"Proprioception," often described as the human body's "6th sense," describes one's ability to know where their body is relative to itself without additional sensation. Proprioception has been proven to be a powerful predictor of the effectiveness of physical therapy, and further, that it is a trainable attribute. For patients recovering from strokes, measuring and training proprioception is a powerful new supplementary tool to use on the road to recovery. While there is one device (the Ankle Measuring Proprioceptive Device) capable of assessing and quantifying ankle proprioception, it is large and difficult to transport, preventing clinical viability. Prospective benefactors and/or test subjects are forced to come to where the device is located to assess and research ankle proprioception. The Portable Ankle Measuring Proprioceptive Device (PAMPD) is a smaller, lighter medical device meant to be brought to clinics to train and assess a patient’s ankle proprioception.
The primary problem PAMPD addresses is the issue of size and mobility. Clinicians and researchers should be able to easily bring the device to their patients and test subjects. To quantify what it means for a device to be “portable”, the device’s weight, length, width, and height were constrained to the guidelines for a Southwest Airlines carry-on (25kg weight limit, 24”x16”x10”). Additionally, the device features an onboard computer to run the software so the device is entirely self sufficient and doesn’t need to be plugged into a separate computer.
Regarding functionality, there are two primary proprioception exercises PAMPD accommodates– “crisscross”, and “joint position reproduction”. These two exercises require the device to have two different states for each ankle– zero and infinite impedance– hence the device is considered a “bi-impedance” robot. The zero-impedance state requires the device to freely allow the patient to move their ankles unobstructed, while infinite impedance locks the patient’s movement to only what the device allows. PAMPD accomplishes this by mechanically engaging and disengaging the drive shaft with drill motor chucks.
As both an assessment and training device, the device also introduces gamification elements to both types of assessments in order to incentivize its use. These elements include scores, sprites, increasing difficulty, and pop culture theming (Star Wars).
As of the completion of Winter Quarter 2026, we have successfully created a prototype that demonstrates several key functionalities of PAMPD. First, the prototype developed proves the feasibility of making a diagnostic ankle proprioception device that is portable, shown through compliance with our requirement of a 24”x16” bounding box and 25kg weight limit. Along with its significant decrease in size when compared to AMPD, PAMPD also possesses a more streamlined and less complex user interface – particularly the addition of an on-board computer and an included monitor – that bolsters usability, and further, its clinical viability. Finally, the gamification of established proprioceptive diagnostic/therapeutic methods done done PAMPD demonstrates its ability to further the role that proprioception plays in the rehabilitation space, as its ability to incentivize continued use, along with its portability, offers patients more the chance to train more for better results.
Beyond device performance, the prototype demonstrates the feasibility of a predominantly 3D-printed construction; all load-bearing components were manufactured using FDM 3D-printing methods for early stage prototyping, however, testing proved that for many of these components, a 3D printed construction more than capable of meeting our specified static and dynamic load requirements. Along with its heavy implementation of 3D printing, the prototype utilizes exclusively off the shelf components, most notably, the use of a DC power drill to both actuate the device and provide bi-impedance capabilities. As such, PAMPD shows great promise as a low-cost, accessible method of providing proprioceptive solutions to interested clinics.