Orientation Capture of a Walker’s Leg Using Inexpensive Inertial Sensors with Optimized Complementary Filter Design

Abstract

Accelerometers and gyroscope are often referred to as inertial sensors. They detect movement and are used for motion tracking systems in many fields. In recent years they have become much smaller, lighter and cheaper which makes them attractive for use in consumer electronics. The goal of this research is to use all these advantages to create a cheap, low cost and accurate motion tracking system. The system that will be developed is using two pairs of accelerometer + gyroscope sensors which communicates with an iOS device using BLE. The sensors are attached to a persons leg to capture the orientation of the leg while walking or running. Studying the movements of a persons leg can be useful regarding both performance and health aspects. To create the system, usage of inertial sensors and how to combine their data using the complementary filter have been studied. Further, several experiments were made to optimize the filter design for this kind of movement. The results shows how the orientation estimation differs in accuracy depending on different values of how the filter is designed. However, by using the right values, a fairly accurate orientation of the leg can be estimated which is proved by the simple visualization of the iOS application.