Master of Science (MS), Ohio University, 2007, Computer Science (Engineering)

This thesis presents implementation and evaluation of a multiple-points haptic rendering algorithm using the PHANToM haptic interface, in the context of our Virtual Haptic Back Project at Ohio University. This algorithm will increase realism in palpation with the Virtual Haptic Back and other virtual haptic palpation tasks when compared to the single point haptic rendering. The single-point haptic rendering cannot provide tool-object interactions in which more than one object is in contact simultaneously at different locations of the tool or finger. Since a single point does not represent the finger haptically well, this thesis uses a multiple-points probe. The multiple-points collision detection is computationally expensive and complicated than the single-point haptic rendering. This thesis constructs the volume object using a sphere. The center of this sphere is the original PHANToM position and the end-points consist of points on the sphere. The collision detection between these line segments and objects in the virtual scene is completed and a resultant force is displayed to the user. The multiple-points haptic rendering algorithm was integrated with simple haptic objects and with the complex Virtual Haptic Back. The multiple-points algorithm is made efficient using concepts such as rasterisation, hashing and spatial decomposition. Experiments have determined that multiple-points haptic rendering can improve the user's experience with virtual reality applications based on this first step in implementation and evaluation.

Committee: Robert Williams II (Advisor) Subjects: Computer Science

Master of Science (MS), Ohio University, 2005, Mechanical Engineering (Engineering)

This thesis presents implementation and evaluation of a haptic playback system using the PHANToM haptic interface, in the context of our Virtual Haptic Back Project at Ohio University. Playback has the potential to improve virtual palpatory diagnosis training by allowing students to follow and feel an expert's motions in virtual reality prior to performing their own palpatory tasks. We have two types of playback system. The first type is called ‘Combined Playback System' and the second one is called ‘Two Mode Playback System'. In the first type we have a combined position and force playback. In the second type of playback system, in mode 1 the human is passive and experiences position playback of the expert's tactile examination via the PHANToM with a PD position controller. In mode 2 the human traces the expert's path actively through visual cues. Mode 2 enables the haptics model so that the trainee feels approximately what the expert did in the original task. Both playback systems are evaluated. Our experiments show that if both playback modes of the ‘Two Mode Playback System' are used together, trainees follow the expert's path with lesser position error than the other group, which doesn't do mode 1 training.

Committee: Robert Williams (Advisor) Subjects: Engineering, Mechanical

Master of Science, Miami University, 2024, Mechanical and Manufacturing Engineering

The demand for haptics in large touchscreen displays (TSDs) has rapidly grown in recent years. However, due to limitations of existing haptic actuators used within mobile devices the technology to implement haptic feedback in large TSDs is immature. To address challenges for generating haptic feedback in large touch screen displays, this study proposes a haptic module based on a “smart” fluid called Electro-Rheological (ER) fluid for use in large TSD applications. An ER haptic module is presented which utilizes ER fluid to provide a means to control vibrations transmitted through the base of the module to an output display mass felt by a user modeling a large TSD. The module is experimentally evaluated to understand its dynamic behavior and the influence of the ER fluid on haptic feedback. Two variables into the ER fluid are controlled: input voltage and frequency. Findings show that the input voltage into the ER fluid directly corresponds to the magnitude of the acceleration response transmitted through the module, with as high as an 88% increase in amplitude observed. Frequency input is shown to affect the shape of the resulting waveform, with various waves with different frequencies present based on the input frequency.

Committee: Jeong-Hoi Koo (Advisor); Jinjuan She (Committee Member); Sk Hasan (Committee Member) Subjects: Mechanical Engineering

Master of Science, Miami University, 2023, Mechanical Engineering

Available devices with smaller touchscreen displays (TSDs) offer users adequate haptic feedback, whereas larger TSDs still lack meaningful tactile sensations. This study is focused on rendering vibrotactile feedback on large TSDs. Existing methods for localized vibrotactile rendering on large TSDs use many actuators. Practically, using many actuators is not desirable due to space constraints, power supply limitations, etc., for consumer-centric large TSD devices. Therefore, this study investigates localized vibrotactile feedback on large TSDs using a restricted number of electrostatic resonant actuators (ERAs). Using flexible boundary conditions combined with multi-frequency excitation, a novel method is presented to render localized vibrotactile feedback for two types of large TSDs: a narrow touch bar and a rectangular touch surface. A method for managing/positioning localized haptic feedback on large TSDs is also investigated. In-house finite-element-based simulation models of TSDs are developed along with experimental prototypes for verifying the vibrotactile performance. The modeling and analysis strategy presented here is general and can be extended for haptic rendering methods of different touch surfaces, actuators, and boundary conditions. Finally, model-based parametric studies are presented for better design considerations and improved vibrotactile intensity.

Committee: Kumar Singh (Advisor); Jeong-Hoi Koo (Advisor); James Chagdes (Committee Member) Subjects: Electrical Engineering; Engineering; Mechanical Engineering

Master of Science, Miami University, 2019, Mechanical and Manufacturing Engineering

Realistic haptic feedback is necessary to provide meaningful touch information to users of numerous technologies, such as virtual reality, mobile devices and robotics. For a device to convey realistic haptic feedback, two touch sensations must be present: tactile feedback and kinesthetic feedback. Tactile feedback is felt at the surface of one's skin and displays textures and vibrations, whereas kinesthetic feedback is felt in one's joints and muscles and transmits position and movement information. While many devices today display tactile feedback through vibrations, most neglect to incorporate kinesthetic feedback due to size constraints. To provide comprehensive feedback, this study investigates a new haptic device based on an unconventional actuation method: electrorheological (ER) fluid, a smart fluid with tunable yield stress under the application of electric field. The device's control electronics and structural components are integrated into a compact printed circuit board, resulting in a slim device suitable for mobile applications. By controlling the ER fluid flow via applied electric fields, the device can generate a wide and distinct range of both tactile and kinesthetic sensations. These sensations were derived analytically from ER fluid's governing equations as well as experimentally. The device may be used as a haptic interface between a user and virtual environment.

Committee: Jeong-Hoi Koo Ph.D. (Advisor); Tae-Heon Yang Ph.D. (Committee Member); Michael Bailey Van Kuren Ph.D. (Committee Member) Subjects: Computer Engineering; Materials Science; Mechanical Engineering

Master of Science, Miami University, 2018, Mechanical and Manufacturing Engineering

Haptic feedback is a highly beneficial feature of touch screens. Due to the limitations of current haptic technologies, devices with large touch screens are unable to provide haptic feedback to users. This study proposes and investigates an electrostatic actuator utilizing frequency beating phenomenon with the goal of generating haptic feedback in devices with large touch screens. A prototype device was fabricated and through experimentation, two unique high intensity vibration patterns were found at each beat frequency. An analytical model of the prototype was developed to. The model produced a peak vibration intensity distribution closely resembling that of the experimental data. The possibility of three input signals was investigated. Variations in beating patterns could be seen, but this provides little benefit in application. A multiphysics model was developed to provide a more accurate representation of the operation of the actuator. This model was also used do investigate the effects of the coupling of displacement and electrostatic force. The multiphysics model was able to produce accurate results but was unstable when using certain input conditions. The displacement coupling creates changes in the computed displacement and intensity response. The model produced the same peak intensity distribution as the experimental data. Improvements can be made to both models to improve accuracy and stability. The models are intended to aid in the refinement of the design of future prototypes.

Committee: Jeong-Hoi Koo Ph. D. (Advisor); Jens Mueller Ph. D (Committee Member); Kumar Singh Ph. D. (Committee Member) Subjects: Design; Mechanical Engineering

Master of Science (MS), Ohio University, 2008, Mechanical Engineering (Engineering and Technology)

The Three Cable Haptic Interface (TCHI) prototype built by Williams et. al (2006) is improved by selecting and installing appropriate motors and designing cable reels which together successfully provided the proper amount of force for the intended application.Simulation was performed which showed that the required cable tension force rises almost linearly with frame size, but rises exponentially as the distance from the base plane (Y distance) decreases. Furthermore, it was determined from simulation that the required cable tension can be significantly lessened if the device is configured in such a way as to limited the workspace to approximately 6 cm from the top and sides and 13 cm from the imaginary diagonal which spans from top right motor to bottom left. The new TCHI prototype is theoretically able to exert 31N of continuous force on the user, a 10 fold improvement over the PHANToM 3.0 and has a nominal position resolution of 0.004mm, a 5 fold improvement over the PHANToM 3.0. The new TCHI prototype is also superior to the PHANToM 3.0 in terms of maximum exertable force, stiffness, cost, and workspace if configured properly.

Committee: Robert L. Williams II (Advisor); John Howell PhD (Committee Member); John Cotton PhD (Committee Member); Israel Urieli PhD (Committee Member) Subjects: Engineering; Mechanical Engineering

Master of Science (MS), Ohio University, 2006, Mechanical Engineering (Engineering)

A simple Three Cable Haptic Interface (TCHI) based upon the WireMan configuration developed by Bonivento et al., is developed, simulated, built and tested in this thesis. Cable systems cannot push on the user but only can provide positive tensions. This TCHI is further limited due to no actuation redundancy and further, forces can only be applied within the tetrahedron formed by the finger tip point and base cable attachment points. The inverse pose kinematics is straight forward for this parallel manipulator configuration and the forward pose kinematics are derived using William's Three Spheres intersection algorithm [23]. A pseudo-statics solution is derived to calculate the required cable tensions to provide the desired force-feed back. Three different control strategies are developed for to perceive soft, hard and both soft and hard combinations of the virtual walls.

Committee: Robert Williams II (Advisor) Subjects: Engineering, Mechanical

Doctor of Philosophy, Case Western Reserve University, 2011, EECS - Electrical Engineering

Haptic interaction refers to interactivity with an environment based on the sense of touch. Haptics is a critical mode of human interface with real or virtual environments, as it is the only active form of perception. All other senses are passive and cannot directly act upon an environment. Haptic interface devices connect users to real or virtual environments through the modality of touch and associated sensory feedback. As the user interacts with environments through the haptic system, it alters the user's perception and motor control, which can affect task performance. Therefore, understanding a haptic system's effects on the sensory-motor system and the implications of these interactions on task performance is important for the design of effective haptic interface systems. This dissertation focused on characterization, modeling, and analysis of human motor performance in the context of stylus-based haptic interface devices. The current work combined human psychophysics experiments with analysis methods from system theory to model and study several aspects of human haptic interaction. The first contribution of this work was the identification of 3D linear dynamics and variability models for the arm and hand configured in a stylus grip. The literature contains many human arm dynamics models, but lacks detailed associated variability analyses. Without them, variability is modeled in a very conservative manner, leading to less than optimal controller and system designs. The current work not only presented models for human arm dynamics, but also developed inter and intra-subject variability models from human experiments. The second contribution of this work was the analysis of 3D point-to-point Fitts' reaching task in both real and virtual environments in order to determine the effect of visual field and haptic workspace co-location on task performance. A key finding was the significant decrease observed in end-point error for tasks performed in a co-located virtual (open full item for complete abstract)

Committee: M. Cenk Cavusoglu PhD (Committee Chair); Wyatt S. Newman PhD (Committee Member); Kenneth A. Loparo PhD (Committee Member); Wei Lin PhD (Committee Member); Roger D. Quinn PhD (Committee Member) Subjects: Biophysics; Electrical Engineering; Systems Science

Master of Sciences, Case Western Reserve University, 2013, EECS - Computer and Information Sciences

Approximately 40 million American adults ages 18 and older, or about 18.1 percent of individuals in this age group in a given year, have an anxiety disorder . One current option for treatment is behavior exposure therapy as provided by a trained professional. This thesis develops an immersive, computer-based, 3D virtual experience as an alternative to exposure therapy. Virtual experiences provide a potential therapy that would be repeatable, represent a safe environment for patient exploration, be widely available, and require minimal support. Two virtual environments, in particular, have been developed and tested: one representing an experience intended to create a generalized anxiety response and the second intended to illicit an obsessive-compulsive behavior. The hypothesis to be examined with these two virtual scenarios is whether the addition of a sense of "touch" as provided by a haptic force feedback device can increase the sense of immersion in anxiety-inducing virtual experiences.

Committee: Marc Buchner Dr. (Advisor); Amy Przeworski Dr. (Committee Member); Murat Cavusoglu Dr. (Committee Member) Subjects: Computer Science

MDES, University of Cincinnati, 2013, Design, Architecture, Art and Planning: Design

Many objects have what psychologist, Donald Norman, calls affordances. Affordances are cues that provide users with information on how to interact with objects. Those cues are mainly based on our visual perception of the object. What about cues for senses other than vision? The purpose of this thesis is to demonstrate the possibility that a product, with information cues applying to more than one of the five senses, can be better understood than a product relying on one sense alone. This demonstration will be to design a piece of equipment for firefighters who are commonly placed in situations where they have to rely on senses other than sight.

Committee: Gerald Michaud M.A. (Committee Chair); Howie Baum B.S. (Committee Member); Tony Kawanari M.A., I.D. (Committee Member) Subjects: Instructional Design