P18043: Tremor Mitigation DAQ
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Detailed Design

Table of Contents

Content related to this node should go in the Detailed Design Documents directory.

Team Vision for Detailed Design Phase

We are fairly confident that we have succeeded in completing these goals.

We are still ironing out definite plans for the first few days we arrive back from semester break.

Progress Report

Tasks the Accomplished as a Team as of 11/21/17:

Individual Plans/Goals for the rest of the semester:

Rich:

Lucas/Saidon:

Dani and Elizabeth:

For Update Edge everyone will review:

Team Decisions:

EMG Testing

Goals:
  1. Practice electrode placement on other team members and again on Patient Alpha to test for consistency.
  2. The placement was slightly changed to meet the needs of the device design. In the preliminary data collection, the reference electrode was on right ankle. For this data collection test, we moved the reference electrodes to just above the elbow to see if this would affect the signal.
  3. Test to see if the 3M Red Dot disposable electrodes would affect the data.
  4. To determine if repeated uses of disposable electrodes is feasible for testing on team members.
  5. See if muscle group action could be matched up with EMG data.

Electrode Placement

Electrode Placements

Electrode Placements

Wrist Movements

Wrist Movements

EMG DATA

ET Data - Patient Alpha performing extension and flexion

ET Data - Patient Alpha performing extension and flexion

Normal Data - Subject 2 performing extension and flexion

Normal Data - Subject 2 performing extension and flexion

Normal Data - Subject 4 performing extension 2x and then flexion 2x

Normal Data - Subject 4 performing extension 2x and then flexion 2x

See test plan documents in the Test Plans section for more details on the procedures and the notes for the above data.

The muscles involved in the above movement are:

Anterior - "In front" or "before"

Posterior - "In back" or "after"

Findings:

  1. The electrode placement was consistent from person to person and when compared to prior tests.
  2. The change in reference electrode placement had no effect on the signal that we could see
  3. The 3M Red Dot disposable electrodes did not affect the signal.
  4. We cannot reuse electrodes.
  5. Out of the series of movements we tested the most noticeable difference in activation occurred during extension and flexion.
    • Using the information from Anatomy SMEs it was found that:
      • Channel four matches up with extensor muscles
      • Channel three matches up with flexor muscles
      • Channel seven matches up with but flexor and extensor muscle (more)
      • Channel eight matches up with extensor muscle (more)
    • Within our scope of knowledge and resources pinpointing specific muscle action will be very difficult, but we can see that certain groups are activated differently during a given movement.

Questions for Guide and Customer:

Prototyping, Engineering Analysis, Simulation

Electrical Testing

9-DOF Sensor Tests

During this phase, the 9-DOF sensors that were purchased were tested to be able to see if we could get accurate orientation and motion data output. For the orientation tests, the sensor was tested to make sure that the correct quaternion outputs were found in each axis (x,y,z). A known circle of values placed under the sensor and the sensor was moved to line up to a known value. If the sensor output the value that was on the circle, the sensor was working properly. After, this test was done initial testing of the accelerometer output. The sensor was moved at a known acceleration in each axis to make sure that the sensor was working properly.

After initial testing, the sensor was put onto a person with Essential Tremors. During these tests, it was found that the orientation and motion data was working properly, but could not pick up the tremors as well as expected. The cause of this is that the sensor was not mounted securely enough to the hand of the patient, so all of the motion of the patient was not sufficiently measured. This will factor into all future physical device prototypes.

Looking forward to MSD II, the data from the 9-DOF sensors will be feed into MATLAB, where the data can be plotted and analyzed.

EMG Sensor Tests

The practicality of the Myoware EMG sensor was tested during this phase. Initially, the sensor was tested on a group member to see if the sensor was working properly. It was found that the sensor does pick up EMG signals properly, but the output of the Myoware still needs to be compared to that of a known EMG system to test the validity of the output. The importance of sensor placement was also on display during these tests because the sensor would not work properly unless properly placed.

The Myoware sensor was then tested on a person with Essential Tremors. The output of the sensor was as expected and was similar to the data that was found using the EMG setup in the lab. Further conclusions could not be made because the data is not able to be saved in large quantity yet. This test will have to be run multiple times in the future as the device becomes more robust and data logging methods are implemented.

Similarly to the 9-DOF sensors, the EMG sensors will be feed into MATLAB in MSD II where the data can be plotted and analyzed. Currently, only one EMG sensor is being tested, but the final device could have as many as 4 different sensors.

Physical Model

Initial Device Location Testing

During the previous phase, it was determined that the electronics for the device, including the Arduino and the battery, would not be able to fit on the wrist. Therefore during this phase one of the key questions was, where should the electronics be placed on the patient. To determine the answer to this question feasibility testing was performed using cardboard mock-ups of the devices.

The following images depict pieces of cardboard cut to the footprints of the known required components. At this point in testing the team was still planning on using a 9V battery to power the device through battery pack feasibility testing was performed at a later date.

Component Footprints

Component Footprints

Using the initial cardboard pieces the team determined that the upper arm in the bicep region had enough area to fit the footprint of the device. Once this was determined a cardboard box was created to represent the minimum volume that the device will occupy.

Minimum System Volume

Minimum System Volume

The box shown in the image above was attached to the outside of the upper arm on multiple teammates and our guide. Once the box was attached it was determined by all participants that the box was not too bulky, uncomfortable, or affected the motion of the arm which were some of our major risks for this phase. Using this information the team determined that a more realistic fit model that included devices on the forearm could be made and tested.

Device Testing and Battery Pack Feasiability

During this phase the team decided that using a rechargeable battery pack instead of a 9V battery would be beneficial for the following reasons:

The negatives or risks associated with using the battery pack are the following:

After a review of our budget, it was determined that the cost of the battery pack was well within our budget. In addition, after reviewing a few different battery pack options we were able to find a couple that fit within the allowable footprint already determined during testing. Lastly, after reviewing the weight online, it was determined that the weight of the packs was within our feasible range. After this initial benchmarking the team decided on a battery pack and purchased it so it could be used for feasibility testing.

In order to determine if our current design, with the addition of the battery pack, was too bulky, heavy or uncomfortable, a basic fit model was made using off the shelf components and then tested. The following image depicts one of our team members wearing the device.

A Student Wearing our Basic Physical Model

A Student Wearing our Basic Physical Model

The device shown in the above image was worn by each of our team members and one of our patients. Each individual who wore it stated that it wasn't too heavy or bulky and that it wasn't intimidating or uncomfortable.

Drawings, Schematics, Flow Charts, Simulations

Hardware Design

In this phase, an overall hardware design was created to be able to describe the follow of data in the system and give a high-level view of how the devices will be connected. The following picture is a high-level view of all of the components and the picture after that is a CAD drawing that has all of the connections. This diagram was made in Fritzing and can be downloaded with the link under the picture.
System Level Design

System Level Design

Hardware Schematic

Hardware Schematic

Electrical CAD File

Software Design

In this part phase, an overall software design flowchart was created to describe how the different part of the device would work together through software. Most of the parts are in individuals parts right now because the programs are used for debugging and testing currently. The following picture shows the current overall software design. The picture shows connections between the functions and how they will work together.
Detailed Software Design

Detailed Software Design

CAD Models

public/CAD_ASM_ISO_4.JPG

public/CAD_ASM_ISO_4.JPG

Isometric View of our Final CAD Design

Isometric View of our Final CAD Design

Isometric View of our Final CAD Design without the Covers

Isometric View of our Final CAD Design without the Covers

A Closeup of the Arm Unit

A Closeup of the Arm Unit

A 3D Pdf of the assembly can be found here: Phase 4 CAD 3D PDF

The CAD files for this phase can be found here: Phase 4 CAD files

Bill of Material (BOM)

The following picture is a snapshot of our BOM spreadsheet. In this document, all the COTS and most of the materials required to manufacture our device are listed. In addition, the document lists the cost of each part, selected vendors, and whether they have been purchased or not. The document can be downloaded using the link under the picture.
Master BOM

Master BOM

Phase 4 Master BOM

Risk Assessments and Test Plans

The following picture is a snapshot of our risk management spreadsheet. In this document, all of our current risks are examined and assigned tests/action items to mitigate them. The document can be downloaded using the link under the picture.
Risks and Test Plans

Risks and Test Plans

Risk Management

Here are links for EMG testing procedures completed during this phase.

Design Review Materials

Include links to:

Plans for next phase

Pending:Still ironing final details. Documents will follow Design Review on 12/7/2017.

(Use the individual 3-week plan template for this)


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