Steady Stride : The Tremor Resistant Cane
Cornell DEBUT (Cornell University)
Situation
Evolve the concept for a novel tremor-resistant cane into a feasible design that is testable with Parkinson’s patients
Assemble the testing methodology and equipment for proving the efficacy of the product
Present product specifications for investors and grant-providers at NIH and other MedTech organizations
Outcomes
Defined relevant mechanical response with a 300+ line MATLAB simulation to optimize hand tremor dampening
Create a successful alpha-prototype with Parkinson’s patients in IRB-approved clinical trials at SUNY Cortland Biomechanics lab, proving ~12% reduction in experimental tremor amplitude
Design a successful minimum-viable product and received quotes from low-volume manufacturers for +5 urethane casted components
Lead creation of investor pitch presentation and script for the Medtronic BMES 2024 Student Design Competition, and won 1st Place ($2,500)
Relevant Skills
Mechanical Simulations in MATLAB/ ANSYS, IRB Clinical Trials, Mechanical Design in Fusion360, Coding Testing Equipment in C/Python Human Factors Design, Rapid Prototyping, Creating Investor Pitches, Engineering Communication/ Presentations
Background (pre-DV Designs)
Cornell DEBUT is an undergraduate biomedical engineering entreprenuerial product development group affiliated with Cornell University. Our group dedicates two years towards market discovery, early-stage ideation, and basic clinical testing to submit novel products for the DEBUT VentureWell grant as a part of the National Institute of Health (NIH).
I was recruited following the market discovery phase isolated the distinct need for devices stabilizing gait for stage II and III Parkinson’s Patients, where my expertise in mechanical design lead played majority in leading the alpha prototype design process.
The basic principles of an assistive walking device were defined by the team at this point: design a cane with an integrated hand tremor dampener to reduce instability, and integrate more robust treading to improve contact with the ground.
Alpha Prototype Design Phase
Tuned-Mass Damper Simulations (MATLAB)
Improved tremor resistance is achieved by adapting tuned-mass damper (TMD) technology from similar Parkinson’s Disease devices (YouTube video on TMD here). Optimization of the tuned-mass damper was conducted by solving the ordinary differential equations (ODEs) associated with the mechanical response from a Parkinson’s hand tremor (for more information, please see the “Simulation Documentation (.PDF).” This is completed with ~350 lines of MATLAB code, which calls a preset mass and spring variables, and stores the values of position in a mutable array, and the average residual in another. After the simulation is computed, two graphs are created:
Graph #1: With a chosen spring and mass value, the displacement of the cane over time (2D-graph of displacement vs. time)
Graph #2: All discrete combinations of spring-mass values and the average residual of simulation (3D graph of mass (x), spring constant (y), and average residual (z))
Images of example outputs are presented at the end of the section
Mechanical Design and Assembly (Fusion360)
Following confirmation through the mathematical modeling, the next steps involved creating more specific designs for the components. Referencing an ideal spring and mass combination from the previous model, in addition to some prior concept sketches, I designed the current iteration of the integrated tuned-mass damper with the tremor-resistant cane.
Additionally, I designed the stabilizing base for in-field experimental testing, implementing flexible TPU as the main material. After all components were sourced from McMaster-Carr and designed in Fusion360, parts were FDM-printed with a Stratasys F170 and assembled with a stock cane from Amazon.
Images of the printed and assembled alpha prototype are provided at the end of the section.
Clinical Testing (IRB-Approved)
After filling for IRB-approval at the start of 2024, our team began developing the final prototype for patient use and design some experimental testing equipment. The final prototype utilized in patient testing is shown in the video, and usage is demonstrated by me. With a functioning design, I created an accelerometer-based sensor connected to a TPU arm-strap to record relative changers in hand tremors. With data acquired from testing at SUNY Cortland’s Kinesiology Lab, I filtered and analyzed the data in MATLAB, determine between a 12-15% decrease in relative hand tremor amplitude for 3 out of 4 of the patients in the direction of tremor propagation.
Individual graphs and data points are not included to avoid any violation of health data confidentiality. Sampling code methods is provided below, and please feel free to reach out with any additional questions about clinical testing and results!
Beta Prototype Design Phase
After completing clinical trials, our team compiled our findings and additional resources into a DEBUT VentureWell report and a BMES/Medtronic Student Design Competition submission. After being selected as a finalist for the BMES/Medtronic Student Design competition, I directed the transition of SteadyStride from a research project into a minimum viable product. One of the major directives I lead was developing the pitch deck utilized for the conference, which included branding, economic projections, and full-design renderings. Additionally, I lead developments to overhaul the experimental design of the original prototype (“works like”), into a more realistic minimum viable product (“looks like, works like”). Compared to the previous cane that was comprised of 4 major individual PLA components that were difficult for manufacturing, I spread headed articulating the individual parts and optimizing with DFM and supply chain logistics in mind. The final result was a more sleek and non-obstructive design that was more in-line with our mission statement for the device
Below is the slide deck utilized for the BMES/ Medtronic Student Design Competition and all future communications with potential investors. Additionally, excerpts from the slide deck are embedded into the website to provide context on the content
