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Paper-to-prototype design of a swing-away mount for wheelchair joysticks. Completed September 2019 - April 2020 for BIOE 4900/4950: Biosystems Engineering Design 3 & 4
Project Summary by: Laurissa Bridgeman
Team Members: Trent Boschman, Laurissa Bridgeman, Sarah Harris, Georgia Loewen, Alyssa Ruta
Problem Statement:
To transfer in/out of a power wheelchair, a swing-away joystick mount may be used to push the joystick out of the way.
Existing mechanical mounts have a limited range and are difficult or impossible to use for those lacking physical dexterity or strength. Thus, wheelchair users are restricted in the number of positions in which they can access the joystick, or require assistance to move their joystick as needed.
Purpose:
Design a joystick mounting system that can swing inwards and outwards efficiently and increase wheelchair users’ independence. The design must be:
Affordable - to increase accessibility
Durable - to withstand daily use
Adaptable - for various wheelchairs and user abilities
The scope of the project was to create a functioning prototype for the client. The prototype had to swing towards the midline of the wheelchair for easier access to the joystick, and to the outside of the wheelchair for transferring and coming up to tables.
Proposed Design
Proposed Design
A motorized mount that utilizes a timing belt to ensure the joystick faces forwards. Controlled via a customizable push button, which allows the user to rotate the mount back and forth from midline to an outer position.
Mechanical components:
2 timing belt pulleys, 1 timing belt, 1 steel enclosure, 2 steel shafts, 1 steel mounting tube, 1 steel motor coupler, 1 steel joystick plate attachment, 4 bushings, and other structural parts.
Electrical components:
1 Arduino Nano Every, 1 H-bridge driver, 1 motor, 1 push button, 2 limit switches, a 12V battery, and a 3D printed enclosure.
Operation:
The mount's motor is controlled by pressing the yellow AbleNet button, plugged into the device with a mono jack, to deliver input to the Arduino which outputs to the motor driver. This button can be placed anywhere on the wheelchair and can be easily swapped for a button with the appropriate activation force for the user.
By pushing the yellow button, the motor moves in one direction. Pushing the button again causes the motor to change direction. The mount rotates until the button is released or until it hits one of the limit switches.
The total range of motion is 250 degrees.
Video of Joystick Mount Operation
Features
Features
Easily mounted with standard wheelchair mounting bracket
Rigid enclosure is durable and protects user from moving parts
Quiet - about 60db when in motion, the level of normal conversation
Easily operated with good button responsiveness
Reasonably affordable - estimated cost of components ~$380
Needed Improvements
Needed Improvements
Reduced weight/bulkiness
Better positioning of electrical box
Added protection for exposed electrical components
Added weather/dust/dirt protection
Increased positioning adjustability for user
Optional code for activation with one press of button instead of sustained hold
Concluding Recommendations
Concluding Recommendations
The team successfully designed and prototyped a motorized joystick mount capable of moving the joystick from the user’s midline to ~250 degrees with the push of a button. Based on the outcomes of prototype testing, the team recommended further reproduction of this device by the client. With the listed modifications/improvements, the project could successfully provide an affordable motorized joystick mount for powerchair users with limited physical ability.
This device has the potential to increase user independence, making it an attractive alternative to existing joystick mount products.
Skills Developed
Skills Developed
Design
Design
Identified engineering specifications from user requirements.
Developed/evaluated multiple concepts.
Prototyped design, conducted verification testing, made recommendations.
Communication
Communication
Collaborated with team members, instructors, healthcare workers, technologists, and wheelchair users.
Team meetings, design reviews, report writing, assembly instructions, engineering drawings.
Project Management
Project Management
Kept work organized and on schedule with Gantt charts, work breakdown structure, meeting agendas/minutes, project update memos, engineering journal, and clear documentation.
Hands-On Skills
Hands-On Skills
SolidWorks
Arduino
Electrical System Design and Implementation
Metal Part Fabrication and Assembly
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