User-controlled physics-based animation for articulated figures

Abstract

We present a physics based system for the guided animation of articulate figures. Based on an efficient forward dynamics simulator, we introduce a robust feedback control scheme and 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 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 use 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.

A Generalized Framework for Interactive Dynamic Simulation for MultiRigid Bodies

“…Isaac [4] is an ongoing project aimed at extending VR into the realm of multibody dynamics, focusing on unifying existing major technologies in geometric modeling, model-driven dynamic simulation, collision handling, motion control, sensory feedback, knowledge representation of the environement, planning, and computational modeling. There are also a number of efforts which specifically focus on human body simulation by developing dynamic control algorithms that deal with realistic human motions [15], [16]. Also, [17] uses various control methods to implement a physics-based torso simulation for humanoid robot, and applied to the task of performing a continous sequence of smooth movements by articulated agents.…”

Motion capture-driven simulations that hit and react

“…Kokkevis, Metaxas, and Badler use a model reference controller and simulation to modify keyframed data based on gravity or external forces such as a large impulse that knocks over a soldier [Kokkevis et al 1996]. Oshita and Makinouchi use a tracking controller and simulation to show a character responding to a mass being dropped on his back [Oshita and Makinouchi 2001].…”

Virtual Humans for Animation, Ergonomics and Simulation

“…In a motion synthesizer, a small number of parameters control a much greater number of joints, for example: end effector position and orientation can control joints along an articulated chain [46,25,44], a path or footsteps can control leg and foot rotations through a locomotion model [16,24], a balance constraint can be superimposed on gross body motions [3,24], dynamics calculations can move joints subject to arbitrary external and internal applied forces [26,30], secondary motions can enhance a simpler form [33,19].…”