is completed with this compliant mechanism.Finally,the performance of the fast steering mirror is tested.Here are the following:(1)Modeling and analysis of mechanical properties of flexure hinges.Based on the theory of elasticity,this paper calculates the static mechanical properties of the flexure hinges,and establishes the mathematical model of the stiffness,rotation precision,maximum torque and maximum angle of the flexure hinges.The dynamic mechanical properties of the flexure hinges are calculated and the natural frequency and fatigue strength mathematical model of the flexure hinges are established.The accuracy of the mathematical model established in this paper is verified by using finite element method and experimental method.The flexure hinge mathematical model established in this paper is used to compare and analyze the flexure hinges of various notch shapes,and the results are of theoretical significance to the design of the flexible unit,the analysis result has guiding significance to the design of flexure hinges theoretically.(2)Design and analysis of two-axis rotating compliant mechanism.In order to design a two-axis compliant mechanism which is suitable for fast steering mirror,the technical index analysis of the two-axis compliant mechanism is firstly carried out.The overall scheme of two-axis compliant mechanism is designed and its stiffness is modeled.The model of flexure hinge established in this paper is used to select the suitable shape of the flexure hinge,and its geometrical dimension is optimized.Then,the flexure hinge is integrated into the design of the compliant mechanism,and the two-axis rotating compliant mechanism is designed to meet the performance index.Finally,the finite element method is used to analyze the mechanical properties of the compliant mechanism.(3)Design and analysis of fast steering mirror.This paper firstly analyzes the technical indexes of the fast steering mirror system based on the overall technical index.Next,a detailed analysis and design of reflector components,supporting components,drive components,sensor components,pedestals and baseplates of the fast steering mirror system are carried out.Then the key components-the voice coil motor and the eddy current sensor,are selected.Finally,a set of high precision fast steering mirror system is processed and installed.(4)The performance test of the fast steering mirror.A fast steering mirror performance index test system was set up to test the static and dynamic indexes of the fast steering mirror system.The results show that the designed fast steering mirror system has an angular resolution of1?rad,a repeatability error of1.5?rad,and a bandwidth of 213 Hz.The static and dynamic indexes of the system meet the design requirements.The test results also verified the accuracy of the design model and method of fast steering mirror based on the compliant mechanism.