Obtaining the wind load distribution on the telescope aperture is very important to estimate its influence and reduce the wind disturbance on the telescope system.The aperture of the radio telescope structure can be a...Obtaining the wind load distribution on the telescope aperture is very important to estimate its influence and reduce the wind disturbance on the telescope system.The aperture of the radio telescope structure can be as large as 100 m and therefore,the uniform wind load on the aperture assumption is not suitable for the radio telescope with large aperture.In this paper,a gradient segments superposition method for calculating the wind load has been proposed.The proposed method has been constructed by combining two regional divisions.First,reflecting surface has been evenly divided in the altitudinal direction.Second,the reflecting surface has been divided into several uniform rings assuming that the wind load coefficient on different rings are different.For the 110 m aperture radio telescope,the wind load estimation results differ by 28%.After that,a structural dynamics model of telescope has been established and a fuzzy PID controller has been designed to reduce wind disturbance.The Root Mean Square Error of telescope pointing under wind disturbance has been reduced by 67.8%.It is suggested that the proposed wind load estimation method has lay a solid foundation for the design of the large telescope system under wind disturbance.展开更多
Large steerable radio telescopes can rotate in azimuth and elevation,with various upwind postures and complex wind load characteristics.In order to obtain the wind load distribution on the reflector and the wind force...Large steerable radio telescopes can rotate in azimuth and elevation,with various upwind postures and complex wind load characteristics.In order to obtain the wind load distribution on the reflector and the wind force coefficients in different upwind postures,this work took the reflector of the Qi Tai Telescope in Xinjiang as the object.The wind pressure distribution,drag coefficient,side force coefficient,lift coefficient,and total force coefficient of 361 groups of reflectors with different upwind postures were calculated and analyzed by a numerical simulation method.The results show that the force on the reflector when the concave surface faces the wind is significantly greater than when the convex surface faces the wind.The surrogate models for calculating wind force coefficients were established based on the polynomial response surface model(PRSM) and regularized minimumenergy tensor-product spline(RMTS).The adjusted R-squared of RMTS is 0.98,and the root mean square error is below 0.1,which proves RMTS is significantly better than PRSM.Compared with the numerical simulation values,the absolute errors of the drag coefficient,side force coefficient,lift coefficient,and total force coefficient of the reflector with azimuth and elevation of 45° predicted by RMTS are 0.02,0.027,0.032,and 0.046,respectively.The relative errors are 2.42%,2.76%,2.23%,and 2.43%,respectively.It is proved that the RMTS surrogate model is reliable and that the predicted data can fast provide sufficient information for the wind-resistant design of the large steerable radio telescopes.展开更多
A large,fully steerable radio telescope is susceptible to the wind load,leading to structure deformation andpointing deviation of the telescope.To effectively suppress the influence of dynamic wind load,the wind resis...A large,fully steerable radio telescope is susceptible to the wind load,leading to structure deformation andpointing deviation of the telescope.To effectively suppress the influence of dynamic wind load,the wind resistancecontrol of the telescope is carried out based on wind speed forecasting.This study developed a wind speedforecasting model to efficiently forecast the wind speed at the telescope position.The proposed model successfullyeliminates the random noise of the original wind speed,effectively extracts the wind speed features and solves theautomatic optimization of the hyperparameters of the forecasting network.This model significantly improves theaccuracy and reliability of wind speed forecasting.To verify the forecasting performance of the proposed model,the wind data from the Qitai Radio Telescope site is examined as a case study.The wind speed forecasting model’sMAE,RMSE and MAPE are 0.0361,0.0703 and 3.87%,respectively.The performance of the proposed modelmeets the requirements of wind resistance control and can provide data support for the radio telescope.展开更多
基金the National Key Research and Development Program of China under No.2021YFC2203600the National Natural Science Foundation of China under Nos.52005377 and 52275268+2 种基金the National Defense Basic Scientific Research Program of China under No.JCKY2021210B007Wuhu and Xidian University Special Fund for Industry-University-Research Cooperation under No.XWYCXY-012021012Youth Innovation Team of Shaanxi Universities under No.201926.
文摘Obtaining the wind load distribution on the telescope aperture is very important to estimate its influence and reduce the wind disturbance on the telescope system.The aperture of the radio telescope structure can be as large as 100 m and therefore,the uniform wind load on the aperture assumption is not suitable for the radio telescope with large aperture.In this paper,a gradient segments superposition method for calculating the wind load has been proposed.The proposed method has been constructed by combining two regional divisions.First,reflecting surface has been evenly divided in the altitudinal direction.Second,the reflecting surface has been divided into several uniform rings assuming that the wind load coefficient on different rings are different.For the 110 m aperture radio telescope,the wind load estimation results differ by 28%.After that,a structural dynamics model of telescope has been established and a fuzzy PID controller has been designed to reduce wind disturbance.The Root Mean Square Error of telescope pointing under wind disturbance has been reduced by 67.8%.It is suggested that the proposed wind load estimation method has lay a solid foundation for the design of the large telescope system under wind disturbance.
基金supported by the National Key Research and Development Program of China(grant No.2021YFC2203600)the National Natural Science Foundation of China(Grant Nos.52275268 and 51975447)+2 种基金the National Defense Basic Scientific Research Program of China(Grant No.JCKY2021210B007)Wuhu and Xidian University Special Fund for Industry-University-Research Cooperation(Grant No.XWYCXY-012021012)Youth Innovation Team of Shaanxi Universities(Grant No.201926)。
文摘Large steerable radio telescopes can rotate in azimuth and elevation,with various upwind postures and complex wind load characteristics.In order to obtain the wind load distribution on the reflector and the wind force coefficients in different upwind postures,this work took the reflector of the Qi Tai Telescope in Xinjiang as the object.The wind pressure distribution,drag coefficient,side force coefficient,lift coefficient,and total force coefficient of 361 groups of reflectors with different upwind postures were calculated and analyzed by a numerical simulation method.The results show that the force on the reflector when the concave surface faces the wind is significantly greater than when the convex surface faces the wind.The surrogate models for calculating wind force coefficients were established based on the polynomial response surface model(PRSM) and regularized minimumenergy tensor-product spline(RMTS).The adjusted R-squared of RMTS is 0.98,and the root mean square error is below 0.1,which proves RMTS is significantly better than PRSM.Compared with the numerical simulation values,the absolute errors of the drag coefficient,side force coefficient,lift coefficient,and total force coefficient of the reflector with azimuth and elevation of 45° predicted by RMTS are 0.02,0.027,0.032,and 0.046,respectively.The relative errors are 2.42%,2.76%,2.23%,and 2.43%,respectively.It is proved that the RMTS surrogate model is reliable and that the predicted data can fast provide sufficient information for the wind-resistant design of the large steerable radio telescopes.
基金the National Key Research and Development Program of China(grant No.2021YFC2203600)National Natural Science Foundation of China(NSFC,grant No.52275268)+3 种基金National Defense Basic Scientific Research Program of China(grant No.JCKY2021210B007)Wuhu and Xidian University Special Fund for Industry-University-Research Cooperation(grant No.XWYCXY-012021012)Youth Innovation Team of Shaanxi Universities(grant No.201926)Fundamental Research Funds for the Central Universities(grant No.XJSJ23122).
文摘A large,fully steerable radio telescope is susceptible to the wind load,leading to structure deformation andpointing deviation of the telescope.To effectively suppress the influence of dynamic wind load,the wind resistancecontrol of the telescope is carried out based on wind speed forecasting.This study developed a wind speedforecasting model to efficiently forecast the wind speed at the telescope position.The proposed model successfullyeliminates the random noise of the original wind speed,effectively extracts the wind speed features and solves theautomatic optimization of the hyperparameters of the forecasting network.This model significantly improves theaccuracy and reliability of wind speed forecasting.To verify the forecasting performance of the proposed model,the wind data from the Qitai Radio Telescope site is examined as a case study.The wind speed forecasting model’sMAE,RMSE and MAPE are 0.0361,0.0703 and 3.87%,respectively.The performance of the proposed modelmeets the requirements of wind resistance control and can provide data support for the radio telescope.
