EVALUATION OF DISCRETE-TIME WELL-CONDITIONED STATE OBSERVERS

Model-based monitoring systems based on state observer theory often ha ve poor performance with respect to accuracy, bandwidth, reliability ( false alarms), and robustness. Previous works have investigated quanti tatively the above limitations from the machine monitoring viewpoint a nd have developed a design methodology for discrete-time well-conditio ned state observers. In this paper, the estimation performance of well -conditioned observers is demonstrated on a DC spindle system designed and built for this purpose. The results show that the robustness of t he estimate is similar to that obtained with the well-known Kalman fil tering technique. Additional simulation-based examples show that the t ransient as well as steady-state error robustness to perturbations is better than or equal to Kalman filter performance depending on the nat ure of the modeling error. Because of this robustness, the well-condit ioned observer for discrete-time systems is an important technique for the development of improved machine monitoring systems.