Abstract In this paper, a cascade acceleration feedback control （AFC） enhanced by a disturbance observa- tion and compensation （DOC） method is proposed to improve the tracking precision of telescope systems. Teles...Abstract In this paper, a cascade acceleration feedback control （AFC） enhanced by a disturbance observa- tion and compensation （DOC） method is proposed to improve the tracking precision of telescope systems. Telescope systems usually suffer some uncertain disturbances, such as wind load, nonlinear friction and other unknown disturbances. To ensure tracking precision, an acceleration feedback loop which can in- crease the stiffness of such a system is introduced. Moreover, to further improve the tracking precision, we introduce the DOC method which can accurately estimate the disturbance and compensate it. Furthermore, the analysis of tracking accuracy used by this method is proposed. Finally, a few comparative experimental results show that the proposed control method has excellent performance for reducing the tracking error of a telescope system.展开更多
Solar radio spectra and their temporal evolution provide important clues to understand the energy release and electron acceleration process in the corona,and are commonly used to diagnose critical parameters such as t...Solar radio spectra and their temporal evolution provide important clues to understand the energy release and electron acceleration process in the corona,and are commonly used to diagnose critical parameters such as the magnetic field strength.However,previous solar radio telescopes cannot provide high-quality data with complete frequency coverage.Aiming to develop a generalized solar radio observing system,in this study,we designed a digital receiving system that could capture solar radio bursts with a broad bandwidth and a large dynamic range.A dual-channel analog-to-digital converter(ADC)printed circuit board assembly(PCBA)with a sampling rate of 14-bit,1.25 Giga samples per second(GSPS)cooperates with the field-programmable-gate-array(FPGA)chip XC7K410T in the design.This receiver could realize the real-time acquisition and preprocessing of high-speed data of up to 5 GB s^(-1),which ensures high time and spectral resolutions in observations.This receiver has been used in the solar radio spectrometer working in the frequency range of 35 to 40 GHz in Chashan Solar Observatory(CSO)established by Shandong University,and will be further developed and used in the solar radio interferometers.The full-power bandwidth of the PCBA in this receiving system could reach up to 1.5 GHz,and the performance parameters(DC–1.5 GHz)are obtained as follows:spur free dynamic range(SFDR)of 64.7–78.4 dB,signal-to-noise and distortion(SINAD)of 49.1–57.2 dB,and effective number of bits(ENOB)of>7.86 bit.Based on the receiver that we designed,real-time solar microwave dynamic spectra have been acquired and more solar microwave bursts with fine spectral structures are hopeful to be detected in the coming solar maximum.展开更多
Friction torque severely weakens the tracking accuracy and low-speed stability of an m-level TCS(telescope control system).To solve this problem,a friction compensation method is proposed,based on high-precision LuGre...Friction torque severely weakens the tracking accuracy and low-speed stability of an m-level TCS(telescope control system).To solve this problem,a friction compensation method is proposed,based on high-precision LuGre friction model parameters identification.Together with dynamometer calibration,we first design a DOB(disturbance observer)to acquire high-accuracy TCS friction value in real time.Then,the PSO-GA(a hybrid algorithm combined particle swarm optimization algorithm and genetic algorithm)optimization algorithm proposed effectively and efficiently realizes the LuGre model parameters identification.In addition,we design a TCS controller including DOB and LuGre model parameters identification based on double-loop PID controller for practical application.Engineering verification tests indicate that the accuracy of DOB calibrated can reach 96.94%of the real measured friction.When azimuth axis operates in the speed cross-zero work mode,the average positive peak to tracking error reduces from 0.8926"to 0.2252"and the absolute average negative peak to tracking error reduces from 0.8881"to 0.3984".Moreover,the azimuth axis tracking MSE reduces from 0.1155"to 0.0737",which decreases by 36.2%.Experimental results validate the high precision,facile portability and high real-time ability of our approach.展开更多
基金supported by the Quantum Communication Project,one of the Strategic Pilot Projects,Chinese Academy of Sciences
文摘Abstract In this paper, a cascade acceleration feedback control （AFC） enhanced by a disturbance observa- tion and compensation （DOC） method is proposed to improve the tracking precision of telescope systems. Telescope systems usually suffer some uncertain disturbances, such as wind load, nonlinear friction and other unknown disturbances. To ensure tracking precision, an acceleration feedback loop which can in- crease the stiffness of such a system is introduced. Moreover, to further improve the tracking precision, we introduce the DOC method which can accurately estimate the disturbance and compensate it. Furthermore, the analysis of tracking accuracy used by this method is proposed. Finally, a few comparative experimental results show that the proposed control method has excellent performance for reducing the tracking error of a telescope system.
基金the National Natural Science Foundation of China 11703017,11790303(11790300),11803017,41774180,41904158,11973031the China Postdoctoral Science Foundation(2019M652385)+2 种基金Open Research Program CAS Key Laboratory of Solar ActivityNational Astronomical Observatories(KLSA201907)Young Scholars Program of Shandong University,Weihai(20820201005)。
文摘Solar radio spectra and their temporal evolution provide important clues to understand the energy release and electron acceleration process in the corona,and are commonly used to diagnose critical parameters such as the magnetic field strength.However,previous solar radio telescopes cannot provide high-quality data with complete frequency coverage.Aiming to develop a generalized solar radio observing system,in this study,we designed a digital receiving system that could capture solar radio bursts with a broad bandwidth and a large dynamic range.A dual-channel analog-to-digital converter(ADC)printed circuit board assembly(PCBA)with a sampling rate of 14-bit,1.25 Giga samples per second(GSPS)cooperates with the field-programmable-gate-array(FPGA)chip XC7K410T in the design.This receiver could realize the real-time acquisition and preprocessing of high-speed data of up to 5 GB s^(-1),which ensures high time and spectral resolutions in observations.This receiver has been used in the solar radio spectrometer working in the frequency range of 35 to 40 GHz in Chashan Solar Observatory(CSO)established by Shandong University,and will be further developed and used in the solar radio interferometers.The full-power bandwidth of the PCBA in this receiving system could reach up to 1.5 GHz,and the performance parameters(DC–1.5 GHz)are obtained as follows:spur free dynamic range(SFDR)of 64.7–78.4 dB,signal-to-noise and distortion(SINAD)of 49.1–57.2 dB,and effective number of bits(ENOB)of>7.86 bit.Based on the receiver that we designed,real-time solar microwave dynamic spectra have been acquired and more solar microwave bursts with fine spectral structures are hopeful to be detected in the coming solar maximum.
基金the National Natural Science Foundation of China(NSFC)under Nos.11803017,41904158,and 41774180the China Postdoctoral Science Foundation under 2019M652385+2 种基金the Open Research Program of the CAS Key Laboratory of Solar Activity under KLSA201907the National Astronomical ObservatoriesYoung Scholars Program of Shandong University,Weihai(20820201005)。
文摘Friction torque severely weakens the tracking accuracy and low-speed stability of an m-level TCS(telescope control system).To solve this problem,a friction compensation method is proposed,based on high-precision LuGre friction model parameters identification.Together with dynamometer calibration,we first design a DOB(disturbance observer)to acquire high-accuracy TCS friction value in real time.Then,the PSO-GA(a hybrid algorithm combined particle swarm optimization algorithm and genetic algorithm)optimization algorithm proposed effectively and efficiently realizes the LuGre model parameters identification.In addition,we design a TCS controller including DOB and LuGre model parameters identification based on double-loop PID controller for practical application.Engineering verification tests indicate that the accuracy of DOB calibrated can reach 96.94%of the real measured friction.When azimuth axis operates in the speed cross-zero work mode,the average positive peak to tracking error reduces from 0.8926"to 0.2252"and the absolute average negative peak to tracking error reduces from 0.8881"to 0.3984".Moreover,the azimuth axis tracking MSE reduces from 0.1155"to 0.0737",which decreases by 36.2%.Experimental results validate the high precision,facile portability and high real-time ability of our approach.
