Robots help to maintain China’s ‘Sky Eye’ BY PROF. CAIHONG SUN (GUIZHOU RADIO ASTRONOMICAL OBSERVATORY)
China’s FAST is the largest single-dish radio telescope in the world. Known as China’s Sky Eye, safely maintaining its vast structure is a significant challenge – one that now has the help of a crew of… robots. The FAST Operation and Maintenance Robot System was set up in December 2019 by the National Key Research and Development Programme of China, with the goal of enabling maintenance checks which are difficult – or sometimes impossible – to achieve manually. In July this year, the robots passed a performance evaluation. One of them is designed to check the system of steel cables and pulleys that support FAST’s feed cabin, which receives radio signals reflected off the collecting surface. The cables keep it suspended 140 m above the surface, so maintenance is crucial for the telescope’s safe operation, but manual inspections are problematic for engineers, particularly the sections within 200 m of the feed cabin which are hardest to reach. The new feed support cable and pulley detection robot has a traction system which allows it to move along the cable, even at a steep angle, to check all the components, including clamps, pulleys, optical and electrical cables. It has robotic arms equipped with cameras to perform the inspections, and a magnetic sensor to detect internal defects in the cable.
There are also robotic helpers to monitor radio interference, to disassemble and assemble the receivers, and to maintain the dish’s more than 2,000 hydraulic actuators, responsible for manipulating the reflective surface to direct waves from different directions into the receiver. The robots operate during regular maintenance periods, to avoid interfering with the telescope’s astronomical observations. This project was undertaken by the Guizhou Radio Astronomical Observatory with contributions from nine facilities including the National Astronomical Observatories of the Chinese Academy of Sciences and Harbin Institute of Technology.
Another robot is tasked with maintaining the telescope’s laser targets, of which there are 2,225 distributed on FAST’s reflector. They are the reference points for measuring the surface shape of the dish, which is composed of aluminium plates with a thickness of only about 1 mm. The surface cannot bear the full weight of a person, and until now the solution was to attach a large balloon to maintenance personnel to support their weight – a weather-dependent and inefficient approach. The new robot is lighter, more efficient, and can remove, clean and replace the targets by itself. ABOVE: The reflector laser target maintenance robot. Credit: Guizhou Radio Astronomical Observatory NOVEMBER
2023
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