Sit-to-Stand Assistive Walker
This project is a year-long design effort in which our team develops a medical device to address a defined clinical need, and performs the appropriate qualification testing to validate its safety, functionality, and effectiveness. Our team’s project focuses on improving the stability of standard walkers during the sit-to-stand transition, addressing an existing challenge for individuals with limited lower-limb strength and balance control.
Investigating Clinical Needs
While investigating clinical needs in mobility assistance, our team met with staff at the Healthy Home Lab, a model home environment used for testing and developing assistive devices. To better understand what solutions already existed and how they addressed user needs, we toured the facility and spoke to an R&D Engineer and Project Coordinator. We were able to observe and handle a range of assistive devices, gaining insight into their design considerations, mechanisms, and limitations. This experience helped inform our understanding of the current state of assistive technology and guided our approach to identifying areas for improvement in our own project.
Refining the Project Topic
We began the design process by broadly exploring various categories of transfer devices. However, after conducting background research and receiving feedback from clinicians as well as input from our peers during the class-wide brainstorming session, we decided to focus our efforts on modifying an existing common walker. When used in its current form as a transfer device for the sit-to-stand movement it carries the risk of destabilizing and harming the patient.
Each of our team members sketched a number of potential solutions which we showed to clinicians in order to gain feedback during the design process. This feedback was especially valuable because we were able to discuss the differences between the "best practices" Nurses and PT's teach their patients for performing functional tasks, vs. the tendencies patients exhibit in real world settings that can increase the likelihood of the patient losing balance or falling.
Prototyping
Our first prototyping session consisted simply of PVC piping and duct tape, allowing us to experiment with the placement of handles and support feet. More than anything this allowed us to better understand the ergonomics of the functional task, and gain intuitive insight into the weight distribution and forces applied during the movement.
Moving Towards Retractable Solutions
A key aspect of making this assistive device functional without creating additional hazards is the ability to retract the support leg, such that it does not catch on loose ground surfaces like carpets or interfere with normal gait in any way. These are models I designed in SolidWorks as one of the solutions which will help us understand which direction to move forward regarding this feature. We aim to use 3D printed models such as these, and others developed by our team in order to test the mechanical function of the device before moving our best solutions into higher resolution materials like steel and aluminum which are appropriate for thorough load testing.
Our team continued to iterate using PVC piping as a base material, arranging it into different configurations and developing custom 3D printed pipe joints and footpads. This allowed us to execute real time testing where a number of different arrangements could be investigated for their affects on the stability of the walker. Each of us simulated the condition of a patient by testing the device while limiting the reliance on our legs while attempting the functional movement.
