Active Regulation of Speed during a Simulated Low-Altitude Flight Task

Proceedings of the Human Factors and Ergonomics Society Annual

2010

During simulated low-altitude flight, participants' control of speed is based on the optical flow rate projected by the ground, even when changes in altitude make this information unreliable and other sources of speed information, such as the flow rate of a cloud layer above the flight path, could help to provide more valid information (Wotring, 2008). This study examined whether this ground bias in perceiving speed could be overcome by using a secondary visual search task to manipulate the attentional focus away from the ground. A task requiring participants to visually scan for potentially-colliding planes either above or below the horizon was coupled with a speed maintenance task similar to the task used by Bennett, Flach, McEwen & Russell (2006) and Wotring, Dyre, & Behre (2008). We found that altitude disturbances induced inappropriate speed control in a similar manner independent of whether the secondary task required the attentional focus to be directed above or below the horizon. These results suggest that ground bias in speed control is robust even when attention is directed above the horizon by a secondary visual task.

Section: Introductionmentioning

confidence: 81%

“…The joystick gains and disturbance time series were subjected to spectral analysis in a manner similar to Bennett et al (2006) and Wotring et al (2008).…”

Section: Spectral Analysis Of Joystick Amplitude At Altitude and Speementioning

confidence: 99%

Attentional Locus and Ground Dominance in Control of Speed during Low Altitude Flight

Adamic

Behre

Proceedings of the Human Factors and Ergonomics Society Annual

2010

“…The joystick gains and disturbance time series were subjected to spectral analysis in a manner similar to Bennett et al (2006), Wotring et al (2008), and Adamic et al (2010).…”

Section: Discussionmentioning

confidence: 99%

Further Evidence for Ground Dominance in Control Of Speed During Low Altitude Flight

Meyer

Adamic

Proceedings of the Human Factors and Ergonomics Society Annual

2013

Previous research found that during simulated low-altitude flight, optical control of speed is based on the flow rate projected by the ground, even when changes in altitude make this information unreliable and other sources of speed information, such as the flow rate of a cloud layer above the flight path, could provide more valid information. However, in these studies factors such as color and contrast differences between the ground and clouds may have contributed to ground dominance. Further, it is possible that ground dominance results from an inability to integrate flow distributed across different surfaces in the environment. Here we report two experiments that test whether these factors contribute to ground dominance. We found ground dominance to be independent of color and contrast differences between the ground and cloud surfaces and that control of speed is based on global optical flow defined across multiple surfaces when these surfaces do not represent the ground.

“…While previous research showed that changes in GOFR due to altitude changes can affect judgments of speed (Ballard, Roach, & Dyre, 1998;Larish & Flach, 1990;Owen & Wolpert, 1984), to date there is no conclusive evidence that altitude changes induce inappropriate control of speed. Bennett, Flach, McEwen, and Russell (2006) developed a sophisticated methodology to examine this issue. Participants in their study attempted to maintain constant forward speed during a simulation of low-altitude flight over a textured planar surface with a clear textureless sky.…”

Section: Introductionmentioning

confidence: 99%

“…Two methodological features of the Bennett et al (2006) study might explain why they failed to find reliable cross-talk between altitude changes and speed control. First, Bennett et al used a ground texture that consisted of a low spatial frequency checkerboard pattern (See Figure 1a).…”

Section: Introductionmentioning

confidence: 99%

Cross-Talk between Altitude Changes and Speed Control during Simulated Low-Altitude Flight

Wotring

Proceedings of the Human Factors and Ergonomics Society Annual

Behr

2008

Simulations of flight over a planar environment create an ambiguous optical stimulus in which changes in altitude can potentially induce inappropriate control of speed. Previous research has shown that changes in altitude produce changes in global optical flow rate that lead to erroneous judgments of speed and increased RMS error in speed control. However, from these studies it is unclear whether erroneous speed control was directly due to misperceiving changes in altitude as changes in speed or simply a response to more complex optical flow masking the optical effects of speed changes. Our experiment used a speed maintenance task during simulated flight over a planar surface to examine the effect of changes in altitude on control of speed. We found that power in participants' speed control input increased at the specific frequencies of the simulated altitude changes relative to power at those same frequencies when no altitude disturbance was present. These results clearly show that controllers respond to altitude changes as if they are changes in speed during simulated flight over a planar environment. Hence, the optical effects of altitude changes appear to be perceived as changes in speed and induce systematic errors in speed control.