For their senior cap­stone design project, a group of mechan­ical engi­neering stu­dents cre­ated a pros­thetic limb designed to help amputee agri­cul­tural workers operate tractors.

The pro­to­type, dubbed the “farm arm,” fea­tures a pros­thetic ter­minal device and set of adap­tors that can be switched in and out to match the con­trols being oper­ated. The design, the stu­dents said, elim­i­nates the need for a grasping mech­a­nism and can be uni­ver­sally used.

Our design emu­lates where the hand would be at the point of inter­face with the tractor con­trols,” said Andrew Waite, E’15, one of five stu­dents com­prising the cap­stone team.

Farm acci­dents are two and a half times more likely to end in ampu­ta­tion than any other injury, and 11 per­cent of all farm acci­dents involve ampu­ta­tions, according to the Farm Injury Resource Center. The stu­dents noted that, despite the high rate of ampu­ta­tion in the agri­cul­tural industry, pros­thetic options often fall short in utility and dura­bility. What’s more, workers in this industry are often geo­graph­i­cally iso­lated, which makes fit­ting and training them for pros­theses chal­lenging, they said.

These fac­tors inspired the stu­dents to design a solu­tion: a pros­thetic arm and adapter that are robust, ergonomic, adapt­able, and can be easily used to engage throttle levers, hydraulic levers, joy­sticks, and steering wheels.

Andrew Waite, left, and Jonathan Leydon, both E'15, demonstrate their capstone project. Photo by Matthew Modoono/Northeastern University.

Andrew Waite, left, and Jonathan Leydon, both E’15, demon­strate their cap­stone project. Photo by Matthew Modoono/​Northeastern University.

The students—Waite, Jacob Cohen, Carly Gajewski, Jonathan Leydon, and Daniel Walsh, all E’15—presented their design in December. Their pro­to­type fea­tures an alu­minum body, a tita­nium end piece, and 3-​​D printed adapters. Now they are refining their design, assessing man­u­fac­turing options, and exploring dif­ferent paths for taking their device to market.

To prop­erly frame their design for end-​​users, the stu­dents estab­lished and main­tained con­stant con­tact with sev­eral pros­thetics experts, industry leaders, and orga­ni­za­tions that work with dis­abled farmers. Late in the project, this led to a key oppor­tu­nity to test their device with a farmer in Rum­ford, Maine, who had lost part of his right arm. He used the “farm arm” on his own tractor, and then pro­vided valu­able feed­back on what worked well and offered sug­ges­tions on how it could be improved.

That’s when the project really came together,” Walsh said. “It pro­vided a good oppor­tu­nity for proof of con­cept and to val­i­date our design.”

The stu­dents noted that their cap­stone project ben­e­fited from their co-​​op expe­ri­ences. Walsh, for example, received reg­u­la­tory training while on co-​​op at Johnson & Johnson, an expe­ri­ence that helped inform the group’s knowl­edge of how to bring their device to market. Cohen’s work on the cap­stone project focused pri­marily on mate­rials research, which was informed in part by his co-​​op at NxStage Med­ical, where his work involved researching, designing, and working with parts for var­ious med­ical devices. Gajewski, for her part, worked on co-​​op at the Center for Tech­nology Devel­op­ment at Mass­a­chu­setts Gen­eral Hos­pital, where she got hands-​​on expe­ri­ence assem­bling a pro­to­type for a novel med­ical diag­nos­tics system. That work trans­lated to her team’s cap­stone, for which she focused on the bio­me­chan­ical aspect of the design process, exam­ining fac­tors such as the operator’s body motions in the tractor cockpit and the ergonomics asso­ci­ated with using the controls.

All five of us drew from our co-​​op expe­ri­ences for this project,” Waite said.

Photo by Matthew Modoono/Northeastern University.

Photo by Matthew Modoono/​Northeastern University.