Simple Feedforward Control for Responsive Motion Capture-Driven Simulations

Abstract

Abstract. Combining physically based simulation and motion capture data for animation is becoming a popular alternative to large motion databases for rich character motion. In this paper, our focus is on adapting motion-captured sequences for character response to external perturbations. Our technique is similar to approaches presented in the literature, but we propose a novel, straightforward way of computing feedforward control. While alternatives such as inverse dynamics and feedback error learning (FEL) exist, they are more complicated and require offline processing in contrast to our method which uses an auxiliary dynamic simulation to compute feedforward torques. Our method is simple, general, efficient, and can be performed at runtime. These claims are demonstrated through various experimental results of simulated impacts.

Interactive Character Animation Using Simulated Physics: A State‐of‐the‐Art Review

“…The motivation for this approach comes from evidence suggesting that biological systems use feed‐forward control for most of their motions and use feedback control only for low‐gain corrections [TSR01]. In physics‐based animation, feed‐forward torques have been acquired through optimization [GT95], inverse dynamics [YCP03], feedback error learning (FEL) [YLvdP07], and by using an on‐line parallel auxiliary simulation of unperturbed motion capture data with high‐gain tracking [NVCNZ08].…”

Tunable Robustness: An Artificial Contact Strategy with Virtual Actuator Control for Balance

“…Control research for simulation often presents important trade‐offs between controller robustness and simplicity, as well as computational cost and interactivity. Further, in physics‐based synthesis for animation, issues of controllability can be at odds with naturalness, especially as simulated character control systems can be instrumented to include ‘super‐human’ components like perfect sensors, zero latency (or even perfect prediction [NVCNZ08]), as well as infinite strength. As simulated characters become more supernatural , they can become arbitrarily robust.…”