Sliding mode based attitude and acceleration controller for a velocity-varying skid-to-turn missile

Sliding mode based roll-pitch-yaw integrated attitude and acceleration controller for a fin-controlled skid-to-turn(STT) missile is proposed. In terms of aerodynamics, the missile model has severe nonlinearities and coupling effect between input channels and roll-pitch-yaw angles that make the controller design challenging. Moreover, the controller should be designed for the entire flight envelope consisting of boost-phase and gliding-phase where rapid velocity variation exists, and therefore parametric robustness with respect to rapid velocity change is strongly required. The attitude autopilot controls the Euler angles of the missile, and is configured as a single-loop. On the other hand, the acceleration autopilot, which is of two-loop structure, is used for the control of STT maneuver. The proposed autopilots use multiple sliding surfaces to generate control inputs for multiple channels simultaneously. Numerical simulation is performed to verify the performance of the proposed controllers.