Power Wheelchair Navigation Assistance Using Wearable Vibrotactile Haptics

Developing a real-time hand-gesture recognition technique for wheelchair control

At present, significant number of people in the world are having motor disabilities. They need to use wheelchair for performing regular movements and activities. However, there are a lot of issues and challenges in using the conventional wheelchairs. Safe navigation, independent mobility and low cost are the key issues for wheelchair users. This paper presents a new mathematical model for an efficient and real-time hand gesture recognition technique for a smart wheelchair control system, in line with contemporary technologies. The model is developed using the positions of the significant hand landmarks, distances among them and some critical thresholds which are determined by good number of samples of hands. The proposed method offers more users' flexibility through less hand movement in operation of the wheelchair. The model is tested for hands of different sizes, irrespective of any background in indoor or outdoor under sunlight. The experimental study demonstrates that it outperforms the existing methods in terms of success rate with good performance metrics.

Future Path Presentation to Passengers of an Autonomous Wheelchair Using Vibrotactile Feedback

While autonomous wheelchairs reduce the burden on passengers, automation can make it difficult for them to anticipate the future path of the wheelchair, potentially causing anxiety or discomfort due to unexpected movements. In this study, we define "path" as the geometric trajectory of the wheelchair position, without considering temporal aspects. Providing passengers with information about this future path is crucial, particularly when multiple pedestrians or obstacles are present. Previous studies have primarily focused on presenting only the direction in which the wheelchair turns. In this study, we propose a path presentation method that conveys both the direction and width of turns by varying the duration of haptic apparent motion according to the turning width. The results from the evaluation experiment showed that presenting the future path, including the extent of avoidance maneuvers, improved user understanding and offered a slightly greater sense of security compared to methods that presented only directional information or no feedback at all.

Visuo-Haptic Rendering of the Hand during 3D Manipulation in Augmented Reality

Manipulating virtual objects with bare hands is a key interaction in Augmented Reality (AR) applications. However, there are still several limitations that affect the manipulation, including the lack of mutual visual occlusion between virtual and real content as well as the lack of haptic sensations. To address the two abovementioned matters, the role of the visuo-haptic rendering of the hand as sensory feedback is investigated. The first experiment explores the effect of showing the hand of the user as seen by the AR system through an avatar, comparing six visual hand rendering. The second experiment explores the effect of the visuo-haptic hand rendering by comparing two vibrotactile contact techniques provided at four delocalized positions on the hand and combined with the two most representative visual hand renderings from the first experiment. Results show that delocalized vibrotactile haptic hand rendering improved perceived effectiveness, realism, and usefulness when provided close to the contact point. However, the farthest rendering position, i.e., on the contralateral hand, gave the best performance even though it was largely disliked. The visual hand rendering was perceived as less necessary for manipulation when the haptic hand rendering was available, but still provided useful feedback on the hand tracking.

Haptic Feedback, Performance and Arousal: A Comparison Study in an Immersive VR Motor Skill Training Task

This article investigates the relationship between fine motor skill training in VR, haptic feedback, and physiological arousal. To do so, we present the design and development of a motor skill task (buzzwire), along with a custom vibrotactile feedback attachment for the Geomagic Touch haptic device. A controlled experiment following a between-subjects design was conducted with 73 participants, studying the role of three feedback conditions - visual/kinesthetic, visual/vibrotactile and visual only - on the learning and performance of the considered task and the arousal levels of the participants. Results indicate that performance improved in all three feedback conditions after the considered training session. However, participants reported no change in self-efficacy and in terms of presence and task load (NASA-TLX). All three feedback conditions also showed similar arousal levels. Further analysis revealed that positive changes in performance were linked to higher arousal levels. These results suggest the potential of haptic feedback to affect arousal levels and encourage further research into using this relationship to improve motor skill training in VR.

Deconstructing Haptic Feedback Information in Robot-Assisted Needle Insertion in Soft Tissues

This paper evaluates the role and effectiveness of different types of haptic feedback in presenting relevant feedback information during needle insertion in soft tissues through a remotely operated robot. We carried out three experiments with human subjects to analyze the effect of grounded kinesthetic feedback, cutaneous vibrotactile feedback, and cutaneous pressure feedback for rendering the elastic and the viscous force components of a simplified needle-tissue interaction model in a simulated environment. Results showed that providing the two pieces of feedback information through different channels, i.e., kinesthetic and cutaneous, led to the best performance, yielding an improvement in detecting a different tissue layer with respect to providing both information through the same commercial grounded kinesthetic interface. Moreover, results indicate that cutaneous pressure feedback is more suited for rendering the elastic component of the interaction with respect to vibrotactile cutaneous sensations. Finally, results suggest that rendering this elastic component where the user holds the input interface is not so important, confirming that delocalized cutaneous sensations can be an effective solution.

Ultrasound Mid-Air Haptics for Hand Guidance in Virtual Reality

This paper presents and evaluates a set of mid-air ultrasound haptic strategies to provide 2-degree-of-freedom position and orientation guidance in Virtual Reality (VR). We devised four strategies for providing position guidance and two for providing orientation guidance. A human subject study evaluated the effectiveness of the proposed techniques in guiding users towards objectives in static and dynamic environments in VR, both in position and orientation. Results show that, compared to visual feedback of the virtual environment alone, the considered strategies significantly improve positioning performance in the static scenario. On the other hand, orientation guidance led to significant improvements only in the dynamic scenario.

Investigating the Haptic Perception of Directional Information Within a Handle

This paper studies the perception of 2-dimensional directional cues presented on a hand-held tangible interface that resembles a cylindrical handle. The tangible interface is designed to be comfortably held with one hand and houses five custom electromagnetic actuators composed of coils as stators and magnets as movers. We carried out a human subjects experiment enrolling 24 participants, analysing the recognition rate of directional cues using the actuators either to vibrate or tap in sequence across the user's palm. Results show an impact of the positioning/holding of the handle, the mode of stimulation, and the directional indication sent via the handle. There was also a correlation between the score and the confidence of the participants, showing that participants are more confident when recognising vibration patterns. Overall, results supported the potential of the haptic handle to provide accurate guidance, with recognition rates higher than 70 % in all conditions and higher than 75 % in the precane and power wheelchair configurations.

Discernment on assistive technology for the care and support requirements of older adults and differently-abled individuals

Assistive technology for the differently abled and older adults has made remarkable achievements in providing rehabilitative, adaptive, and assistive devices. It provides huge assistance for people with physical impairments to lead a better self-reliant daily life, in terms of mobility, education, rehabilitation, etc. This technology ranges from simple hand-held devices to complex robotic accessories which promote the individual's independence. This study aimed at identifying the assistance required by differently-abled individuals, and the solutions proposed by different researchers, and reviewed their merits and demerits. It provides a detailed discussion on the state of art assistive technologies, their applications, challenges, types, and their usage for rehabilitation. The study also identifies different unexplored research areas related to assistive technology that can improve the daily life of individuals and advance the field. Despite their high usage, assistive technologies have some limitations which have been briefly described in the study. This review, therefore, can help understand the utilization, and pros and cons of assistive devices in rehabilitation engineering and assistive technologies.

Finger-Gesture Controlled Wheelchair with Enabling IoT

Modern wheelchairs, with advanced and robotic technologies, could not reach the life of millions of disabled people due to their high costs, technical limitations, and safety issues. This paper proposes a gesture-controlled smart wheelchair system with an IoT-enabled fall detection mechanism to overcome these problems. It can recognize gestures using Convolutional Neural Network (CNN) model along with computer vision algorithms and can control the wheelchair automatically by utilizing these gestures. It maintains the safety of the users by performing fall detection with IoT-based emergency messaging systems. The development cost of the overall system is cheap and is lesser than USD 300. Hence, it is expected that the proposed smart wheelchair should be affordable, safe, and helpful to physically disordered people in their independent mobility.

Action-Specific Perception & Performance on a Fitts's Law Task in Virtual Reality: The Role of Haptic Feedback

While user's perception and performance are predominantly examined independently in virtual reality, the Action-Specific Perception (ASP) theory postulates that the performance of an individual on a task modulates this individual's spatial and time perception pertinent to the task's components and procedures. This paper examines the association between performance and perception and the potential effects that tactile feedback modalities could generate. This paper reports a user study (N=24), in which participants performed a standardized Fitts's law target acquisition task by using three feedback modalities: visual, visuo-electrotactile, and visuo-vibrotactile. The users completed 3 Target Sizes × 2 Distances × 3 feedback modalities = 18 trials. The size perception, distance perception, and (movement) time perception were assessed at the end of each trial. Performance-wise, the results showed that electrotactile feedback facilitates a significantly better accuracy compared to vibrotactile and visual feedback, while vibrotactile provided the worst accuracy. Electrotactile and visual feedback enabled a comparable reaction time, while the vibrotactile offered a substantially slower reaction time than visual feedback. Although amongst feedback types the pattern of differences in perceptual aspects were comparable to performance differences, none of them was statistically significant. However, performance indeed modulated perception. Significant action-specific effects on spatial and time perception were detected. Changes in accuracy modulate both size perception and time perception, while changes in movement speed modulate distance perception. Also, the index of difficulty was found to modulate all three perceptual aspects. However, individual differences appear to affect the magnitude of action-specific effects. These outcomes highlighted the importance of haptic feedback on performance, and importantly the significance of action-specific effects on spatial and time perception in VR, which should be considered in future VR studies.

Crowd Navigation in VR: Exploring Haptic Rendering of Collisions

Virtual reality (VR) is a valuable experimental tool for studying human movement, including the analysis of interactions during locomotion tasks for developing crowd simulation algorithms. However, these studies are generally limited to distant interactions in crowds, due to the difficulty of rendering realistic sensations of collisions in VR. In this article, we explore the use of wearable haptics to render contacts during virtual crowd navigation. We focus on the behavioral changes occurring with or without haptic rendering during a navigation task in a dense crowd, as well as on potential after-effects introduced by the use haptic rendering. Our objective is to provide recommendations for designing VR setup to study crowd navigation behavior. To the end, we designed an experiment (N=23) where participants navigated in a crowded virtual train station without, then with, and then again without haptic feedback of their collisions with virtual characters. Results show that providing haptic feedback improved the overall realism of the interaction, as participants more actively avoided collisions. We also noticed a significant after-effect in the users' behavior when haptic rendering was once again disabled in the third part of the experiment. Nonetheless, haptic feedback did not have any significant impact on the users' sense of presence and embodiment.

Vibrotactile-Based Operational Guidance System for Space Science Experiments

On-orbit astronauts and scientists on the ground need to cooperate closely, to complete space science experiments efficiently. However, for the increasingly diverse space science experiments, scientists are unable to train astronauts on the ground about the details of each experiment. The traditional interaction of visual and auditory channels is not enough for scientists to directly guide astronauts to experimentalize. An intuitive and transparent interaction interface between scientists and astronauts has to be built to meet the requirements of space science experiments. Therefore, this paper proposed a vibrotactile guidance system for cooperation between scientists and astronauts. We utilized Kinect V2 sensors to track the movements of the participants of space science experiments, process data in the virtual experimental environment developed by Unity 3D, and provide astronauts with different guidance instructions using the wearable vibrotactile device. Compared with other schemes using only visual and auditory channels, our approach provides more direct and more efficient guidance information that astronauts perceive is what they need to perform different tasks. Three virtual space science experiment tasks verified the feasibility of the vibrotactile operational guidance system. Participants were able to complete the experimental task with a short period of training, and the experimental results show that the method has an application prospect.