Design Of Active Optics Hydraulic Support Control System

The demand for observation and research of targets in the deep space has promoted the increase of aperture of telescope primary mirror.With the telescope primary mirror aperture increases,the impact on primary mirror by the gravity and external factors also significantly increased.However,the stiffness of the primary mirror support structure is limited;when the telescope is working,the relative position between the primary mirror and the mirror room will be changed slightly,thus affecting the optical alignment,resulting in pointing errors.Therefore,it is necessary to control the position of primary mirror relative to the mirror chamber.In the paper,the hydraulic support control system is designed,and the position information acquisition,calculation and position control of the primary mirror are completed.The paper is composed of four parts:1 Based on the literature review,the development of telescope is reviewed,the principle of active optics and telescope primary mirror support are summarized.The development status of active optics technology is summarized,and the research status of primary mirror position control The active optical system of a certain telescope in the laboratory is used to illustrate the research contents of this paper.2 The principle and requirement of the position determination of primary mirror are discussed in detail.Absolute displacement sensor is used to acquire the displacement information of the primary mirror.According to the spatial geometrical relationship of the primary mirror position,the primary mirror position calculation algorithm is designed.The test system is constructed,and the calculation of the axial displacement and radial displacement are tested.3 The demand of the primary mirror position acquisition is analyzed in detail,including the analog channel selection,the networking mode,the differential signal filtering method of the displacement sensor output and the selection of the processor.Hardware and software of displacement sensor signal acquisition circuit are designed,then builds experimental platform and tests the performance of the acquisition circuit.4 The structure and control principle of the hydraulic support system are explained.Then,the experimental system is set up to test on the electric cylinder with simulated load.The acquisition circuit designed in this paper has high precision and can meet the requirement of the position monitoring of primary mirror.The selected electric cylinder and actuator have better control performance and can meet the position control requirement of the primary mirror.