Simulation Validation Through Linear Model Comparison

Abstract : The Manned Flight Simulator at the Naval Air Warfare Center in Patuxent River, MD maintains high fidelity fixed and rotary wing simulation models. The aircraft simulations are utilized for a wide range of activities including flight test support, pilot training, and control law analysis and design. Validating aircraft math models against flight test data is an important part of the simulation process. Linear model comparison was used to validate the lateral-directional dynamic modes of the V-22 tilt-rotor aircraft in airplane mode. In this technique, linear model approximations of the simulation and aircraft dynamics are calculated independently and then compared. The simulation linear state-space model was extracted from the nonlinear V-22 simulation using a perturbation method. The aircraft linear state-space model was fit to flight test data from lateral-directional maneuvers using parameter identified tools. Time history comparison were used to verify both linear models. Comparison of the lateral-directional modes and the stability and control derivatives of the two models were made. The differences between the two models were used to locate potential problems with the nonlinear simulation.