A Wireless Motion Capture System for Shoulder Rehabilitation based on RFID Passive Tag Antenna Array

In this paper, a home-based wireless motion capture monitoring system for graded Range of Motion (ROM) Arc device of shoulder rehabilitation using ultra-high frequency (UHF) radiofrequency identification (RFID) at 920 MHz is proposed to realize self-service rehabilitation from 0 degrees to 180 degrees. This device applies to emerging 5G telemedicine, eliminating the need for manual monitoring. Using an array of 11 passive UHF RFID tags, each tag is labeled and represents a 15-degree angle along the arc. The tag's Received Signal Strength Indicator (RSSI) variations from tag backscattering response are used to determine the degree of the patient's shoulder motion. An experimental prototype with the user interface is built based on conventional ROM, where the patient's shoulder motion can be automatically captured for further analysis by a therapist. From the experiment, we determined the degree of the patient's shoulder motion mapping average 35 dB RSSI variation from -80 dBm (with full hand contact) to -45 dBm (without hand contact) averaged.