The 500 meter Aperture Spherical Radio Telescope (FAST) in China, commonly known as the "Eye of Heaven," is the world's largest and most sensitive single aperture radio telescope, located in a karst depression in Pingtang County, Guizhou Province. The project, led by the National Astronomical Observatory of the Chinese Academy of Sciences, aims to promote China's research in radio astronomy to be in line with international standards, and provide a powerful tool for exploring pulsars, neutral hydrogen, fast radio bursts (FRBs) in the universe and searching for extraterrestrial civilization signals. The FAST project began construction in 2011 and after five years, was officially completed and put into operation in September 2016, marking an important step forward for China in the field of astronomy research.

Figure 1 FAST Eye

The design and construction of FAST face numerous technical and engineering challenges. Its huge reflector diameter reaches 500 meters, far exceeding the 305 meter aperture of the world's largest radio telescope (located at the Arecibo Observatory in Puerto Rico). The reflective surface of FAST is composed of approximately 4450 triangular aluminum panels with adjustable shapes. These panels can adjust the curvature by adjusting the posture of the support structure, thereby maintaining the accuracy of the reflective surface and ensuring precise focusing of radio waves in different viewing directions. The high-sensitivity radio receiver and advanced data processing system of the entire system are capable of capturing and analyzing extremely weak signals from the distant universe, which gives FAST the ability to detect signals at the edge of the universe.

In FAST (500 meter Aperture Spherical Radio Telescope), the application of parallel mechanisms is mainly reflected in the feed support system, which is one of the key technologies for achieving high-precision observations in FAST.

Composition and Function of Parallel Robots

Composition: The feed support system of FAST adopts a two-stage parallel robot structure. The first level is a cable parallel robot with a span of 600 meters, used to tow a feed cabin weighing up to 30 tons to achieve large-scale movement at an altitude of over 140 meters and within a range of 207 meters. The second level is located inside the feed cabin and is a large Stewart platform (six bar parallel robot) used to achieve high-precision positioning of the receiver inside the feed cabin, with an accuracy of up to 10 millimeters.

The feed cabin adopts a six degree of freedom control system, which achieves precise positioning and adjustment through a complex suspension mechanism. The feed cabin is suspended above a huge reflective surface and connected to six surrounding support towers by six steel cables. Each steel cable is independently adjusted in length by a computer-controlled electric winch. This design enables the feed cabin to move in six degrees of freedom in space, including forward, backward, left, right, and up and down translation along the X, Y, and Z axes, as well as pitch, yaw, and roll rotation around these three axes. By coordinating and controlling the length changes of these six steel cables, the feed cabin can be accurately moved to the designated position, ensuring that radio signals can always be accurately focused on the receiver in different observation directions, thereby achieving efficient signal reception and processing. This six degree of freedom parallel control system is one of the core technologies for FAST to perform high-precision and wide-ranging astronomical observations.

Function: This two-stage parallel robot structure enables FAST to flexibly adjust the position and attitude of the feed cabin to accurately align with the observation target. The receiver inside the feed cabin is responsible for receiving radio signals from the universe and transmitting them to the ground control system for analysis and processing.

Figure 2 Feed cabin

FAST Eye is not only a pride of Chinese astronomy, but also an important tool for humans to explore the mysteries of the universe. Its parallel mechanism technology demonstrates the infinite possibilities of industrial automation and provides new directions for future astronomical observations and research. Thank you for reading. If you have more interest or questions about parallel robots, please feel free to leave a comment in the comment section for discussion. Let's explore the infinite possibilities of industrial automation together!