Week 7 (10/23-10/29)

This week's focus was designing modules for the new disc-based design and shakedown testing.

The photos below shows brainstorming for an adjustable seat cushion design.

This simple "grid lock" system allows for easy disc re-positioning, but does not account for replacing the support material after the discs have been moved.

This week, we realized that the anatomical pressure points which mark the center of each disc are actually quite close together. This greatly reduces the disc size and effectiveness.

As a result, we are in the process of completely redesigning the capstone project from scratch, while also moving forward with our current disc-based design.

Additionally, shakedown parts have been ordered from McMaster-Carr and ordered from the 3D printing lab. Testing will begin this next week.

Week 6 (10/16/17-10/22/17)

Teams Main Idea

The figure above shows the one idea of rotating disk that we plan to shakedown.  

The figure above shows one idea of our teams mechanical system

Brainstorming of Teams Main Idea Pictures

The figure above shows the more  shakedown ideas of the team

The figure above shows the brainstorming of different shape moldings and shakedown testing

The figure above shows different shape disk indicating some with different depths and grooves

The figure above shows the brainstorming ideas of the group of the rotating disk.

More Brainstorming on Shakedown testing

Our team was brainstorming on more shakedown testing.
Some ideas of the teams shakedown:

Work on different moldings for disk to figure which has more durability such as:

•            3D printing
•            60A urethane
•            80A urethane,
•            ceramic
•            wax
•           epoxy sculpt

Small particles to see the rotations of the particles:

•               Bag of water
•               glitter
•               cotton balls
•               paper

Different motor movements to rotate disk:

•                     3 gears system
•                     4 gears system
•                     Sprocket gears with chains
•                     Pully's with tension belt attach to motor

Week 5 (10/9/17 - 10/15/17)

The following were done in this week:

• On Tuesday: the team met and we brainstormed about the new prototype of our device because we noticed that our old design could not work. We also did the shakedown test plan.                                                                                                       -The pictures of our brainstorming ideas are shown below:
  
  
  
  

                -The pictures of our shakedown test plan are shown below:

• On Friday: The team met and we discussed what to put on our presentation after we divided the tasks. The pictures below show how we shared the tasks: 

• On Sunday: the team met and we did the three types of budgets (the lowest, the nice to have and the highest). The pictures below show those budgets:
  

Week 4 (10/2/17-10/08/17)

Brainstorming Modules

The figure above shows the different modules from brainstorming. Our team did different modules for 1: Fluid Pump, 2: Flexible/breathable/ comfortable device-skin interface, and 3: Hydraulic/Pneumatic fluids for low and temperature-consistent viscosity.

The figure above shows an idea for a pump system that requires a compressor

The figure above shows three different ideas from our teams pump system

Top Three Modules From Each Concept

The table above shows the top three modules for the fluid pump. Our team agreed that the two parallel cylinder by electric motor gear rotation was the best choice based on our criteria. Our team decided that durability, comfort (defined support wave), and size were important aspects in our decision making.

The table above shows the top three modules for the flexible/breathable/comfortable device-skin interface. Our team agreed that the multi-layered polymer composite was the best choice due to that fact that in obtained friction, comfort, elasticity, durability, and waterproof compared to the two other fabrics.

The table above shows the top three modules for hydraulic/pneumatic fluids for low and temperature-consistent viscosity. Our team agreed with to use air because it is low in viscosity, weight, and reasonable viscosity index.

The schematic above indicates the function of the two parallel cylinder function with motor gears.

Research for Flexible, Breathable, Comfortable Device-Skin Interface:

1. Silk
1. From a sequential lymphedema pump (Patent: US 8206416) [1] the outer material is composed of silk
2. Described as a porous textile, firm, and non-stretchable
3. Porous but firm textile will prevent distention of the cloth.
4. Porosity allows for breathability and management of the moisture created from the individual's skin

2. Cotton
1. From Rehabmart website [2], by the description of posey encapsulating bootie heel guards device, it describes the good qualities of cotton to treat pressure ulcers
2. Helps keep moisture away from the foot
3. Shape conforms to the person's feet
4. However, dermatherapy website [3], describes the disadvantages that cotton may have to treat or prevent pressure ulcers.
5. The disadvantages are that cotton promotes allergens, retains moisture with the progression of time, and causes skin-irritating friction

3. Multi-Polymer Compositions
1. Hulet Smith, the CO-Founder and CEO of Rehabmart [4] recommends wheelchair users to use a urethane honeycomb wheelchair cushion.
2. This thermoplastic cushions are constructed of many individual cells, much like those found in a beehive.
3. Air pockets, made of thermoplastic urethane, can help with distributing the weight and pressure evenly without risk of fluid leakage from within the air pockets.
4. Air flows efficiently through the air pockets and numerous open spaces.
5. These cushion helps against  skin breakdown  by keeping the skin cool and dry.
6. Cushion is lightweight and provides the utmost in shock absorption and sitting support.

Future Shakedown Testing

Materials needed:

• PVC piping
•  60A or 80A urethane rubber
• 3D print molding case
• Air hoses
•  Bicycle pump
•  Valves. 

1. We will begin shakedown testing by making our own tube system. 
2. We will test the material, to see the one which is air tight and we will try to make a torus-shaped air pockets. 
3. We will test to see if our expandable torus-shaped air pockets will be able to connect to the pumping system and make a closed system.
4. We will test to see if our expandable torus-shaped air pockets will be able to contain the planned ratio volume (0%,50%, and 100%  of the total cylinder pump volume).

Week 3 (9/25/17-10/01/17)

 Research on ratio manual wheelchair to power wheelchair

• According to a research article in 2003, Demographics of Wheeled Mobility Device Users, only 17 percent of wheeled mobility device users actually use electric chairs or scooters with the vast majority using manual chairs.

• The website KDSmartchair.com indicates the expected market of manual wheelchairs and powered wheelchairs in 2018 as shown in the figure below.

Based on KDSmartchair website, we investigated the average value of manual ($500) and powered wheelchairs ($1400). Based on the average cost, it shows that 32.45% of individuals use powered wheelchairs and 67.55% use manual wheelchairs.

The figure above shows the mathematics for the percentage of powered wheelchairs and manual wheelchairs.

• Those who use powered wheelchairs tend to be individuals with spinal cord injuries, cerebral palsy, and elderly patients

Brainstorming Concepts for the Prevention of Pressure Ulcers

    The figure above shows the team brainstorming important concepts to promote blood circulation for long-term wheelchair users.

The figure above shows the brainstorming concepts to reduce tissue pressure for long-term wheelchair users

The figure above shows the brainstorming concepts to promote skin integrity for long-term wheelchair users

9 Concepts Selection from Brainstorming

Reduce Pressure

• Compression Cushion Material
• Air (Powered) Fluidized Material
• Additional Horizontal Support

Promote Circulation

• Periodic Motion Support
• Stagnant Limb Compression
• Visual Sensor Feedback

Promote Skin Integrity

• Regulate Temperature
• Breathable Materials
• Sanitary Environment

The figure above shows the pros and cons of our nine concepts to determine which concept is best suitable for our goal.

The table above shows our top criteria that determine which concept will help to lead us to the best design. 

Based on the table, it shows that the compressible cushion material would be of utmost priority when compared to the rest of the concepts due it being energy efficient, mobile (not too bulky or heavy), and durable. Breathable and compressible materials scored the same amount of points, however, our team decided that a design focused on a compressible material would better suit our engineering background and skills.