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- Creators: Helms Tillery, Stephen
- Creators: School of Mathematical and Statistical Sciences
Description
Dexterous manipulation is a representative task that involves sensorimotor integration underlying a fine control of movements. Over the past 30 years, research has provided significant insight, including the control mechanisms of force coordination during manipulation tasks. Successful dexterous manipulation is thought to rely on the ability to integrate the sense of digit position with motor commands responsible for generating digit forces and placement. However, the mechanisms underlying the phenomenon of digit position-force coordination are not well understood. This dissertation addresses this question through three experiments that are based on psychophysics and object lifting tasks. It was found in psychophysics tasks that sensed relative digit position was accurately reproduced when sensorimotor transformations occurred with larger vertical fingertip separations, within the same hand, and at the same hand posture. The results from a follow-up experiment conducted in the same digit position-matching task while generating forces in different directions reveal a biased relative digit position toward the direction of force production. Specifically, subjects reproduced the thumb CoP higher than the index finger CoP when vertical digit forces were directed upward and downward, respectively, and vice versa. It was also found in lifting tasks that the ability to discriminate the relative digit position prior to lifting an object and modulate digit forces to minimize object roll as a function of digit position are robust regardless of whether motor commands for positioning the digits on the object are involved. These results indicate that the erroneous sensorimotor transformations of relative digit position reported here must be compensated during dexterous manipulation by other mechanisms, e.g., visual feedback of fingertip position. Furthermore, predicted sensory consequences derived from the efference copy of voluntary motor commands to generate vertical digit forces may override haptic sensory feedback for the estimation of relative digit position. Lastly, the sensorimotor transformations from haptic feedback to digit force modulation to position appear to be facilitated by motor commands for active digit placement in manipulation.
ContributorsShibata, Daisuke (Author) / Santello, Marco (Thesis advisor) / Dounskaia, Natalia (Committee member) / Kleim, Jeffrey (Committee member) / Helms Tillery, Stephen (Committee member) / McBeath, Michael (Committee member) / Arizona State University (Publisher)
Created2014
Description
The goal of this project was to use the sense of touch to investigate tactile cues during multidigit rotational manipulations of objects. A robotic arm and hand equipped with three multimodal tactile sensors were used to gather data about skin deformation during rotation of a haptic knob. Three different rotation speeds and two levels of rotation resistance were used to investigate tactile cues during knob rotation. In the future, this multidigit task can be generalized to similar rotational tasks, such as opening a bottle or turning a doorknob.
ContributorsChalla, Santhi Priya (Author) / Santos, Veronica (Thesis director) / Helms Tillery, Stephen (Committee member) / Barrett, The Honors College (Contributor) / Mechanical and Aerospace Engineering Program (Contributor) / School of Earth and Space Exploration (Contributor)
Created2014-05
Description
In this experiment, a haptic glove with vibratory motors on the fingertips was tested against the standard HTC Vive controller to see if the additional vibrations provided by the glove increased immersion in common gaming scenarios where haptic feedback is provided. Specifically, two scenarios were developed: an explosion scene containing a small and large explosion and a box interaction scene that allowed the participants to touch the box virtually with their hand. At the start of this project, it was hypothesized that the haptic glove would have a significant positive impact in at least one of these scenarios. Nine participants took place in the study and immersion was measured through a post-experiment questionnaire. Statistical analysis on the results showed that the haptic glove did have a significant impact on immersion in the box interaction scene, but not in the explosion scene. In the end, I conclude that since this haptic glove does not significantly increase immersion across all scenarios when compared to the standard Vive controller, it should not be used at a replacement in its current state.
ContributorsGriffieth, Alan P (Author) / McDaniel, Troy (Thesis director) / Selgrad, Justin (Committee member) / Computing and Informatics Program (Contributor) / School of Mathematical and Statistical Sciences (Contributor) / Economics Program in CLAS (Contributor) / Computer Science and Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
Description
This paper presents a study done to gain knowledge on the communication of an object’s relative 3-dimensional position in relation to individuals who are visually impaired and blind. The HapBack, a continuation of the HaptWrap V1.0 (Duarte et al., 2018), focused on the perception of objects and their distances in 3-dimensional space using haptic communication. The HapBack is a device that consists of two elastic bands wrapped horizontally secured around the user’s torso and two backpack straps secured along the user’s back. The backpack straps are embedded with 10 vibrotactile motors evenly positioned along the spine. This device is designed to provide a wearable interface for blind and visually impaired individuals in order to understand how the position of objects in 3-dimensional space are perceived through haptic communication. We were able to analyze the accuracy of the HapBack device through three vectors (1) Two different modes of vibration – absolute and relative (2) the location of the vibrotactile motors when in absolute mode (3) and the location of the vibrotactile motors when in relative mode. The results provided support that the HapBack provided vibrotactile patterns that were intuitively mapped to distances represented in the study. We were able to gain a better understanding on how distance can be perceived through haptic communication in individuals who are blind through analyzing the intuitiveness of the vibro-tactile patterns and the accuracy of the user’s responses.
ContributorsLow, Allison Xin Ming (Author) / McDaniel, Troy (Thesis director) / Duarte, Bryan (Committee member) / School of Mathematical and Statistical Sciences (Contributor) / Computer Science and Engineering Program (Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2019-12