Upper Limbs Extension and Flexion Angles Calculation and Visualization Using Two Wearable Inertial Measurement Units

Abstract

Human motion analysis is widely used in many fields such as physical reha-bilitation, athlete training, health status diagnosis and others. Upper limb’s movement analysis is important because we need our hands to conduct daily works such as driving, eating and others. But the existed equipment can only be used to analyse the upper limb’s movement by trained personnel such as physicians or therapists. Besides, the existed system that used the cable wire for data transmission was limited their workspace to detect the upper limb motion. The objective of this research is to develop a system using multiple Inertial Measurement Units (IMU) to analyse the upper limb motion that can transfer data by using Bluetooth Low Energy (BLE) and develop a program to visualize the motion. In this research, a system had developed to measure the upper limb angle using wearable sensors. The wearable sensor we used is an Inertial Measurement Unit (IMU) which is Intel CurieNano to measure the upper limb angle. Intel CurieNano combines accelerometer and gyroscope was used as a sensor. The data from accelerometer and gyroscope were combined using the Complementary filter to get the joint angle. The IMU is connected to a program Python and the data is sent from IMU to the program through BLE. The program displayed the data and visualized the motion. The IMU is used to measure some certain angles such as 10º, 30º, 60º and 90º, and the correlation coefficient is 0.9967 with goniometer. The upper limb’s angle is measured using the system and compared the data with goniometer for determining the accuracy of the system. This system can achieve 95% of accuracy compared to goniometer.