Thrust Control for a Turbofan Engine Using Estimation

Abstract

A thrust control concept for a military turbofan engine is evaluated at sea level and static operation. Most of the design is performed in the linear domain and most validations are done by simulations of nonlinear models. The thrust control is included as an add-on to a robust and multivariable control concept. The presented methods are also applicable for control of other estimated properties. The thrust in this concept is estimated from engine measurements and engine control inputs and both a linear and a nonlinear estimator are presented. The simulation results are promising and the design methods are straight forward. For the estimator a Kalman filter is designed and the thrust control loop are simplified to a single input single output system with the estimator included, which allows standard design methods to be applied. For the operating regime the linear designs have also shown to be applicable to the nonlinear system.

Performance Comparison of Control Strategies for a Variable-Thrust Solid-Propellant Rocket Motor

“…Since it is hard to obtain thrust information directly in flight status, the thrust feedback control system uses an indirect method that estimates the thrust information using combustion pressure and nozzle throat area information as the dashed line in Figure 10. Generally, the Luenberger observer or Kalman filter, based on the mathematical model of the system, is used for the indirect method [39][40][41]. In this study, we assumed a ground test that can obtain thrust information directly by using a force sensor as the dotted line in Figure 10 to be simplified.…”