Many environments are inaccessible or hazardous for humans. Remaining debris after earthquake and fire, ship hulls, bridge installations, and oil rigs are some examples. For these environments, major effort is being placed into replacing humans with robots for manipulation purposes such as search and rescue, inspection, repair, and maintenance. Mobility, manipulability, and stability are the basic needs for a robot to traverse, maneuver, and manipulate in such irregular and highly obstructed terrain. Hexapod walking robots are as a salient solution because of their extra degrees of mobility, compared to mobile wheeled robots. However, it is essential for any multi-legged walking robot to maintain its stability over the terrain or under external stimuli. For manipulation purposes, the robot must also have a sufficient workspace to satisfy the required manipulability. Therefore, analysis of both workspace and stability becomes very important. An accurate and concise inverse kinematic solution for multi-legged robots is developed and validated. The closed-form solution of lateral and spatial reachable workspace of axially symmetric hexapod walking robots are derived and validated through simulation which aid in the design and optimization of the robot parameters and workspace. To control the stability of the robot, a novel stability margin based on the normal contact forces of the robot is developed and then modified to account for the geometrical and physical attributes of the robot. The margin and its modified version are validated by comparison with a widely known stability criterion through simulated and physical experiments. A control scheme is developed to integrate the workspace and stability of multi-legged walking robots resulting in a bio-inspired reactive control strategy which is validated experimentally.

This thesis seeks to answer the following question: “could a machine be capable of consciousness?” I begin to tackle this question by providing a presumed definition of consciousness, employing Bernard Baars’ Global Workspace Theory. Next, I look to various discussions of machine intelligence and whether or not this would be sufficient for categorizing a machine as conscious. And lastly, I explore the notion that the human brain may be a sort of computational system itself and the implications this notion has for the potential that non-human systems may achieve consciousness. Through these sections, I ultimately conclude that a machine could potentially mimic the cognitive systems of the human brain that produce consciousness (at least insofar as these systems and consciousness itself are defined by Global Workspace Theory). And therefore, a machine could indeed be capable of consciousness.

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In a fast-paced office setting, information workers inevitably experience expected and unexpected interruptions daily. As the volume and the diversity of information and application types grow, the impact of frequent interruptions on their task performance gets more severe. To manage the negative effects of interruptions on work performance, workers often engage in task management activities to ensure they are better prepared to resume suspended task less stressfully. However, managing tasks causes additional cognitive burden and a time cost to users who already are experiencing the tight attention and time economies. This dissertation presents an approach to augmenting users' task performance by allowing them to manage and retrieve desired work contexts with ease. The Context Browser, the implementation of the proposed approach, is designed to help the users to explore narratives of their workspace manner and restore their previous work contexts. The goals of implementing the Context Browser are to 1) unload the users? burden of taking care of their task-related or task status information promptly and thus help them focus solely on executing a given task, 2) allow them to browse their previous workspace intuitively, and 3) enhance continuity of their tasks by supporting them to retrieve desired work context more quickly and easily. In order to validate the proposed approach, a user study comparing task performances of the group with the Context Browser to the one without the Context Browser was conducted. The study produced both quantitative and qualitative results. The study confirmed that with the Context Browser subjects expressed better quantitative numbers than the ones without. Subjects using the Context Browser were able to restore and retrieve their desired work setting and task-related information more quickly and correctly. Qualitative results showed that the subjects using the Context Browser found that various contextual cues and the interfaces responsible for providing the cues offered effective artifacts to help them recover both cognitive and work contexts, while the other subjects experienced a difficult time in restoring the desired contexts that were necessary to perform their assigned tasks. In addition, we re-invited 6 subjects from the group without the Context Browser 6 weeks after the study. We asked them to perform the same tasks as the ones they did 6 weeks before with the Context Browser. It showed that with the Context Browser they outperformed their previous performance even after a lengthy period.

This research investigates computer-based collaborative design environments, in particular issues of real-time collaborative 3D CAD. The thesis first presents a broad perspective of collaborative design environments with a preliminary case study of team design activities in a conventional and a computer mediated setting. This study identifies the impact and the feasibility of computer support for collaborative design and suggests four kinds of essential technologies for a successful collaborative design environment: information-sharing systems, synchronous and asynchronous co- working tools, project management systems, and communication systems. A new conceptual framework for a real-time collaborative 3D design tool, Shared Stage, is proposed based upon the preliminary study. The Shared Stage is defined as a shared 3D design workspace aiming to smoothly incorporate shared 3D workspaces into existing individual 3D workspaces. The addition of a Shared Stage allows collaborating designers to interact in real-time and to have a dynamic and interactive exchange of intermediate 3D design data. The acceptability of collaborative features is maximised by maintaining consistency of the user interface between 3D CAD systems. The framework is subsequently implemented as a software prototype using a new software development environment, customised by integrating related real-time and 3D graphic software development tools. Two main components of the Shared Stage module in the prototype, the Synchronised Stage View (SSV) and the Data Structure Diagram (DSD), provide essential collaborative features for real-time collaborative 3D CAD. These features include synchronised shared 3D representation, dynamic data exchange and awareness support in 3D workspaces. The software prototype is subsequently evaluated to examine the usefulness and usability. A range of quantitative and qualitative methods is used to evaluate the impact of the Shared Stage. The results, including the analysis of collaborative interactions and user perception, illustrate that the Shared Stage is a feasible and valuable addition for real-time collaborative 3D CAD. This research identifies the issues to be addressed for collaborative design environments and also provides a new framework and development strategy of a novel real-time collaborative 3D CAD system. The framework is successfully demonstrated through prototype implementation and an analytical usability evaluation.

This thesis is an investigation into the role of architecture as a tool for connections. It explores this idea in four scales: the urban scale, the immediate context, the scale of the building and the interpersonal scale. Architecturally, it addresses the complexities of an intervention in an urban fabric and embraces the contextual it is an attempt to reanimate the core of Downtown Roanoke, through the adaptive reuse of an inert built mass by opening it up to put it in conversation with its surroundings. Programmatically, it responds to a collaborative transient workspace catering to individual entrepreneurs or small groups of independent start-up enthusiasts or simply mobile workers. The thesis focuses on connections as the language through which these stories find their expression. / Master of Architecture

The goal of theoretical part of the thesis is to sumarise basic procedures and algorithms for robotic workspace monitoring. The first chapter is focused on those procedures. Another important topic of thesis is problematics of floating point error in calculations accuracy. Representations of cones and conical surfaces are discussed in the last theoretical chapter. The practical part of the thesis is focused on implementation of cone AND truncated cone workspace monitoring algorithm in C++.

This paper presents the research and development of a 3-legged micro Parallel Kinematic Manipulator (PKM) for positioning in micro-machining and assembly operations. The structural characteristics associated with parallel manipulators are evaluated and the PKMs with translational and rotational movements are identified. Based on these identifications, a hybrid 3-UPU (Universal Joint-Prismatic Joint-Universal Joint) parallel manipulator is designed and fabricated. The principles of the operation and modeling of this micro PKM is largely similar to a normal size Stewart Platform (SP). A modular design methodology is introduced for the construction of this micro PKM. Calibration results of this hybrid 3-UPU PKM are discussed in this paper. / Singapore-MIT Alliance (SMA)

Cable robots are a type of robotic manipulator that has recently attracted interest for large workspace manipulation tasks. Cable robots are relatively simple in form, with multiple cables attached to a mobile platform or end-effector. The end-effector is manipulated by motors that can extend or retract the cables. Cable robots have many desirable characteristics, including low inertial properties, high payload-to-weight ratios, potentially vast workspaces, transportability, ease of disassembly/reassembly, reconfigurability and economical construction and maintenance. However, relatively few analytical tools are available for analyzing and designing these manipulators. This thesis focuses on expanding the existing theoretical framework for the design and analysis of cable robots in two areas: disturbance robustness and workspace generation. Underconstrained cable robots cannot resist arbitrary external disturbances acting on the end-effector. Thus a disturbance robustness measure for general underconstrained single-body and multi-body cable robots is presented. This measure captures the robustness of the manipulator to both static and impulsive disturbances. Additionally, a wrench-based method of analyzing cable robots has been developed and is used to formulate a method of generating the Wrench-Feasible Workspace of cable robots. This workspace consists of the set of all poses of the manipulator where a specified set of wrenches (force/moment combinations) can be exerted. For many applications the Wrench-Feasible Workspace constitutes the set of all usable poses. The concepts of robustness and workspace generation are then combined to introduce a new workspace: the Specified Robustness Workspace. This workspace consists of the set of all poses of the manipulator that meet or exceed a specified robustness value.

A failure recovery methodology based on decomposing the platform task space into the major and secondary subtasks is proposed which enables the manipulator to minimize the least-squares error of the major subtasks and to optimize the secondary criterion. A methodology for wrench recovery of parallel manipulators is proposed so that the platform task is divided into the recoverable and non-recoverable subtasks based on the number and type of actuator failures, manipulator configuration and task/application purposes. It is investigated that when the Jacobian matrix of the manipulator is of full row-rank and the minimum 2-norm of the joint velocity vector satisfies the velocity limits of the joints, the full recovery of the platform twist will be provided. If the full recovery of the platform twist cannot be achieved, the optimization method followed by the partitioned Jacobian matrix is used to deal with the failure recovery. It is verified that the optimization method recovers as many as possible components of the platform velocity vector when the objective function, 2-norm of the overall velocity vector of the healthy joints, is minimized. To model uncertainty in the kinematic parameters, the interval analysis is proposed. Different interval-based algorithms to enclose the solution set to the interval linear systems are applied and the solution sets are compared. A novel approach in characterizing the exact solution of the interval linear system is proposed to deal with the failure recovery of parallel manipulators with velocity limits of the joints and uncertainty in the kinematic parameters. Simulation results show how the solution sets of the joint velocity vector are characterized by introducing uncertainties in the kinematic parameters. The calculation of the exact solution takes more computation time compared to the interval-based algorithms. However, the interval-based algorithms give the wider solution box with less computation time. The effect of variations and/or uncertainties in design parameters on the workspace of wire-actuated parallel manipulators without and with gravity is investigated. Simulation results show how the workspace size and shape are changed under variations in design parameters. / Thesis (Ph.D, Mechanical and Materials Engineering) -- Queen's University, 2014-03-09 16:18:12.74