In order to maintain relative position of main mirror and mirror chamber unchanged

improve image quality of telescope

main mirror position detection and control method is studied. Primary mirror position detection system uses six high precision LVDT straight line displacement sensors

which can calculate displacement change of primary mirror on five degrees of freedom and radius change of major mirror caused by temperature in real-time.On the basis of the primary mirror position detection

feedback control method for primary mirror position is designed

using PID control algorithm for closed-loop correction of primary mirror position. The proposed position detection and control methods is validated

experimental results show that this method can accurately calculate and control the primary mirror position

which can meet actual needs of engineering.