Integrated flight control design and handling qualities analysis for a tilt rotor aircraft

Design of a tilt rotor aircraft control system to acheive consistent handling qualities throughout the operational flight envelope is a difficult task and results in substantial cost and time. Development of integrated methods for flight control design and handling qualities analysis can greatly expedite the design process. In this study, a model inversion based flight control system is developed for a XV-15 tilt rotor aircraft simulation model, and the system is evaluated for handling qualities across the envelope of a predefined Search and Rescue mission. This work finds that the controller achieves Level 1 handling qualities for most of the specifications. Some notable exceptions are found to be due to actuator rate limits and are deemed to be unavoidable with the given actuator specifications. Mission-task-elements evaluations were performed by test pilots using the HELIFLIGHT simulation facility at University of Liverpool, where the pilots provided Cooper-Harper handling qualities ratings to evaluate the perceived workload and performance. There were some issues with the airplane mode controller during evaluation, however, the hover and low speed controllers showed Level 1 handling qualities during piloted simulation tests.