Cost Disruptive Reflector Surface for Large Deployable Antennas

2018 ◽  
pp. 95-105
Author(s):  
Mike Lawton ◽  
Juan R Reveles ◽  
Zhong You ◽  
Ashley Dove-Jay ◽  
Amjad Khan ◽  
...  
Keyword(s):  
Reflector Surface

Real-time Closed-loop Active Surface Technology of a Large Radio Telescope

2022 ◽  
Vol 134 (1031) ◽  
pp. 015003
Author(s):  
Yong Zhang ◽  
Guoping Li ◽  
Guohua Zhou ◽  
Qishuai Lu ◽  
Heng Zuo ◽  
...  
Keyword(s):  
Real Time ◽  
Radio Telescope ◽  
Closed Loop ◽  
Preliminary Test ◽  
Active Surface ◽  
Angle Measurement ◽  
Quality Data ◽  
Surface Accuracy ◽  
Surface System ◽  
Reflector Surface

Abstract The surface accuracy of a large radio telescope’s primary reflector is easily affected by gravity and temperature change during observations. An active surface system is crucial to ensure the regular operation and high-quality data output of the radio telescope. We propose a real-time closed-loop active surface system including two components. The first component, a new type of photoelectric edge sensor, detects the angle change of the adjacent panels. The second component, the displacement actuator, adjusts the panels’ position and posture to compensate for the angle changes. So, over the entire observation, the closed-loop surface control system with these two components could actively maintain the primary reflector’s accuracy in real time. Using this approach, we constructed an experimental active surface system for the Xinjiang Qitai 110 m Radio Telescope (QTT) to test the maintenance of the surface accuracy. The angle measurement accuracy is better than 0.″2, and the positioning accuracy of the displacement actuator could achieve ±15 μm over the whole 50 mm stroke. The preliminary test results show that the accuracy requirements of the QTT’s primary reflector surface can be met using the active surface system we propose.

Fabrication of electrically-pumped resonance-cavity membrane-reflector surface-emitters on silicon

2013 ◽  
Author(s):  
Wenjuan Fan ◽  
Deyin Zhao ◽  
Santhad Chuwongin ◽  
Jung-Hun Seo ◽  
Hongjun Yang ◽  
...  
Keyword(s):  
Electrically Pumped ◽  
Reflector Surface ◽  
Resonance Cavity

Research on Catenary Characteristics of FAST Tie-Down Cable and its Effect on Actuator and Joint

2014 ◽  
Vol 875-877 ◽  
pp. 664-670
Author(s):  
Jian Xing Xue ◽  
Xue Dong Gu ◽  
Li Qiang Song ◽  
Qi Ming Wang ◽  
Xue Bin Zhai ◽  
...  
Keyword(s):  
Tangential Force ◽  
Steel Cable ◽  
Initial Tension ◽  
Cable Length ◽  
Experimental Scheme ◽  
Reflector Surface ◽  
Equilibrium Differential Equation ◽  
And Control ◽  
Measurement And Control ◽  
Mechanics Characteristics

To study catenary characteristics of FAST (Five-hundred-meter Aperture Spherical radio Telescope) tie-down cable, this paper establishes tie-down cable equilibrium differential equation and cable length formula based on catenary theory, analyzes numerical simulation of multi-segment bar element method, and designs an experimental scheme. Taking 1×7 Ø12.7steel cable and Ø10 CFRP (Carbon Fiber Reinforced Polymer) cable for example, we can obtain three results respectively through manners mentioned above, and the agreement among them is excellent. Meanwhile, difference between results and elastic deformation of no-weight cable is not so big that catenary of two cables can be negligible. Further research shows that cable length is more sensitive to catenary than horizontal angle; cable longer deformation will benefit actuator to meet position precision effortlessly, however, stroke and velocity of actuator will increase and initial tension displacement of tie-down cable decrease correspondingly, this alteration should be compensated during reflector surface measuring and controlling; due to chord-tangent angle and tangential force is less than 1.28°and 241.4N, catenary effect on joint pose is weaker; generally speaking, CFRP cable has less catenary problem than steel cable, better mechanics characteristics, but bigger stroke and velocity for actuator and smaller initial tension displacement for tie-down cable. The research will provide references for design of tie-down cable, actuator, joint, and reflector measurement and control.

Design for Free-Form Reflector Surface Based on Foci Mapping Ellipse Flow-Line Methods and Gradient Optimization

2014 ◽  
Vol 51 (5) ◽  
pp. 052201
Author(s):  
张航 Zhang Hang ◽  
李梅花 Li Meihua ◽  
马宇飞 Ma Yufei ◽  
梁雪 Liang Xue ◽  
严金华 Yan Jinhua
Keyword(s):  
Flow Line ◽  
Free Form ◽  
Gradient Optimization ◽  
Reflector Surface
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