Cooperative Nonlinear Aircraft Defense Using Super Twisting Algorithm with State Constraints

This paper addresses the problem of cooperative guidance design for aircraft defense systems involving a target, a defender, and an attacker, using a super-twisting algorithm and barrier Lyapunov function. The system dynamics involve unknown functions, which are treated like disturbances and estimated using an observer. Imposing practical assumptions on the lateral accelerations of the vehicles, we propose a robust guidance design also to constrain the system states by definite bounds. We derived the controller using generalized triangle guidance concepts that provide these bounds for the states. Guidance commands are derived without any kind of linearizations that enable a wider domain of applicability of the proposed approach. The convergence is analyzed using a Lyapunov function. Simulation results are presented to study the efficacy of the proposed approach.