Upon its completion, the Five-hundred-meter Aperture Spherical radio Telescope (FAST) will be the largest single dish
radio telescope ever in the world. The construction has been initiated in March 2011 in Guizhou province of China. The
whole construction process is expected to be completed in September 2016, with duration of 5.5 years.
With an aperture of 500 meters and an illumination aperture of 300 meters, the active reflector is one of the most
important parts of FAST. The reflector is composed of a ring beam, a cable net and thousands of panels, tie-down cables,
actuators and anchors. For the observation process of source switching and source tracking, the parabola shape of the
reflector is achieved by drawing back of the tie-down cables by the actuators. The motion performance and the reliability
of the actuators are of great importance to the telescope.
In this paper, the motion models of the actuators are analyzed for the observation process of source switching and source
tracking. Several design schemes are proposed, including mechanical and hydraulic design. The electric, mechanical and
hydraulic characteristics of these designs are discussed. Related experimental studies are performed to investigate the
electric and mechanical performances of these actuator prototypes. Based on the analysis and test results, a final type of
actuator will be optimally concluded to meet the requirements of the reflector of FAST.
FAST, five-hundred-meter aperture spherical radio telescope will be the largest radio telescope in the world which has
been established science and research items recently. One of the innovative engineering concepts is the active main
reflector which corrects spherical aberration on the ground to achieve full polarization and a wide band without
involving a complex feed system. Besides the reflector simulation, it is very important to study the supporting
structure for the reflecting surface. As the cable-net structure has been adopted, the in-depth study of back-structure is
very important which is connected between cable-net and panel. In this paper, structure forms and parameters are studied
in detail due to catch the costs and technical requirements. Throughout analysis, parameters are compared and modified.
Meanwhile, Comparing experiments has carried out on some sample frames. The stiffness experiments with different
load situations are going to confirm the feasibility of certain back-structure. Some conclusions is obtained, which can
avail in further study.