Wearable Mobile Arm Support

Our client, The University of Idaho, (U of I), proposed the capstone project “Wearable Mobile Arm Support for Shoulder/Elbow Assistance”. We were sent to continue working on the device that supports the arm to help stroke patient rehabilitate. The goal of this project is to improve the existing system by reducing friction, making it wearable, and enhancing comfort/aesthetics. These will be accomplished by analyzing the current system, developing a pulley/friction test, and developing new components.

Background
Patients with neurological damage to the brain from events such as stroke often exhibit a loss in arm range of motion on the contralateral side of the body. It has been shown that by simulating a low-gravity environment, through gravitational support to the arm, a patient can achieve a larger range of motion. This increased range of motion may be sufficient to allow the completion of otherwise unattainable movements and tasks such as functional ADLs (activities of daily living) or tasks that are beneficial to promote further recovery of lost range of motion. The University of Idaho has designed an arm support that supports the arm and could allow stroke patients to regain lost function and mobility. Our objective is to understand its shortcomings, identify sources of error, and improve the system.

Design Constraints

 * Device must
 * Safe to the user
 * Low friction to allow for close mapping of desired forces
 * Wearable/Mobile
 * Device should
 * Be comfortable for extended use
 * Sleek enough to avoid collisions with environment
 * Wearable
 * Able to put on and taken off in under 2 minutes
 * Be aesthetically pleasing
 * Improve elbow stability when the arm is extended

=Project Learning=

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Pulley Board Trial Run
To help ensure that the pulley system in the arm was optimal we decided to run a pulley board test to find the best combination to reduce friction. The set up can be seen in the image to the left. In this setup we manually moved the load which lead to inaccurate data so I decided to improve our testing method which can be seen in the design section. We did however learn that more pulleys and higher loads lead to increased friction. The cable we are using in the arm support consistently had higher friction values than other cables as well.

Preliminary Arm Testing
Preliminary data was taken on the arm so we had something to compare to after making modification. The torque provided at the shoulder and elbow were taken in several position and we acquired an accurate baseline. This data was then used to compare after completing all of the following procedures. It proved incredibly valuable as several complications came to light later in the process.

Pulley Board 2.0 Design
IMAGE OF SETUP How it works Results and discussion

System Design Modification
As the device was in motion we found a location where the cams within the elbow bracket were contacting the bracket itself. This material was removed in order to reduce friction and address hysteresis in the elbow torque plots.  After repeated disassembly of the arm support we found that the shaft was deforming. This lead to a complete redesign of the shaft (I need to contact for images here). After the modifications were made the torque being supplied by the shoulder continued to decline. This raised concern so we compared the desired mapping torques to the values we were acquiring experimentally and found we were well below that mark. To address this issue we decided to test the surgical tubing for fatigue.
 * Bracket Material Removal
 * Shaft Redesign
 * Modification Problems

As can be seen from the spring constant graph the old bands are fatiguing. We believe that this is the main cause of the lost torque and the primary causes of fatigue is the constant tension on the surgical tubing, repeated use, and exposure to the environment. For the intended use of the device we will need to know the life time of these tubes and if it is too short a simple way to replace the bands will need to be implemented.

Wearable/Mobile
Need a more complete model to complete this section

Meeting Minutes

 * [[Media:2014_FuelRodDefectDetection_Sep16_2014_Minutes.pdf|September 16, 2014]]


 * [[Media:2014_FuelRodDefectDetection_Sep30_2014_Minutes.pdf|September 30, 2014]]


 * [[Media:2014_FuelRodDefectDetection_Oct7_2014_Minutes.pdf|October 7, 2014]]


 * [[Media:2014_FuelRodDefectDetection_Oct28_2014_Minutes.pdf|October 28, 2014]]


 * [[Media:2014_FuelRodDefectDetection_Nov6_2014_Minutes.pdf|November 6, 2014]]


 * [[Media:2014_FuelRodDefectDetection_Nov13_2014_Minutes.pdf|November 13, 2014]]


 * [[Media:2014_FuelRodDefectDetection_Jan20_2015_Minutes.pdf|January 20, 2015]]


 * [[Media:2014_FuelRodDefectDetection_Feb10_2015_Minutes.pdf|February 10, 2015]]


 * [[Media:2014_FuelRodDefectDetection_Feb17_2015_Minutes.pdf|February 17, 2015]]


 * [[Media:2014_FuelRodDefectDetection_Mar3_2015_Minutes.pdf|March 3, 2015]]


 * [[Media:2014_FuelRodDefectDetection_Mar24_2015_Minutes.pdf|March 24, 2015]]


 * [[Media:2014_FuelRodDefectDetection_Apr21_2015_Minutes.pdf|April 21, 2015]]

Other
Project Timeline

[[Media:2014_FuelRodDefectDetection_SPERT_Tests_Summary.pdf|INL SPERT Tests Summary]]

[[Media:2014_FuelRodDefectDetection_Profilometer_Research_Summary.pdf|Profilometer Research Summary]]

[[Media:2014_FuelRodDefectDetection_Team_Contract.pdf|Team Contract]]

[[Media:2014_FuelRodDefectDetection_Design_Review.pdf|Design Review (November 21, 2014)]]

[[Media:2014_FuelRodDefectDetection_Expo_Presentation.pdf|2015 Expo Technical Presentation]]