HapStick: A High Fidelity Haptic Simulation for Billiards Venkatraghavan Gourishankar Govindarajan Srimathveeravalli Thenkurussi Kesavadas Virtual Reality Laboratory, State University of New York Buffalo, USA E-mail: [vg26, gks2, kesh]@eng.buffalo.edu Abstract This paper presents the work in developing a high fidelity haptic device and virtual environment for playing billiards. The haptic device features a natural user interface to simulate realistic play of billiards. The paper also discusses the physics behind the virtual reality game, the kinematics and dynamics of the force feedback device and finally an implementation of a computed torque control for providing haptic feedback. Complete information about calibration and comparative performance measures for the device has also been provided. The paper also aims to serve as a template for anyone who is interested in building their own beginner level haptic interface. Information regarding the device and the necessary code and blueprints has been uploaded on the lab’s research website to facilitate the same. 1. Introduction The computer gaming industry has made rapid technological progress over the last decade by improving visual and auditory realism of the games. This includes development of better graphical rendering techniques, physics engines with tighter storylines and art. Computer gaming and sports were amongst the first fields expected to greatly benefit with development of haptic and force-feedback technology. Haptic technology with the promise of adding further detail and realism has been touted to be the biggest thing to happen to gaming since the introduction of pong on personal computers [1]. Finally, with the introduction of hardware such as the Microsoft’s Sidewinder force feedback joystick and Nintendo’s Wii and multiple games supporting force feedback [2], it can be said that haptic technology combined with prior developments are bringing games closer to immersive experience. In spite of all these developments in gaming, the user input interfaces are still lagging in terms of intuitiveness and user friendliness. For example highly kinesthetic games such as archery or tennis require not only physical and visual realism, but also a natural haptic interface to simulate realism. Hence, the next thrust in haptics research for gaming and sports should focus on developing inexpensive natural user interfaces which will exploit the power of computer without deviating from natural game play. Such games, called pervasive games, utilize virtual and real objects and Augmented Reality (AR) to allow gamers to play in the most natural fashion [3], but such games rarely involve haptic interfaces. Earliest work on integration of games and haptics can be traced back to the development of the Impulse Engine force feedback joysticks by Immersion, Ouhyoung et al. [4] and Bae et al [5]. These groups developed different designs for a two degree of freedom force feedback joysticks. PHANToM™, developed by Sensable Technologies has also been adapted for a few gaming applications. Morris et al [6] developed the BattlePong and Andrews et al. [7] the HaptiCast. Owing to the nature of these two games (tennis and wand based magic casts) the PHANToM’s kinematic linkage lent itself to a somewhat normal game play. Other notable game using natural force feedback interfaces are the AirBat used for Airkanoid [8], Virtual tennis [9] and the Torquebar [10]. The AirBat was developed to provide haptic feedback to play in Airkanoid (a “Bricks” like game). The Torquebar was developed to provide a feedback for simulating inertia for a variety of games. In this paper, an innovative haptic interface for playing Billiards has been described. Billiards is amongst the most popular table top social games in the world. Millions of people play various forms of this game worldwide. Billiards is also amongst one of the first to be transformed into computer and arcade games and a popular version of the game is available online at [11]. Previously developed multiple AR based Billiards trainers [12, 13, 14] lack any form of force feedback. Only the billiard game developed by [17] has haptic feedback but lacks a natural human-machine interface. Second Joint EuroHaptics Conference and Symposium on Haptic Interfaces for Virtual Environment and Teleoperator Systems (WHC'07) 0-7695-2738-8/07 $20.00 © 2007