Matching Items (4)

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Exoskeletal Hand Fixture for use with Tool Balancing arm for Packing/Warehouse Applications

Description

Many industries require workers in warehouse and stockroom environments to perform frequent lifting tasks. Over time these repeated tasks can lead to excess strain on the worker's body and reduced

Many industries require workers in warehouse and stockroom environments to perform frequent lifting tasks. Over time these repeated tasks can lead to excess strain on the worker's body and reduced productivity. This project seeks to develop an exoskeletal wrist fixture to be used in conjunction with a powered exoskeleton arm to aid workers performing box lifting types of tasks. Existing products aimed at improving worker comfort and productivity typically employ either fully powered exoskeleton suits or utilize minimally powered spring arms and/or fixtures. These designs either reduce stress to the user's body through powered arms and grippers operated via handheld controls which have limited functionality, or they use a more minimal setup that reduces some load, but exposes the user's hands and wrists to injury by directing support to the forearm. The design proposed here seeks to strike a balance between size, weight, and power requirements and also proposes a novel wrist exoskeleton design which minimizes stress on the user's wrists by directly interfacing with the object to be picked up. The design of the wrist exoskeleton was approached through initially selecting degrees of freedom and a ROM (range of motion) to accommodate. Feel and functionality were improved through an iterative prototyping process which yielded two primary designs. A novel "clip-in" method was proposed to allow the user to easily attach and detach from the exoskeleton. Designs utilized a contact surface intended to be used with dry fibrillary adhesives to maximize exoskeleton grip. Two final designs, which used two pivots in opposite kinematic order, were constructed and tested to determine the best kinematic layout. The best design had two prototypes created to be worn with passive test arms that attached to the user though a specially designed belt.

Contributors

Agent

Created

Date Created
  • 2016-12

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Advancements in Prosthetics and Joint Mechanisms

Description

Robotic joints can be either powered or passive. This work will discuss the creation of a passive and a powered joint system as well as the combination system being

Robotic joints can be either powered or passive. This work will discuss the creation of a passive and a powered joint system as well as the combination system being both powered and passive along with its benefits. A novel approach of analysis and control of the combination system is presented.

A passive and a powered ankle joint system is developed and fit to the field of prosthetics, specifically ankle joint replacement for able bodied gait. The general 1 DOF robotic joint designs are examined and the results from testing are discussed. Achievements in this area include the able bodied gait like behavior of passive systems for slow walking speeds. For higher walking speeds the powered ankle system is capable of adding the necessary energy to propel the user forward and remain similar to able bodied gait, effectively replacing the calf muscle. While running has not fully been achieved through past powered ankle devices the full power necessary is reached in this work for running and sprinting while achieving 4x’s power amplification through the powered ankle mechanism.

A theoretical approach to robotic joints is then analyzed in order to combine the advantages of both passive and powered systems. Energy methods are shown to provide a correct behavioral analysis of any robotic joint system. Manipulation of the energy curves and mechanism coupler curves allows real time joint behavioral adjustment. Such a powered joint can be adjusted to passively achieve desired behavior for different speeds and environmental needs. The effects on joint moment and stiffness from adjusting one type of mechanism is presented.

Contributors

Agent

Created

Date Created
  • 2017

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An improved framework for design concept generation based on experiential and intuitive methods

Description

Conceptual design stage plays a critical role in product development. However, few systematic methods and tools exist to support conceptual design. The long term aim of this project is to

Conceptual design stage plays a critical role in product development. However, few systematic methods and tools exist to support conceptual design. The long term aim of this project is to develop a tool for facilitating holistic ideation for conceptual design. This research is a continuation of past efforts in ASU Design Automation Lab. In past research, an interactive software test bed (Holistic Ideation Tool - version 1) was developed to explore logical ideation methods. Ideation states were identified and ideation strategies were developed to overcome common ideation blocks. The next version (version 2) of the holistic ideation tool added Cascading Evolutionary Morphological Charts (CEMC) framework and intuitive ideation strategies (reframing, restructuring, random connection, and forced connection).

Despite these remarkable contributions, there exist shortcomings in the previous versions (version 1 and version 2) of the holistic ideation tool. First, there is a need to add new ideation methods to the holistic ideation tool. Second, the organizational framework provided by previous versions needs to be improved, and a holistic approach needs to be devised, instead of separate logical or intuitive approaches. Therefore, the main objective of this thesis is to make the improvements and to resolve technical issues that are involved in their implementation.

Towards this objective, a new web based holistic ideation tool (version 3) has been created. The new tool adds and integrates Knowledge Bases of Mechanisms and Components Off-The-Shelf (COTS) into logical ideation methods. Additionally, an improved CEMC framework has been devised for organizing ideas efficiently. Furthermore, the usability of the tool has been improved by designing and implementing a new graphical user interface (GUI) which is more user friendly. It is hoped that these new features will lead to a platform for the designers to not only generate creative ideas but also effectively organize and store them in the conceptual design stage. By placing it on the web for public use, the Testbed has the potential to be used for research on the ideation process by effectively collecting large amounts of data from designers.

Contributors

Agent

Created

Date Created
  • 2014

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Modeling aqueous organic chemistry in experimental and natural systems

Description

In many natural systems aqueous geochemical conditions dictate the reaction pathways of organic compounds. Geologic settings that span wide ranges in temperature, pressure, and composition vastly alter relative reaction rates

In many natural systems aqueous geochemical conditions dictate the reaction pathways of organic compounds. Geologic settings that span wide ranges in temperature, pressure, and composition vastly alter relative reaction rates and resulting organic abundances. The dependence of organic reactions on these variables contributes to planetary-scale nutrient cycling, and suggests that relative abundances of organic compounds can reveal information about inaccessible geologic environments, whether from the terrestrial subsurface, remote planetary settings, or even the distant past (if organic abundances are well preserved). Despite their relevance to planetary modeling and exploration, organic reactions remain poorly characterized under geochemically relevant conditions, especially in terms of their reaction kinetics, mechanisms, and equilibria.

In order to better understand organic transformations in natural systems, the reactivities of oxygen- and nitrogen-bearing organic functional groups were investigated under experimental hydrothermal conditions, at 250°C and 40 bar. The model compounds benzylamine and α-methylbenzylamine were used as analogs to environmentally relevant amines, ultimately elucidating two dominant deamination mechanisms for benzylamine, SN1 and SN2, and a single SN1 mechanism for deamination of α-methylbenzylamine. The presence of unimolecular and bimolecular mechanisms has implications for temperature dependent kinetics, indicating that Arrhenius rate extrapolation is currently unreliable for deamination.

Hydrothermal experiments with benzyl alcohol, benzylamine, dibenzylamine, or tribenzylamine as the starting material indicate that substitution reactions between these compounds (and others) are reversible and approach metastable equilibrium after 72 hours. These findings suggest that relative ratios of organic compounds capable of substitution reactions could be targeted as tracers of inaccessible geochemical conditions.

Metastable equilibria for organic reactions were investigated in a natural low-temperature serpentinizing continental system. Serpentinization is a water-rock reaction which generates hyperalkaline, reducing conditions. Thermodynamic calculations were performed for reactions between dissolved inorganic carbon and hydrogen to produce methane, formate, and acetate. Quantifying conditions that satisfy equilibrium for these reactions allows subsurface conditions to be predicted. These calculations also lead to hypotheses regarding active microbial processes during serpentinization.

Contributors

Agent

Created

Date Created
  • 2017