Development of a Wireless Inertial Measurement System for Pitching Motion Analysis

Abstract

This paper presents a wireless inertial measurement system to analyze three- dimensional (3D) pitching movement of baseball. Developed wireless inertial measurement unit (WIMU) sizes 43.7×45.2×25.7 [mm], weighs 48 [g] including Lithium-Ion battery, and consists of two types of 3D accelerometers, two types of 3D gyroscopes, release sensor, a microcontroller (MCU), flash memory, and an RF module. Synchronization of start and completion of measurement procedure for plural WIMUs are wirelessly controlled by a host computer. Three-dimensional pitching form of upper limb and trunk is produced by the numerical integration of the acceleration and angular velocity. The experimental results show that 3D posture, trajectory and joint torque in overhand and sidearm throwing are successfully estimated using the proposed system.