Evaluation of Helicopter Performance Indicators for use in the Development of Digital Twin based on Physiological Sensor Data from the Aviator
Authors: Feltman Kathryn , Kelley Amanda 
Published: June 2024

Ongoing work within the military, as well as in the civilian sector, continues to pursue the goal of operator state monitoring (OSM) through physiological metrics. The overarching goal of this effort is to provide a near real-time objective assessment of an operator’s state that is predictive of performance degradation. It is anticipated that such an endeavor would result in a human digital twin system (HDTS) (Miller & Spatz, 2022), whereby the physiological data collected from the human operator would be used to model and predict operator states under different flight conditions, subsequently used to predict future performance. Creation of such a system will require large quantities of data that will need to be accumulated from a variety of flight conditions (i.e., weather) and types of maneuvers (e.g., hover, takeoff). Although significant progress has been made to-date, a key component remains undefined. We have yet to define what aspects of performance are critical to be predicted within such a system. To maximize the utility of OSM within an operational setting, detecting when performance is likely to degrade, or has begun to degrade, is essential for the system to make use of this information, ultimately engaging some form of adaptive automation – through an HDTS. While a plethora of work has been completed to-date to determine the performance parameters necessary for implementing various cues to the aviator or in some cases, automation (e.g., automatic ground collision avoidance system), much of this work has been done with a relatively narrow scope. Ongoing work, through literature review, is aimed at evaluating performance parameters to determine what aspects of aviator performance have been demonstrated to indicate adequate performance across different maneuvers. Alongside this effort, we have recently evaluated the effects of various cues (auditory and tactile) within a UH-60 full-motion simulator on different performance outcomes (Feltman et al., 2024). While manipulating these cues, we evaluated the physiological data and performance outcomes of 16 Army aviators. From this study, we measured approach performance using a parameter derived from one of the visual cues (vertical speed indicator). The performance outcome was the amount of time participants spent within the target range of this visual cue, which indicated adequate performance for the task. Using this as an outcome measure, we demonstrated that auditory and tactile cueing combinations had different effects on this measure, F(3, 297) = 3.76, p = 0.011. The physiological data collected concurred with the findings of performance data, where those with better performance on this outcome measure showed increased physiological arousal (increased heart rate, F[3, 118] = 8.02, p < 0.0001, decreased heart rate variability, F[3, 118] = 9.39, p < 0.0001). Taken together, the result of this study provides an initial step toward defining flight performance outcomes that correspond with changes in physiological parameters of the aviator. Ongoing work continues to evaluate various types of performance measures that may be used independently or in combination with others (to create an index) for the purposes of OSM/HDTS development.