P19011: Wheelchair Accessible Restroom
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Systems Design

Table of Contents

Team Vision for System-Level Design Phase

Our Plan

Our team planned to incorporate feedback from the customer that we received during the Problem Definition Design Review into our process moving forward. We aimed to further define our goals through benchmarking, generate concepts to address the functions outlined in the functional decomposition, analyze feasibility of concepts, and end with selecting a hybrid concept for the team to move forward with.

What we accomplished

Our team continued to benchmark our product to compare against other products on the market, and completed an analysis to determine which design concepts were the best choices for our product. The team researched standards that our product will have to comply with.

Functional Decomposition

Below is an overview of our functional decomposition chart. It outlines the general functions for our product.
Functional Decomposition

Functional Decomposition

Benchmarking

The team analyzed products currently on the market that fall into a similar category of accessibility aide. The previous team's prototype was then compared to these market products.

Cost Comparison

Cost Comparison

Benchmarking Table

Benchmarking Table

The team also researched standards that our product will have to comply with and will influence the design decisions and concept selection.

Link to live standards document here

Concept Development

The team brainstormed conceptual design solutions to some of the functions defined previously.

Concept Generation

Concept Generation

Concept Generation

Concept Generation

Concept Generation

Concept Generation

Concept Generation

Concept Generation

Concept Generation

Concept Generation

Feasibility: Prototyping, Analysis, Simulation

What type of design would be the most comfortable for wheelchair users?

In order to answer this question, we will take the approach of user feedback to this list of questions:

What would the maximum allowable static coefficient of friction be between linear bearings and guide rods so that the mechanism does not seize or "stick" when actuated upward?

Initially, the friction force from the bearings was neglected in order to relate the applied force from the user, P, to the bearing reaction force, R. Using this relation, the maximum coefficient of static friction was found such that the upwards force of the cylinder will always overcome the downward forces of friction and the user's weight.

Bearing Feasibility Analysis

Bearing Feasibility Analysis

What are the dimensions of the average public toilet that our device has to fit on? And what are the dimensions in the restroom our device has to fit within?

Additional research into the ADA standard restroom was conducted to find these points:

How much force should a typical wheelchair user exert on the casing of the device in order to prevent potential breakage?

Assumptions used for this analysis include:

Force Feasibility Analysis

Force Feasibility Analysis

Preliminary Hydraulic System Concept Design

Preliminary Hydraulic System Concept Design

Morphological Chart and Concept Selection

Morph Chart

Morph Chart

Functions chosen: Adjustable Seat Height: Lift/lower seat using hydraulics Accepts User Input: Lever Arm Rest: Swinging Back Support: Ergonomically contoured Prevent Slippage: Curved arm rests with grips

Link to live document here

Concept Selection

Sample Selection of Pugh Chart Analysis

Sample Selection of Pugh Chart Analysis

Pugh Combinations

Pugh Combinations

Link to live document here

Systems Architecture

Systems Architecture

Systems Architecture

Link to live document here

Designs and Flowcharts

Flow Chart of User Inputs and Loads

Flow Chart of User Inputs and Loads

Risk Assessment

Updated Risk Management Table

Updated Risk Management Table

Live document here

Design Review Materials

The Systems Design Review presentation can be found here

Notes from the review can be found here

Plans for next phase

Here is an overview of the team's plan for the next phase:
Plan overview for the next phase

Plan overview for the next phase

Link to live project plan here

During the next phase of the project, the team will focus on the design of the subsystems of the product, selecting components to create the product, and design for manufacture and assembly.

Links to each team members' Three Week Plan:

Rachel Ackles

Rachel Berry

Nate Bracalente

Don Phan

Daniel Vetere


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