Cross-track control of UAVs during circular and straight path following using sliding mode approach

This paper presents a sliding mode based lateral (cross-track) control scheme for Unmanned Aerial Vehicles (UAVs). Proposed scheme is based on a non-linear sliding surface that gives good performance during both large and small cross track errors. The main contribution of this paper is to develop a robust lateral control law that can keep cross track error near to zero during straight path following as well as during circular path following. A major problem of control saturation is also addressed here and control effort boundedness with proposed control law is proved here in this paper. Proposed control law is implemented on a 6-degrees-of-freedom (6-dof) simulation of a UAV and different scenarios of straight/circular path following is simulated. Proposed control law gives good performance in all cases in the presence/absence of environmental disturbances.