Physically-based models have been adopted widely for character animtion. Originated from robotics, biped models for character animation also took a form of robots. The robot-like biped models have joint motors, so that the motors are controlled to rotate bodies to make desired poses.
In this thesis, we present a biped model based on the biomechanical information that human movement is controlled with tensions of muscle fibers attached to skeletal structures instead of actuated motors on joints which do not even exist in a human body. With the proposed biped model, we designed a locomotion tracker that follows given motion trajectories by optimizing the muscle fiber tensions.