天文望远镜为大型高精密仪器,对望远镜的控制系统性能提出了极高的要求。作为控制系统的核心器件,伺服控制器的性能决定了控制系统的性能。介绍了一种基于PMAC(Programmable Multi Axes Controller)控制器的天文望远镜控制系统,研究了P...天文望远镜为大型高精密仪器,对望远镜的控制系统性能提出了极高的要求。作为控制系统的核心器件,伺服控制器的性能决定了控制系统的性能。介绍了一种基于PMAC(Programmable Multi Axes Controller)控制器的天文望远镜控制系统,研究了PMAC伺服控制原理、PID参数整定方法及基于PMAC的天文望远镜运动控制系统基本原理,并以此为基础设计了天文望远镜伺服控制系统软、硬件体系。基于PMAC的天文望远镜控制系统主要特点在于,伺服系统采用了传统的PID反馈控制算法和前馈控制算法相结合的组合控制算法,有效地克服了外界扰动对望远镜控制过程的影响,获得了较好的动、静态性能;同时,针对望远镜不同的轴系传动方式,如直驱方式和齿轮传动方式,应用不同的PID参数整定方法,如阶跃整定法和基于速度测量+阶跃整定相结合的参数整定方法,可分别使系统获得较为理想的PID控制参数;另外,基于PMAC的天文望远镜控制系统,对于不同的驱动电机和不同的轴角测量元件,均具有较好的适应性。该系统已在国家天文台2.16 m天文望远镜上得到了应用,该项应用中,采用了"IPC+PMAC"的双CPU分级控制方式,并以VC++为软件平台,通过对于PMAC Pcomm32底层接口函数的调用,实现了基于工控机的望远镜界面操作和控制,同时,以PID反馈控制算法和前馈控制算法为基础,采用了PID参数自适应控制算法,保证了望远镜高速的运行平稳性,也实现了低速精确性和快速性的控制要求。技术研究和运行实践表明,基于PMAC的望远镜控制系统具有较高的控制精度和良好的通用性,可广泛应用在不同类型的天文望远镜系统。展开更多
In the archive of the Ground Wide Angle Camera(GWAC),we found 43 white light flares from 43 stars,among which,three are sympathetic or homologous flares,and one of them also has a quasi-periodic pulsation with a perio...In the archive of the Ground Wide Angle Camera(GWAC),we found 43 white light flares from 43 stars,among which,three are sympathetic or homologous flares,and one of them also has a quasi-periodic pulsation with a period of 13.0±1.5 minutes.Among these 43 flare stars,there are 19 new active stars and 41 stars that have available TESS and/or K2 light curves,from which we found 931 stellar flares.We also obtained rotational or orbital periods of 34 GWAC flare stars,of which 33 are less than 5.4 days,and ephemerides of three eclipsing binaries from these light curves.Combining with low resolution spectra from LAMOST and the Xinglong 2.16 m telescope,we found that L_(Hα)/L_(bol) are in the saturation region in the rotation-activity diagram.From the LAMOST medium-resolution spectrum,we found that Star#3(HAT 178-02667)has double Hαemissions which imply it is a binary,and two components are both active stars.Thirteen stars have flare frequency distributions(FFDs)from TESS and/or K2 light curves.These FFDs show that the flares detected by GWAC can occur at a frequency of 0.5to 9.5 yr^(-1).The impact of flares on habitable planets was also studied based on these FFDs,and flares from some GWAC flare stars may produce enough energetic flares to destroy ozone layers,but none can trigger prebiotic chemistry on their habitable planets.展开更多
基金supported by the National Natural Science Foundation of China(NSFC)with grant No.12073038supported by the Joint Research Fund in Astronomy U1931133 under cooperative agreement between the National Natural Science Foundation of China(NSFC)and Chinese Academy of Sciences(CAS)+1 种基金the NSFC with grant No.61941121the Beijing Natural Science Foundation,No.1222029。
文摘In the archive of the Ground Wide Angle Camera(GWAC),we found 43 white light flares from 43 stars,among which,three are sympathetic or homologous flares,and one of them also has a quasi-periodic pulsation with a period of 13.0±1.5 minutes.Among these 43 flare stars,there are 19 new active stars and 41 stars that have available TESS and/or K2 light curves,from which we found 931 stellar flares.We also obtained rotational or orbital periods of 34 GWAC flare stars,of which 33 are less than 5.4 days,and ephemerides of three eclipsing binaries from these light curves.Combining with low resolution spectra from LAMOST and the Xinglong 2.16 m telescope,we found that L_(Hα)/L_(bol) are in the saturation region in the rotation-activity diagram.From the LAMOST medium-resolution spectrum,we found that Star#3(HAT 178-02667)has double Hαemissions which imply it is a binary,and two components are both active stars.Thirteen stars have flare frequency distributions(FFDs)from TESS and/or K2 light curves.These FFDs show that the flares detected by GWAC can occur at a frequency of 0.5to 9.5 yr^(-1).The impact of flares on habitable planets was also studied based on these FFDs,and flares from some GWAC flare stars may produce enough energetic flares to destroy ozone layers,but none can trigger prebiotic chemistry on their habitable planets.
