Backstepping based Nonlinear Flight Control Strategy for 6 DOF Aerial Robot

In this paper a nonlinear model of a 6-DOF quad rotor aerial robot is derived, based on Newton-Euler formalism, and backstepping based PID flight control strategy is implemented for motion control of the derived model. The derivation comprises determining equations of motion of quad rotor aerial robot in three dimensions and seeking to approximate actuation forces through modeling of the aerodynamic coefficients and electric motor dynamics. The derived MIMO model, constituted of translational and rotational subsystem, is dynamically unstable. A nonlinear control strategy that includes integrator backstepping control for the translational subsystem and backstepping based PID control for the rotational subsystem is implemented for the quad rotor aerial robot. The stability of the control design is ensured by Lyapunov global stability theorem. The performance of the nonlinear control algorithm is evaluated using nonlinear simulation. Results from nonlinear simulation validate effectiveness of the designed control strategy for quad rotor aerial robot near quasi stationary (hover or near hover) flight.