New Predictive Filters for Compensating the Transport Delay on a Flight Simulator

Abstract

The problems of transport delay in a flight simulator, such as its sources and effects, are reviewed. Then their effects on a pilot-in-the-loop control system are investigated with simulations. Three current prominent delay compensators—the lead/lag filter, McFarland filter, and the Sobiski/Cardullo filter were analyzed and compared. This paper introduces two novel delay compensation techniques—an adaptive predictor using the Kalman estimator and a state space predictive filter using a reference aerodynamic model. Applications of these two new compensators on recorded data from the NASA Langley Research Center Visual Motion Simulator show that they achieve better compensation over the current ones. Nomenclature t d = transport delay = state transition matrix = integral matrix of the state transition matrix K = Kalman gain matrix x a = aircraft state vector x = filter state vector x p = predicted filter state vector y = aircraft state output to the visual system y p = predicted aircraft state output u = control input from the simulator operator % = Estimation by the Kalman estimator i = time index during simulation s = Laplace operator