Development of wearable motion capture system using fiber bragg grating sensors for measuring arm motion

Motion capture systems are gaining much attention in various fields, including entertainment, medical and sports fields. Although many types of motion capture sensor have been emerging, they have limitations and disadvantages such as occlusion, drift and interference by electromagnetic fields. Here, we introduce the novel wearable motion capture system using fiber Bragg gratings (FBGs) sensors. Since the human joints have different degrees of freedom (DOF), we developed three types of sensors to reconstruct the human body motion from the strains induced on the FBGs. First, a shape sensor using three fibers provides the position and orientation of joints in three dimensional space. Second, we introduce the angle sensor which is capable of measuring bending angle with high curvature using single fiber. Lastly, to detect the twisting of joints, a sensor with fiber attached on a soft material spirally is used. With the optical fiber based motion capture sensors, we reconstruct the motion of arm in realtime. In detail, the joints of the arm include the sternoclavicular, acromioclavicular, shoulder and elbow. By arranging the three types of sensors on the joints in accordance with the DOF, the accuracy of the reconstructed motion is evaluated, resulting in an average error below 2.42°. Finally, to prove the feasibility of applying in virtual reality, we successfully manipulate the virtual avatar in real-time.