1,720,988 research outputs found
Wearable Haptics for Remote Social Walking
Full text linkWalking is an essential activity for a healthy life, which becomes less tiring and more enjoyable if done together. Common difficulties we have in performing sufficient physical exercise, for instance the lack of motivation, can be overcome by exploiting its social aspect. However, our lifestyle sometimes makes it very difficult to find time together with others who live far away from us to go for a walk. In this article, we propose a novel system enabling people to have a 'remote social walk' by streaming the gait cadence between two persons walking in different places, increasing the sense of mutual presence. Vibrations provided at the users' ankles display the partner's sensation perceived during the heel-strike. In order to achieve the aforementioned goal in a two users experiment, we envisaged a four-step incremental validation process: i) a single walker has to adapt the cadence with a virtual reference generated by a software; ii) a single user is tasked to follow a predefined time-varying gait cadence; iii) a leader-follower scenario in which the haptic actuation is mono-directional; iv) a peer-to-peer case with bi-directional haptic communication. Careful experimental validation was conducted involving a total of 50 participants, which confirmed the efficacy of our system in perceiving the partners' gait cadence in each of the proposed scenarios
Design and Comparison of Haptic Policies for Human Guidance
No full textIn this work we compare haptic-based human guidance approaches. We considered both delivering to the user step-by-step instructions towards the goal, and a sensory augmentation policy that provides the knowledge necessary to complete the task using a self-selected strategy. The approaches were evaluated in a collaborative scenario with couples of participants carrying a bulky object under the sole guidance of haptics. Stimuli were generated by a vibrotactile belt according to three haptic policies. Results revealed that the availability of the direction to the destination was a crucial aspect for achieving best temporal performance and high usability ratings
A Human Gesture Mapping Method to Control a Multi‐Functional Hand for Robot‐Assisted Laparoscopic Surgery: The MUSHA Case
Full text linkThis work presents a novel technique to control multi-functional hand for robot-assisted laparoscopic surgery. We tested the technique using the MUSHA multi-functional hand, a robot-aided minimally invasive surgery tool with more degrees of freedom than the standard commercial end-effector of the da Vinci robot. Extra degrees of freedom require the development of a proper control strategy to guarantee high performance and avoid an increasing complexity of control consoles. However, developing reliable control algorithms while reducing the control side's mechanical complexity is still an open challenge. In the proposed solution, we present a control strategy that projects the human hand motions into the robot actuation space. The human hand motions are tracked by a LeapMotion camera and mapped into the actuation space of the virtualized end-effector. The effectiveness of the proposed method was evaluated in a twofold manner. Firstly, we verified the Lyapunov stability of the algorithm, then an user study with 10 subjects assessed the intuitiveness and usability of the system
Generating Kinesthetic Feedback Using Self Contact and Velocity Scaling
No full textDespite the considerable technological progress of haptic technology in recent years, to date there are still no wearable systems capable of providing both kinesthetic and cutaneous feedback that are universally recognized and adopted outside the research contexts. This is particularly evident when dealing with virtual reality, where the lack of truthful tactile feedback has often been addressed by exploiting Pseudo-Haptics methods. Being designed to indirectly stimulate the somatosensory system, these methods are not meant to be integrated with haptic devices. With the idea of providing a meeting point between the haptic and pseudo-haptic fields, this work proposes Self Contact: exploiting the pseudo-haptic principles to lead the user in generating a real kinesthetic feedback through the contact between his/her fingers. Self Contact can be implemented alone or in combination with haptic thimbles, allowing to complete the set of tactile stimuli that is necessary for a realistic interaction with virtual objects in pick and place operations. A step-wise validation demonstrated that the proposed approach is suitable for recovering the kines-thetic feedback into virtual reality, towards the development of increasingly immersive environments
Mobile augmented reality integrating fingertip haptic devices and wrist-worn visual displays
No full textIn the context of Mobile Augmented Reality (MAR), hand-based interaction with virtual environments is still an open challenge. Virtual objects projected on the smartphone screen are on a different layer than the camera-captured images, hence the user's hand cannot get in contact with virtual entities. In this work, we present an improvement to a previously published proof-of-concept that aims at overcoming current MAR limitations by mapping the hand in the virtual reference. To this end, we developed an ad hoc ring interface for finger tracking and haptic feedback, designed with wearability in mind. A wrist-worn display compacts the hardware on a single-arm, leaving the other completely free. The overall system is affordable thanks to the use of the smart-phone as core technology and provides "on-demand"augmented reality, tailored for daily activities scenarios. Eighteen users were enrolled to compare the wristband based system and the standard hand-held smartphone montage. Quantitative and qualitative results show that our system was positively received by the subjects, that completed the experimental task achieving similar performance in the two conditions but expressed their preference for the wrist-worn display
Feedback of Head Gestures in Audio-haptic Remote Communication
No full textIn this brief, we present the preliminary design of a wearable system able to detect and haptically display head motions of conversation participants. The aim of the system is to allow for remote communication to not have to rely on visual social cues. To demonstrate the design principles of the system, we recorded data from a single participant during a remote walking conversation using Zoom
Combining Wristband Display and Wearable Haptics for Augmented Reality
No full textTaking advantages of widely distributed hardware such as smartphones and tablets, Mobile Augmented Reality (MAR) market is rapidly growing. Major improvements can be envisioned in increasing the realism of virtual interaction and providing multimodal experiences. We propose a novel system prototype that locates the display on the forearm using a rigid support to avoid constraints due to hand-holding, and is equipped with hand tracking and cutaneous feedback. The hand tracking enables the manipulation of virtual objects, while the haptic rendering enhances the user's perception of the virtual entities. The experimental setup has been tested by ten participants, that expressed their impressions about usability and functionality of the wrist-mounted system w.r.t. the traditional hand-held condition. Subjects' personal evaluations suggest that the AR experience provided by the wrist-based approach is more engaging and immersive
Haptic Guidance in Dynamic Environments Using Optimal Reciprocal Collision Avoidance
Full text linkHuman guidance in situations where the users cannot rely on their main sensory modalities, such as assistive or search-and-rescue scenarios, is a challenging task. In this letter, we address the problem of guiding users along collision-free paths in dynamic environments, assuming that they cannot rely on their main sensory modalities. In order to safely guide the subjects, we adapt the optimal reciprocal collision avoidance to our specific problem. The proposed algorithm takes into account the stimuli which can be displayed to the users and the motion uncertainty of the users when reacting to the provided stimuli. The proposed algorithm was evaluated in three different dynamic scenarios. A total of 18 blindfolded human subjects were asked to follow haptic cues in order to reach a target area while avoiding real static obstacles and moving users. Three metrics such as time to reach the goal, length of the trajectories, and minimal distance from the obstacles are considered to compare results obtained using this approach and experiments performed without visual impairments. Experimental results reveal that blindfolded subjects are successfully able to avoid collisions and safely reach the targets in all the performed trials. Although in this letter we display directional cues via haptic stimuli, we believe that the proposed approach can be general and tuned to work with different haptic interfaces and/or feedback modalities
Online Minimization of the Robot Silhouette Viewed From Eye-to-Hand Camera
Full text linkRedundant robots have the potential to perform internal joints motion without modifying the pose of the end-effector by exploiting the null-space of the Jacobian matrix. Capitalizing on that feature, we developed a control technique for minimizing the robot visual appearance when observed from an eye-to-hand camera. Such algorithm is instrumental in contexts where quickly adjusting the perspective to see objects obstructed by the robot is impractical (e.g., teleoperation in narrow environment). Diminished reality techniques are frequently employed in these cases to mitigate the robot intrusion into the environment, although these techniques may sometimes compromise the perceived realism. The experimental evaluation confirmed the effectiveness of our control algorithm, demonstrating an average reduction of 4.67% of the area covered by the robot within the frame when compared to the case without the optimization action
Design, development, and preliminary evaluation of a highly wearable exoskeleton
No full textWe present the design of a highly wearable exoskeleton of hand fingers that can be used for rehabilitation applications. One of the main challenges in the design of this type of device is to reduce as much as possible the encumbrance and weight, and at the same time to guarantee performance suitable to provide a realistic and reliable motion to the user. In the proposed solution each finger is actuated by means of a single motor, and finger joint rotations are coupled to produce a natural and intuitive movement of the finger, for this reason, we exploited the concept of postural synergies. The paper presents the main design steps, the criteria adopted to choose the mechanical structure of the exoskeleton, and the features of its prototype. Compared to other solutions present in the literature, the device presented in this paper has limited weight (40 g per finger) with an interesting level of performance in terms of force (15 N)
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