Unmatched Perturbation Accommodation for an Aerospace Launch Vehicle Autopilot Using Dynamic Sliding Manifolds

Sliding mode control of a launch vehicle during its atmospheric flight phase is studied in the presence of unmatched disturbances. Linear time-varying dynamics of the aerospace vehicle is converted into a systematic formula and then dynamic sliding manifold as an advanced method is used in order to overcome the limited capability of conventional sliding manifolds in minimizing the undesired effects of unmatched perturbations on the control system. At the end, simulation results are evaluated and the performance of two approaches are compared in terms of stability and robustness of the autopilot.