Training to Improve the Landing of an Uninjured Leg in Crutch Walk Using AR Technology to Present an Obstacle

A patient who unexpectedly sustains a lower leg injury often uses crutches for walking, to both assist the patient and prevent further injury until a full recovery is made. In this study, a novel crutch walk training system was developed; a head-mounted display (HMD) was introduced to present a virtual obstacle for trainees using crutches. Through repetitions of the training, it was expected that the trainees would improve their overall body stability. Healthy subjects participated in experimental training exercises using the developed training system. As a result, the participants acquired the skill of walking well with crutches without losing their body balance significantly, even in the event of facing a virtual obstacle, during the five training sessions.

Improvements on the virtual obstacle method

While the artificial potential field has been widely employed to design path planning algorithms, it is well-known that artificial potential field-based algorithms suffer a severe problem that a robot may sink into a local minimum point. To address such problems, a virtual obstacle method has been developed in the literature. However, a robot may be blocked by virtual obstacles generated during performing the virtual obstacle method if the environments are complex. In this article, an improved virtual obstacle method for local path planning is designed via proposing a new minimum criterion, a new switching condition, and a new exploration force. All the three new contributions allow to overcome the drawbacks of the artificial potential field-based algorithms and the virtual obstacle method. As a consequence, feasible collision-free paths can be found in complex environments, as illustrated by final numerical simulations.

Obstacle Crossing in a Virtual Environment Transfers to a Real Environment

Obstacle crossing, such as stepping over a curb, becomes more challenging with natural aging and could lead to obstacle-related trips and falls. To reduce fall-risk, obstacle training programs using physical obstacles have been developed, but come with space and human resource constraints. These barriers could be removed by using a virtual obstacle crossing training program, but only if the learned gait characteristics transfer to a real environment. We examined whether virtual environment obstacle crossing behavior is transferred to crossing real environment obstacles. Forty participants (n = 20 younger adults andn = 20 older adults) completed two sessions of virtual environment obstacle crossing, which was preceded and followed by one session of real environment obstacle crossing. Participants learned to cross the virtual obstacle more safely and that change in behavior was transferred to the real environment via increased foot clearance and alterations in foot placement before and after the real environment obstacle. Further, while both age groups showed transfer to the real environment task, they differed on the limb in which their transfer effects applied. This suggests it is plausible to use virtual reality training to enhance gait characteristics in the context of obstacle avoidance, potentially leading to a novel way to reduce fall-risk.