P17044: Human Tremor Mitigation
/public/

Detailed Design

Table of Contents

Team Vision for Detailed Design Phase

Key Questions for This Phase

Will the Electrical System work with Actuators

  1. How are we going to attach magnets to electrical system?
  2. How does the magnet function on the test fixture while attached to the electrical system?

Can we attach the prototype electrical system to Fabric?

  1. How will electronics fasten to fabric?
  2. What elasticity fabric do we need?
  3. How rigid do we need the ribbing along device to be?

How will the magnetic brake attach to electrical system?

How will different materials perform as brakes?

  1. Test different materials in braking fixture.
  2. How hard is it to fabricate each material?
  3. How does the Fixture results map to our actual system?

How will external forces effect the system?

Progress Report

Thanksgiving Progress Report here

What has been accomplished so far:

We purchased a glove, designed the ribbing and then attached the ribbing to provide a support structure to prevent the glove from bunching up when the actuators are used.

We also built and tested our electromagnet design for the actuator.

The 9DOF Accelerometer, Gyroscope, and Magnetometer System on Chip (SoC) has been verified and now all sensors that have been intended for use on the device have been verified and are ready to be merged into a system

For electronics, the next steps are to develop some code to merge the devices, and provide some level of monitoring of hand motion to show the capabilities of the sensors in the system. After that, mimicking actuator action with LEDs will demonstrate the system response to tremors.

Theoretical Modelling of Coulomb Friction

It was attempted to model the system as a Coulomb frictional model. The tremor supplies a force that pulls the system causing it to oscillate and to trigger a sensor that applies a force normal to the motion of the braking plate. The normal force causes the motion to be damped due to the friction between the metal and the rubber, assumed to have a frictional factor of 1. The motion is assumed to be over damped due to the absence of the overshoot; and the stabilization effect it has on the system.

Some analysis were attempted to test and explore the possibilities and consequences of different masses when places in the hand. However, it proved complicated to model the system as a coulomb frictional system due to the absence of a spring like system causing uniform resonance. Moreover, an over simplified version of the analysis will not aid to the information or help bring the estimation closer due to all the key variables not being considered in the analysis.

Prototyping, Engineering Analysis, Simulation

Mark 1 Prototype Design

Mark 1 Prototype Design

Parts Integration While Moving

Parts Integration While Moving

The Glove is sensitive to all range of motions. One of the concerns that were addressed is: would the system see and be sensitive to small motions that are caused by minor tremors? The system's reaction based on this test fixture was satisfactory, behaving as expected.

Plates Attachment on hand

Plates Attachment on hand

Another concern that arose was: Would the plates and the force distributors placement on the hand be uncomfortable? would it limit any functions or restrict hand activities and grip? after placing the plates on the hand, it was observed that the system would not restrict motion range or limit grip. Moreover, Pinching effects were eliminated as much as possible using this unique design for the plates.

Plates Not limiting Functions

Plates Not limiting Functions

The plates also have multiple holes throughout the surface, they help to aid ventilation and aid in force distribution within the solid surface. Moreover, to prevent slipping effect, the line is predicted to go through multiple holes when attaching to the plate. Furthermore, multiple straps surround the hand and try to enclose its volume to avoid overall system backward slipping when the actuators are active.

Braking assembly model 1. PLA 3D printed material

Braking assembly model 1. PLA 3D printed material

Brake test with magnet off. Proof of free motion

Brake test with magnet off. Proof of free motion

Brake test with magnet on. Proof of dampening ability

Brake test with magnet on. Proof of dampening ability

Brake Pad Testing here

The initial brake assembly proved that the concept was valid, however there were many improvements that needed to be made to make it usable.

A revised brake assembly was created to address the issues experienced with the first.

Braking assembly model 2

Braking assembly model 2

The new assembly was printed with some major advancements.

- Revised mechanism to lock the two parts together.

- Holes along the base to be attached to the glove.

- Widened center slide space to avoid contact with brake line and spring.

- Reinforced top section with cut outs for magnet wires.

Brake model 2 with spring attachment point

Brake model 2 with spring attachment point

The revised model also has an attachment point for a screw so different springs or bands can be tested.
Brake model 2 inner brake pad

Brake model 2 inner brake pad

The inside has a cut out for a brake pad. This will prevent damage to the magnet as well as allow for testing of different friction materials.
Adding stabilization to the glove

Adding stabilization to the glove

Adding stabilization to the glove

Adding stabilization to the glove

Electrical Engineering

The 9DOF Accelerometer, Gyroscope, and Magnetometer System on Chip (SoC) has been verified and now all sensors that have been intended for use on the device have been verified and are ready to be merged into a system

Test Circuitry for 9DOF

Test Circuitry for 9DOF

Test Circuitry for 9DOF

Test Circuitry for 9DOF

Electrical systems detailed in the previous phase with circuit diagrams and control diagrams were implemented on the prototype glove. This is shown in the photo below.

Electronics Layout on Arm

Electronics Layout on Arm

These prototype implementations were made to prove out the functionality of the sensors in their application. Several things were learned by testing on a prototype:

  1. . The Gyro and Accelerometer need calibrated and compensated for drift.
  2. . stretch sensors need to be mounted on solid surfaces
  3. . The magnet is not currently receiving the power it needs to operate and a larger supply will be needed, or battery source.

Thanks to the layout on the arm, we were also able to create fake tremor data by wearing the glove and sampling while the wearer improvised a tremor. The gyroscopes response can be seen in the graph below.

Improvised Tremor Response

Improvised Tremor Response

Lastly, code was developed to actuate the magnet in the brake whenever the users hand moved in a direction away from the brake. This will be demonstrated in presentation.

Drawings, Schematics, Flow Charts, Simulations

The assembly made by Sarah represents our current idea for our prototype, it currently consists of the glove and battery made by Sarah, 4 braking systems made by Jamey, the top and bottom plate as well as the bracelet made by Ramy and an Arduino which was taken from GrabCAD.
Image of our prototype model concept

Image of our prototype model concept

Arduino used

Arduino used

Battery

Battery

Top support plate

Top support plate

Bottom support plate

Bottom support plate

Braking mechanism

Braking mechanism

Bracelet used to guide wires

Bracelet used to guide wires

Bill of Material (BOM)

Bill of Material (BOM)

Bill of Material (BOM)

Link to document here

Test Plans

Engineering Requirements with Test Plans

Engineering Requirements with Test Plans

Link to document here

Link to the IRB Form here

Link to the Participant Consent Form here

Link to the Project Abstract here

Link to Preliminary Test Plans here

Risk Assessment

Logistical Risks

Logistical Risks

Technical Risks

Technical Risks

Link to Risk Document here

Plans for next phase

  1. Testing, Testing, Testing
  2. Increase power to magnets
  3. Decrease brake size / decrease slide gap size
  4. Chose brake pad material
  5. Building Functional Mark 2 Device
  6. Develop a more comprehensive control algorithm

Link to Gantt Chart here

Imagine RIT Vision

Poster

Demonstration

  1. Video of Tremor Mitigation in a loop.
  2. Have a 60 second presentation of our project ready.
  3. Have pamphlet with project details and contact info to hand out.
  4. Have diagrams to help explain the systems.
  5. Possibly have a person with tremor there to help demonstrate device.
| Planning & Execution | Imagine RIT

Background and Research | Problem Definition | Systems Design | Preliminary Detailed Design | Detailed Design

Build & Test Prep | Subsystem Build & Test | Integrated System Build & Test | Integrated System Build & Test with Customer Demo | Customer Handoff & Final Project Documentation