Feedforward Compensation Enhanced Disturbance Rejection Control for a Spin-Stabilized Guided Projectile Subject to Actuator Rate Limit

This article addresses the control problem for a spin-stabilized guided projectile which is subject to strong couplings, disturbances, and actuator rate limit. The internal uncertainties and external disturbances are lumped as a state, which is estimated by a reduced-order extended state observer. To enhance the decoupling performance, the dynamics related to the inertia, aerodynamic, and manipulation couplings are compensated by feedforward. Further, to alleviate the adverse effect of the actuator rate limit on the control performance, the describing function method is employed to design the feedforward rudder deflection command. Stability margin tester method is proposed to facilitate the tuning process. Finally, nonlinear 6-DOF simulations are performed to validate the effectiveness of the proposed control method.