A Combined Technique for Inverse Simulation Applied to Rotorcraft Shipboard Operations

Inverse simulation techniques are computational methods that determine the control inputs to a dynamic system required to produce desired system outputs. Such techniques can be useful tools for the analysis of rotorcraft shipboard operations. A combined technique is developed that serves as an efficient inverse simulation tool for analyzing rotorcraft maneuvering flight. This inverse technique is a combination of the integration based and differentiation based approaches in such a fashion that the numerical differentiation and Newton iterations are only performed at selected points along the flight trajectory rather than at each time step. The resulting control history is then set as an input to a forward simulation and the tracking error is corrected by an online feedback compensator. Examples of inverse solutions for a helicopter shipboard departure and a shipboard approach are presented.