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This thesis is missing page 222, the other copies of this thesis are missing the page as well. -Digitization Centre / N/A / Thesis / Master of Science (MS)

No description available.

No description available.

This thesis is centered upon the published A Novel Method and Exoskeletons for Whole-arm Gravity Compensation (Turner, Hull 2020), and includes a novel concept for supporting the weight of a person's arm or robotic linkage. The design is capable of supporting weights held near the hand, and provides support regardless of position. This support is provided with a pantograph. The upper-arm and forearm bars are mirrored by smaller copies. Force applied to a pull point on the scaled copy of the arm is flipped and applied at a support point on the forearm or to a tool near the hand. Two exoskeletons, using different linkages make use of the pantograph design. These include the Panto-Arm Exo, which uses it's slim, reduced size to comfortably assist users in lifting their arm, and the Panto-Tool Exo which is designed for a support point that coincides with a mass representing a heavy tool. The differing topologies and purposes of these two devices resulted in different qualities regarding their ability to lift weight. The Panto-Arm Exo was specifically used in human subject testing, in which fourteen users wore electromyography electrodes and performed simple arm movements and holding tasks. While the Panto-Arm Exo did not undergo stringent design improvements or user-specific optimization, the device was shown to reduce muscle use in the measured upper-arm muscles for certain arm positions. / Master of Science / This thesis is centered upon the published A Novel Method and Exoskeletons for Whole-arm Gravity Compensation (Turner, Hull 2020), includes a new way to lift a person's arm or robotic linkage. The design can lift weights close to the hand regardless of arm placement. This support is provided with a pantograph. The pantograph design is based on a mirrored, smaller copy of the upper-arm and forearm bars, which is pulled downwards to create an upwards support force at chosen support point. This point is based underneath the forearm or at a heavy tool. The concept is similar to pushing down on a teeter-totter in order to prevent the other end from dropping. Two exoskeletons, using different linkages make use of this pantograph design. The Panto-Arm Exo is slim and light. It is made to help users in lift their arm by supporting its weight. The Panto-Tool Exo has a support point that located where a mass representing a heavy tool sits. The changes between both devices means that they display different lifting qualities. The Panto-Arm Exo was worn by 14 people, also wearing electrodes that measured muscle activation. These users held weights and moved their arms around while muscle activation was recorded. While the Panto-Arm Exo wasn't fine-tuned or adjusted for individual people, it was shown to reduce muscle activation in the measured upper-arm muscles for some of the arm placements.

We present and analyze two arm exoskeletons based on a pantograph linkage that allow for the support of 89~N (20~pounds) at the user's hand. Using a pantograph linkage allows for a constant force to be created at the hand in any orientation when a constant vertical force is supplied to the other side of the pantograph. We present several topologies and analyze them based on feasibility of manufacture and ability to provide a near vertical force to the pantograph linkage. Simulations are created using the best topologies and the resulting forces at the hand are reported. The mechanical design of an unpowered (passive) exoskeleton which uses a gas spring mechanism is presented. Additionally, simulations and block-CAD of a powered (active) exoskeleton which uses a motor for the supply of force are presented. The performance of the passive exoskeleton is qualitatively compared with simulations. / Master of Science / A wearable device or exoskeleton is presented which is designed to help a user support a weight of 20 pounds (89~N) at their hand. A pantograph linkage arm exoskeleton provides forces to the hand which are equal to the force provided to the linkage divided by the linkage's ratio. Providing a force to the linkage that is purely vertical will result in a purely vertical force at the hand. Layouts of the exoskeleton components which produce a near-vertical force for the linkage are explored. The more promising layouts are simulated and the forces are compared based on how vertical the forces are. The design of an unpowered exoskeleton is also presented, which uses a gas spring mechanism to provide force. Additionally, simulation results for the unpowered exoskeleton and the basic design and analysis of a powered exoskeleton are presented.

Lymphedema of the arm is a complication that occurs in about 10-20% of women treated for breast cancer. Breast cancer treatment can damage or disrupt normal lymphatic pathways, causing fluid to accumulate in the arm. This condition is called lymphedema. Swelling of the arm can be painful and disfiguring, negatively impacting the quality of life of afflicted individuals. Lymphedema is a progressive disorder that requires prompt diagnosis and treatment to prevent the occurrence of more serious complications, such as infection or severe disability of the arm. Past research have attempted to identify risk factors that influenced the development of lymphedema, however conflicting results were observed between studies. Therefore, a comprehensive literature review was conducted to identify studies that examined the effect of prognostic and/or personal factors on lymphedema. In the meta-analyses, results from each independent study were abstracted and pooled with other studies using the random-effects model. In an effort to examine additional factors that were not widely studied, a retrospective cohort study was conducted on women diagnosed with breast cancer in Iowa during 2004. A questionnaire was developed to collect information on arm activities, co-morbidity, and lymphedema-related symptoms. Eligible women were identified from the State Health Registry of Iowa and data were collected through computer-assisted telephone interviews. At the end of the interview, each woman was asked to measure the circumference of her right and left arm one hand width above and below the elbow crease. The meta-analysis found that mastectomy (as opposed to a lumpectomy), axillary dissection (as opposed to sentinel node biopsy), radiation therapy, presence of positive nodes, obesity (body mass index >30), low education (less than high school), presence of any co-morbidity, injury and infection increased the risk of developing lymphedema. The cohort study found that the presence of axillary dissection and radiation, cancer stage, positive nodes, large tumor size, high body mass index, and younger women increased the risk of lymphedema.

The ulnar collateral ligament (UCL) is the primary restraint against valgus forces at the elbow. This structure cannot support the entire load placed upon the medial elbow during overhand throwing motions such as pitching a baseball. In this study we measured the contributions that different muscle groups make to the stability of the medial elbow, under conditions intended to reproduce the loads during pitching by varying the forearm position and loading conditions. We also evaluated the strength of the elbow musculature for the possibility of a training effect in the dominant arm of 11 male high school baseball pitchers. We collected surface EMG data in the two forearm positions to determine if the different positions used in various pitches have an effect on muscular action. We also tested an isometric and dissipative loading condition to determine if the muscles activity was load reactive. The four muscle groups tested were the flexor-pronator group (FP), the extensor-supinator group (ES), the tricep brachii (TB), and the pectoralis major (PM). We found significantly (p-value=0.001) higher peak activity levels of the flexor-pronator group in the neutral forearm position (79.4% MVIC �� 27.0% MVIC full trial peak, 30.8% MVIC �� 20.8% MVIC initial l50ms peak following activation) when compared to the supinated position (55.5% MVIC �� 29.6% MVIC full trial peak, 16.9% MVIC �� 14.8% MVIC initial l50ms peak following activation), which may explain the link between breaking pitches and medial elbow injury. We found an increase (p-value=0.001) in force output of the dominant arm (49.3 N/kg �� 12.5 N/kg) over the non-dominant arm (38.1 N/kg �� 11.0 N/kg). This finding is attributed to a training effect, which assists in protecting the elbow. These findings help provide baseline muscle activity information on protection of the medial soft tissue structures of the elbow. / Graduation date: 2004