Orientation tracking for humans and robots using inertial sensors

Joint angle determination for robots with flexible links can be difficult. Inertial orientation tracking combined with RF positioning provides an accurate method for determining end effector orientation and location. The same technology could also be used to determine human posture for the purpose of inserting humans in synthetic environments. Orientation filters based upon Euler angles suffer from singularities. This paper describes the design, implementation, and preliminary testing of an inertial tracking system using a "complementary" filter based upon quaternions. This filter is capable of tracking a rigid body through all orientations and is more efficient than those based on Euler angles. Results of qualitative tests of a prototype inertial angle tracking device are presented.