Verifiable Control System Development for Gas Turbine Engines

Abstract

A control software verification framework for gas turbine engines is developed. A stability proof is presented for gain scheduled closed-loop engine system based on global linearization and linear matrix inequality (LMI) techniques. Using convex optimization tools, a single quadratic Lyapunov function is computed for multiple linearizations near equilibrium points of the closed-loop system. With the computed stability matrices, ellipsoid invariant sets are constructed, which are used efficiently for DGEN turbofan engine control code stability analysis. Then a verifiable linear gain scheduled controller for DGEN engine is developed based on formal methods, and tested on the engine virtual test bench. Simulation results show that the developed verifiable gain scheduled controller is capable of regulating the engine in a stable fashion with proper tracking performance.