| 其他摘要 | Visible-light detector can be used for real-time observation, aerial trajectory measurements, target recognition, target tracking and targeting. Making the equipment on-board can enhance the mobility. Because of the load limit of the vehicle, the weight indicators have certain requirements in the process of designing the structure of the visible-light detector. Meanwhile, with the continuous development of detection technology, requirements of imaging quality of detector are increasing, while stiffness performance of visible light detector structure under operation directly affects the imaging quality of the structure. Therefore, it is of great significance to study in lightweight design of the visible-light detector under the premise of ensuring its stiffness performance.
The visible-light detector is driven by tracking turntable in operation. the changes of posture will lead to the corresponding changes of stress condition, which is called alternating load. There are many problems in the optimization process: firstly, establishing of optimization model is based on accurate mathematical and physical model, and the analysis process also requires the designer to have enough experience; Secondly, the optimization process for optimization model usually requires a series of iterations, but for the entire visible light detector structure one cycle of calculation requires a large amount of work; Thirdly, irregularity of the design space and the interference from random error will adversely affect the accuracy of the model, meanwhile, the response of objectives and constraints and the sensitivity of response function to the design variables usually are not smooth and continuous. This paper aims to build a reasonable approximation model for the lightweight research for the visible-light detector structure while meeting certain accuracy requirements.
Firstly, this paper introduces a design of modular visible-light detector, discusses the design index of the visible-light detector and gives the main indicators of the visible-light detector. Then 3D geometric model and PATRAN finite element model of this detector structure are built, based on which stiffness performance analysis and modal analysis are carried out to verify the feasibility of the design of the detector as well as the necessity of lightweight. The simulation results are verified by experiments. Through a comprehensive analysis of the structure parameters and the optical imaging quality, constraint conditions and boundary conditions of the lightweight model are determined. For the visible-light detector structure, this paper proposes a lightweight plan based on approximate model. This plan uses Latin hypercube experiment design method to obtain sample data; Then according to the different response characteristics of design variables and objective constraints, an approximation model of quality and design variables is built with polynomial fitting, and an approximation model of stiffness index and design variables is built with moving least square fitting. Then the mathematical model of lightweight of visible-light detector structure is built. Finally, iterative optimization is carried out by sequential quadratic programming, that is, to find a appropriate design point by changing the structural parameters of several main parts of the detector, making the overall quality of the visible-light detector to be the minimum under the premise of ensuring its stiffness performance. The fitting errors of approximation models built in this paper are all less than 1.5%. After lightweight design, the quality of the visible-light detector is 34.09kg. Compared with the traditional lightweight design, the lightweight rate reaches 16.26%. |
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