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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

Modeling And Control Of A Hyper Redundant Manipulator

Bayram, Atilla 01 February 2010 (has links) (PDF)
The hyper redundant manipulators (HRMs) have excessively large degrees of freedom. As a special but practicable subset, the binary HRMs use binary (on-off) actuators with only two stable states such as pneumatic cylinders and solenoids. Such actuators are simple, cheap, and easy to control. Therefore, a binary HRM has been studied in this thesis. The thesis work covers the conceptual design of a spatial binary HRM together with its controlled motion simulations. The manipulator consists of many modules, each of which has the same constructive characteristics and consists of three submodules which are two cascaded variable geometry truss structures working in mutually orthogonal planes and a discrete twister. The manipulator is assumed to be powered with pneumatic on-off actuators. Because of the discrete nature of the binary actuators, a small but continuously actuated manipulator with six degrees of freedom is installed as the last module of the HRM in order to compensate the discretization errors. To solve the inverse kinematics problem of the HRM, three methods have been presented. These are the spline fitting, the extended spline fitting, and the workspace filling methods. The spline fitting method is based on forcing the spine (i.e. the center line) of the manipulator to approximate a spatial reference spline which is specified as a desired curve. In the extended spline fitting method, the result found in the first method is improved by using a genetic algorithm. In the work space filling method, the workspace of the manipulator is filled randomly with a sufficiently large finite number of discrete configurational samples. If it is desired to have concentration on a particular region of the work space, then that region is filled by using a genetic algorithm. After the filling stage, the sample closest to the desired configuration is determined by a suitable search algorithm. Finally, in order to simulate the motion of the HRM between two successive configurational steps, the equations of motions of the HRM are obtained in terms of the pressure forces generated by the binary pneumatic actuators. Then, the necessary simulations are carried out to demonstrate the performance of the HRM in some typical applications.
2

Development of an Instrumented and Powered Exoskeleton for the Rehabilitation of the Hand

Abolfathi, Peter Puya January 2008 (has links)
Doctor of Philosophy (PhD) / With improvements in actuation technology and sensory systems, it is becoming increasingly feasible to create powered exoskeletal garments that can assist with the movement of human limbs. This class of robotics referred to as human-machine interfaces will one day be used for the rehabilitation of paralysed, damaged or weak upper and lower extremities. The focus of this project was the development of an exoskeletal interface for the rehabilitation of the hands. A novel sensor was designed for use in such a device. The sensor uses simple optical mechanisms centred on a spring to measure force and position simultaneously. In addition, the sensor introduces an elastic element between the actuator and its corresponding hand joint. This will allow series elastic actuation (SEA) to improve control and safely of the system. The Hand Rehabilitation Device requires multiple actuators. To stay within volume and weight constraints, it is therefore imperative to reduce the size, mass and efficiency of each actuator without losing power. A method was devised that allows small efficient actuating subunits to work together and produce a combined collective output. This work summation method was successfully implemented with Shape Memory Alloy (SMA) based actuators. The actuation, sensory, control system and human-machine interface concepts proposed were evaluated together using a single-joint electromechanical harness. This experimental setup was used with volunteer subjects to assess the potentials of a full-hand device to be used for therapy, assessment and function of the hand. The Rehabilitation Glove aims to bring significant new benefits for improving hand function, an important aspect of human independence. Furthermore, the developments in this project may one day be used for other parts of the body helping bring human-machine interface technology into the fields of rehabilitation and therapy.
3

Development of an Instrumented and Powered Exoskeleton for the Rehabilitation of the Hand

Abolfathi, Peter Puya January 2008 (has links)
Doctor of Philosophy (PhD) / With improvements in actuation technology and sensory systems, it is becoming increasingly feasible to create powered exoskeletal garments that can assist with the movement of human limbs. This class of robotics referred to as human-machine interfaces will one day be used for the rehabilitation of paralysed, damaged or weak upper and lower extremities. The focus of this project was the development of an exoskeletal interface for the rehabilitation of the hands. A novel sensor was designed for use in such a device. The sensor uses simple optical mechanisms centred on a spring to measure force and position simultaneously. In addition, the sensor introduces an elastic element between the actuator and its corresponding hand joint. This will allow series elastic actuation (SEA) to improve control and safely of the system. The Hand Rehabilitation Device requires multiple actuators. To stay within volume and weight constraints, it is therefore imperative to reduce the size, mass and efficiency of each actuator without losing power. A method was devised that allows small efficient actuating subunits to work together and produce a combined collective output. This work summation method was successfully implemented with Shape Memory Alloy (SMA) based actuators. The actuation, sensory, control system and human-machine interface concepts proposed were evaluated together using a single-joint electromechanical harness. This experimental setup was used with volunteer subjects to assess the potentials of a full-hand device to be used for therapy, assessment and function of the hand. The Rehabilitation Glove aims to bring significant new benefits for improving hand function, an important aspect of human independence. Furthermore, the developments in this project may one day be used for other parts of the body helping bring human-machine interface technology into the fields of rehabilitation and therapy.

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