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
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
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.