Simulation evaluation of a pilot interface with an automated rotorcraft obstacle avoidance system

Pilot interface with an automated nap-of-the-earth (NOE) rotorcraft guidance and control system was investigated in the NASA Ames Research Center´s fixed-base Interchangeable Cab (ICAB) simulator facility. The interface concept, referred to as pilot-directed guidance (PDG), involves interpreting pilot inputs as high-level commands to an inner-loop automatic guidance and control system. With this interface, a pilot can concentrate upon primary course guidance and secondary cockpit tasks by delegating obstacle detection and avoidance tasks to an automatic system. An advantage of the PDG concept is that it allows far continuous pilot interaction which has been shown to be important for pilot acceptability. The paper first describes the inner loop Automated Nap-of-the-Earth Guidance and Control System (ANGCS) and the associated PDG interface, followed by the findings from the fixed-base simulation. The simulation was designed to assess pilot-in-the-loop performance of the PDG-ANGCS technology and determine its effectiveness at reducing pilot workload. Head-up symbology, including inertial course information and critical aircraft states, was presented to the pilot through the Integrated Helmet and Display Sighting System (IHADSS) with head tracking. A typical NOE obstacle course was flown both manually and with the PDG system at various airspeeds and visibility conditions for a comparative performance and workload study