P18044: Tremor Mitigation Device 2
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Preliminary Detailed Design

Table of Contents

All documents, pictures, and videos related to this Review can be found in the Prelim Design Documents directory.

Team Vision for Preliminary Detailed Design Phase

During this phase the team...

Updated Documents from Previous Phases

Updates to Key Documents

Updates to Key Documents

Link to document: Updated Documents

Links to updated documents: Customer Requirements, Engineering Requirements, Risk Assessment

Prototyping, Engineering Analysis, Simulation

Video Analysis of John Thomas

Purpose

We hope to get a better understanding of the frequency and magnitude of John Thomas’s tremors in the 6 directions (Flexion, Extension, Radial, Ulnar, Supination and Pronation) by taking and analyzing video footage frame by frame. Tracking a point can provide a lot of valuable information, position, velocity, acceleration and even force if a mass or moment of inertia is determined.

Procedure

First the arm will be constrained at the elbow in the block. Line up camera, aiming it down the length of the forearm such that when the wrist is flexed, the camera should be pointed between the radius and ulna. The hand and arm should then be marked with points to track. This can be done with stickers or pen marks. Recording should then started and the motions performed. Total there will be 10 tests:

  1. Loose Wrist, elbow straight
  2. Loose Wrist, elbow at 90 degrees
  3. Loose Wrist, elbow fully bent
  4. Hand straight, elbow straight
  5. Hand straight, elbow at 90 degrees
  6. Hand Straight, elbow fully bent
  7. Holding 5 lbs, loose wrist, elbow straight
  8. Holding 5 lbs, straight wrist, elbow straight
  9. Holding 10 lbs, loose wrist, elbow straight
  10. Holding 10 lbs, straight wrist, elbow straight

Results

Flexion and Extension by Displacement from Test 2

Flexion and Extension by Displacement from Test 2

Flexion and Extension by Displacement from Test 3

Flexion and Extension by Displacement from Test 3

Supination and Pronation by Tilt from Test 8

Supination and Pronation by Tilt from Test 8

Supination and Pronation by Tilt from Test 9

Supination and Pronation by Tilt from Test 9

Radial and Ulnar Motion by Displacement from Test 1

Radial and Ulnar Motion by Displacement from Test 1

Radial and Ulnar Motion by Displacement from Test 6

Radial and Ulnar Motion by Displacement from Test 6

Interpretations

While some of the results were not ideal due to human error in the motions, test and data analysis, the data that was good was more than sufficient. From the select graphs above, one can see that all 3 directions of motion have a 6-7 Hz tremor. So, the frequency at which our brakes need to fire can be near constant. In addition, from this test data we can get an idea of the magnitudes. In general, the results show that Flexion/Extension Motion is most prominent. But the others are also present. The big take away for magnitude/amplitude is that the values are repetitive. Each peak is equally high as the last. This is valuable because in open loop system we can easily create an adequate response and in a closed loop system the translation between input and output will be more straightforward and predictive output is possible.

Conclusions

Going forward the control system design can be simplified slightly, and a few previous unknowns can now be more easily determined. While this test is not sufficient to draw any conclusions about all tremor patients, it was sufficient in giving us that knowledge that tremors are not as random as they appear. The data from this analysis will be reused in several parts of our project development including simulations and pseudo control code.

Link to document: Video Analysis Report

Videos used for Analysis

EMG Analysis of John Thomas

Purpose

Methods of Data Collection

Electrode Placement Example

Electrode Placement Example

Data Processing

Results

Raw data from resting EMG signal from subject with no tremor, no trends apparent.

Raw data from resting EMG signal from subject with no tremor, no trends apparent.

Resting EMG signal from subject with essential tremor. Channels 8 and 4 appear to have a periodic trend.

Resting EMG signal from subject with essential tremor. Channels 8 and 4 appear to have a periodic trend.

Average maximum cyclic height compared between electrode pair position and healthy vs. tremor subject.

Average maximum cyclic height compared between electrode pair position and healthy vs. tremor subject.

FFT of EMG signal from tremor patient from electrode channel with most “visible” tremor (greatest average cyclic height).

FFT of EMG signal from tremor patient from electrode channel with most “visible” tremor (greatest average cyclic height).

Conclusions

Next Steps

Link to Document: EMG Analysis Report

CAD Model of Prototype

CAD Prototype Model

CAD Prototype Model

Matlab Simulation of Breaking System using Video Data

public/Prelim Design Documents/SimulationResults/18044_Phase3_Simulation_Figure1.JPG

public/Prelim Design Documents/SimulationResults/18044_Phase3_Simulation_Figure2.JPG

public/Prelim Design Documents/SimulationResults/18044_Phase3_Simulation_Figure3.JPG

public/Prelim Design Documents/SimulationResults/18044_Phase3_Simulation_Figure4.JPG

public/Prelim Design Documents/SimulationResults/18044_Phase3_Simulation_Figure5.JPG

public/Prelim Design Documents/SimulationResults/18044_Phase3_Simulation_Figure6.JPG

Link to Document: Simulation Report

Feasibility: Prototyping, Analysis, Simulation

Design Schematic

Schematic of Preliminary Design

Schematic of Preliminary Design

Brainstorming Development

Brainstorming Session

Brainstorming Session

Brainstorming Photos

Mockup of Preliminary Design

View One of Mockup

View One of Mockup

View Two of Mockup

View Two of Mockup

All Mockup Pictures

Current Prototype Force Calculations

public/Prelim Design Documents/18044_Phase3_FrictionAnalysisFigure1.JPG

Link to Document: Friction Analysis

Battery Draw Calculations

public/Prelim Design Documents/18044_Phase3_BatteryDraw.JPG

Drawings, Schematics, Flow Charts, Simulations

Functional Decomposition

Revised Functional Decomposition

Revised Functional Decomposition

Pseudo Code

This is a first attempt of an idea for the control logic of the mitigation device with pseudo code. There are limitations in the amount of detail due to decisions still being made on the design of the device.

Future Changes

* Strength of magnet equation - current*number of turns
* Limitations - Heat Dissipation
* Factors that affect performance - interference in contact to metal, current, number of coil turns, need feedback diode
* Types - Holding electromagnets

Link to Document: Control Logic

Microcontroller Flow Chart

Revised Mirocontroller Flow Chart

Revised Mirocontroller Flow Chart

Electrical Flow Chart

Revised Electrical Flow Chart

Revised Electrical Flow Chart

Mechanical Flow Charts

Both systems are essentially the same. The goal of each is to minimize the slop as a result of interactions like those at 2., 3.5, and 6. in the figures and to optimize the braking system at 4. To better do this our system made the following changes:

* Moved the anchor, 1., to the upper arm. The anchor there is significantly better in all 3 directions. Because it is a better anchor point, the unquantified spring and dampening constants at 2. are greater. The greater the values, the more our system approaches the ideal system.
* By rigidly connecting the brakes to the brace (4. to 3.) we can minimize the slop between the points. The interaction, 3.5, in the old system is essentially eliminated.
* The final critical difference is in 6. The values in our system will be higher as a result of a better glove to hand connection.

Old System Flow Chart

Last year’s general system free body diagram

Last year’s general system free body diagram

New System Flow Chart

This year’s general system free body diagram

This year’s general system free body diagram

Link to Document: Free Body Diagrams

Bill of Material (BOM)

Draft of Bill of Materials

Draft of Bill of Materials

Link to Document: BOM

Test Plans

Test Plans Based on Engineering Requirements

Test Plans Based on Engineering Requirements

Link to Document: Engineering Requirements

Risk Assessment

Updates to Risk Assessment

Updates to Risk Assessment

Link to Document: Risk Assessment

Design Review Materials

Presentation

Notes from review

Action Items

Plans for Next Phase

Key Questions for Next Phase

Goals for Next Phase

Plans For Next Phase

Individual Phase Plans


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