Live Control of a Physically Plausible Virtual Biped, Using the Kinect

Abstract

With the availability of affordable motion capture solutions, like the Microsoft Kinect, live data-driven control of a virtual character has become more relevant. In order to provide both intuitive control of a virtual biped, as well as grounding that character in the virtual environment, we propose a system for real-time control of a physically plausible virtual biped using the Microsoft Kinect sensor. In order to deal with the varying skeletal dimensions present in Kinect data, we propose an inverse kinematics based real-time data processing method, which avoids positional errors of the limbs in the virtual character, while maintaining the pose present in the Kinect data. In order to allow for arbitrary in-place motions to be performed by the physically plausible character without losing balance, we combine proportional derivative controllers with a simple balance strategy that controls the center of mass of the character by rotating the ankle joints. Experimental results show that with a limited range of balanced in-place motions, our system is able to reproduce these motions with the physics simulated character in close to real-time. Our system achieves this using solely physically plausible internal torques and using the Kinect data stream as its only motion data input.