SDRE based integrated roll, yaw and pitch controller design for 122mm artillery rocket

State-dependent Riccati equation (SDRE) based controller design is an emerging trend in real world applications. This paper describes the design of an integrated roll, yaw and pitch attitude controller for a fin stabilized and canard controlled 122mm artillery rocket using SDRE technique. The rocket configuration considered is with front canards and foldable straight tail fins, and is given initial spin at the time of launch. Tails fins are deployed immediately after launch and offer high roll damping moment thereby reducing the spin rate to zero within six seconds of flight. The canards are then deployed and the roll orientation of rocket is regulated to zero with the canard deflection commands generated by the SDRE based roll autopilot. Once the roll orientation of rocket is brought to zero, the full state integrated roll, yaw and pitch autopilot comes into action. Elements of the state weighing matrix for Riccati equation have been chosen to be state dependent to exploit the design flexibility offered by the Riccati equation technique. Simulation results show significant reduction in impact point dispersion with the attitude controlled trajectory as compared to uncontrolled trajectory. Monte Carlo simulations have been performed to prove the efficacy of the proposed controller design even in the presence of wide range of deviations in rocket parameters.