Performance of Non-linear Observers for Closed loop Terminal Sliding Mode Control of Quadrotor UAV

This paper deals with the comparative analysis of high gain Observer (HGO), sliding mode observer (SMO) and sliding mode observer with super-twisting algorithm (STSMO) for a remotely controlled quadrotor UAV. Under the restriction that inertial co-ordinates and attitude angles are available for measurement while angular and linear velocities are estimated. This paper is solved in two steps for each observer. First, the observers (HGO, SMO and STSMO) are designed and then, in second stage a terminal sliding mode technique is being applied on the basis of estimated states to design controller. The performance of the non-linear observers are appraised in terms of their output feedback response, ability to confront with model fallibility and uncertainties such as sensor noise and random initial conditions. Simulations results shows the closed loop output feedback based performance comparison of aforementioned observers with terminal sliding mode control as a control scheme.