Position trajectory tracking of a quadrotor helicopter based on L1 adaptive control

We present an adaptive backstepping controller for the position trajectory tracking of a quadrotor. The tracking controller is based on the L1 adaptive control approach and uses a typical nonlinear quadrotor model. We slightly modify the L1 adaptive control design for linear systems to comply with the time-varying nonlinear error dynamics that arise from the backstepping design. Our approach yields a stable adaptive system with verifiable bounds on the tracking error and input signals. The adaptive controller compensates for all model uncertainties and for all bounded disturbances within a particular frequency range, which we specify a priori. The design of this frequency range involves a trade-off between control performance and robustness, which can be managed transparently through the L1 adaptive control design. Simulation results show the powerful properties of the presented control application.