Autopilot design of longitudinal STT cruise missile based on NDI

A longitudinal controller of STT cruise missile based on nonlinear dynamic inversion is presented according to the feature that the longitudinal model of STT missile is highly nonlinear and includes parameter uncertainties. The states of the missile´s dynamics are divided into two subsystems based on the time-scale separation, which is the inner and the outer loop. Common control method is adopted to the faster loop and NDI method based on variable structure is designed to the slower one. Simulation studies demonstrate that the proposed method is rightness and effectiveness, can ensure the flight stability of the cruise missile and is valid in vertical velocity command and air speed command tracking.