Fatigue Evaluation of a MH-60 Helicopter Input Device

Abstract

A preliminary report from a crew station working group (CSWG) suggested that the 0° orientation (from an aerial view) of a new trackball for the MH-60 may introduce undue fatigue for operators. Feedback from the CSWG suggested that this fatigue may be reduced by rotating the trackball inboard in order to keep the wrist straight. To investigate this, in Experiment 1 participants used the trackball for an extended period of time (90 minutes) from various angles (0°, 12°, and 90°). The results from Experiment 1 suggested that 12° was the preferred angle, but qualitative comments suggested that more cant was needed. To address this, in Experiment 2 the angle of the trackball was adjustable from 15° to 35°. Linear regression models estimated the optimal angle to be approximately 25°, confirming the earlier qualitative comments from Experiment 1. Given the broad range in preferred angles, a rotatable trackball was recommended. Furthermore, the qualitative comments from Experiment 1 and 2 were organized into various categories in order to provide additional recommendations for the design of the trackball.