Comparison of Nonlinear Tracking Controllers for a Compressible Flow Process

Abstract

Comparisons are made of two pressure-temperature controllers for a wind-tunnel type compressible flow process that includes control of pressures across a converging nozzle. Nonlinear flow characteristics of the nozzle present the key challenge for tracking rapid command trajectories. One controller is a linear integral-plus-state feedback configuration with gain scheduling. The other is a model-following controller that includes a feedforward inverse-process model to decouple and linearize the system. Simulation testing is used to compare the controllers, and sensitivity to feedforward modeling errors and feedback bandwidth is evaluated. Operational and implementation features are also compared.