Stem II

Dr. Crowthers

A Sit to Stand Assistive Device

CEO: Vanessa Fobid, CIO: Nihitha Reddy, CTO: Mihika Chalasani, CMO: Travis Tran

Advisor: Dr. Kevin Crowthers, Ph.D. (Massachusetts Academy of Math and Science)

Problem Statement

It is impossible and dangerous for some to stand up from bed or from a chair and to sit back down. Our device would be able to help its users get into a standing position. Unlike other products, this will both be portable, have side bars for assistance, and aid the user all the way up, until they are fully on their feet. This chair can also help them from their initial standing position to their seated position. Overall the different components this device shall have are supportive bars, the ability to raise in height, a tilting component, and a motor control or application to control it.


This product is directed towards the elderly community in order to address the problem of easy mobility when getting in and out of chairs. The device is also beneficial to those with disabilities and injuries that limit leg mobility. Increased difficulty in this seemingly simple task can heavily impact the quality of life for many demographics. Currently, it is difficult for these communities to sit down and stand up due to the pressure it exerts on their lower limbs. In order to alleviate that pressure, our portable cushion will extend to an angle that doesn’t cause our client to have to bend as much when moving. They will be able to keep their posture steady therefore generating less pain and struggle.

Design Approach

After we decided what models we wanted to go with, we started to design our prototypes. First, we used an online drawing platform called Notability the sketch our models. This gave us an idea of how we wanted everything to look and be sized so that we could start designing them with CAD. We got our measurement by comparing our model’s base to normal chair seats.

Build Process

The building process involved many iterations in order to get everything to perfection. We first made a proof of concept out of materials like cardboard and hot glue so that we knew everything would function properly. After this, we spend a lot of time at WPI’s robotics lab in order to put parts together and cut materials. The main components that our models included were the springs and pneumatic actuators, wood, 3-d printed support bases, and screws to secure everything.

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Final Device

The final design of the first spring prototype for this project was determined through feedback from the client as well as the engineering design matrix. The spring prototype was the most stable design, had the largest seat, and was also the cheapest to prototype and create. It also passed the greatest number of requirements compared to all other prototypes. Through the long process of testing with our client and modifying the prototype iteration to accommodate their needs, the spring prototype became the best one and our final assistive device for this project. The pros of our final design are that it is cheap, light, significantly decrease the effort it takes the client to stand by 5 points on a 10-point scale, lifts at least 180 pounds at least 6 inches from the seat, significantly decrease pain felt by the client when standing/sitting by 5 points on a 10-point scale, comfortable, has the ability to attach armrests if the original chair does not have them (modularity), is large enough for comfortable seating, among the other passes in the final engineering design matrix shown below. The cons are that it is not motorized, does not significantly decrease the effort it takes the client to sit by 5 points on a 10-point scale, does not have heated/cooled seats, not available in a variety of colors easily for the caretaker, and cannot be mastered very quickly.


Instructions for use

Take a look at our handout below for instructions on how to use and replicate our device. Feel free to reach out with any questions.

Final Presentation

Down below is our final poster that reviews our background, methods, and results. Feel free to look through it!