Dynamic compensator for a synthetic-jet-like compression driver actuator in closed-loop cavity flow control

Abstract

This paper considers development of an dynamic compensator for a synthetic-jet-like compression driver actuator, which has been successfully used for feedback control of subsonic cavity flow. System identification and feedback control design are performed using the experimental data of actuator dynamics. Subspace-based identification method is implemented to construct an control-oriented actuator model containing time delay. The resulting model matches the physical system effectively in the frequency domain, covering the frequency range of cavity oscillation where the actuator operates. Based on a Smith-predictor-type control structure, H∞ mixed-sensitivity method is employed to synthesize a feedback controller for the actuator system. The feedback controller forces the actuator output to closely follow a control signal generated by a cavity now controller, thereby compensating the undesirable actuator dynamics. Integration of the actuator compensator with the cavity control system improves the overall control performance by reducing uncertainties caused by the actuator dynamics.