Helicopter inverse simulation for workload and handling qualities estimation
Helicopter handling qualities are investigated using inverse simulation as the method of providing state and control information for the appropriate quantitative metrics. The main aim of the work was to develop a more comprehensive and versatile method of quantifying handling qualities levels using the available inverse algorithm "Helin v". Subsequently, the assessment of the helicopter model inherent in Helinv, "Helicopter Generic Simulation", (HGS) for its suitability to handling qualities studies was paramount. Since the Helinv inverse algorithm operates by initially defining a mathematical flight test manoeuvre for the vehicle to "fly", considerable time was given to modelling suitable handling qualities assessment manoeuvres. So-called "attitude quickness" values were then calculated thus providing an initial objective insight into handling qualities level of the vehicle under test. Validation of the tasks formed an integral part of successfully fulfilling the flight test manoeuvre development objective. The influence of the human is captured by the inclusion of a pilot model and the development of a novel method of parameter estimation, supplements the overall objective of modifying Helinv results to achieve potentially more realistic responses and thus correspondingly more realistic handling qualities. A comparative study of two helicopters, one based on the Westland Lynx battlefield/utility type and the other, a hypothetically superior configuration effectively demonstrates the capability of inverse simulation to deliver results adequate for initial handling qualities studies. Several examples are used to illustrate the point. Helinv has been shown to be versatile and efficient and can be used in initial handling qualities studies. The advantages of such a technique are clear when it is seen that actual flight testing, ground based or airborne is extremely costly, as the flight test manoeuvres must be representative of real life, reproducible and of course, as risk free as possible. Many inverse simulation runs and handling qualities calculations have been carried out for different helicopter configurations and manoeuvres thus illustrating the advantages of the technique and fulfilling all the aims mentioned above.