A Tanh Control Method for The Third Mirror’s Z Axis of Large Optical Telescope

The position accuracy of the third mirror’s Z axis will directly affect measurement optical telescope, so it is necessary to improve accuracy. In order control performances Z-axis a large this paper proposes novel algorithm based on hyperbolic tangent function (tanh). proposed used replace traditional integral separated proportional-integral (IS-PI) controller which widely in industry servo system. Firstly, mathematical model established. Secondly, tanh proposed, and characteristics stability are analyzed. Thirdly, parameters tuning method given. simulation results show that has higher tracking than IS-PI controller. Finally, experiments carried out telescope’s axis. experiments, compared, greatly improved.