Integrated guidance and control based on block backstepping sliding mode and dynamic control allocation

A novel integrated guidance and control (IGC) design method based on the block backstepping sliding mode and extended state observer is proposed for the near space interceptor (NSI) with aerodynamic fins and reaction jets. Initially, the IGC model is employed by combining the interceptor-target relative motion model with the nonlinear dynamic of the NSI. Subsequently, the ESO is constructed to estimate the target acceleration and autopilot loop disturbance. Based on the estimated value and block backstepping sliding mode method, the IGC algorithm is given to obtain the virtual control moment. The stability of the closed-loop IGC system is also proven based on the Lyapunov theory. Moreover, a new dynamic control allocation algorithm is proposed to distribute the previously virtual control moment among the redundant actuators, while the actuator saturation and rate constraints are also taken into account. Finally, simulation results demonstrate that the proposed IGC algorithm can not only obtain a small miss distance, but also ensure the stability of the NSI dynamic.