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Adapted Scooter


Design or adapt a motorized electric scooter to assist with mobility for a girl with special needs

Matt Light, Andrew Gordy, Zachary Rose, Seth Singleton,Fahad Alnakaza

Problem Statement

An 8th grade girl at a local school experiences fatigue during her daily routine due to issues within her nervous system. During a normal day she finds it difficult to keep up with her peers from class to class or during any prolonged physical activity. Because of this her parents feel she could make use of a motorized scooter to help her get around. We would need to build something that she could use throughout her high school career and beyond.

Design Specifications

  1. Lightweight (Light enough to be operated by our client)
  2. Able to be transported in a an average vehicle
  3. Compact for use in busy school hallway
  4. Stable base for maximum balance with little input
  5. Outdoor usability

Background Research

There are many mobility scooters available today. Customers today can choose from the very popular Segway scooter, to the very simple Zappy 3 wheel electric scooter. There are also collapsible lightweight options out there such as the Luggie Travel Scooter.

Issues with available scooters

  • Heavy weight designs
  • Not compact or portable
  • Little to no storage compartment
  • Unable to handle outdoor terrain
  • High in cost
  • Concerns with stability

Concept Design 1

  • Three wheeled electric scooter
  • All aluminum design
  • Front wheel powered motor
  • Wide flat base for stability

Concept Design 2

  • Three wheeled, rear wheel powered scooter
  • Compact Aluminum Frame
  • Collapsible/Folding handle bar

Concept Design 3

  • three 8″ pneumatic tires
  • hand operated rear brake
  • all steel frame and fork

Selected Concept Design

In the end after considering the amount of time and money needed to for each proposed design we reconsidered our approach. We sat down, as a team, and decided to find an existing scooter on the market and modify it to fit our needs.

Overview of Selected Design

We decided on a design that would take a light weight scooter and add material to it to enable the scooter to stand up on its own and stay upright during use.

Describe Design Details

Our final design will involve the adaptation of an electric Razor scooter. The design will add suspension components to the scooter to improve stability and add footrests for comfort. The scooter selected, the Razor E300s comes with a standard seat that will further benefit the accessibility of the scooter.

Engineering Analysis 1

We first evaluated the minimum required diameter for the axle using 304 steel with the 100% of the power from the motor being transmitted to the wheels.

Engineering Analysis 2

Then we evaluated the torsion using our torque solved for from the first analysis using our selected 1/2 inch diameter.

Engineering Analysis 3

Finally we evaluated the shear stress being applied to the axle assuming a force of 150 lbs being applied directly over the center of the bearing.

CAD Drawings

Bill of Materials

Document Fabrication Process

Testing Results

Our focus for testing was to find what surfaces the scooter could handle. During our testing we found the scooter could handle indoor surfaces very well. But when it came to outdoor use the scooter was best operated on paved surfaces. The hard material of the skateboard wheel does not allow free movement over rough gravel or grassy surfaces.

Instructions for Safe Use

Always wear a helmet when operating outdoors.

Maximum recommended load of 200 lbs.

Only one individual should ride the scooter at a time.

Maintain a safe speed when navigating turns.

Keep tires inflated to recommended 45 psi.

Do not use the device unless supervised by an adult that has been fully understood the safe use of this product.


Spring 2015