Attitude tracking of KKV based on adaptive backstepping sliding mode control

Aiming at the problem of exo-atmospheric kinetic kill vehicle (KKV) attitude tracking with the characters of constant thrust, nonlinearity, strong couplings and parameter uncertainties, a novel sliding mode controller was designed which is based on adaptive backstepping theory. The attitude coupling mode was established which considered about interaction between three channels and control torque in control loop. The actual control laws and virtual control laws were derived based on the design procedures of sliding mode control and backstepping control, respectively. An adaptive method was introduced to estimate and compensate the model couplings and uncertainties, which improved the accuracy of altitude control. The pulse control laws which could be used for attitude control directly, were calculated from the continuous laws with PWPF modulation. The simulation results show that attitude tracking still satisfies requirements with parameters and disturbance uncertainties.