Abstract: Autonomous unmanned aerial vehicles provide the possibility of performing tasks and missions that are currently hazardous or can cost lives. Here a nonlinear model of the unmanned aerial vehicle is used in order to describe the longitudinal dynamics which is highly complicated in itself. Therefore an adaptive back stepping controller is employed, the underlying feature of which is a dynamic parameter adaptation law. The control input is derived based on the Lyapunov stability theorems, that guarantees asymptotic stability design phase itself. The control law along with the parameter adaptation law gives a better regulation when compared with other linear control techniques. Software implementation is carried our using MATHLAB Simulink. Simulation results validate the fact that the controller works satisfactory.

Keywords: Unmanned Aerial Vehicles; Lyapunov stability; Adaptive back stepping controller