Position and Attitude Separation Control for Tiltable Quadrotors: An Appointed-Time Prescribed Performance Anti-Disturbance Approach

Aiming at the position and attitude separation control problem of the “X” configuration tiltable quadrotor, an appointed-time prescribed performance anti-disturbance control method is proposed. Firstly, the tiltable quadrotor’s model description and dynamic model are presented, in which the virtual control inputs are defined to solve the non-affine control allocation problem trickly. Then, appointed-time prescribed performance control laws are designed for position and attitude angle control subsystems to guarantee tracking errors’ transient and steady-state performance. Furthermore, fixed-time extended state observers are designed to compensate for the lumped disturbance in velocity and angular rate control subsystems. And the quadratic programming method is used to solve the control allocation problem considering energy optimization. Finally, the simulation results demonstrated the effectiveness of the proposed method.