Design of a Range of Motion Sensor for Ankle Rehabilitation Monitor

Abstract

<p>The purpose of this project is to design a convenient and cost-effective way for a physiotherapist or other health-care professional to quantitatively measure progress in the rehabilitation of a patient’s range of motion in their injured ankle in a clinical setting. Ankle injuries are one of the most common types of athletic injuries and can severely affect performance and daily functioning and proper rehabilitation is frequently necessary to recoup diminished proprioception and range of motion in the joint. Currently, no fast, cost-effective, and convenient quantitative method of tracking a patient’s improvement in range of motion in a clinical setting is available. This project attempts to accomplish this result using two bend sensing resistors embedded in an ankle sleeve along the anterior and lateral sides. These sensors have a variable resistance, which changes for each sensor when the ankle moves in plantarflexion/dorsiflexion and in inversion/eversion. The sensors are attached to a voltage divider circuit that outputs two voltages that vary relative to the changes in resistance of each sensor. The output voltages are converted to the respective angles of bend in the two different directions on the computer and are displayed on graphs vs. time on the computer. The data acquired from the sensors during an exercise specified by the health-care professional can be saved on the computer for further review and can be compared with other past results in order to gain a quantitative perspective of the patient’s improvement in range of motion over different sessions. All of these components were designed and assembled for the prototype. The prototype components of this project are all fully functioning except for the bend sensors, which produce neither precise nor accurate results, and do not function properly or consistently. Because of this, the prototype does not achieve the desired goals, but if a more precise or accurate bend-sensing product were available the design concept would function.</p>