Liquid crystal phased array beam deflection control with triple-step method

This paper proposes a triple-step control method to achieve rapid, accurate, and stable beam deflection of a liquid crystal phased array (LCPA). The LCPA model is obtained with a system identification method, and a triple-step method controller is designed that comprises three parts: quasi-steady state control, reference feedforward control and error feedback control. Among them, the quasi-steady state control is used to improve the system’s response speed and the accuracy of control; the reference feedforward control is used to improve the system’s tracking performance; and the error feedback control is used to reduce the errors caused by modeling deviation and external disturbance. The controller has a simple structure, and each control step has a clear meaning. The system performance is analyzed with step response test, tracking performance test and robustness test. The results show that the LCPA beam deflection system with the triple-step method has a rapid response speed, high control accuracy, good tracking performance and strong robustness.