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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Realization and Lateral Stable Workspace Analysis of an Axially Symmetric Scalable Hexapod Robot

Qu, Long 12 September 2013 (has links)
"The maintenance and inspection of societal structures and equipment such as skyscrapers, bridges, and ship hulls are important to maintaining a safe lifestyle. Improper maintanance and delayed inspection can lead to catastrophic failure. In lieu of placing humans in potential harm, mobile robotic machining systems can be used to enable remote repair and maintenance within constrictive, hazardous, and inaccessible environments. Due to their intrinsic high mobility and 6-DOF control, hexapod walking robots are a salient solution to mobile machining. However, the static structure of traditional hexapod robots can be rather limiting when attempting to traverse over irregular terrain or manipulating objects. This research realizes a new scalable hexapod robot and analyzes the lateral stable workspace of the robot under different external loading conditions. The scalable design allows the robot to extend its legs which enhances the workspace and improves stability while manuevering through constrictive and irregular terrain. The design incorporates two additional prismatic joints into the legs of the traditional hexapod robot design providing a compact, rigid, and efficient design. The electronic printed circuit boards were designed and assembled in-house. A distributed control architecture was implemented to off-load low-level leg control to dedicated leg controllers. An analysis on the lateral stable workspace of the scalable hexapod robot under different external loading conditions is presented. A dynamic stable workspace criterion is derived. The stable workspace criterion provides a metric for comparing stable workspaces between hexapod robots with different configurations. Multiple simulations and physical experiments were conducted to demonstrate the advantages of a scalability in hexapod designs."
2

Two novel off-screen navigation techniques

Nezhadasl, Mahtab 23 April 2009 (has links)
In large workspaces that do not fit on the screen space, users have to navigate to various regions outside the viewport to locate items of interest. Researchers have developed a variety of different navigation techniques to improve the performance of working with large workspaces. In this thesis I design, implement, and evaluate two novel navigation techniques to access off-screen content. I call these techniques Multiscale Window and Crystal Ball. The design of these two techniques was based on two hybrid interaction systems WinHop and Multiscale Zoom. Multiscale Window takes advantage of Multiscale Zoom to provide an overview of the context by incorporating full-detail object representations (proxies), and Crystal Ball is an improvement to WinHop. The implemented techniques were designed to alleviate the shortcomings of both hybrid techniques; Multiscale Zoom lacks the ability to provide detail information of overlapped proxies, and WinHop does not facilitate navigation to the off-screen region due to the animation. I evaluated the Multiscale Window and Crystal Ball techniques in two experiments. In the first experiment (N = 14) a Tablet PC with a digital pen as an input device was used. Results showed that there was no significant difference between Multiscale Window and Multiscale Zoom. However, Crystal Ball showed improved effects over WinHop in most tasks. The second experiment (N = 14) compared the same techniques as in experiment one, on a PC with a mouse as input device. The results indicated that subjects were faster with Crystal Ball than WinHop. Like the first experiment, Multiscale Window did not show any significant improvement over Multiscale Zoom. / May 2009
3

Two novel off-screen navigation techniques

Nezhadasl, Mahtab 23 April 2009 (has links)
In large workspaces that do not fit on the screen space, users have to navigate to various regions outside the viewport to locate items of interest. Researchers have developed a variety of different navigation techniques to improve the performance of working with large workspaces. In this thesis I design, implement, and evaluate two novel navigation techniques to access off-screen content. I call these techniques Multiscale Window and Crystal Ball. The design of these two techniques was based on two hybrid interaction systems WinHop and Multiscale Zoom. Multiscale Window takes advantage of Multiscale Zoom to provide an overview of the context by incorporating full-detail object representations (proxies), and Crystal Ball is an improvement to WinHop. The implemented techniques were designed to alleviate the shortcomings of both hybrid techniques; Multiscale Zoom lacks the ability to provide detail information of overlapped proxies, and WinHop does not facilitate navigation to the off-screen region due to the animation. I evaluated the Multiscale Window and Crystal Ball techniques in two experiments. In the first experiment (N = 14) a Tablet PC with a digital pen as an input device was used. Results showed that there was no significant difference between Multiscale Window and Multiscale Zoom. However, Crystal Ball showed improved effects over WinHop in most tasks. The second experiment (N = 14) compared the same techniques as in experiment one, on a PC with a mouse as input device. The results indicated that subjects were faster with Crystal Ball than WinHop. Like the first experiment, Multiscale Window did not show any significant improvement over Multiscale Zoom.
4

Two novel off-screen navigation techniques

Nezhadasl, Mahtab 23 April 2009 (has links)
In large workspaces that do not fit on the screen space, users have to navigate to various regions outside the viewport to locate items of interest. Researchers have developed a variety of different navigation techniques to improve the performance of working with large workspaces. In this thesis I design, implement, and evaluate two novel navigation techniques to access off-screen content. I call these techniques Multiscale Window and Crystal Ball. The design of these two techniques was based on two hybrid interaction systems WinHop and Multiscale Zoom. Multiscale Window takes advantage of Multiscale Zoom to provide an overview of the context by incorporating full-detail object representations (proxies), and Crystal Ball is an improvement to WinHop. The implemented techniques were designed to alleviate the shortcomings of both hybrid techniques; Multiscale Zoom lacks the ability to provide detail information of overlapped proxies, and WinHop does not facilitate navigation to the off-screen region due to the animation. I evaluated the Multiscale Window and Crystal Ball techniques in two experiments. In the first experiment (N = 14) a Tablet PC with a digital pen as an input device was used. Results showed that there was no significant difference between Multiscale Window and Multiscale Zoom. However, Crystal Ball showed improved effects over WinHop in most tasks. The second experiment (N = 14) compared the same techniques as in experiment one, on a PC with a mouse as input device. The results indicated that subjects were faster with Crystal Ball than WinHop. Like the first experiment, Multiscale Window did not show any significant improvement over Multiscale Zoom.
5

The In-Betweenness: Work Space of the Future

Davari Dehkordi, Ava 27 July 2023 (has links)
Individuals spend so many hours every day in their work spaces of different kinds. Different people have different needs in term of the quality of the space in which they are working. As a result it's important to provide a variety of spaces for people to be able to choose from and spend their work day in that space, or choose to transition in between spaces with different qualities during the day. This can positively affect employees' efficiency, productivity and even mental health. The main idea here is to design different spaces with different degrees of openness. These spaces start from being completely closed to completely open and just being defining by a single wall, roof or floor. And it also include every other degree of openness between these two states and having different combinations of walls, roofs and floors. / Master of Architecture / In Betweenness is about how to choose our position as designers when we are making changes into the earth to build livable spaces for human kind. We are surrounded by different In-betweennesses every day in indoor or outdoor spaces. Being aware of how to use this condition can make us better at forming stronger connections to nature, respecting the earth and following its movements, have more adaptability in our built environments, and having more transition, continuity and mobility in our spaces. This project is a work space building focused on health in architecture. considering biophilic design guidelines and active design guidelines I was focused on designing an adaptable workspace and finding design solutions for encouraging users to follow a healthier lifestyle, be more productive and motivated.
6

Pre programming: evaluation of workspace types and workspace alternatives in educational settings

Nome, Carlos Alejandro 15 May 2009 (has links)
The overall objective of this research was to improve the understanding of worker attitudes and perceptions toward different workspace types and workspace alternatives and how they are related to processes and activities native to a given organization. The specific goals of this study were: •The development of a methodology to assess workers attitudes toward different workspace alternatives for use in the planning stages of new offices. •Identification of workspace variables that affect perceptions and preferences regarding the alternatives based on the proposed units of analysis (individual, interpersonal relations, and organizational). This research consisted of mixed methodology. It was a cross departmental study of needs and preferences of workers regarding key variable and choices of workspace types and workspace alternatives. The main research instrument was a four stage web based survey. The secondary component was focus groups. By tracking these declared needs, preferences and choices regarding workspace types and workspace alternatives it was possible to identify if they associate with demographic information, work performance, and the proposed units of analysis, within a given organizational structure. This information provided a substantial knowledge base for decision makers in the planning stage of relocation of people, and the allocation of space processes. This study provided decision makers in the above mentioned processes a tested methodology that enables the development of a proactive approach to innovative workspace planning. The results are relevant to designers, managers and facility managers as it provides a perspective to understand or identify potential space and layout improvements in existing and future workplaces based on the core activities of any given organization. Such information will allow managers to make informed decisions about future workspace changes, as well as planning new workspace alternatives to continually support the organization’s objectives.
7

Workspace Analysis Of The Stewart Platform Manipulator

Pradeep, R 10 1900 (has links) (PDF)
No description available.
8

Physical Workspace and Creative Performance - The Role of Moods and Habituation

Lin, Szu-Yin 18 August 2009 (has links)
Differ from previous research which mainly focus on the organizational climate and social influence in the work environment, this study examined the effects of physical workspace; also we incorporated mood and habituation to the model. Regression analyses indicated that positive moods (relaxation and enthusiasm) mediates the relationship between physical workspace and creative performance. Habituation effects were found insignificant in this study. Results suggest that the physical workspace can best lead to creative performance by fostering positive relaxed and enthusiastic moods, we also concluded that the stimuli provided by immobile settings like physical workspace may be limited.
9

WORKSPACE GENERATION FOR WIRE-ACTUATED PARALLEL MANIPULATORS

McColl, Derek 20 October 2009 (has links)
This thesis focuses on the methods and results of the workspace formulation of wire-actuated parallel manipulators. Four methods of workspace generation are studied. The null space method, based on the calculation of wire tensions, is used to formulate the workspaces of example manipulators. The results of this method are used to verify the results of the following methods. This thesis presents that the convex hull workspace formulation method, a geometric analysis of the manipulator’s Jacobian matrix, can be extended to manipulators that have an external wrench and/or gravity applied to the mobile platform. The convex hull method is applied to the example manipulators investigated with the null space method. The workspace envelope characterization, an analytical approach of defining the borders of the workspace using the formulation of the kernel of the manipulator’s Jacobian matrix, is applied to the example planar manipulators investigated with the previous methods. A new process, presented in this thesis, of identifying the contribution of each set of four wires/forces of a planar manipulator allows the workspace envelope characterization to be applied to redundant planar manipulators and planar manipulators that have an external wrench and/or gravity applied to the mobile platform. The discrete and analytical antipodal methods, based on theorems from multi-fingered grasping manipulators, are presented and applied to the example planar manipulators investigated with the previous methods. This research generalizes the use of these theorems, which determine wrench-closure poses of planar four-wire manipulators that share wire-connection points on the base or mobile platform, to the discrete and analytical workspace formulation of planar three-degree-of-freedom wire-actuated manipulators with no restrictions on the number of wires or the configuration of the manipulator. Comparing all methods investigated in this thesis, the null space method results in the workspace that takes into account the maximum and minimum wire tensions and is recommended for use in the design of both spatial and planar wire-actuated parallel manipulators. All the other methods presented in this thesis, have similar results when compared to the null space method but formulate the maximum workspace which assumes the wires can operate with very high to infinite wire tension. / Thesis (Master, Mechanical and Materials Engineering) -- Queen's University, 2009-10-14 09:02:25.562
10

An optimization approach to the determination of manipulator workspaces

Du Plessis, Lukas Johannes 01 June 2009 (has links)
Please read the abstract in the section 00front of this document / Dissertation (MEng)--University of Pretoria, 2009. / Mechanical and Aeronautical Engineering / unrestricted

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