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Improved design of three-degree of freedom hip exoskeleton based on biomimetic parallel structurePan, Min 01 July 2011 (has links)
The external skeletons, Exoskeletons, are not a new research area in this highly
developed world. They are widely used in helping the wearer to enhance human strength,
endurance, and speed while walking with them. Most exoskeletons are designed for the
whole body and are powered due to their applications and high performance needs.
This thesis introduces a novel design of a three-degree of freedom parallel robotic
structured hip exoskeleton, which is quite different from these existing exoskeletons. An
exoskeleton unit for walking typically is designed as a serial mechanism which is used
for the entire leg or entire body. This thesis presents a design as a partial manipulator
which is only for the hip. This has better advantages when it comes to marketing the
product, these include: light weight, easy to wear, and low cost. Furthermore, most
exoskeletons are designed for lower body are serial manipulators, which have large
workspace because of their own volume and occupied space. This design introduced in
this thesis is a parallel mechanism, which is more stable, stronger and more accurate.
These advantages benefit the wearers who choose this product.
This thesis focused on the analysis of the structure of this design, and verifies if
the design has a reasonable and reliable structure. Therefore, a series of analysis has been
done to support it. The mobility analysis and inverse kinematic solution are derived, and
the Jacobian matrix was derived analytically. Performance of the CAD model has been
checked by the finite element analysis in Ansys, which is based on applied force and
moment. The comparison of the results from tests has been illustrated clearly for stability
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and practicability of this design. At the end of this thesis, an optimization of the hip
exoskeleton is provided, which offers better structure of this design. / UOIT
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3 DOF, LONG RANGE PLANAR LIFT AND SLIDE MICRO-CONVEYOR WITH VISION-BASED CONTROL SYSTEMEllerington, Neil 22 May 2012 (has links)
The purpose of this thesis is to introduce a novel method of dry micro-object manipulation and to demonstrate predictable vision-based control. The Lift and slide conveyors presented utilize three main components: pads, lifters and a floating platform. The pads have a small planar displacement in the XY axis and lifters have a small Z axis displacement. Together they can be used to create minute displacements per cycle while carrying a floating platform that can hold the desired objects to be moved. These platforms can be handed off to other pad-lifter groups to create an unlimited planar envelope. Two degree of freedom control was established using LabView with open and closed loop routines. A model is presented that predicts the resonance frequencies with different loading and geometric characteristics to aid in design optimization for various applications. Parameters such as velocity, drift and traction are well characterized for different operating conditions.
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Multi-Objective Design Optimisation of a Class of Parallel Kinematic MachinesIlya Tyapin Unknown Date (has links)
One of the main advantages of the Gantry-Tau machine is a large accessible workspace\footprint ratio compared to many other parallel machines. The Gantry-Tau improves this ratio further by allowing a change of assembly mode without internal link collisions or collisions between the links and the moving TCP platform. In this Thesis some of the features of the Gantry-Tau structure are described and results are presented from the analysis of the kinematic, elastostatic and elastodynamic properties of the PKM. However, the optimal kinematic, elastostatic and elastodynamic design parameters of the machine are still difficult to calculate and this thesis introduces a multi-objective optimisation scheme based on the geometric approach for the workspace area, unreachable area, joint angle limitations and link collisions as well as the functional dependencies of the elements of the static matrix and the Laplace transform to define the first resonance frequency and Cartesian and torsional stiffness. The method to calculate the first resonance frequency assumes that each link and universal joint can be described by a mass-springdamper model and calculates the transfer function from a Cartesian (TCP) force or torque to Cartesian position or orientation. The geometric methods involve the simple geometric shapes (spheres, circles, segments, etc) and vectors. The functional dependencies are based on the properties between the kinematic parameters. These approaches are significantly faster than analytical methods based on the inverse kinematics or the general Finite Elements Method (FEM). The reconfigurable Gantry-Tau kinematic design obtained by multi-objective optimisation gives the following features: • Workspace/footprint ratio more than 3.19. • First resonance frequency greater than 48 Hz. • Lowest Cartesian stiffness in the workspace 5N/μm. • The unreachable space in the middle of the workspace is not detected. • No link collisions. The results show that by careful design of the PKM, a collision free workspace without the unreachable area in the middle can be achieved. High stiffness and high first resonance frequency are important parameters for the the Gantry-Tau when used in industrial applications, such as cutting, milling and drilling of steel or aluminium and pick-and-place operations. These applications require high static and dynamic accuracy in combination with high speed and acceleration. The optimisation parameters are the support frame lengths, actuator positions,endeffector kinematics and the robot’s arm lengths. Because of the fast computational speed of the geometric approaches and computational time saving of the methods based on the functional dependency, they are ideal for inclusion in a design optimisation framework, normally a nonlinear optimisation routine. In this Thesis the evolutionary algorithm based on the complex search method is used to optimise the 3-DOF Gantry-Tau. The existing lab prototype of this machine was assembled and completed at the University of Agder
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Multi-Objective Design Optimisation of a Class of Parallel Kinematic MachinesIlya Tyapin Unknown Date (has links)
One of the main advantages of the Gantry-Tau machine is a large accessible workspace\footprint ratio compared to many other parallel machines. The Gantry-Tau improves this ratio further by allowing a change of assembly mode without internal link collisions or collisions between the links and the moving TCP platform. In this Thesis some of the features of the Gantry-Tau structure are described and results are presented from the analysis of the kinematic, elastostatic and elastodynamic properties of the PKM. However, the optimal kinematic, elastostatic and elastodynamic design parameters of the machine are still difficult to calculate and this thesis introduces a multi-objective optimisation scheme based on the geometric approach for the workspace area, unreachable area, joint angle limitations and link collisions as well as the functional dependencies of the elements of the static matrix and the Laplace transform to define the first resonance frequency and Cartesian and torsional stiffness. The method to calculate the first resonance frequency assumes that each link and universal joint can be described by a mass-springdamper model and calculates the transfer function from a Cartesian (TCP) force or torque to Cartesian position or orientation. The geometric methods involve the simple geometric shapes (spheres, circles, segments, etc) and vectors. The functional dependencies are based on the properties between the kinematic parameters. These approaches are significantly faster than analytical methods based on the inverse kinematics or the general Finite Elements Method (FEM). The reconfigurable Gantry-Tau kinematic design obtained by multi-objective optimisation gives the following features: • Workspace/footprint ratio more than 3.19. • First resonance frequency greater than 48 Hz. • Lowest Cartesian stiffness in the workspace 5N/μm. • The unreachable space in the middle of the workspace is not detected. • No link collisions. The results show that by careful design of the PKM, a collision free workspace without the unreachable area in the middle can be achieved. High stiffness and high first resonance frequency are important parameters for the the Gantry-Tau when used in industrial applications, such as cutting, milling and drilling of steel or aluminium and pick-and-place operations. These applications require high static and dynamic accuracy in combination with high speed and acceleration. The optimisation parameters are the support frame lengths, actuator positions,endeffector kinematics and the robot’s arm lengths. Because of the fast computational speed of the geometric approaches and computational time saving of the methods based on the functional dependency, they are ideal for inclusion in a design optimisation framework, normally a nonlinear optimisation routine. In this Thesis the evolutionary algorithm based on the complex search method is used to optimise the 3-DOF Gantry-Tau. The existing lab prototype of this machine was assembled and completed at the University of Agder
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Evaluation of Motion Cueing Algorithms for a Limited Motion Platform Driver-in-Loop SimulatorSekar, Rubanraj 13 August 2020 (has links)
No description available.
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Nonlinear Adaptive Control and Guidance for Unstart Recovery for a Generic Hypersonic VehicleGunbatar, Yakup 30 December 2014 (has links)
No description available.
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