Adaptive Dynamic Programming-Based Attitude Optimal Tracking Control for a Quadrotor with Unmeasured Velocities and Model Uncertainties

This paper proposes an optimal output feedback tracking control scheme of the quadrotor unmanned aerial vehicle (UAV) attitude system with unmeasured angular velocities and model uncertainties. First, neural network (NN) is used to approximate the model uncertainties. Then, an NN velocity observer is established to estimate the unmeasured angular velocities. Further, a quadrotor output feedback attitude optimal tracking controller is designed, which consists of an adaptive controller designed by backstepping method and an optimal compensation term designed by adaptive dynamic programming. All signals in the closed-loop system are proved to be bounded. Finally, numerical simulation example shows that the quadrotor attitude tracking scheme is effective and feasible.