Author Morten Engell-Nørregård

This PhD thesis concerns itself with modelling and simulation of human motion. The research subjects in this thesis have at least two things in common.
First, they are concerned with Human Motion. Even though the models may be used for other things as well, the main focus is on modelling the human body.
Second, they are all concerned with simulation as a tool to synthesize motion and thus, get animations. This is an important point since it means we are not only creating tools for animators to make fun and interesting animations, but also models for simulation of realistic motion. As the project progressed, the focus has shifted from purely graphics oriented to something which may be at least as interesting for the biomechanics community:
The main scientific contributions of this work are:
• An efficient method for solving interactive constrained inverse kinematics problems, using an optimization based approach. The method is usable for motion planning of complex articulated mechanisms, with a large degree of interdependency between different parts such as a human body.
• A general and fast joint constraint model. The joint constraint model is well suited for modelling joints with highly non-convex limits and multiple degrees of freedom. Even though this constraint model may have many other uses we believe it is very well suited for the modelling of human joints which exhibit both non-convexity and multiple degrees of freedom.
• A general and versatile model for activating soft bodies. The model may be used as an animation tool but would be equally well suited for simulation of human muscles since it adheres to basic physical principles. Further, it can be used with any softbody simulation method such as finite elements or mass spring systems.
• A control method for deformable bodies based on the space time optimization. The method may be used to control the contraction of muscles in a muscle simulation.

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