Real-Time Shape Estimation Of Long Baseline Antenna Of Flexible Wing

The electrical properties of long baseline antenna mounted on flexible wing worsened by wing flexure, so shape estimation is needed to compensate these errors by adjusting the phase shifter. And the accuracy of estimation is affected by the positions and the total number of sensors. In this paper, we investigate real-time shape estimation of long baseline antenna of flexible wing and its sensor layout optimization.1) Based on the FEA wing model, strain based real-time shape estimation methods are studied. Modal Approach is not suitable for large deformation measurement, as for Ko Displacement Theories, large number of sensors is needed, which weakens the applicability for shape estimation of flexible wing. According to the situation right now, A Combination Modal approach has been proposed in this paper, rough estimation is obtained by Ko Displacement Theories with fewer sensors than usual, after that high precision estimation for relative deformation will be achieved with the help of Modal Approach. The Combination Modal approach could improve the accuracy of estimation and reduce the number of sensors at the same time.2) A nonlinear mathematical programming model has been built to minimize the estimation error and the total number at the same time. The design variables are positions and sensor number, and the objectives are the estimation accuracy and the total number of sensors. Both the continuous variables and discrete variable are included in this model In order to solve the problem, variable forms must be unified then variable substitution is needed. And according to each sensor’s contribution to shape estimation, number of sensors could be modified during iteration, the sensor whose contribution is the smallest would be removed when the accuracy meets the requirements, new sensor would be added between two best sensors when the requirements can’t be satisfied. At last, analysis about a cantilever beam simplified from a wing has been done. The numerical results show the correctness and effectiveness o f the model and method.3) A test wing plate has been designed and manufactured taking the test device built by NASA Dryden Flight Research Center as reference then experimental platform has been built After that, validation test for Modal Approach and Ko displacement theories under four different kinds of loads has been conducted. It shows that both method work well and acceptable results has been obtained.