Stephen Paul Linder 

Robust Qualitative and Quantitative Methods
for
Disturbance Rejection and Fault Accommodation

Tuesday December 16th
3:30 PM
206 Egan Center

Abstract

Disturbances caused by unmeasured inputs, plant perturbations or faulty actuators degrade the robustness and performance of both control and diagnostic systems. When these disturbances are unknown, robust accommodation of disturbances requires elaborate architectures. We, however, propose two new simple accommodation methodologies: one quantitative and the other qualitative. The quantitative methodology uses the integral action of the Proportional Integral (PI) Observer and Adaptive Observer to estimate and accommodate disturbances. Our second methodology is based on qualitative models and uses stability and tracking behaviors, implemented with fuzzy rules, to achieve robust rejection of disturbances. Validation studies show that integral action is effective in estimating disturbances caused by unmeasured inputs, plant perturbations or faulty actuators, and a PI Observer-based controller will even outperform a Linear Quadratic Regulator in the presence of nonlinear actuator faults. The qualitative approach was validated with the 1992 ACC Robust Control Benchmark. Our fuzzy controller is the first published intelligent controller for the Benchmark, and achieves stability robustness and tracking robustness comparable to the best published compensators for the Benchmark.