Thrust Estimation System for Military Engine Test Cell Applications

Test cell acquisition of thrust data for the Joint Strike Fighter is often corrupted by vibrations, noise and interference associated with the test cell environment. Impact Technologies is partnering with Pratt and Whitney and Saratoga Control Systems, Inc. to develop a thrust estimation system based on a hybrid physics-based/empirical engine model to provide"virtual"measurements of thrust and other parameters of interest to test cell data reduction. The estimation system under development employs high-fidelity Numerical Propulsion System Simulation (NPSS) models as the embedded engine model in a constant-gain extended Kalman filtering structure. Employing this filtering structure in conjunction with a neural network empirical model allows for errors due to engine-to-engine variation, degradation, and test stand dynamics to be captured even during aggressive transients, resulting in a highly-robust reconstruction of thrust. To ensure penetration across engine platforms and test cell sites, it is proposed to first develop the estimation system using a commercial engine platform, then extend to a multi-axis military engine platforms. The multi-staged Phase II project is designed for full integration of the thrust estimation software in DoD/commercial engine test cells, while also fostering strong opportunities for insertion in on-board, model-based controls and diagnostic systems.