Interactive Rigid-Body Dynamics and Deformable Surface Simulations with Co-Located Maglev Haptic and 3D Graphic Display

We have developed a system which can combine realtime dynamic simulations, 3D display, and magnetic levitation to provide high-fidelity co-located haptic and graphic interaction. Haptic interaction is generated by a planar horizontal array of cylindrical coils which act in combination to produce arbitrary forces and torques in any direction on magnets fixed to an instrument handle held by the user, according to the position and orientation sensed by a motion tracking sensor and the dynamics of a realtime physical simulation. Co-located graphics are provided by a thin flat screen placed directly above the coil array so that the 3D display of virtual objects shares the same volume as the motion range of the handheld instrument. Shuttered glasses and a head tracking system are used to preserve the alignment of the displayed environment and the interaction handle according to the user’s head position. Basic interactive environments have been developed to demonstrate the system feasibility and operation, including rigid bodies with solid contacts, suspended mass-spring-damper assemblies, and deformable surfaces. Interactive physical simulation of these environments requires real-time collision detection between geometric models; numerical, discrete-time numerical integration to calculate the physics of networks of mass, spring, and damper elements; and calculation and actuation of interactive forces to the user in haptic rendering. Incorporating these functions into a single executable requires multiple program threads with various update rates, ideally performed using a multicore processor PC. Details and discussion of various simulations are given with experimental results. Keywordshaptics, interaction, simulation