I was the lead designer for the BURT project at Barrett Technology. This neurorehabilitation robotic arm assists individuals with stroke, traumatic brain injury, and other neuromuscular disorders relearn how to use their upper extremities. I was involved in all aspects of the design process, including user observations and collaboration, specification development, iterative prototyping, mechanical design for manufacturing, and testing.

We began the project in mid-2012 with visits to Braintree Rehabilitation Hospital and the Rehabilitation Institute of Chicago to observe and interview patients, therapists, and researchers using traditional and robotic neuro-rehabilitation therapies. Coupled with many hours of research on neuromuscular conditions and competitors’ products, I came up with design goals: the robot must accommodate 95% of patients and wheelchairs without special setups, setup for a new patient had to take less than 5 minutes, it must cost significantly less than our competitors, it must easily move from room to room, it must be as safe to use as possible, and it must look attractive and inviting to use. We then selected a kinematic configuration and built an adjustable mockup to test out the proper link lengths, and I calculated maximum expected forces on the robot. With these quantitative and qualitative specifications defined, and with my prior knowledge of the design of a cable-driven robot from my work with the WAM Arm (also a Barrett Technology product), I began mechanical design. Among the tools I used to design were brainstorming sessions, paper sketches, spreadsheets, SolidWorks, FEA analysis, designed experiments, prototypes built of stock and 3D-printed parts, user tests with therapists and researchers, and many design reviews. I loosely progressed from sketches to calculations to CAD design to prototypes, but I modified this process based on the complexity and the design risk of each assembly.

Early sketch of arm cradle

Early sketch of arm cradle

Early prototype of arm cradle

Final cradle design

I also worked with electrical engineers to specify the functionality of circuit boards in the design and with software engineers to translate the needs of patients and therapists into specifications for games and interfaces. Through the complexity and scale of this project, I learned a great deal about user design, industrial design, mechanical design, and interdisciplinary projects.