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Many individuals with disabling conditions have difficulty with gait and balance control that may result in a fall. Exoskeletons are becoming an increasingly popular technology to aid in walking. Despite being a significant aid in increasing mobility, little attention has been paid to exoskeleton features to mitigate falls. To develop improved exoskeleton stability, quantitative information regarding how a user reacts to postural challenges while wearing the exoskeleton is needed. Assessing the unique responses of individuals to postural perturbations while wearing an exoskeleton provides critical information necessary to effectively accommodate a variety of individual response patterns. This report provides kinematic and neuromuscular data obtained from seven healthy, college-aged individuals during posterior support surface translations with and without wearing a lower limb exoskeleton. A 2-min, static baseline standing trial was also obtained. Outcome measures included a variety of 0 dimensional (OD) measures such as center of pressure (COP) RMS, peak amplitude, velocities, pathlength, and electromyographic (EMG) RMS, and peak amplitudes. These measures were obtained during epochs associated with the response to the perturbations: baseline, response, and recovery. T-tests were used to explore potential statistical differences between the exoskeleton and no exoskeleton conditions. Time series waveforms (1D) of the COP and EMG data were also analyzed. Statistical parametric mapping (SPM) was used to evaluate the 1D COP and EMG waveforms obtained during the epochs with and without wearing the exoskeleton. The results indicated that during quiet stance, COP velocity was increased while wearing the exoskeleton, but the magnitude of sway was unchanged. The OD COP measures revealed that wearing the exoskeleton significantly reduced the sway magnitude and velocity in response to the perturbations. There were no systematic effects of wearing the exoskeleton on EMG. SPM analysis revealed that there was a range of individual responses; both behaviorally (COP) and among neuromuscular activation patterns (EMG). Using both the OD and 1D measures provided a more comprehensive representation of how wearing the exoskeleton impacts the responses to posterior perturbations. This study supports a growing body of evidence that exoskeletons must be personalized to meet the specific capabilities and needs of each individual end-user.
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Gaze Behavior and Mental Workload While Using a Whole-Body Powered Exoskeleton: A Pilot Study
The mental demands associated with operating complex whole-body powered exoskeletons are poorly understood. This study aimed to explore the overall workload associated with using a powered wholebody exoskeleton among expert and novice users, as well as the changes in workload resulting from novices adapting to exoskeleton-use over time. We used eye-tracking measures to quantify the differences in workload of six novices and five experts while they performed a levelwalking task, with and without wearing a whole-body powered exoskeleton. We found that only novices’ pupil dilation (PD) increased, while experts showed a greater proportion of downward-directed pathfixations (PF) compared to novices while wearing the exoskeleton. These results indicate that novices’ mental demands were higher, and that experts and novices exhibited distinct visuomotor strategies. Eyetracking measures may potentially be used to detect differences in workload and skill-level associated with using exoskeletons, and also considered as inputs for future adaptive exoskeleton control algorithms.
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- Award ID(s):
- 1839946
- PAR ID:
- 10469890
- Publisher / Repository:
- SAGE Publications
- Date Published:
- Journal Name:
- Proceedings of the Human Factors and Ergonomics Society Annual Meeting
- Volume:
- 67
- Issue:
- 1
- ISSN:
- 1071-1813
- Format(s):
- Medium: X Size: p. 980-981
- Size(s):
- p. 980-981
- Sponsoring Org:
- National Science Foundation
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