Continuous and discrete gust responses of elastic missiles

Elastic missiles in atmosphere may have intense response due to gust excitation, which has great influence on structural safety, flight performance, and attack precision. Approaches of the calculations of aeroservoelastic response to the continuous and discrete gust for missiles were presented. The equations of motion considered the interaction of rigid-body modes and elastic vibration modes, and the generalized aerodynamic forces were formulated in a way of quasi-steady aerodynamics. The approach of the continuous gust response was based on the calculation of the power spectral density (PSD) using frequency-domain transfer functions. The approach of the discrete gust response was a time-domain integral based on the state-space formulation of the aeroservoelastic system. An actual process of evaluating aeroservoelastic stability, calculating continuous and discrete gust response, and modifying flight control system for a cruise missile was demonstrated. Numerical results indicate that adverse coupling between structure and control system may deteriorate the stability and gust response of the system. An appropriate structural notch filter in the control loop can effectively alleviate the adverse effects of elastic modes.