Case Study

Student project uses Solid Edge to help disabled children

Saginaw Valley State University

Feeding device cut meal eating assistance by 75 percent

Disabled children are more independent at meal times thanks to the work of engineering students at Saginaw Valley State University and their design software, Solid Edge®. Senior mechanical engineering students at Saginaw Valley State University used the design software, Solid Edge, to create a robotic device that helps disabled children feed themselves. When using the automatic feeding system, a child with severe physical limitations is able to perform 75 percent of the tasks involved in eating a meal. Without it, he is completely dependent on others. “Someone must still prepare the food, but the device allows much more independence at meals,” says Mike Woodley, one of the students who worked on the project.

The feeding device was the result of a two-semester design sequence at the university, located in University Center, Michigan, near Saginaw. Woodley and fellow students, Adam Walls and Jason Alderson, took on the challenge of designing the device during the first semester and then building a working prototype during the second semester. The idea came from the nearby Millet Learning Center, a school for children with moderate to severe physical disabilities as well as for the medically fragile. Occupational therapists at the Millet Learning Center had actually approached the engineering students’ advisor, Dr. Brooks Byam, five years earlier with the request for a feeding system that would be less expensive than what was available at the time. Byam says he was “waiting for the right group of students,” to take on a project of this magnitude, and adds that “these guys (Woodley, Walls and Alderson) were it.” Their final grade was to be determined in part by the success of the device, which would be tested by nine-year-old Zachary Kischnick, a student at the Millet Learning Center whose cerebral palsy prevents him from eating by himself.

The existing system cost approximately $3,500 and the therapists at Millet Learning Center were hoping for something more affordable since most insurance doesn’t cover this type of equipment. “We faced the challenge of a complex design task because the device required a lot of moving mechanisms in a small space, light weight, low noise output and at a much lower cost than what’s on the market,” says Woodley. “Solid Edge handled the complex design requirements with ease.”

Self-taught solid modeling

The engineering students had learned enough about mechanical design to know that solid modeling was the tool of choice for a complex assembly such as the feeding device. “We wanted to be able to visualize what we were doing, both for our own sake during the design, and for presentations,” says Woodley. “With solid modeling, we could make sure we didn’t have interferences, and that things like bolt holes lined up, far better than we could with a 2D system. And solid modeling would give us nice visuals to use in our final presentations, which are a big part of the grade.”

As students at Saginaw Valley State University, Woodley, Walls and Alderson had access to the solid modeling program, Solid Edge, but they had not used the program before taking the senior design sequence. They each taught themselves how to use the software by following the tutorials that came with it. “Solid Edge has great tutorials. I learned how to use Solid Edge in about two days and it was like that for everyone I knew,” says Woodley. He notes that the previous year, some engineering students had designed a race car in Solid Edge, “every single part, every bolt, screw, washer. Those students came in, did the tutorials and used Solid Edge to design an entire car.”

Once Woodley and his team were comfortable with the software, they began building the feeding device as an assembly of solid objects. The software had no trouble handling an assembly of that complexity, and every piece of the device was included in the Solid Edge assembly model. As they worked, the students found many features of Solid Edge to be helpful. The software’s sheet metal modeling environment was particularly useful for the brackets within the device, according to Woodley. “Solid Edge was great because it automatically unfolded the parts, and we could use the Solid Edge data to cut parts with a CNC mill.”

Woodley took advantage of Solid Edge interoperability with the finite-element analysis software, DesignSpace from Ansys, to check his engineering calculations. “That worked perfectly. There wasn’t a hiccup in going between the two programs,” he notes. He and his teammates also appreciated how Solid Edge automatically calculated mass properties. “Some of our parts were oddly shaped and to calculate things like the moment of inertia or the radius of gyration would have been very difficult to do by hand,” he explains. Mass properties information was important for determining things such as the inertia of a gear.

The visualization capabilities of Solid Edge were well used in this project. The students used solid models and animations in their presentations to the Millet Learning Center Center. Then, for their final presentation, they created a fly-around that showed all the complexities of the final assembly in a dramatic way. The fly-around was the last part of their presentation – a strategic move on the students’ part. “At the end of the presentation the faculty members ask you questions. Having that fly-around sort of got the focus off us,” Woodley says.

The most important audience was Zachary, however, who now uses the device regularly. He activates it by a protruding lever that was customized for him. The lever activates a spoon which scoops food from a plate and slowly brings it toward his mouth. It stops right at the point where his lips can reach it. The device has been so successful for him that his occupational therapist says he now needs help with only about 25 percent of meal-time tasks.

The students built the prototype for a cost of $1,200 and believe that with further work they could get the cost down closer to $900. Some other specifications: the device weighs less than 22 pounds, the noise it produces is lower than 30 decibels and it is powered by either a 110-volt current or a battery. For the three students who took on this project, there was much satisfaction in creating something that has such a beneficial application. They got close to Zachary in the process, and he to them. Another nice outcome for the engineering students was the opportunity to use Solid Edge. “It’s a great package and I’m incredibly grateful I got to work with it,” concludes Woodley.

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