Zhenyu Liao’s research while affiliated with Tohoku University and other places

Nowadays, the number of people facing mobility difficulties is growing. While these individuals can use assistive tools like wheelchairs for daily activities, participating in sports alongside individuals with typical abilities remains a challenge. In this paper, we propose a robotic system to facilitate Inclusive Sports, allowing people to enjoy sports and compete together regardless of age and disabilities. The system employs pedaling mechanisms, such as cycling wheelchairs and tricycles, as personal mobility tools. These machines, equipped with at least three wheels, aim to reduce the risk of users falling. Additionally, a power assist function is integrated to enable users with limited leg mobility to independently operate the tools. We also introduce control policies for the robots to navigate during sports competitions for people with visual impairment. Through experiments, we confirm the feasibility of the proposed system, demonstrating its potential for use in Inclusive Sports.

Participating in sports is of great significance to people's physical and mental well-being. While physical activity is commonplace for healthy individuals, it presents challenges for those with visual impairments, as they can not rely on visual cues to perceive essential information related to sports participation, such as their surroundings. Many related studies including our previous work for assisting users in doing sports using sensory augmentation technology, which couples haptic feedback with people's desired movements, are proposed for this challenge. On the basis of these studies, we propose a system for guiding visually impaired users running outdoors using a drone-based robotic system to locate a user and a track, calculate desired moving directions, and provide haptic feedback to the user. We conduct an experiment to explore how accurately people can recognize the directions conveyed by the proposed guidance method. Subjects were asked to select their felt directions on a tablet while running on a treadmill at 6.5 km/h and 7.5 km/h. The results show subjects could recognize the cued directions with an average resolution of $\mathbf {19.8^{\circ }}$ and $\mathbf {19.6^{\circ }}$ at different speeds, respectively, and there is no significant difference exist between the two speeds. In addition, we guide users in realistic running scenarios on sports tracks. Subjects in this experiment wore an eye mask to simulate the visually impaired. They were instructed to run by following the perceived directions conveyed by haptic feedback. According to the results, they could run within a specific track 81% of the time with the proposed system.

In recent years, multiple navigation systems using vibrotactile feedback have been studied, due to their ability to convey information while keeping free the visual and auditory channels, besides eliciting rapid responses from users. In the current stage, most navigation systems with vibrotactile feedback in the literature focus on guiding users around space using a fixed number of vibrotactile cues, which are limited by the number of vibrators. Achieving more precise guidance with a limited number of conveyable directions is difficult, as users cannot be directly guided to the desired position. In this letter, we present an approach to guide people around space using multidirectional vibrotactile feedback (MVF). The MVF can produce vibratory cues on the user's left lower leg with an average directional resolution of $\mathbf {15.35}^{\circ }$ for cases when the user is not moving, using only six vibration motors, by exploiting a vibrotactile illusion called Phantom Tactile Sensation (PTS). In a preliminary test of dynamic direction recognition experiment, users reported they tend to become less sensitive to vibration under long-time continuous vibration. As a result, besides offering users a continuous vibration to indicate directions, we also considered producing the cues during either the swing or stance phase to users in this experiment. The result of a direction recognition experiment while walking shows that the average recognition error for the cues when produced in the swing or stance phases are lower than the recognition error when the cues are continuously produced. We carried out a navigation experiment to test the feasibility of using the proposed direction display to guide people around an open area in real-time. In this experiment, users were able to reach the goal within the time limit guided only by the proposed feedback around 90% of the times for both gait phases.