User-controlled physics-based animation for articulated figures

We present a physics based system for the guided animation of articulated figures. Based on an efficient forward dynamics simulator we introduce a robust feedback control scheme and a fast two stage collision response algorithm. A user of our system provides kinematic trajectories for those degrees of freedom (DOFs) of the figure they want direct control over. The output motion is fully generated using forward dynamics. The specified motion trajectories are the input to a control system which computes the forces and torques that should be exerted to achieve the desired motion. The dynamic controllers, designed based on the Model Reference Adaptive Control paradigm, continuously self adjust for optimal performance in trajectory following. Moreover, the user is given a handle on the type and speed of reaction of the figure's controlled DOFs to sudden changes in their desired motion. The overall goal of our system is to provide a platform for generating and studying realistic, user controlled motion at interactive rates. We require minimal user involvement in specifying non intuitive parameters.