Mechanism And Method Research Of High-precision Profile Adjustment Based On Thermal Deformation Of Large Reflective Surface Antenna

The reflection surface of the antenna is an important part of the satellite.Due to the large temperature gradient in space,the accuracy of the reflection surface will change,which will affect the working accuracy of the antenna.The research object is the reflection surface of the fixed-plane antenna.The modeling methods,dynamic characteristics,progressive damage characteristics and thermal characteristics of reflector are studied.According to different assumptions,different modeling methods and different adjustment algorithms for its thermal deformation are proposed.The main content of the paper is as follows:(1)A finite element model of the antenna reflection surface of composite skin honeycomb interlayer is established.In this paper,the dynamic characteristics of the reflector antenna are analyzed by the modal analysis method.The damage of the composite skin is defined by the Hashin damage criterion.The interface layer damage of the skin is defined by the secondary stress criterion.The performance of progressive damage of the reflection surface is analyzed.(2)The parametric model of the reflector antenna is established in this paper,including the reflector finite element model considering only the panel and the reflector finite element model considering the piezoelectric ceramic actuator and truss.Among them,finite element model of the reflection surface panel is the thermal-structure coupling model under unconstrained conditions,and the finite element model considering the piezoelectric actuator and truss is the thermal-electrical-structure coupling model under inequality constraints.This paper also uses a neural network to establish a none-parameter model of the reflector antenna.(3)For the thermal-structure coupling model of the reflector antenna,this paper derives the mathematical expression between the accuracy of the reflector surface and the input displacement.Through derivation of the input displacement vector,the optimal input displacement of the thermal-structure coupling model under unconstrained conditions is proposed.Through this adjustment algorithm,this paper adjusts the profile error under thermal load from 33.931 um to 19.964 um,reducing the profile error by 41.1%.(4)For the thermo-electric-structure coupling model of the reflector antenna,the mathematical expression between the accuracy of the reflector surface and the input voltage of the piezoelectric ceramic is derived.Aiming at this inequality constraint model,this paper introduces Lagrange multiplier method to solve the optimal solution.Finally,this chapter adjusted the profile accuracy from 33.931 um to 21.747 um under the influence of thermal load,reducing the profile error by 35.9%.In addition,this paper introduces the parabolic surface fitting algorithm,which can further achieve the effect of high precision adjustment by performing parabolic surface fitting on the profile nodes.Based on comprehensive consideration of parabolic surface fitting and actuator adjustment,this paper further adjusts the profile accuracy of the reflective surface to 11.465 um through genetic algorithm.(5)For the none-parameter model of the neural network,this paper takes the finite element model as a virtual machine,adopts the most Latin hypercube sampling method to collect sampling data,and performs training and error analysis on the model.In this paper,the optimal solution is solved by particle swarm optimization,and the optimal regulated input voltage can be obtained in about twenty iterations.Through the adjustment of the piezoelectric ceramic actuator,the surface accuracy of the solidsurface antenna can be significantly improved.Through the analysis of the mechanical behavior of the solid reflector,the research of the system modeling and the algorithm of the thermal deformation adjustment,this paper can provide guidance for the thermal deformation adjustment of the reflector of the on orbit antenna.