| This paper mainly study the related problems of real-time monitoring and shape adjustment of cable net deployable antenna.Large cable net deployable antenna play an significant role in the telecommunications of satellites and the ground.However,the shape and location of the antenna will be different with the change of the position of feed,so the antenna should be real-time monitoring.At the same time,the reflect surface of the antenna is the most significant part on information collection.So it should has very high precision,even the tiny error of the reflector may directly affect the antenna's electrical performance.And now,with the change of communication requirements,large Cable net deployable antenna are moving in the direction of large diameter,long-lifetime,wide frequency and high precision,so it request more high quality design,production and install of the antenna.However,the error of the antenna is inevitable,which means that adjustment of the reflect surface of the antenna is inevitable,Only through surface precision adjustment,can the antenna achieve the required precision,it has great significance of satellite to improve communication's quality.First,this paper put forward a type of new method to select key modal via computing modal error,modal error is D-value that we can obtain by computing difference between displacement based on modal superposition and displacement from real body.And then,this paper derived an effective independence formula which is suitable for the strain sensor and proved that the strain modal also have Orthogonality.In addition,the paper discussed the design theory of pretension.Finally,finite element model of 2m hoop truss deployable antenna and 12 m?14 m rectangular truss deployable antenna were established.And then,this paper do a pretension analysis and modal analysis.The paper selected the key modal of the two model.And the same time,strain sensor optimal layout of two types cable net antenna's structure mentioned earlier was carried out based on effective independent method.The result shows that it is effective via modal confidence criterion and rule of condition number criterion.Second,there are determined and limited working condition for large cable net deployable antenna.The paper through the analysis of different working condition of the antenna's displacement and strain based on this characteristic.And then assembled them into displacement matrix and strain matrix.Subsequently,we calculate of strain displacement transition matrix by finding generalized inverse by importing the least square thought.Undoubtedly,this matrix contains all of working condition's information,the cable net antenna's structure can reconstruct by transition matrix and sensor if it working on a specified condition.This paper reconstruct the two model mentioned earlier.The result shows that we got sufficient precision.Third,this paper put forward a new method to model updating based on sensitivity technique.And then apply it into model adjustment.In this process,we selected cable tension as corrective coefficient.The paper obtained the aim state by reconstruction via strain when we applied a type of load on structure of antenna,then we adjusted any other state to our aim state by sensitivity analysis.The two models mentioned earlier were adjusted from ideal model to real model.The result shows that only by several times adjustment,the antenna can obtain the required accuracy of engineering.Cable tension has a clear physical meaning and overcome the problem that it consider the influence of cable tension difference compared to the absolute nodal coordinates when every times adjustment. |
PDF Full Text Request