No description available.

This research explores the development of vibration-based haptic feedback for a mouse-like computer input device. The haptic feedback is intended to be used in 3D virtual environments to provide users of the environment with information that is difficult to convey visually, such as collisions between objects. Previous research into vibrotactile haptic feedback can generally be split into two broad categories: single tactor handheld devices; and multiple tactor devices that are attached to the body. This research details the development of a vibrotactile feedback device that merges the two categories, creating a handheld device with multiple tactors. Building on previous research, a prototype device was developed. The device consisted of a semi-sphere with a radius of 34 mm, mounted on a PVC disk with a radius of 34 mm and a height of 18 mm. Four tactors were placed equidistantly about the equator of the PVC disk. Unfortunately, vibrations from a single tactor caused the entire device to shake due to the rigid plastic housing for the tactors. This made it difficult to accurately detect which tactor was vibrating. A second prototype was therefore developed with tactors attached to elastic bands. When a tactor vibrates, the elastic bands dampen the vibration, reducing the vibration in the rest of the device. The goal of the second prototype was to increase the accuracy in localizing the vibrating tactor. An experiment was performed to compare the two devices. The study participants grasped one of the device prototypes as they would hold a computer mouse. During each trial, a random tactor would vibrate. By pushing a key on the keyboard, the participants indicated when they detected vibration. They then pushed another key to indicate which tactor had been vibrating. The procedure was then repeated for the other device. Detection of the vibration was faster (p < 0.01) and more accurate (p < 0.001) with the soft shell design than with the hard shell design. In a post-experiment questionnaire, participants preferred the soft shell design to the hard shell design. Based on the results of the experiment, a mould was created for building future prototypes. The mould allows for the rapid creation of devices from silicone. Silicone was chosen as a material because it can easily be moulded and is available in different levels of hardness. The hardness of the silicone can be used to control the amount of damping of the vibrations. To increase the vibration damping, a softer silicone can be used. Several recommendations for future prototypes and experiments are made.

This research explores the development of vibration-based haptic feedback for a mouse-like computer input device. The haptic feedback is intended to be used in 3D virtual environments to provide users of the environment with information that is difficult to convey visually, such as collisions between objects. Previous research into vibrotactile haptic feedback can generally be split into two broad categories: single tactor handheld devices; and multiple tactor devices that are attached to the body. This research details the development of a vibrotactile feedback device that merges the two categories, creating a handheld device with multiple tactors. Building on previous research, a prototype device was developed. The device consisted of a semi-sphere with a radius of 34 mm, mounted on a PVC disk with a radius of 34 mm and a height of 18 mm. Four tactors were placed equidistantly about the equator of the PVC disk. Unfortunately, vibrations from a single tactor caused the entire device to shake due to the rigid plastic housing for the tactors. This made it difficult to accurately detect which tactor was vibrating. A second prototype was therefore developed with tactors attached to elastic bands. When a tactor vibrates, the elastic bands dampen the vibration, reducing the vibration in the rest of the device. The goal of the second prototype was to increase the accuracy in localizing the vibrating tactor. An experiment was performed to compare the two devices. The study participants grasped one of the device prototypes as they would hold a computer mouse. During each trial, a random tactor would vibrate. By pushing a key on the keyboard, the participants indicated when they detected vibration. They then pushed another key to indicate which tactor had been vibrating. The procedure was then repeated for the other device. Detection of the vibration was faster (p < 0.01) and more accurate (p < 0.001) with the soft shell design than with the hard shell design. In a post-experiment questionnaire, participants preferred the soft shell design to the hard shell design. Based on the results of the experiment, a mould was created for building future prototypes. The mould allows for the rapid creation of devices from silicone. Silicone was chosen as a material because it can easily be moulded and is available in different levels of hardness. The hardness of the silicone can be used to control the amount of damping of the vibrations. To increase the vibration damping, a softer silicone can be used. Several recommendations for future prototypes and experiments are made.

No description available.

The purpose of this dissertation was to establish how vibrotactile guidance cues can be used to improve marksmanship. This work originated in an effort to provide covert communication, navigation, and weapon aiming cues for infantrymen. It is predominantly an application-driven investigation rather than driven a priori by specific theoretical predictions from models of human performance. Three experiments are presented. Experiment 1 established the affect on initial response to vibrotactile guidance cues of tactor placements on the palmer versus dorsal surface of the hand, and targets appearing left versus right of center. Results suggest that tactile cues provided on the left side of the medial line of the hand afford moving the hand to the left, while tactile cues provided on the right side of the medial line afford moving the hand to the right. Experiment 2 established the affect of continuous relative distance cues and on- versus off-target vibrotactile stimuli on reaction time and accuracy for target selection. Results indicated an interaction between the pulse rate of vibrotactile stimuli and the method used to highlight an "on-target" condition; the suppressed target condition was superior to the enhanced target condition when the pulse rate increased as the cursor moved closer to a target. Experiment 3 established if there are performance differences between discrete and continuous distance information for target selection, and investigated the interaction between the near-target pulse rate and on-target cues. Results indicate that maximizing the difference between near-target guidance cues and on-target cues reduces the target selection time, particularly when the near-target pulse rates are fast (ISI = 10 msec). The results also suggest that, as with vision, the vibrotactile off-target guidance cues are not necessary during the whole target selection task. Rather, the guidance cues can be provided only during the initial pop-up condition and during the sub-movements closing on the target.

Recent hand tracking systems have contributed to enhancing user experience in the virtual environment (VE) due to its natural and intuitive interaction. In addition, wearable haptic devices are another approach to provide engaging and immersive experiences. However, controllers are still prevalent in VR (Virtual Reality) games as a main interaction device. Also, haptic devices are rare and not widely accepted by users because they get bulky to implement sophisticated haptic sensation. To overcome this issue, I conducted experiments (Study 1 and Study 2 of this Thesis) to investigate the effect of interaction method (controller and whole-hand interaction using hand tracking) and vibrotactile feedback on user experience in the VR game. In Study 1 of this Thesis, I recruited 36 participants and compared the user's sense of presence, engagement, usability, and task performance under three different conditions: (1) VR controllers, (2) hand tracking without vibrotactile feedback, and (3) hand tracking with vibrotactile feedback at fingertips through the gloves I developed. The gloves deliver vibrotactile feedback at each fingertip by vibration motors. I observed that whole-hand interaction using hand tracking enhanced the user's sense of presence, engagement, usability, and task performance. Further vibrotactile feedback increased the presence and engagement more clearly. Based on the participants' feedback, I could further modify the form factor to make it more usable in the VR game and comfortable to wear on a regular basis. In this sense, in Study 2 of this Thesis, I developed a new thimble-shape device to deliver vibrotactile feedback only at one fingertip rather than ten fingertips. Further, social VR is an emerging VR platform where multiple users can interact with one another. However, most social VR applications have not provided a sense of touch. I recruited 24 participants and conducted an experiment that explored the effects of interaction method and fingertip vibrotactile feedback on the user's sense of social presence, presence, engagement, and task performance in a cooperative VR game under four different conditions: (1) VR controllers without vibrotactile feedback, (2) VR controllers with vibrotactile feedback, (3) hand tracking without vibrotactile feedback, and (4) hand tracking with vibrotactile feedback with the fingertip vibrotactile device. The results showed that whole-hand interaction using hand tracking increased the level of presence. In addition, multiple items in the presence questionnaire indicated that vibrotactile feedback enhanced the level of presence as well. However, I could not observe the significant difference in social presence due to the unique setting of this experiment. Unlike the previous studies, my task was sufficiently cooperative, and thus, the participants felt high level of social presence regardless the conditions, which led to the ceiling effect. I also observed that there was no significant difference in engagement. Controller conditions had higher performance than hand tracking due to the technological limitations in hand tracking. Results are discussed in terms of implications for the components of interaction in the VR with hands, a touch in social VR, cooperative VR game, and practical design guidelines. / Master of Science / Recent hand tracking systems have contributed to enhancing user experience in the virtual environment (VE) due to its natural and intuitive interaction. In addition, wearable haptic devices are another approach to provide engaging and immersive experiences. However, controllers are still prevalent in VR (Virtual Reality) games as a main interaction device. Also, haptic devices are rare and not widely accepted by users because they get bulky to implement sophisticated haptic sensation. To overcome this issue, I conducted experiments (Study 1 and Study 2 of this Thesis) to investigate the effect of interaction method (controller and whole-hand interaction using hand tracking) and vibrotactile feedback on user experience in the VR game. In Study 1 of this Thesis, I recruited 36 participants and compared the user's sense of presence, engagement, usability, and task performance under three different conditions: (1) VR controllers, (2) hand tracking without vibrotactile feedback, and (3) hand tracking with vibrotactile feedback at fingertips through the gloves I developed. The gloves deliver vibrotactile feedback at each fingertip by vibration motors. I observed that whole-hand interaction using hand tracking enhanced the user's sense of presence, engagement, usability, and task performance. Further vibrotactile feedback increased the presence and engagement more clearly. Based on the participants' feedback, I could further modify the form factor to make it more usable in the VR game and comfortable to wear on a regular basis. In this sense, in Study 2 of this Thesis, I developed a new thimble-shape device to deliver vibrotactile feedback only at one fingertip rather than ten fingertips. Further, social VR is an emerging VR platform where multiple users can interact with one another. However, most social VR applications have not provided a sense of touch. I recruited 24 participants and conducted an experiment that explored the effects of interaction method and fingertip vibrotactile feedback on the user's sense of social presence, presence, engagement, and task performance in a cooperative VR game under four different conditions: (1) VR controllers without vibrotactile feedback, (2) VR controllers with vibrotactile feedback, (3) hand tracking without vibrotactile feedback, and (4) hand tracking with vibrotactile feedback with the fingertip vibrotactile device. The results showed that whole-hand interaction using hand tracking increased the level of presence. In addition, multiple items in the presence questionnaire indicated that vibrotactile feedback enhanced the level of presence as well. However, I could not observe the significant difference in social presence due to the unique setting of this experiment. Unlike the previous studies, my task was sufficiently cooperative, and thus, the participants felt high level of social presence regardless the conditions, which led to the ceiling effect. I also observed that there was no significant difference in engagement. Controller conditions had higher performance than hand tracking due to the technological limitations in hand tracking. Results are discussed in terms of implications for the components of interaction in the VR with hands, a touch in social VR, cooperative VR game, and practical design guidelines.

No description available.

Vibrotactile feedback offers a unique opportunity to augment or reconstruct impaired tactile sensations, whether that be in the form of enhancing prosthetics or specialized protective clothing. Important information about temperature and object slippage serve to endanger the human operator or equipment. This thesis presents three experiments which investigate amplitude modulated vibrotactile signals as a scalar dimension of roughness, the effect those signals and their locations (finger pad, forearm, bicep) have on the performance of two tasks: the sensing of temperatures simulated by vibrotactile signals and gripping an object of simulated surface texture. The results show task performance increase when the feedback and site of action are co-located for sensory tasks and decrease for manipulatory tasks.

The vibrissal system of pinnipeds relies on sturdy, specialized vibrissae and supporting neural architecture apparently designed for the reception of waterborne disturbances. Although it is known that pinnipeds can use their vibrissae for fine-scale tactile discrimination and hydrodynamic detection, many aspects of vibrissal function remain poorly understood. The present work examined the adaptive significance of vibrissal structure, the sensitivity of the vibrissal system, and the signals received by this system. All of these points were considered with respect to their function in hydrodynamic reception. Four methods of study: laser vibrometry, computed tomography (CT) scanning, psychophysical testing and animal-borne tagging were used to investigate the functioning of this sensory system. Laser vibrometer recordings were used to investigate the effect of vibrissal surface structure and orientation on flow-induced vibrations in excised vibrissae. Vibrations were recorded from the shaft of excised vibrissae exposed to laminar water flow in a flume tank. Samples from three pinniped species were tested: the harbor seal (Phoca vitulina), northern elephant seal (Mirounga angustirostris) and California sea lion (Zalophus californianus). The vibrissae of the seals had an undulated surface structure, while the vibrissae of the sea lion had a smooth surface. No significant difference between species, and therefore surface structure, was observed. However, when vibrissae were tested at three angles of orientation to the water flow, a strong effect of orientation on vibration frequency and velocity was observed across species. CT scanning data revealed that the vibrissae of all the species tested had flattened cross-sectional profiles. This cross-sectional flattening could account for the observed orientation effects. Furthermore, this morphological characteristic may represent an adaptation for improved functioning in the aquatic environment by reducing self-induced-noise from swimming and potentially enhancing detection of signals from other planes. Psychophysical testing was conducted with a trained harbor seal in order to investigate the sensitivity of the vibrissal system of this species. A behavioral procedure was used to measure absolute detection thresholds for sinusoidal stimuli delivered to the vibrissae by a vibrating plate. Thresholds were measured at 9 discrete frequencies from 10 to 1000 Hz. The seal's performance in this stimulus detection task showed that the vibrissal array was sensitive to directly coupled vibrations across the range of frequencies tested, with best sensitivity of 0.09 mm/s at 80 Hz. The velocity thresholds as a function of frequency showed a characteristic U-shaped curve with a gradual low-frequency roll-off below 80 Hz and a steeper high-frequency roll-off above 250 Hz. The thresholds measured for the harbor seal in this study were about 100 times more sensitive than previous in-air measures of vibrissal sensitivity for this species. The results were similar to those reported by others for the detection of waterborne vibrations, but show an extended range of frequency sensitivity. Animal-borne tagging methods were used to investigate the signals received by the vibrissae and better understand the relevant signal components involved in hydrodynamic detection. A novel tagging system, wLogger, was developed to record vibrations directly from a vibrissa by means of an accelerometer coupled to the vibrissal shaft. Laboratory testing using excised whiskers in a water flume confirmed that the tag is capable of recording vibrational signals without hampering the natural movement of the vibrissa. In addition, the tag successfully measured vibrations from the vibrissae of a harbor seal during active swimming and hydrodynamic detection. Live animal testing, along with the supplemental recordings from excised vibrissae, revealed that interaction with hydrodynamic disturbances disrupted the vibrational signal received by the whisker. When exposed to a hydrodynamic signal, whisker vibrations increased in bandwidth, spreading energy across a wider range of frequencies. This finding suggests that modulation of the vibrational signal may play a key role in the detection of hydrodynamic stimuli by the seal. The results of this dissertation research provide insight into the functioning of the vibrissal system in pinnipeds and establishes the groundwork for future pathways of investigation. By investigating the vibrissal system from the focal points of structure, sensitivity and received signals, a more comprehensive understanding of this refined sensory modality is emerging.

Following lower-limb amputation, patients suffer from sensory loss within the prosthesis/residuum complex leading to diminished proprioception and balance. Artificial sensory systems have the potential to improve rehabilitation outcomes including better functional usage of lower-limb prostheses to achieve a higher quality of life for the prosthetic users. The purpose of this work was to develop and test the e fficacy of a vibrotactile feedback system for lower-limb amputees that may augment feedback during complex balance and movement tasks. Responses to different vibrotactile stimuli frequencies, locations, and physical conditions were assessed. Key outcome measures for this work were the response time and response accuracy of the subjects to the different stimulator configurations. Frequencies closer to 250 Hz applied to the anterior portion of the thigh resulted in the quickest reaction times. When multitasking, reaction times increased. These preliminary results indicate that vibrotactile sensory feedback may be viable to use by lower-limb amputees.