Development of a compact precision linear actuator for the active surface upgrade of the Delingha 13.7-m radio telescope

The Delingha 13.7-m radio telescope is to be upgraded with an active surface for multi-beam observation at 3 mm wavelength. Its primary reflector is paved with 72 aluminum panels which are originally supported by 480 fixtures. One of the critical tasks associated with the upgrade program is development of precision linear displacement actuators to replace the panel fixtures hence to Listed first in the upgrade program is actively drive and position the panels. The linear actuator is required to fit the existing positions, dimensions and connections of the panels and the backup structure, also implicitly required to be as compact and lightweighted as possible. This paper is to report in detail the development and experiment of the compact, folded, precision linear actuator according to given technique requirements and constraints, including the description of the flexible adaption of the fixture of the actuators and the special design of the connecting mechanism with the panels. The experiment system is established with one of the spare panels of the telescope, and six sets of actuator and control electronics are included for driving the panel. This paper will present the test results measured on a single actuator prototype as well as the actuators working together in the spare panel experiment. The test results prove that the actuator manifests positioning accuracy of microns and load capacity of 12 kg. The related connection and electronics design of the actuator also meets the requirements of the update program of the telescope.