Using Tactile Cueing to Enhance Spatial Awareness under Degraded Visual Environment

Spatial orientation is critical for air operations. Perception of orientation is continuously maintained by accurate information from the visual, vestibular, and somatosensory systems in daily terrestrial activities. The various contributions of these senses can be significantly altered in variable gravitoinertial environments, or when one of the sensory cues is markedly reduced. The visual orientation system can be compromised during low visibility, or as a result of sudden loss of visual cues during ‘brownout’ while flying/landing in the desert or during ‘whiteout’ while flying/landing in snowy terrains. Current desert operations have led to an unacceptable number of terminal area aborts, mishaps and fatalities involving rotary wing aircraft throughout NATO due to "brownout". The use of a tactile interface as a “more natural” approach to convey position and motion perception was proposed some years ago [1]. Proof of concept studies has been conducted [2]. However, it is known that human perception of motion in 3 dimensional space involves roll, pitch, yaw, heave, sway and surge. Specifically, our ability to detect roll, pitch and heave are less sensitive. This study is to investigate if tactile cueing can enhance the detection and/or correction of roll, pitch and heave movements in degraded visual environments. A six degrees-of-freedom motion platform (MOOG 6DOF2000E) was used to generate the requisite motion in roll, pitch and heave separately. The tactile display system consists of a torso vest with a 3 rows by 8 columns array of tactors (EAI Inc C2 model), and tactors on two shoulder and two thighs straps respectively. Based on tactile cueing, blind-folded subject were to 1) indicate motion perception when devoid of all visual, auditory and artificial tactile cues, 2) return to vertical from an offset, 3) maintain straight and level while the platform is continuously in motion. The first study examines the effects of tactile cues along the spinal axis (heave motion) and a second study examines the effects on the roll and pitch axes separately. The experimental design is a within subjects repeated measures. The variables are: with and without tactile cues and the axis of motion. In this manuscript, we will present the data on the effects of tactile cueing in detecting heave motion only. Results showed that the tactile navigation system improves subjects’ performance in the ability to maintain neutral position along the spinal axis in the absence of visual and auditory cues. Tactile cueing also improves the subjects’ confidence in being able to return to the original position from an offset and that tactile cues were rated to be useful consistently. In conclusion, it appears that tactile cueing in the absence of auditory and visual cues; was useful in providing situation awareness and limits the amount of error made in the roll, pitch and heave axes. Future studies are required to study its effectiveness under simultaneous motion from all three axes.