Calibration and Evaluation for Visuo-haptic Collocation in Haptic Augmented Virtuality Systems

Haptic augmented virtuality systems can provide users with a highly immersive haptic experience by visuo-haptic collocation of physical objects with their corresponding virtual objects. The collocation can be accomplished by an encounter-type haptic display system where a robotic device provides a physical prop that represents a whole or partial virtual object in real-time and in the space occupied by the virtual object in the virtual environment. For efficient and accurate visuo-haptic collocation, this paper proposes a novel yet simple, efficient and accurate calibration method. The method employs a high-accuracy position device such as an industrial robot that can place physical objects quickly and accurately. The transformation between the reference frames of the real (robot) and virtual worlds is obtained by the simple motion of the robot’s end-effector equipped with a real object that is in turn tracked by a VR tracker system such as the HTC VIVE tracker. An evaluation of the proposed method indicates that it is possible to achieve acceptable accuracy with a few data points as compared to existing calibration methods that require a large number of data points.