An estimated 11.1% of US adults have severe mobility issues, and 6.4%
of US adults have difficulty living independently (CDC, 2023). For
these people, the daily task of feeding oneself can be incredibly
difficult. As we age, our bodies and muscles weaken, and acute
conditions such as inflammatory disease can make these symptoms appear
sooner and with greater severity. Everyday movements, such as walking,
bathing, and driving are painful and difficult for people with
mobility limitations. While many suffer from such diseases,
individuals who lack upper body mobility face many more challenges due
to the importance of hands and arms in many day-to-day activities.
Therefore, it is common to require a full time caretaker, which can be
stressful, exhausting, and expensive for most people involved.
For
many, assistive technologies are inaccessible for financial or other
reasons, and individuals without them are often fed by a caretaker.
While caretakers can be an effective solution, some individuals may
feel as if the basic right to feed oneself is taken away (Sarsby,
2020). In addition, the caretaker can be kept from partaking in
mealtime as they must provide assistance.
This impact can
cause the patient to feel guilt, resulting in reduced food intake,
malnutrition, reduced social interaction, and a lost sense of purpose.
Furthermore, these consequences can cause downstream ramifications,
from medical effects including weight loss, a potentially dangerous
repercussion, to social consequences, such as embarrassment in public
settings and the reduction to family mealtime. Assistive feeding
devices can offer a sense of freedom to individuals with special
needs, particularly those who are unable to eat without assistance.
Though a variety of different assistive feeding devices exist, most
devices with higher functionality are prohibitively expensive, and
cheaper alternatives lack crucial functions required for independent
eating (Naotunna et al., 2015). Therefore, more inexpensive devices
with critical functions are needed to support individuals requiring
its assistance.
We worked with a client who suffers from Merosin-Deficient Muscular
Dystrophy, which weakens muscles and causes contractions (Dimachkie &
Barohn, 2014), making mealtime and other activities difficult. Our
goal was to create a robotic feeding device that allowed our user to
eat independently and required limited motor ability to use
effectively. By working with a client who suffers from upper body
mobility issues, we were able to receive specific feedback on
improvements they would like to see on existing competitors in the
market.
Though we worked with a specific client, this device
is also meant to be used by people with upper-body weakness who have
trouble feeding themselves. The overall goal was to create a device
that would enable a user to feed themselves independently. This
objective would be achieved through a robotic arm that would be able
to move to the plate, pick up food, and deliver it to the user’s mouth
with minimal user input. In addition, other quality of life features
such as machine learning to recognize the position of the mouth were
considered. Since the safety of the client was the number one
priority, in addition, the user was also provided with an emergency
stop button in order to minimize the chances of injury. In order to
make this technology as accessible as possible, different ways of
triggering this emergency stop were researched as well. Overall, while
this device was developed specifically in collaboration with our
client and also focused on users with upper body mobility issues, the
device can ultimately be used by anyone who has difficulty feeding
themself.
We aimed to design a robotic feeding device that was safe to use and
required limited user input to function. In particular, we focused on
the movement of the device and accessibility for a wide range of
users.
There were 3 main steps in the building of
our current prototype:
CAD and 3D printed parts – we CADed
all of our parts on Onshape after prototyping work on cardboard and
vex parts, and sent them to the WPI Robotics Lab as well as one of our
advisors, Dr. C ,to print them out.
We started by CADing the
major parts of our device and assembling them all together in OnShape.
This allowed us to ensure everything fit together and was located
appropriately before printing. It also allowed us to plan out what was
needed for each part of our device.
Assembly of the robot –
there were a lot of problems that needed troubleshooting with both the
hardware and software aspect of the robot. For the hardware part, we
broke several parts by accident, had to change the design of the arm
because it did not extend as much as we thought it would, and adjusted
a lot of the robot’s final prototype so that it did not fall over or
loosen. As for the software side, towards the end, our Raspberry PI
died and we had to get a new one. Assembling took the most time since
a lot of things kept going wrong.
Testing – As mentioned
briefly earlier, there was plenty of troubleshooting that had to be
done for the robot during its testing phase. We used rice, M&Ms, and
broken up taco shells to test the spooning mechanism. This allowed us
to test for different particle sizes. It was also during the testing
phase that the overall structure of our robot changed a lot, as we
discovered more areas for improvements and adjustments.
We
went through many iterations and prototypes. Our device consisted of
three major parts: the elevator mechanism for vertical movement, the
telescoping tube for horizontal movement, and the spoon for scooping.
Throughout the design process, we went through a lot of trial and
error. However, throughout we made sure to keep the client in mind as
this was developed specifically for our client.
Overall, our final design consisted of a telescoping arm with a continuous rigged design that allowed for horizontal movement to the user. It was attached to a platform that slid on our two sliders. Two threaded rods at the center supported the platform and allowed for vertical movement controlled by two stepper motors at the base for up and down movement of the telescoping arm, a VEX motor mounted next to the telescoping arm on the upper platform for arm extension, and sturdy bottom platform with a counterweight in the back to hold the robotic device in place during movement. Our final assembly of the robotic device can be seen below.