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STEM II

Problem Statement

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. While many suffer from such diseases, individuals who lack mobility, especially in the upper body, face extraordinary challenges. Everyday movements, such as walking, bathing, and driving are painful and difficult for people with mobility limitations. Therefore, it is common to require a full time caretaker, which can be stressful, difficult, 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 this can be an effective solution, it 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 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 meal-time. Assistive feeding devices can offer a sense of freedom to individuals with special needs, particularly those who are unable to eat without assistance. There currently exists a variety of assistive feeding devices, ranging from adaptive utensils to automated robotic arms. However, lack of affordability is a primary issue with many options (Meet Obi, n.d.; Naotunna et al., 2015). Most devices with higher functionality are prohibitively expensive, and cheaper alternatives lack crucial functions required for independent eating (Naotunna et al., 2015). Therefore, cheaper devices with the critical functions are needed to support individuals requiring its assistance. This device focuses on people who have upper-body weakness but still possess enough control to operate an emergency stop button. We aim to provide an inexpensive avenue for people with upper-body immobility to eat independently.

Design Approach

When designing the robot our group focused on different aspects of the robot. We first worked on the elevator design of the robot which in and of itself consisted of 3 different approaches: An elevator design with 2 stepper motors moving a shaft up and down a threaded rod, a pulley system with a wire pulling a shaft up and down, as well as a chain system essentially moving the chains up and down using a servo motor. In the end, we ended up going with the first design because it was an effective concept that allowed us to have more flexibility with the rest of the device. We then moved on to the telescoping arm mechanism as shown in the scopey image below. We began with a two-level telescoping arm meaning the arm only had two tubes going in and out. We then realized that a three-level telescoping arm would allow for the utensil at the end of it to move farther out. The arm would have a strong string coiled around a pole being rotated by a motor in order for the in-out motion to be executed. Lastly, we focused on the design of the utensil at the end of the telescoping arm. We realized that in order for food to be effectively picked up from a plate or bowl, the spoon would have to rotate in two pieces: one piece moving out one way, and another piece moving out another way. The two pieces would come together and gather the food—almost like a claw machine with a spoon design. After putting all of these elements together, we were able to create a fully functioning robot. We ended up adding some other aspects to make the robot look presentable and more physically adept as well.

Initial Prototype Designs

Final Prototype

STEM II Presentation