This is a study of the body and architecture, the way in which the two experience one another, the way in which one can inform the other. This thesis was centered around the consideration of the senses not as separate inputs, but as one harmonious quality of perception. The project began as an attempt to explore how the non-visual senses could inform the architectural gestation and developed into an exercise using the visual medium of drawings to illicit qualities beyond sight alone. The attempt to capture material quality through abstraction was likened to the search for the divine through our carnal existence on earth. The results attempted to express sensual qualities through a mixture of different media and their layering to demonstrate the development of the whole through the gestation and gradual realization of its fragments. A site in Old Town Alexandria, Virginia was chosen for its relationship to the tidal water of the Potomac River and the opportunities its previous life as a shipyard presented, as half of the site was excavated into the shoreline. The proposal of a spiritual home, a Cistercian monastery on a site that straddles land and water fit ideally with the theme of addressing materiality and abstract representation, the phsycial and spiritual, and the mind and body. Both the site and the program provided a fruitful counterpoint with which the thesis developed. / Master of Architecture

Consumers evaluate products in the market place using their senses and often form mental representations of product properties. These mental representations have been studied extensively. Imagery has been shown to interact with perception within many perceptual modalities including vision, auditory, olfactory, and motor. This dissertation draws on the vast visual imagery literature to examine imagery in the haptic, or touch, modality. Two studies were undertaken to examine the relationship between haptic imagery and haptic perception The first study is based on studies from cognitive psychology that have used similar methods for examining visual imagery and visual perception. In study 1, sighted and visually impaired participants were asked to evaluate objects haptically, to form a haptic image of that object during a short interval, and then to compare the haptic image to a second object. In Study 2, sighted and visually impaired participants listened to five radio advertisements containing imagery phrases from multiple modalities. After listening to the advertisements, participants were asked to recall the ad content and assess both the ad and the product while haptically evaluating the product in the ad. Though results were mixed and further exploration will be necessary, these studies offer broad implications for consumer use of haptic imagery in shopping environments. The implications for both sighted and blind consumers are discussed.

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We consider the problem of enabling a robot to efficiently obtain a dense haptic map of its visible surroundings Using the complementary properties of vision and tactile sensing. Our approach assumes that visible surfaces that look similar to one another are likely to have similar haptic properties. In our previous work, we introduced an iterative algorithm that enabled a robot to infer dense haptic labels across visible surfaces in an RGB-D image when given a sequence of sparse haptic labels. In this work, we describe how dense conditional random fields (CRFs) can be applied to this same problem and present results from evaluating a dense CRF’s performance in simulated trials with idealized haptic labels. We evaluated our method using several publicly available RGB-D image datasets with indoor cluttered scenes pertinent to robot manipulation. In these simulated trials, the dense CRF substantially outperformed our previous algorithm by correctly assigning haptic labels to an average of 93% (versus 76% in our previous work) of all object pixels in an image given the highest number of contact points per object. Likewise, the dense CRF correctly assigned haptic labels to an average of 81% (versus 63% in our previous work) of all object pixels in an image given a low number of contact points per object. We compared the performance of dense CRF using uniform prior with a dense CRF using prior obtained from the visible scene using a Fully Convolutional Network trained for visual material recognition. The use of the convolutional network further improves the performance of the algorithm. We also performed experiments with the humanoid robot DARCI reaching in a cluttered foliage environment while using our algorithm to create a haptic map. The algorithm correctly assigned the label to 82.52% of the scenes with trunks and leaves after 10 reaches into the environment.

Virtual reality (VR)-based surgical simulators using haptic devices can increase the effectiveness of surgical training for surgeons when performing surgical procedures in hard tissues such as bones or teeth milling. The realism of virtual surgery through a surgical simulator depends largely on the precision and reliability of the haptic device, which reflects the interaction with the virtual model. The quality of perceptiveness (sensation, force/torque) depends on the design of the haptic device, which presents a complex design space due to its multi-criteria and conflicting character of functional and performance requirements. These requirements include high stiffness, large workspace, high manipulability, small inertia, low friction, high transparency, and cost constraints. This thesis proposes a design methodology to improve the realism of force/torque feedback from the VR-based surgical simulator while fulfilling end-user requirements. The main contributions of this thesis are: 1. The development of a model-based and simulation-driven design methodology, where one starts from an abstract, top-level model that is extended via stepwise refinements and design space exploration into a detailed and integrated systems model that can be physically realized. 2. A methodology for creating an analytical and compact model of the quasi-static stiffness of a haptic device, which considers the stiffness of actuation systems, flexible links and passive joints. 3. A robust design optimization approach to find the optimal numerical values for a set of design parameters to maximize the kinematic, dynamic and kinetostatic performances of a 6-degrees of freedom (DOF) haptic device, while minimizing its sensitivity to variations in manufacturing tolerances and cost, and also satisfying the allowed variations in the performance indices. 4. A cost-effective approach for force/torque feedback control using force/torque estimated through a recursive least squares estimation. 5. A model-based control strategy to increase transparency and fidelity of force/torque feedback from the device by compensating for the natural dynamics of the device, friction in joints, gravity of platform, and elastic deformations. / <p>QC 20140415</p>

The past decade has seen the release of numerous software packages aimed at enhancing anatomical education. However, there has been little research undertaken by the manufacturers of these products into the benefit or otherwise of these packages for student learning. In addition, while many of the existing software packages include interactive three-dimensional models, none of them truly offer virtual dissection i.e. the cutting through anatomical layers with a haptic (tactile) interface. This study investigated the haptic ‘dissection’ of a three dimensional digital model of the hand and wrist in anatomy education at both undergraduate (UG) and postgraduate (PG) levels. The model was used as a teaching and revision aid both prior to and after dissection of a real cadaver. A haptic enabled version of the model, allowing for real-time cutting was compared with a non-haptic version, using instead a keyboard and mouse ‘point and click’ style interface. Both versions were tested on students of gross anatomy in relation to test results and student experience. The model was based upon Computerised Tomography (CT) and photographic slice data from the Visible Human Project female data set. It was segmented and reconstructed using Amira® 5.2.2. From here each structure was exported as a separate STL file and imported into Geomagic Freeform® Modelling TM. Once imported into Freeform® Modelling TM, the individual structures each required varying degrees of re-modelling where detail had been lost during the segmentation process. Some smaller structures such as the nerves, veins and arteries were modelled freehand. The final model could be dissected using FreeForm® ModellingTM, the same software in which it was created. Using FreeForm® ModellingTM as a prototype VR dissector, each anatomical structure could be selected and virtually ‘dissected’ with the PHANTOM® Desktop™ haptic tool. Three methods of interacting with the model were identified: 1) using a cutting tool to cut through the selected layer; 2) using a selection paintball to first select and then delete the layer; and 3) using planes to cut the selected structure in standard anatomical views. The study ran over five successive years and was split into three discreet phases. Phase one compared the results of PG students across control, non-haptic and haptic groups. Phase two compared the results of UG students between control and haptic groups. Phase three compared the results of UG students across control, non-haptic and haptic groups. Due to small group sizes and a largely non-normal distributions the results were analysed using Mann-Whitney U tests. Results for all phases indicate that use of the model, both through haptic and non-haptic interfaces produced some significantly improved test results. The non-haptic version of the model performing equal or better than those with access to the haptic version. This is likely due to cognitive load being adversely affected by the addition of the haptic device. Some students reported that the haptic device was not intuitive to use and took some time to get used to, if at all. No student used either version of the model for more than five hours, with over 40% using it for less than one hour. It is possible that with increased exposure to the haptic device students may find it easier and thus beneficial. The findings of this study indicate that when used for a short period of time only ( < 5 hours) the haptic device may impede rather than enhance learning.

The manipulation contact forces convey substantial information about the manipulation state. This paper address the fundamental problem of interpreting the force signals without any additional manipulation context. Techniques based on forms of the generalized sequential likelihood ratio test are used to segment individual strain signals into statistically equivalent pieces. We report on our experimental development of the segmentation algorithm and on its results for contact states. The sequential likelihood ratio test is reviewed and some of its special cases and optimal properties are discussed. Finally, we conclude by discussing extensions to the techniques and a contact interpretation framework.

In order to make the task of controlling Mobile-Manipulator Systems (MMS) simpler, a novel command strategy that uses a single joystick is presented to replace the existing paradigm of using multiple joysticks. To improve efficiency and accuracy, virtual fixtures were implemented with the use of a haptic joystick. Instead of modeling the MMS as a single unit with three redundant degrees-of-freedom (DOF), the operator controls either the manipulator or the mobile base, with the command strategy choosing which one to move. The novel command strategy uses three modes of operation to automatically switch control between the manipulator and base. The three modes of operation are called near-target manipulation mode, off-target manipulation mode, and transportation mode. The system enters near-target manipulation mode only when close to a target of interest, and allows the operator to control the manipulator using velocity control. When the operator attempts to move the manipulator out of its workspace limits, the system temporarily enters transportation mode. When the operator moves the manipulator in a direction towards the manipulator’s workspace the system returns to near-target manipulation mode. In off-target manipulation mode, when the operator moves the manipulator to its workspace limits, the system retracts the arm near to the centre of its workspace to enter and remain in transportation mode. While in transportation mode the operator controls the base using velocity control. Two types of virtual fixtures are used, repulsive virtual fixtures and forbidden region virtual fixtures. Repulsive virtual fixtures are present in the form of six virtual walls forming a cube at the manipulator’s workspace limits. When the operator approaches a virtual wall, a repulsive force is felt pushing the operator’s hand away from the workspace limits. The forbidden region virtual fixtures prevent the operator from driving into obstacles by disregarding motion commands that would result in a collision. The command strategy was implemented on the Omnibot MMS and test results show that it was successful in improving simplicity, accuracy, and efficiency when teleoperating a MMS. / UOIT

Master-Slave teleoperation systems are designed to extend a human's manipulation capability to remote tasks. Recent applications of these systems are in robotic therapy, telesurgery, and medical simulators. In practice, due to the uncertainties in the operator and environment dynamics, and time delay, stability and performance are compromised. Stability-based and performance-based controllers are introduced for these systems. A major class of the former controllers are based on the passivity theory and suffer from the assumed unbounded range of dynamics which is rather unrealistic. The latter class of controllers are mostly adaptive methods that are based on performance optimization. The theme of this thesis is on the development of new stability analysis methods, control strategies, and implementation techniques for enhanced trade-off between stability and performance. I have developed a less conservative passivity-based robust stability method and introduced, for the first time, the notion of Bounded Impedance Absolute Stability. The method provides mathematical and visual aids to incorporate bounds of the passive environment impedance for less conservative guaranteed stability conditions, promising a better compromise between stability and performance. I have extended the new method to include the dynamic range of the human operator for increased stability margins. I have also used the new method to develop a bilateral controller robust to time delays. Furthermore, I have investigated the effect of sampling position versus velocity for various sampling models to obtain less conservative coupled stability conditions for haptic simulation systems. Estimates of the environment dynamics are required to include their variations. Therefore, I have proposed two new real-time parameter estimation methods for linear and nonlinear contacts and experimentally evaluated and compared them with the available techniques. Finally, I have introduced needle insertion as a task in telerobotic systems to combine the expertise of the surgeon with robotic control. Here, the very first few steps needed to effectively control the targeting needles have been taken. I have developed a mechanics-based dynamic model for bevel-tip flexible needles inserted into soft tissues. Finite element models are used to estimate soft tissue deformation, while the mechanics-based model is used to predict needle deflections due to bevel-tip asymmetry. / Thesis (Ph.D, Electrical & Computer Engineering) -- Queen's University, 2011-12-23 01:19:47.535

This thesis falls into the field of tactile displays that are meant to produce realistic tactile sensations, which replicate tactile sensations arising naturally when humans interact with the real world. / To begin with we need to know the biomechanics of the glabrous skin in human subjects. To this end, small patches of fingerpad skin are tested in vivo for their biomechanical properties under tangential loading. The skin is quasi-statically stretched and sheared to obtain its effective Young's modulus. Moreover, isotonic and isometric testing conditions are implemented to identify the viscoelasticity model of the skin. The results show a great deal of variability across subjects and it is observed that the glabrous skin exhibits nonlinear stiffening in tangential traction. The skin is consistently more elastic across the ridges, compared to along the ridges, regardless of the location of the sample on the fingerpad. The skin behaves visco-elastically but relaxes about twice as fast as it creeps. Finally, it is found that under large deformation, there is consistently 80% of hysteretic loss for a wide range of loading conditions. / Based on the results obtained by controlled testing, a high performance distributed display is designed. The display has a compact, yet modular structure. Its 6x10 piezo bimorph actuator array has a spatial resolution of 1.8x1.2 millimeters and a wide temporal bandwidth. The actuator mounting method is improved from conventional cantilever to dual-pinned lever, giving the actuator the capability of optimally coupling with glabrous skin. By using previously measured biomechanical data of the skin, we tune the parameters of the actuators to be optimal in terms of real deflection when they couple with the skin. The blocked force of the individual actuators can be adjusted from 0.15 N to 0.22 N to accommodate different applications. It is self-contained in a 150 cm3 volume and may be interfaced to most computers, provided that two analog outputs and six digital IO lines are available. Both public demonstration and psychophysical experiments have validated its effectiveness in rendering virtual tactile features. / The availability of a display raises the question of what signals should be used to drive it in order to render specific sensations. Some progress is made in this direction by analyzing the contact mechanics of fundamental cases, such as isolated indentation and traveling undulation. With the intention of explaining a tactile illusion engendered by straining the fingertip skin tangentially in a progressive wave pattern, resulting in the perception of a moving undulating surface, we carry out a contact mechanics analysis to derive the strain tensor field induced by a sinusoidal surface sliding on a finger, as well as the field created by a tactile transducer array deforming the fingerpad skin by lateral traction. We find that the first field can be well approximated by the second. Our results imply that, first, tactile displays using lateral skin deformation can generate tactile sensations similar to those using normal skin deformation. Second, there is a synthesis approach to achieve this result given constraints on the design of tactile stimulators. Third, the mechanoreceptors embedded in the skin must respond to the deviatoric part of the strain tensor field and not to its volumetric part. Finally, many tactile stimuli might represent for the brain an inverse problem to be solved. / Using the results of these investigations, we have demonstrated the feasibility of producing high-fidelity virtual tactile sensations.