Automatic Inceptor Decoupling System in Electronically Coupled Active Sidesticks for Dual Pilot Helicopters

Abstract

The active inceptor system provides the ability to electronically couple the pilot’s and copilot’s inceptors in dual pilot helicopters. Also, a novel inceptor decoupling can be programmed in order to prioritize one pilot control station in case of inceptor obstruction or force fight between pilots. Through the measurement of the forces in real time, the inceptors are automatically decoupled if both pilots apply forces in opposing directions above the specified force threshold. The paper aims to investigate maximum force threshold for the automatic inceptor decoupling that still can be acceptable in terms of controllability. To this end, four test pilots participated in the experimental tests in a ground-based simulator featuring active inceptors in a dual pilot helicopter cabin. The safety severity envelope were developed and validated through takeover control tasks in low level flights. The maximum force threshold for automatic inceptor decoupling is found to be 30 N in pitch axis, i.e., that the maximum force threshold which control oscillations are linked at least to level 2 handling qualities. Additionally, an active force fading logic is implemented and showed to effectively reduce the control activity and helicopter attitude variation during the automatic inceptor decoupling.