P17082: Elbow Model
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Preliminary Detailed Design

Table of Contents

Team Vision for Preliminary Detailed Design Phase

The plans for the preliminary detailed design phase were to focus on developing models & drawings and to evaluate feasibility & test plans so that a preliminary design can be proposed. The goal of this phase and review is to have a design and plan that is proven to be a valid and appropriate solution that can be used as the guidelines for the final detailed design review.

In the preliminary detailed design phase our created models and drawings for the proposed product solution, contacted partners for design input and plans for production, and evaluated the engineering requirements, test plans, risks, and costs of the designed systems. We also began to determine what the largest challenges of the design will be, how successful designs and subsystems will be evaluated, and identifying sources and triggers for risk mitigation.

The full status of the action plans for this phase is:

Individual Contributions

Shannon

Chris

Amanda

Maria

Prototyping, Engineering Analysis, Simulation

Analysis:

Free Body Diagrams and Analysis of Model

Free Body Diagrams and Analysis of Model

Prototyping Plans:

A model of the system will be 3D printed using PLA filament to assess proper functionality.

  1. First joints will be printed to make sure they work well together
  2. Complete bones will be printed to create a full working model

Manufacturing Plans - Molding

Once a prototype is completed we will cast the models to create molds, which we can then use to create as many models as needed.

Why?

Time, cost, and material choice.

Feasibility: Prototyping, Analysis, Simulation

Feasibility of Model

Feasibility of Model

SME Feedback:

Anatomy:

Manufacturing Process:

Data acquisition was verified using Capstone.The collection of data from 3 muscles via 3 load cells and the angle data collection from one goniometer is possible. The images below show what students would see when completing a lab and how they'd export their data.

3 Loadcells obtaining data simultaneously

3 Loadcells obtaining data simultaneously

Table of data from each loadcell in Capstone

Table of data from each loadcell in Capstone

Drawings, Schematics, Flow Charts, Simulations

3D Model

3D Model

Bill of Material (BOM)

Bill of Materials

Bill of Materials

Test Plans

To be completed by team members to indicate the validity of a prototype or model and show the satisfaction of the engineering requirements for the project.

These test plans are based on and in response to an updated version of the Engineering Requirements.

Engineering Requirements Revision 2

Engineering Requirements Revision 2

Engineering Req Revision 2

Materials required for tests:

Plans:

  1. ER1 – Static Force of Muscle A – Attach load cell to break in muscle A string, hang 250kg 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.
  2. ER2 – Dynamic Force of Muscle A – Attach load cell to break in muscle A string, hang 250kg mass from hand hook, allow arm to rotate and fall with weight, then get the peak force value through Capstone. Validity- Force achieved at rest must match accepted anatomical value.
  3. ER3 – Static Force of Muscle B – Attach load cell to break in muscle A string, hang 250kg 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.
  4. ER4 – Dynamic Force of Muscle B – Attach load cell to break in muscle A string, hang 250kg mass from hand hook, allow arm to rotate and fall with weight, then get the peak force value through Capstone. Validity- Force achieved at rest must match accepted anatomical value.
  5. ER5 – Static Force of Muscle C – Attach load cell to break in muscle A string, hang 250kg 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.
  6. ER6 – Dynamic Force of Muscle C – Attach load cell to break in muscle A string, hang 250kg mass from hand hook, allow arm to rotate and fall with weight, then get the peak force value through Capstone. Validity- Force achieved at rest must match accepted anatomical value.
  7. ER7 – 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 180o.
  8. ER8 – Hang a max load of 500kg 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.
  9. ER9- 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.
  10. ER10 & ER11- Set the model in each possible position with the 250kg 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.
  11. ER12- Begin with an unassembled device. Start a timer and begin assembly, including the addition of base structure (and separate assembly if necessary), strings, load cells, goniometer, and arm straps. Also, include all hardware cables necessary for data acquisition (loadcells, goniometer). Assemble device to match model and plans provided. Validity – The full assembly takes approximately 20 minutes or less to assemble and can support a 250kg weight from the hand hook upon completion.
  12. ER13- 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 250kg 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.
  13. ER14- 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.

Design and Flowcharts

Functional Decomposition

Functional Decomposition

Benchmarking

Benchmarking

Risk Assessment

  1. The Running risk assessment can be found in this document_Updated Risk Assessment Document P17082
Risk Analysis

Risk Analysis

Concerns and Issues:

Design Review Materials

Preliminary Design Review Power Point Presentation

Plans for next phase

The full schedule and list of action items for the next design phase can be found here.

Full Schedule of Action Items For The Next Phase

Action Item Schedule for the Next Phase

Action Item Schedule for the Next Phase

SUMMARY

The main focus will be on preparations for printing, casting, prototyping. Mainly addressing remaining modeling and design needs, and ensuring models will function and are printable.

INDIVIDUAL PLANS

_Three-Week Plan Christopher Harley

_Three-Week Plan Shannon Keenan

_Three-Week Plan Maria Romero-Creel

_Three-Week Plan Amanda Cook


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