Unmanned aerial vehicles (UAVs) comprise various types of aircrafts such as conventional fixed-wing aircraft, helicopters, blimps, and air- ships. Among these, helicopters are classified as planar vertical take off and landing (PVTOL) aircraft by which it means that unlike a fixed-wing aircraft, it can take off and land in a limited space, hover in the air, and move sideways and backwards. This superior maneuverability allows performing important roles in many areas, which conven- tional aircraft could not achieve. The type of their useful work includes: dangerous applications such as in a war, victim rescue and volcano monitoring, where other types of vehicle are inaccessible, commercial application such as film making, and agricultural applications, farm monitoring and spreading chemicals [1]. The demand for UAVs keeps increasing. Unfortunately these exclusive maneuverability advantages give a big complexity and instability in its dynamics, hence making it hard to control. The development of a UAV is challenging, and it is an emerging area in nonlinear control study among researchers.