Performance Evaluation of Active and Passive Haptic Feedback in Shape Perception

In this work, we evaluate the impact of passive haptic feedback on touch-based menus, given the constraints and possibilities of a seated, desk-based scenario in VR. Therefore, we compare a menu that once is placed on the surface of a desk and once mid-air on a surface in front of the user. The study design is completed by two conditions without passive haptic feedback. In the conducted user study $(n=33)$ , we found effects of passive haptics (present vs-non-present) and menu alignment (desk vs. mid-air) on the task performance and subjective look & feel. However, the race between the conditions was close. An overall winner was the mid-air menu with passive haptic feedback, which however raises hardware requirements.

There is an increasing interest in deployable virtual military training systems. Haptic feedback for these training systems can enable users to interact more naturally with the training environment, but is difficult to deploy. Passive haptic feedback is very compelling, but it is also inflexible. Changes made to virtual objects can require time-consuming changes to their physical passive-haptic counterparts. This poster explores the possibility of mapping many differently shaped virtual objects onto one physical object by warping virtual space and exploiting the dominance of the visual system. A first implementation that maps different virtual objects onto dynamically captured physical geometry is presented, and potential applications to deployable military trainers are discussed.

Interactions with the physical environment, such as passive haptic feedback, have been previously shown to provide richer and more immersive virtual reality experiences. A strict correspondence between the virtual and real world coordinate systems is a staple requirement for physical interaction. However, many of the commonly employed VR locomotion techniques allow for, or even require, this relationship to change as the experience progresses. The outcome is that experience designers frequently have to choose between flexible locomotion or physical interactivity, as the two are often mutually exclusive. To address this limitation, this paper introduces reactive environmental alignment, a novel framework that leverages redirected walking techniques to achieve a desired configuration of the virtual and real world coordinate systems. This approach can transition the system from a misaligned state to an aligned state, thereby enabling the user to interact with physical proxy objects or passive haptic surfaces. Simulation-based experiments demonstrate the effectiveness of reactive alignment and provide insight into the mechanics and potential applications of the proposed algorithm. In the future, reactive environmental alignment can enhance the interactivity of virtual reality systems and inform new research vectors that combine redirected walking and passive haptics.

Virtual Reality (VR) is increasingly being used to promote mindfulness practice. However, the impact of virtual and multimodal interactive spaces on mindfulness practice and presence is still underexplored. To address this gap, we conducted a mixed-method user study (N=12). We explored the impact of various multimodal feedback, in particular tactile feedback (passive haptic feedback by artificial grass) and auditory feedback (footstep sound) at feet level on both mindfulness and presence. We conducted semi-structured interviews and collected quantitative data through three validated questionnaires (SMS, IPQ, WSPQ). We found a significant effect of passive haptic feedback on presence and mindfulness. Tactile feedback improves the focus on the self, facilitates spatial presence and increases involvement. Auditory feedback did not significantly affect presence or mindfulness. While ambient sound was perceived as beneficial for presence, footstep sound subjectively disrupted both presence and mindfulness. Based on our results, we derive design recommendations for multimodal VR applications supporting mindfulness practice.

We show a novel encountered‐type haptic system, H‐Wall, to enable haptic feedback using a manipulator of seven degrees of freedom suitable for simulating indoor virtual reality environments, which are characterized and confined by a set of vertical walls and revolving doors. At runtime, our system tracks hand motion using a red–green–blue depth sensor and locates its configuration. Then, the robotic manipulator plans a trajectory for the end effector, attached to a rectangular rigid board, to make contact with the hand to deliver a sense of touch as long as the perceived hand contact force is substantial. The force feedback is generated in a passive sense for static walls that the rigid board, corresponding to a vertical wall, holds its position as long as the perceived hand contact force is substantial. For a revolving door, the force feedback is generated in an active sense based on impedance control. In order to address the issue of limited workspace, we also propose a new reachability map, calledper‐plane reachability map, that is optimized to answer whether passive haptic feedback can be generated by a manipulator when the user touches a vertical wall at a given orientation. We successfully demonstrate our system to provide an illusion to the user in a virtual environment with touch sensation to the surrounding environment.

This paper explores the influence of passive haptic feedback on presence and task performance using two important interaction metaphors. We compared direct interaction with the user's hand with interaction using a stylus. Twenty-four participants performed a simple selection task consisting of pressing buttons while playing a memory game, with haptic feedback and interaction metaphor as the independent variables. We measured task performance by computing errors and time between button presses. We measured presence with questionnaires and through a new method based on users' involuntary movements. Our results suggest that passive haptic feedback improves both presence and task performance. However, small but significant differences related to the interaction metaphor were only apparent when haptic feedback was not provided.

We present an immersive virtual reality training system cryoVR with passive haptic feedback for training biological scientists preparing bio-sample for Cryo-Electron Microscopy (CryoEM). CryoEM requires the user to conduct careful operations on expensive delicate equipment. To minimize the risk and interruption of crucial research work, we tried to mimic the real lab using VR to let trainer practice in a virtual environment. We used 3D printed objects to provide passive haptic feedback in order to achieve a more realistic training experience. Participants are able to interact with the equipment in the virtual environment by moving or touching physical models. We developed all the necessary operations with haptic feedback, including moving, clicking, pouring, rotating, polling and pushing. By following instructions provided by our virtual reality simulator and interacting with physical objects, trainees will learn how to operate CryoEM with low cost and risk. By developing our training system, we explore the benefits, limitations and precautions of embedding haptic feedback to scientific VR training.

This paper presents the results of a pilot study that assesses the effect of passive haptics on the user experience in virtual reality simulations of recreation and sports activities. A virtual reality kayaking environment with realistic physics simulation and water rendering was developed that allowed users to steer the kayak using natural motions. Within this environment the users experienced two different ways of paddling using: a) a pair of typical virtual reality controllers, and b) one custom-made “smart paddle” that provided the passive haptic feedback of a real paddle. The results of this pilot study indicate that the users learned faster how to steer the kayak using the paddle, which they found to be more intuitive to use and more appropriate for this application. The results also demonstrated an increase in the perceived level of enjoyment and realism of the virtual experience.

If Walking-in-place (WIP) techniques are to be considered a useful way of facilitating virtual locomotion, it is crucial that the user remains stationary with respect to the physical environment. However, it has recently been documented that WIP locmotion may lead to Unintended Positional Drift (UPD). Users walking in place while wearing a head-mounted display tend to physically drift in the direction which they are headed within the virtual environment. This paper details a within-subjects study evaluating different methods for minimizing UPD. The study included 14 conditions: 13 different types of feedback informing the user that a certain amount of drift had occurred and a control condition devoid of feedback. The feedback differed in terms of sensory modality (auditory, visual or audiovisual), onset mode (gradual or sudden) and presentation mode (either the feedback constituted a warning or a deprivation of the stimuli used to represent the virtual world). Finally, a condition providing passive haptic feedback (a circular carpet) was included. The types of feedback were assessed in terms of how effectively they reduced UPD as well as how helpful and intrusive they were perceived. The results suggest that both passive haptic feedback and feedback types with gradual onset are the most efficient at controlling the user's physical movement. However, the passive haptic feedback was regarded as more helpful and perceived as less disruptive than some of the feedback types with a gradual onset.

One of the major yet little recognized challenges in robotic vitreoretinal surgery is the matter of tool forces applied to the sclera. Tissue safety, coordinated tool use and interactions between tool tip and shaft forces are little studied. The introduction of robotic assist has further diminished the surgeon's ability to perceive scleral forces. Microsurgical tools capable of measuring such small forces integrated with robotmanipulators may therefore improve functionality and safety by providing sclera force feedback to the surgeon. In this paper, using a force-sensing tool, we have conducted robotassisted eye manipulation experiments to evaluate the utility of providing scleral force feedback. The work assesses 1) passive audio feedback and 2) active haptic feedback and evaluates the impact of these feedbacks on scleral forces in excess of aboundary. The results show that in presence of passive or active feedback, the duration of experiment increases, while the duration for which scleral forces exceed a safe threshold decreases.

Interacting with smart environments through gestures faces the challenge of false positives, also known as the Midas touch problem. To enable seamless and robust gesture activation, we selected activation microgestures performed simultaneously on a ring during gesture execution. A user study revealed a clear preference for activating the ring with the thumb over the middle finger, based on usability and physical demand. Interestingly, while activating a push button requires more force than pressing a smooth pressure sensor, the soft button caused significantly higher physical demand than pressing a push button, which provides clear passive haptic force feedback indicating when the button has been pushed. The lack of force feedback from the pressure sensor appears to cause users to continue pressing after the sensor has been activated. In summary, activating index-finger gestures using a thumb press is a promising technique for easy, usable, and robust ubiquitous gesture interaction.

The haptic interface or force feedback device improves the quality of human computer interaction by accommodating the sense of touch in a computer simulation. A haptic device enables a two way communication between the user and the host computer. The applications of force feedback device cover a wide area such as in medical training, systems for the visually impaired, engineering research, and creative art-work. The role of haptic feedback varies depending on the applications in question and the devices used. This includes haptic as a teaching tool, and a communication aid. Despite the benefits of haptic feedback, its deployment to support interactions in a virtual environment is still slow. This is due to the high cost of the haptic devices in the market. We address this issue by presenting a conceptual framework in designing and implementing a cost-effective haptic device; building on similar concepts obtained from existing technologies. The device is developed using those gadgets that are mainly available in-house. It is projected that haptic feedback generated from the device could benefit teaching abstract concepts to students.

Virtual reality has been used in recent years for artistic expression and as a tool to engage visitors by creating immersive experiences. Most of these immersive installations incorporate visuals and sounds to enhance the user’s interaction with the artistic pieces. Very few, however, involve physical or haptic interaction. This paper investigates virtual walking on paintings using passive haptics. More specifically we combined vibrations and ultrasound technology on the feet using four different configurations to evaluate users’ immersion while they are virtually walking on paintings that transform into 3D landscapes. Results show that participants with higher immersive tendencies experienced the virtual walking by reporting illusory movement of their body regardless the haptic configuration used.

In this paper, we present a study that evaluates the effect of visual and haptic feedbacks and their relevance to human performance in a needle insertion task. A virtual needle insertion simulator with a four-layer tissue model (skin, fat, muscle, and bone) and haptic feedback is used for perceptual experiments. The task was to detect the puncture of a particular layer using haptic and visual cues provided by the simulation. The results show that the addition of force feedback reduces error in detection of transitions between tissue layers by at least 55%. The addition of real-time visual feedback (image overlay) improved user performance by at least 87% in scenarios without force feedback. Presentation of both force and visual feedback improved performance by at least 43% in comparison to scenarios without feedback. These results suggest that real-time image overlay provides greater improvement in performance than force feedback.

We propose a novel wearable haptic device that can provide kinesthetic haptic feedback for stiffness rendering of virtual objects in augmented reality (AR). Rendering stiffness of objects using haptic feedback is crucial for realistic finger-based object manipulation, yet challenging particularly in AR due to the co-presence of a real hand, haptic device, and rendered AR objects in the scenes. By adopting passive actuation with a tendon-based transmission mechanism, the proposed haptic device can generate kinesthetic feedback strong enough for immersive manipulation and prevention of inter-penetration in a small-form-factor, while maximizing the wearability and minimizing the occlusion in AR usage. A selective locking module is adopted in the device to allow for the rendering of the elasticity of objects. We perform an experimental study of two-finger grasping to verify the efficacy of the proposed haptic device for finger-based manipulation in AR. We also quantitatively compare/articulate the effects of different types of feedbacks across haptic and visual sense (i.e., kinesthetic haptic feedback, vibrotactile haptic feedback, and visuo-haptic feedback) for stiffness rendering of virtual objects in AR for the first time.