Teleoperation of hydraulic manipulators is of potential when the presence of the operator, in a remote location, is inconvenient or dangerous. Augmenting such teleoperated systems using haptic sensation will further enhance performance, safety, and convenience. The advantage of using haptic force becomes more evident when it is employed to compensate for undesirable phenomena such as existence of a delayed and lossy communication channel or excitation of the manipulator base. The focus of this thesis is on haptic-enabled control of base-excited hydraulic manipulators that are controlled through a wireless communication channel. The targeted application is live transmission line maintenance. Both unilateral and bilateral controls of teleoperated hydraulic manipulators are studied. On the unilateral front, position error is shown to be an important issue, especially when the position accuracy of the slave manipulator is violated due to fast motion of the operator’s hand at the master site, lack of responsiveness in actuation system, or poor quality of communication channel. With respect to bilateral control, three main challenges are identified, and solutions to these challenges are investigated: (i) accurate control of the slave manipulator when the communication channel is delayed and/or lossy, (ii) control of the teleoperated system when the slave manipulator is mounted atop a moving platform, and (iii) transparent force feedback to improve the position tracking of the system. First, effects of network quality and slave manipulator base excitation are examined on performance of the teleoperated system. The position error between the haptic device implement and the hydraulic manipulator end-effector is shown to increase when the network is delayed and lossy. Next, excitation of the slave manipulator base deviates the end-effector from its reference trajectory, and the position error therefore becomes larger. To alleviate the position inaccuracy, a position referenced force feedback scheme is proposed. The scheme makes the input dynamics a better match with the slave dynamics. Combined with the virtual fixture force, the virtual fixture is shown to aid the operator in following a predefined virtual fixture trajectory. Due to complexity of dynamics, performance evaluations are mostly conducted using experimental validations on actual system in a laboratory setting.

Several researchers have successfully developed realistic models of real world objects/ phenomena and then have simulated them in the virtual world. In this thesis, we propose the opposite: instantiating virtual world events in the real world. The interactive 3D virtual environment provides a useful, realistic 3D world that resembles objects/phenomena of a real world, but it has limited capability to communicate with the physical environment. We argue that new and intuitive 3D user interfaces, such as 3D virtual environment interfaces, may provide an alternative form of media for communicating with the real environment. We propose a 3D virtual world-based add-on architecture that achieves a synchronized virtual-real communication. In this framework, we explored the possibilities of integrating haptic and real world object interactions with Linden Lab's multiuser online 3D virtual world, Second Life. We enhanced the open source Second Life viewer client in order to facilitate communications between the real and virtual world. Moreover, we analyzed the suitability of such an approach in terms of user perception, intuition and other common parameters. Our experiments suggest that the proposed approach not only demonstrates a more intuitive mode of communication system, but also is appealing and useful to the user. Some of the potential applications of the proposed approach include remote child-care, communication between distant lovers, stress recovery, and home automation.

The haptic exploration of 2-D images is a challenging problem in computer haptics. Research on the topic has primarily been focused on the exploration of maps and curves. This thesis describes the design and implementation of a system for the haptic exploration of photographs. The system builds on various research directions related to assistive technology, computer haptics, and image segmentation. An object-level segmentation hierarchy is generated from the source photograph to be rendered haptically as a contour image at multiple levels-of-detail. A tool for the authoring of object-level hierarchies was developed, as well as an innovative type of user interaction by region selection for accurate and efficient image segmentation. According to an objective benchmark measuring how the new method compares with other interactive image segmentation algorithms shows that our region selection interaction is a viable alternative to marker-based interaction. The hierarchy authoring tool combined with precise algorithms for image segmentation can build contour images of the quality necessary for the images to be understood by touch with our system. The system was evaluated with a user study of 24 sighted participants divided in different groups. The first part of the study had participants explore images using haptics and answer questions about them. The second part of the study asked the participants to identify images visually after haptic exploration. Results show that using a segmentation hierarchy supporting multiple levels-of-detail of the same image is beneficial to haptic exploration. As the system gains maturity, it is our goal to make it available to blind users.

Thesis (MScEng)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: Telerobotics is a field of robotics interested in controlling robots from a distance. Incorporating visual and haptic (touch) feedback allows the operator greater accuracy in manipulating objects in a remote environment. This project endeavours to develop a telerobotic system by using two similar industrial robotic manipulators, one acting as a haptic input device (known as the Master), the other as the telerobot (known as the Slave). This project makes use of a diverse range of technologies to achieve a telerobotic system. As such it makes use of Systems Engineering and Technology Management principles to guide the development process of converting standard industrial robots into a telerobotic system that allows the operator to “see” and “feel” in the remote environment. The ability of the robot to perceive touch is accomplished by incorporating a multi-axis force and torque sensor to both industrial robots to measure any applied force or torque acting on each robot’s end-effector. A communication system is developed that receives the force and torque readings from each sensor as well as transmit the robot instructions to both Master and Slave. Haptic feedback is achieved by combining the force and torque readings from both sensors within a control system before manipulating the data into a robot instruction that is used to control both Master and Slave. Testing of the developed telerobotic system indicates that a functional system has been developed. However, several issues were identified that limit the control capabilities the operator has over the Slave and as such could lead to safety concerns. / AFRIKAANSE OPSOMMING: Telerobotika is ’n veld van robotika wat belangstel in die beheer van robotte oor ’n afstand. Die insluiting van visuele en hapties (voel) terugvoer stel die operateur instaat om voorwerpe in ’n afgeleë omgewing met hoër akkuraatheid te manipuleer. Hierdie projek streef daarna om ’n telerobotiese stelsel te ontwikkel deur gebruik te maak van twee soortgelyke industriële robot manipuleerders, een wat optree as ’n meganiese invoer toestelle (bekend as die Meester), die ander as die telerobot (bekend as die Slaaf). Hierdie projek maak gebruik van ’n verskeidenheid van tegnologieë om ’n telerobotiese stelsel te ontwikkel. Sodanig word tegnologie bestuur en stelsels ingenieurswese beginsels deur die loop van die projek geïmplementeer om die ontwikkelings proses te lei - van standaard industriële robotte tot ’n telerobotiese stelsel wat dit moontlik maak vir die operateur om te “sien” en “voel” in ’n afgeleë omgewing. Die robot se vermoë om fisiese kontak te ervaar word bereik deur middel van ’n multi-as krag en torsie sensor wat aan beide industriële robotte toegepas word. ’n Kommunikasie stelsel is ontwikkel wat die krag en torsie lesings van beide sensors kan ontvang sowel as die robot instruksies na elke robot (Meester en Slaaf) kan stuur. Haptiese terugvoer word bereik deur die krag en torsie lesings van beide sensors te kombineer in ’n beheer stelsel voordat dit verder gemanipuleer word in die form van ’n robot instruksie wat gebruik word vir die beheer van beide Meester en Slaaf. Toetsing van die ontwikkelde telerobotiese stelsel dui aan dat ’n funksionele stelsel ontwikkel is. Daar is egter verskeie kwessies geïdentifiseer wat die operateur se beheer vermoeëns oor die Slaaf beperk wat sodoende na veiligheids kwessies kan lei.

abstract: Typically, the complete loss or severe impairment of a sense such as vision and/or hearing is compensated through sensory substitution, i.e., the use of an alternative sense for receiving the same information. For individuals who are blind or visually impaired, the alternative senses have predominantly been hearing and touch. For movies, visual content has been made accessible to visually impaired viewers through audio descriptions -- an additional narration that describes scenes, the characters involved and other pertinent details. However, as audio descriptions should not overlap with dialogue, sound effects and musical scores, there is limited time to convey information, often resulting in stunted and abridged descriptions that leave out many important visual cues and concepts. This work proposes a promising multimodal approach to sensory substitution for movies by providing complementary information through haptics, pertaining to the positions and movements of actors, in addition to a film's audio description and audio content. In a ten-minute presentation of five movie clips to ten individuals who were visually impaired or blind, the novel methodology was found to provide an almost two time increase in the perception of actors' movements in scenes. Moreover, participants appreciated and found useful the overall concept of providing a visual perspective to film through haptics. / Dissertation/Thesis / M.S. Computer Science 2011

This thesis explores what I call 'physical spectatorship' as it is generated by a group of films concerned with the mutilation of the human body. Focusing on the representation of mutilation on the screen and the physical responses this evokes, the thesis is organised around the study of a series of dynamic engagements that reconfigure the film-viewer relationship; these include: corporeal mimicry and the cinematic visualisations of mutilation; generalised anxiety and experimental use of sound; and the nausea generated by audio-visual techniques that both signify and locate the filmic gut in the viewer's body. Combining close textual analyses with theoretical approaches, this thesis draws upon psychoanalytic, phenomenological and feminist theories of film and spectatorship. Throughout the chapters, my argument builds upon the work of Vivian Sobchack and Laura Marks in order to interrogate further what might be meant by the notion of the embodied spectator. The chapters explore this notion, alongside that of the film viewer, to generate a dialogue with previous theorists of the cinematic spectator, including Christian Metz and Richard Rushton. Exploring through close textual analyses the specific filmic techniques that generate intense physical responses, this thesis argues that the mutilation film demands a rethinking of some of the key categories in theories of spectatorship. Extending across national cinemas and reaching beyond conventional generic distinctions, the mutilation film produces a visceral aesthetic that has yet to be analysed. Focusing on particular aspects of the mutilation film, such as the assault narrative sequence, use of extreme frequencies and haptic sounds and images, the thesis offers detailed readings of the following texts: Dans Ma Peau (Marina de Van, 2002), Irréversible (Gaspar Noé, 2002), Saw II (Darren Lynn Bousman, 2005) Saw III (Darren Lynn Bousman, 2006) Saw IV (Darren Lynn Bousman, 2007) Saw V (David Hackl, 2008) Saw VI (Kevin Greutert, 2009) Saw 3D (Kevin Greutert, 2010), Hostel (Eli Roth, 2005), À l'intérieur (Alexandre Bustillo and Julien Maury, 2007), The Human Centipede: First Sequence (Tom Six, 2009) and The Human Centipede: Full Sequence (Tom Six, 2011).The analyses that form this thesis demonstrate the problems with separating notions of the 'spectator as textual construction' from that of the 'viewer as physically embodied'; yet these readings also indicate the necessity of continuing the task of conceptualising their interrelatedness, rather than simply using them interchangeably. The conclusion argues that the concept of physical spectatorship offers one way to understand how particular contemporary aesthetics have reconfigured the boundary between viewer and film.

We are investigating the use of ultrasound in Haptic applications. Initially abrief background of ultrasonic transducers and its characteristics were presented.Then a theoretical research was documented to understand the concepts that govern haptics. This section also discusses the algorithm adopted by various researches to implement haptics in the professional world. Then investigations were made to understand the behavior of ultrasonic transducers and conduct soft-ware simulations to obtain various results. At first simulations were conducted on Field II software. This simulations involved the creation of elements in trans-ducers, transducer’s spatial impulse responses, transducer’s impulse responsein time and frequency domain, effect of adding apodization to the transducers,pulse echo response of the transducers, beam profile variation along the focallength of the transducers. Then a Matlab based GUI was used to study the relationship between number of elements in transducers, the frequency of the input signal and duty cycle variation of the input wave. A concept of phase shift, which explains the time delay generation was also coded in Matlab.

This thesis explores how to design for the visually impaired. During the course of work, a literature study and interviews with blind and visually impaired people were conducted. The objective was to investigate what contextual information is wanted in new and unfamiliar spaces outside their home. The interviews also explored how they experience digital tools they are using today and what they think of the possibilities of voice and other user interfaces. The main finding from the study is that there are indications that multimodal interfaces are preferred. The interface should combine voice, haptic and graphics since the participants wanted to interact in different ways depending on functionality and context. Three main problem areas were identified, navigation, public transportation and shopping. Another result was that when developing for the visually impaired it should always be tested on people with a wide variation of vision loss to find the correct contextual information.

The human body has a unique mechanism for perceiving surrounding temperatures. When an object is in contact with the skin, we do not feel its temperature. Instead, we feel the temperature change that is caused on our skin by that object. The faster the heat is transferred, the more intense the thermal sensation is. In this dissertation, a new dynamic thermal display method, where different rates of warm and cold are applied on the skin to generate a unique sensation, is presented. The new method can be related in a wide range of applications including thermal haptics and virtual reality. To understand the perception of temperature and the general thermal state of the human body, the first aspect of this dissertation focuses on investigating the interaction between temperature change and perception on a large scale. Three field surveys were conducted inside airconditioned buildings to investigate the change in the thermal state and temperature perception of occupants when the room temperature changes. The results showed that the participants’ prediction of constant operating temperature was poor, however, their prediction was significantly improved when temperature changes were presented. In order to more accurately investigate the perception of temperature on the skin, a new thermal display method using multiple-channel thermal actuators was developed. The principle of this method is to apply slow and fast rates of temperature change simultaneously on the skin. The slowly changing temperatures are below the perceptual threshold of the thermal receptors, therefore will not be detected whereas the quickly changing temperatures are above the perceptual threshold, hence, will be detected. The idea here is to keep the average surface temperature of the skin constant, however a person will perceive a sensation of continuous cooling. This method was tested through a series of experiments, and the results showed that it is capable of generating a continuous cooling sensation without changing the average temperature of the stimulation area. Multiple variations of this method were tested including different heating and cooling rates of change, different skin locations and patterns of stimuli. Also, a continuous warming was generated using similar concept. To further investigate the temperature distribution that is caused by this method and its effect on the skin, a computational simulation was conducted. An approximate model of the skin was used to monitor its surface temperature and record the temperatures in the stimulation area when the continuous cooling method is applied. The results of the simulation showed that the temperature under the surface of the stimulation area was affected by the continuous cooling method that was applied on the skin model, however this method did not affect the average surface temperature of the skin. These findings may later determine the efficiency and intensity of the method of continuous cooling, and allow us to investigate different technically challenging variations of this method.

Thermal sensation is one of the most dynamic stimulus-response systems in the human body. It is relied upon for safety, comfort and general equilibrium of the human body. Thermal sensation is dependent upon many variables such as area of effected skin, rate of temperature change and location of stimulation. It has been shown that certain rates of change can intensify the sensation of heating or cooling. Conversely, sufficiently low rates of change can go undetected by the skin. As such, the thermal response system can be manipulated by the proper combination of applied hot and cold stimuli. Previous research has shown that through precise application of an asymmetrically heated and cooled thermal display, a sensation of constant cooling can be perceived. This thesis seeks to (1) explore the heat flux characteristics of the thermal display through the use of computer simulations, (2) test a hypothesis about the relationship between thermal sensation and heat flux and (3) examine modifications of the thermal display patterns with the intention of producing more intense thermal sensations. To characterize the heat flux patterns produced by the thermal display, finite element simulations, performed using commercially available software ANSYS©. Simulations are conducted on individual heating and cooling rates to examine the expected values of heat flux as temperatures approach and diverge from skin temperature. Evaluated in the cylindrical coordinate system (axial, angular and radial), the simulations showed a slight nonlinear heat flux generation at the beginning of heating and cooling, but after the initial transient period, this gave way to a strong linear generation of increasing or decreasing heat flux. Simulations were performed that represent the physical experiments implemented in pre- vious research. These simulations were done in two parts: the first examines a small subregion with finer detail on the area between heating and cooling stimuli, the second is a larger scale examination of the heat flux profile of the thermal display. Initially it was observed that directly under the thermal stimulus, in the radial direction, the heat flux was almost perfectly in-phase with the oscillation of temperature whereas between the stimuli, it was nearly 180 degrees out of phase. The heat flux in the axial and angular directions under the thermal stimulus were negligible. Additionally, between stimuli, the values were nearly 180 degrees out of phase with temperature. Additionally, it was observed that the heat flux profiles for all patterns used in the thermal display were approximately identical. From the data gathered by the simulations in conjunction with the thermal sensation data from previous research, a linear relationship is hypothesized that relates these two quantities. This relationship was then used to determine the theoretical thermal sensations of newly developed thermal display patterns in order to determine which are best suited for future physical experimentation.