Adaptive optics correction technique based onfuzzy control

Abstract

In an adaptive optics system, proportion-integration-differentiation (PID) controller is widely used for correcting wave front, but the controller is strictly dependent on the response model of deformable mirror. In this paper, a novel wave front correction method is proposed. The method, combining fuzzy control and PID control, does not depend on the response model of the deformable mirror. Based on rapid wave front reconstruction, the wave front evaluation indexes, extracted from the reconstructed wave front, are employed for the input of fuzzy controller and PID controller. Thus, the model response matrix of deformable mirror is not required. Each actuator of deformable mirror corresponds to an independent fuzzy PID controller. By designing the fuzzy controller, including fuzzy rule base selection and fuzzy reasoning, the three parameters of PID controller, the proportional kp, the integral ki and the differential kd, are adjusted automatically. A high rapid DSP hardware platform is constructed to verify the method. Test results show that the method can be used to correct the diffraction limit multiplication factor of the light spot from 10-12 to 3-4, which is basically the same as the traditional PID control, but its stability is better. Because the model does not need to calibrate the deformable mirror, the installation of the deformable mirror is easier.