Upper body motion measurement system and upper body motion measurement method

An upper body motion measurement system comprising:

• at least one central processing unit comprising
• a plurality of inertia sensor units, each of which includes a set of an angular velocity sensor that detects an angular velocity and an acceleration sensor that detects an acceleration and which are attached to places that are different from each other on an upper body of a subject;
• a sensor unit attitude estimating unit configured to estimate an attitude of each of the inertia sensor units in a motion environment of the subject based on a detection value of an angular velocity and a detection value of an acceleration indicated by detection outputs of the angular velocity sensor and the acceleration sensor of each of the inertia sensor units attached to the upper body of the subject;
• a sensor unit acceleration estimating unit configured to estimate an acceleration of each of the inertia sensor units observed in a global coordinate system set in the motion environment of the subject based on a detection value of an acceleration indicated by a detection output of the acceleration sensor of each of the inertia sensor units attached to the upper body of the subject, and the attitude of each of the inertia sensor units estimated by the sensor unit attitude estimating unit;
• and
• an upper body angular acceleration estimating unit configured to estimate an angular acceleration of the upper body of the subject observed in the global coordinate system based on a set of accelerations estimated by the sensor unit acceleration estimating unit on each of the plurality of the inertia sensor units.