Helicopter Handling Qualities: A study in pilot control compensation

Abstract

The research reported in this paper is aimed at the development of a metric to quantify and predict the extent of pilot control compensation required to fly a wide range of mission task elements. To do this, the utility of a range of time- and frequency-domain measures to examine pilot control activity whilst flying hover/low-speed and forward flight tasks are explored. The tasks were performed by two test pilots using both the National Research Council (Canada)’s Bell 412 Advanced Systems Research Aircraft and the University of Liverpool’s HELIFLIGHT-R simulator. Handling qualities ratings were awarded for each of the tasks and compared with a newly developed weighted adaptive control compensation metric based on discrete pilot inputs, showing good correlation. Moreover, in combination with a time-varying frequency-domain exposure, the proposed metric is shown to be useful for understanding the relationship between the pilot’s subjective assessment, measured control activity and task performance. By collating the results from the subjective and objective metrics for a range of different mission task elements, compensation boundaries are proposed to predict and verify the subjective assessments from the Cooper-Harper Handling Qualities Rating scale.

Advanced pilot modeling for prediction of rotorcraft handling qualities in turbulent wind

“…It can be found that pilots use a combined tracking/compensatory control strategy to achieve a steady coordinated turn in forward flight [42]. The primary control is centered on the lateral axis and the compensation control activities in the other three axes are required to reduce undesired rotorcraft responses suffering from inter-axis coupling and atmospheric disturbances.…”

“…Therefore, lateral control plays the leading role when a pilot rates the HQs level for the UH-60A helicopter flying a slalom MTE while the other channels are secondly important to coordinate with the primary control [42].…”

Moving Spatial Turbulence Model for High-Fidelity Rotorcraft Maneuvering Simulation

“…The metric is defined as the ratio of the total number of A η that the pilot applies a particular control (>a threshold value) to the period of the task. The threshold value in this paper is selected as 2.5% of the full control range to capture 'productive' control inputs accounting for guidance and stabilization control activity [30]. The control activity rate (A ηR ) indicates the average 'busyness' metric of the task, but it masks local peaks in pilot control activity.…”

“…However, pilots assign the level of HQR based on the most challenging phase of a task rather than the average. To identify the phase(s) within the task where a pilot is working hardest, Memon et al [30] extended the metric to a time-varying localized attack activity rate (A t ηR ). The method includes the formulation of a control segmentation approach using a moving 5-s window with 2.5-s overlap between windows…”

“…Hz for Level 2[30]. This paper selects the intermediate values of 0.65 Hz for Level 1 HQR and 1.8 Hz for Level 2.Figures 13 and 14present the time profiles of desired velocities and wind conditions.…”