**6. Discussions**

This chapter presented an IBS controller derived based on the Backstepping controller for quadrotor UAVs leader-follower team formation problem. Two loops control scheme was used in simulation to find the total thrust and torques. A *PD*<sup>2</sup> controller was used for attitude part control, while the IBS controller was used to control the translation part of the quadrotors. The dynamic model of the quadrotor was derived based on Euler angles and the effect of the external disturbance and the model parameter uncertainties are also considered.

It is well-known that IBS control is a methodical approach to build the Lyapunov function ahead with the control input design. Thus by the cancellation of the indefinite error terms, the stability of the derivative of the Lyapunov function can

## *Integral Backstepping Controller for UAVs Team Formation DOI: http://dx.doi.org/10.5772/intechopen.93731*

be secured. Although the stability of the Lyapunov function is guaranteed, this does not guarantee the performance of the system. In this work, a suitable Lyapunov function was used to derive the controller stability conditions.

The simulation results prove that the performance by using the IBS controller had significantly small errors. It is also obvious that using the IBS controller led to a smooth and fast performance with small overshoot. Moreover, the response of using the proposed controller in rejecting the external disturbances was fast enough.

As a result, the proposed IBS controller indeed produced good control performance in all circumstances.
