Sit to stand device

This project was done by a team of 4. Arjun Thapa, Usman Akbar, Joyce Chow and Anthony Chen at Stony Brook, New York.

Sit-to-Stand Device For Children With Cerebral Palsy

The product is a device that assists people with neuromuscular diseases, such as Cerebral Palsy (CP), to stand from a sitting position. Although this device would also be useful for the elderly, the main design is focused on helping children with CP from ages 6-12 learn how to stand by themselves. The design is similar to a walker, but it features an adjustable seat harness that attaches the person to the device. The seat harness would be worn by the child sitting down and the child would be able to control the pace that they would be lifted up by the device. The design will be lightweight, portable, and weigh less than 15 kg. The device will be rated for 90kg and the child’s center of gravity will be in a position where the device is not likely able to tip over.

The main reason why someone would need this product is if they have a neuromuscular disease, like CP, and they have trouble standing up or sitting down. They may be able to walk, but standing or sitting requires much more muscular activation, so they might need some assistance to perform those actions.

The main goal for this project is to create and build a sufficient device that will last long enough and be convenient to use for an average 6-12 year old with CP to learn to stand and sit. Our group is planning to design and create concepts of this device in the first few months, and then later on buy the necessary materials to build the device and test it. We will split the design and research among us, but each of us can help in all categories, such as CAD, circuits, and coding.

Analyzing the shoulder and hip curve of the human body during sittting and standing

The Human body follows a curve i.e shoulder curve and hip curve while standing from the sitting position. To begin, our team started recording each other's motion , and analyzed the shoulder and hip curves using the software Kineova. The resulting curve was similar but since we were designing the product for kids of age 6-12 years, we also analyze the motion curve of a 9 -year old kid. After coming up with a perfect curve, the next step was to design a mechanism that would be able to operate along this curve.

Designing A Six-bar linkage

We choose to design a six bar linkage that would operate along the motion curve of the children. For this we used a software called motiongen. All 4 of us designed and iterated one linkage per person and eventually choose one linkage that operates without failure.

Using Linear actuators to move the linkage

Once we design the final linkage, we decided to use 2 linear actuators on both side of the device to move the linkages along the shoulder curve.

Using Battery to power the device and stopper on both side for smooth operation

The device was powered by 12V rechargeable battery . We also integrated some electronics like stopper and remote control to make the operation of the device smoother and safer.

From here on, I have shared the CAD designs, FEA results, First prototype, the final product along with a you tube link to our product.

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