Comparative analysis of linear and non-linear extended state observer with application to motion control

The design of observer for estimating states, disturbances, and uncertainty in plant dynamics is an important step for achieving high performance model based control schemes. This paper gives the estimation of states and lumped uncertainty by using extended state observer (ESO) and feedback linearization technique; moreover the question raised in this paper is which ESO stands effectively when maximum information of plant is not known? And can we achieve robust control if sensor calibration fails in real time? Simulation results says that nonlinear extended state observer (ESO) actively estimate the states, uncertainty and unknown disturbances when maximum information of the plant is not known as compared to linear extended state observer (LESO). The beauty of estimating lumped uncertainty by extended state of ESO adds an advantage that, dependency of sensor is no more required.