In-Flight Turbulence Emulation for Fixed-Wing Aircraft using Equivalent Multisine Excitations

A procedure is discussed for designing control-equivalent turbulence input (CETI) excitations to emulate a fixed-wing aircraft response to turbulence while flying through calm air. These excitations are added to the actuator commands to produce the same motion of the aircraft that would have resulted from flying in actual turbulence. Although CETI models are usually shaping filters driven by white noise inputs, the equivalent control inputs in this report were constructed as multisine excitations, which enables mimicking the response to turbulence with arbitrary power spectra, within hardware limitations. Practical aspects of the approach are discussed, such as actuator dynamics, model uncertainty, actual in-flight turbulence, and others. The procedure is demonstrated using a flight dynamics simulation model of a subscale generic jet transport aircraft.