Three-dimensional human kinematic estimation using magneto-inertial measurement units

Abstract

This chapter deals with the estimation of human kinematics using magneto and inertial sensing technology. A magneto-inertial measurement unit typically embeds a triaxial gyroscope, a triaxial accelerometer, and a triaxial magnetic sensor in the same assembly. By combining the information provided by each sensor within a sensor fusion framework, it is possible to determine the unit orientation with respect to a common global coordinate system. Recent advances in the construction of microelectromechanical system devices have made possible the manufacturing of small and light devices. These advances have widened the range of possible applications to include areas such as human movement. This chapter aims at providing the reader with a picture of the state of the art in the measurement and estimation methods for the description of human joint kinematics using magneto-inertial sensing technology. In the first section, fundamental concepts of rigid body kinematics are introduced with special reference to magneto-inertial measurements. Then a short description of the operationalcharacteristics of accelerometers, gyroscopes, and magnetometers is provided. The third section reports theory and methods for the estimation of the orientation and position of magneto-inertial measurement units along with the implementation of a Kalman filter for 3D orientation estimate as an example. In the last section, a critical review of the most common methodologies for the joint kinematic estimation is reported.