P17082: Elbow Model
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Subsystem Build & Test

Table of Contents

Team Vision for Subsystem Level Build & Test Phase

The goal for this project phase was to complete a model to prototype and begin the process of testing & evaluating the model and building process. It was also expected to begin evaluating ongoing problems and determining solutions, formalizing the test plans and their evaluation standards, and to begin the ground work for several of the final deliverables of the project: an Imagine RIT presence, a project summary paper, and possible competition submissions.

During this section we completed a testable model and created a formal framework for testing and evaluating this model. Not all test plans were applied to the model, but documentation progress for the plan standards, assembly, problem tracking, and subsystem integration was created. Also, long term plans like a final paper and an Imagine RIT submission were started.

Action Items Status:

Individual Contributions:

Test Results Summary

Testing Plans

ER1 – Static Force of Muscle A – Attach load cell to break in muscle A string, hang 250g mass from hand hook, wait for arm to lower under the weight and settle, then get read out from Capstone. Validity- Force achieved at rest must match accepted anatomical value.

ER2 – Static Force of Muscle B – Attach load cell to break in muscle A string, hang 250g mass from hand hook, wait for arm to lower under the weight and settle, then get read out from capstone. Validity- Force achieved at rest must match accepted anatomical value.

ER3 – Static Force of Muscle C – Attach load cell to break in muscle A string, hang 250g mass from hand hook, wait for arm to lower under the weight and settle, then get read out from Capstone. Validity- Force achieved at rest must match accepted anatomical value.

ER4 – With each muscle attached and load cells strung, and the goniometer attached and reading out to Capstone, the arm is bent at the elbow and moved through the available range of motion. Validity- readout must show that the arm can move from approximately 0o and 90o.

ER5 – Hang a max load of 500g from the hand hook while holding the lower arm up to the upper arm so that the angle of the elbow is approximately 0¬o. release the lower arm and allow the weight and lower arm to fall. Validity- the arm must be able to fall and stop while still holding the weight, staying upright and stable (no concern of it being easily knocked over), and produce steady force and angel change graphs/tables through capstone. There should be no bending or material failure in a valid case, and the entire base must still be resting on the tabletop.

ER6- With load cells in place, no weights, and the lower arm resting so that the angle of the elbow is approximately 90o, measure the angles of the muscles with the bones and the distance of the muscle attachment to the bones. Validity – Both values must be within ±5%of the average adult.

ER7 & ER8- Set the model in each possible position with the 250g weight. For each position (supinated wrist, pronated wrist, flexed elbow), allow the position to be set and then allow the device to sit, with no contact with a person or extra support from an outside object (excluding tabletop), for 1 minute. Validity – The position set by the user must not deviate by more than ±1cm during the wait period.

ER9- With all loadcells attached to the muscles and the goniometer strapped to track the elbow, use Capstone software to record 30 seconds of data for each sensor by creating 4 graphical readouts of force (N) by time (s) for the loadcell sensor and angle (degrees) by time (s) for the goniometer, and then a table with a column of force readouts (N) or angle (degree) for each sensor and a column of time (s). Record the data results as a 250g weight is hung from the hook hand of the device and the elbow extends. Validity – each graph or table column can be produced, clearly shows the impact of the weight on the device, and can be saved and exported as a .txt, .m, or .xls file.

ER11- Measure the dimensions of the final model, upright, holding no weight and the elbow in such a way that the elbow is flexed and the lower arm does not extend past the base of the model. Strings may be loosened or untied to best minimize size of model. No loadcells or goniometer should be attached. Validity – The base of the device must be within 2ft by 2 ft.

Updated Bill of Materials

Updated Bill of Materials

Updated Bill of Materials

Testing Plans Tracking File

Testing Plans Tracking Document

Design Updates

Structure Solidworks Designs

Structure Solidworks Designs

Structure Drawings

Structure Drawings

Full Model Images

Full Model Images

The up to date drawing can be found below

Structure Drawing Rev B

Humorous Drawing Rev C

Radius Drawing Rev B

Radius Drawing Rev B

Risk and Problem Tracking

Problem Tracking for this phase focused on issues encountered with 3D printing. A found solution to one of these problems involves having a team member observe the start of each print to catch potential failures. The tracking for the problem solving process can be found here: Problem tracking.

Problem Tracking

Problem Tracking

Functional Demo Materials

Action Items From Review:

Plans for next phase

The focus on the next phase will be on test plan results, creating more models, and verifying new models. This will be done by tracking problems, comparing measurements of each model, continuing to print bones, and regularly testing models on the same scale and standards.
Project Plan Schedule

Project Plan Schedule

The full schedule for the phase can be found here:Project Plan

Summary

Shannon's Three Week Plan

Amanda's Three Week Plan

Chris' Three week plan


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