Transcript No Slide Title
Abstract
A speech generation device is a critical tool for an individual whose speech is impeded by a disability. However, for those confined to a wheelchair and who are also unable to physically move and position the device, the everyday operation and handling of the machine may be difficult. In addition, the position required for use of the device may interfere with one’s ability to see or perform other functions. If the position does cause a significant decrease in the user’s field of vision, the ability to drive or maneuver a wheelchair may be compromised. The goal for this semester is to develop a motorized wheelchair mounting system for a speech generation device that requires minimal user effort and input and enables physically impaired users to position the device in proper locations for use and storage.
Background Cerebral palsy (CP)
• Non-progressive condition of brain damage that causes physical impairment that affects body movement and posture: • 75% of all cases of CP are developed during pregnancy.
• There is no cure for this condition at this time, therapy treatments continue to make advancements and improve quality of life.
End-user is an 18 yr. old male CP patient:
• Motor skills have been strongly affected; therefore he uses a wheelchair for mobility.
• Speech has been strongly affected, which impairs communication with unfamiliar persons.
• Great progress made in tactile use of left hand, which has enabled the use of a touch-activated speech generation device (VanguardPLUS) • Left side movement only; all focus channeled to the left side when left hand accesses the joystick • To facilitate device operation, the device is mounted on the left side of his wheelchair near his face so that he can easily see the display and comfortably touch the screen.
Current Mounting Device Proposed Stowage Position
Current Devices Current Mount:
• Fabricated by end-user’s father.
• Consists of a horizontal steel cylinder and bracket to mount Vanguard device.
• Steel cylinder welded to top of a vertical steel rod attached to armrest of wheelchair.
• Does not stow or load, but remains in position until removed by attendant.
• Device impairs line of vision during wheelchair navigation because of stationary mount.
• Current mount does not facilitate consistent operation of the speech generation device.
Commercial Devices:
• No applicable motorized systems commercially available .
• Current stationary devices do not satisfy user-specific needs.
Tyler Lark, Richard Bamberg, Dustin Gardner, Nick Harrison Advisor: Thomas Yen, Ph.D. Client: Andrea E. Johnson, CASC OTR/IT Problem Statement Statement:
The end user currently drives an electric wheelchair without a mounted Vanguard device because it impedes his line of vision when navigating the wheelchair. Our goal is to design a motorized wheelchair mounting system for a Vanguard speech generating device in order to: • Allow safe and efficient stowage/loading of the Vanguard device.
• Enable unhindered wheelchair navigation.
• Increase the end user’s independence via increase in accessibility.
Collar and Track Frame:
This Vanguard will be carried by a slotted steel pipe.
The pipe runs along a bolt screwed down to a ball bearing in order to inhibit rotational movement of the pipe, emulating a track.
The PVC collar used runs parallel to the ball bearing and allows concerted horizontal and vertical translational movement of the steel pipe while free rotation for the collar is present.
The steel pipe will engage in elliptical motion to achieve both stow and load positions.
Main: Collar and Track. Inset: Collar-Bearing Connection
Client Expectations Client Requirements:
• Vanguard should be stowed in position that does not impede user’s line of vision.
• User must be able to drive wheelchair while device is still connected.
• Device stored in a safe position free from external collision damage • Budget $1000.
Design Requirements:
Performance requirements: Safety:
Quiet, ergonomic, easy to use Must be safe for use and transport
Accuracy and Reliability:
Consistently relocate to intended position
Operating Environment:
Must be able to withstand and endure collisions with walls, doorways, etc.
Size:
Should not extend beyond wheelchair perimeter or interfere with user.
Weight:
Should not exceed 10 kg.
Final Design
The final design idea will allow the Vanguard Plus to be tucked into the lap of the end user with the screen facing upwards. In this stowed position, all system functions can be accessed without impeding the end user’s line of vision when navigating the wheelchair.
Gear and Bicycle Chain System:
Gear and Bicycle Chain System Attached to end of the steel pipe is a mandrel that fastens to a pin-loaded custom made brace, used to link this mechanism to the gear and bicycle chain system.
The brace is attached to a bicycle chain that smoothly runs along the teeth of two free rotating gears.
The gears serve to move the chain in order to stow or load the Vanguard in position.
This system will eventually be linked with a motor and switch system that will allow full automation of the design prototype.
Metal Safety Housing:
All components are installed on and contained within a metal plate, which serves as a protective barrier between the mechanical equipment and the end user or other bystanders. The plate also serves as a location to mount a motor, which will innervate the gears and cause the bicycle chain to move in the specified directions to stow or load the Vanguard device.
Superimposed Prototype Position
Costs Material / Product
Aluminum Sheet Metal Wood Frame Mounting Brackets Misc. Hardware
Total
Future Work Price
$36.00
$12.36
$8.24
$16.11
$72.71
• Purchase and install electric motor to automate the chain-driven system.
• Build motor operation circuit and integrate into wheelchair controls.
• Upgrade materials to improve durability and decrease overall weight.
• Attach system to end-user’s wheelchair • Introduce system of levers and/or hinges to flatten and rotate the screen to meet end user specifications.
•
Usability Testing:
• Meets or exceeds function of current mount • Ergonomically sound for repeated operation.
• Accessible in transit • Does not interfere with wheelchair mobility or other functions.
• Withstands repeated wear and tear.