college of engineering white

Project 4b: Motorized Walker


The goal of this project is to design and fabricate a motorized walker for a child suffering from a mobility issue that stems from Spina Biffida. This will allow the child to keep up with his classmates throughout the day.

Team Members: Wade Snider, Austin Richardson, Noah Rodriguez, David Cantrell

Problem Statement

The child assigned to us was diagnosed with Spina Biffida prenatally, which has left him with limited mobility and stamina since birth. Our team has been asked to modify the current design of his walker such that it can be driven by the child manually like a normal walker, and so it can be motor driven when he gets tired. We’ve also been asked to create a foldable step for the child to stand on as he maneuvers the walker while the motors are engaged. When meeting the child and assessing his current mobility, our team decided to make both steering and safety features priorities as well to improve upon the limitations of his current walker’s design.

Design Specifications

Family Requested Features:

– Motorization

– Foldable Step

– Safety Upgrades

– Ability to Grow with the Child

Technical Specifications:

– Lightweight (so it can be used as a conventional walker by a child)

– Accessible (with simple controls a child could learn to use quickly)

– Safe

– Durable

– Long-Lasting (so it can grow alongside the child)

– High Battery Life (so it can be used for long distance travel)

Background Research

Klip 4-Wheel Walker

Size specifications for the Klip 4-wheel walkers.

When we were trying to figure out some ideas on how to design this walker we went through some patents of motorized walkers that are already made. Also, we were able to meet the child and see his walker and how it is used to know how we can modify it with designs that have already been made to best suit him.

Concept Design 1

Our first concept design is a modified walker with independently driven rear wheels. This walker includes a seat which will be different from the original walker and will allow him to be seated when he wants to use the motorized function.

One issue with his current walker is turning restriction. This design will allow him to make sharper corners so he can better maneuver around his house and daycare. It works by rotating the walker like a tank, one wheel moving forwards and the other backwards while the front wheels follow.

The motorized movement will be facilitated by controls on the grips of the walker.

Concept Design 2

This second design is a walker with an open back design. It has mechanical steering and a foldable step. This design is based off modifying the current Klip 4-Wheel design our child uses with added mechanical steering and spongy material to absorb some impact in the case of a collision.

Concept Design 3

Our final design was based off a more standard walker. It has two electrical motors which will be used to enable the ability to turn left and right. Instead of a step, it has a fold-down seat for the child to sit in. The folding down of the seat would engage a gear in the gear box such that the motors could drive the rear wheels. When the seat is flipped up, a gear in the gear box disengages and the walker can be used manually as usual.

Selected Concept Design

We decided to compare our three concept designs through a decision matrix to help make the best choice. We ranked them out of three maximum points per category, and the one with the most points is the one that we chose to create. The design with the most points in a particular category is the one we viewed as the best. (ex) Cost being a 3 means its the cheapest.

Since all the designs were based on being driven by electric motors, the price and weight category rankings were based on other added features (seats, steps, safety features, extra raw material, etc.).

The accessibility category ranking was determined by how steep the estimated learning curve would be for each design.

Finally, the manufacturability category ranking was based on how easy we thought it would be to acquire and use the necessary materials for each design.

Decision Matrix

Overview of Selected Design

Our selected design is based off of concept 1. Using two motors, an Arduino, and joystick controls we will modify a four-wheel Klip walker.

Describe Design Details

In essence, the design adapts a common arduino robot to the walker. Motors and power are upscaled to drive a small child.

Engineering Analysis 1

We needed to determine the torque needed to drive the combined weight of the walker and the child.

Engineering Analysis 2

We needed to determine our battery’s life with respect to its load.

Engineering Analysis 3

Our final analysis was doing the Arduino for the whole circuit to work properly.

Bill of Materials

Document Fabrication Process

Project Summary/Reflection


2022 Fall