Performance Comparison of Different Observers for Pendubot

Amjad J. Humaidi, Abdullah A. Mohammed


The aim of the work is to study the robust characteristics and performance of four different observers when used to estimate the states of underactuated mechanical system (Pendubot). This work include four observation techniques for state estimation which are Extended State Observer (ESO), nonlinear extended state observer (NESO), Linear Extended State Observer (LESO) and High gain observer (HGO). The Extended State Observer is a model independent observer which includes (NESO, LESO and ESO); it is used for state disturbance observation beside state observation and it has been applied to many practical applications. HGO has a special design of the observer gain that makes it robust to the uncertainties of the nonlinear functions. The effectiveness of each observer is evaluated in terms of its tracking speed and the variance of estimation error which is produced when the system is subjected to noise, disturbance and uncertainties. The observers performances are compared based on simulations using MATLAB package. The simulation results showed that NESO outperforms the other observers where it could give better robust characteristics under noise and uncertainty.


Pendubot; ESO; NESO; LESO; HGO.

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