A goal of virtual reality is the simulation of the physical world and convincing displays of the simulation. Although progress has been made in developing visual, auditory, and haptic displays, virtual environments are still generally unconvincing. One hypothesis is that a totality of sensory effects is necessary to create a realistic sense of immersion, including atmospheric effects such as wind, smell, and radiance, yet there has been little systematic research on incorporating such effects. In this project, the PI and his team will create the Treadport Active Wind Tunnel (TPAWT), a 3D wind display enhancement for the Treadport locomotion interface, which comprises a large tilting treadmill, a CAVE-like visual display, and an active mechanical tether attached to the torso. Taking into account geometrical constraints such as the presence of frontal screens, a system of controlled directional vents will be placed around a user. Air will be discharged from the vents using a dedicated programmable air-handling unit. Flows will be precisely mixed, based on model reduction techniques, and controlled to produce a sensation of wind from any direction and up to speeds of 20 mph. Nonlinear feedback controllers will be devised to sense and regulate airflow near a user. Odors and chemicals will be displayed to users by injection into the airflow system, while infrared lamps arrayed in the ceiling will generate radiant heat. The PI expects the integration of 3D wind and olfactory capabilities into the existing Treadport system to reinforce the graphical, auditory and locomotion effects will result in a new degree of realism in the immersive virtual reality interface. To test out and fine-tune the system, wind generation will be incorporated into an urban virtual environment, which includes pedestrians and cars generating noises and smells. The simulation of the magnitude and direction of the wind, as well as the dispersion of odors or air-borne chemicals, will be based on the QUIC (Quick Urban & Industrial Complex) dispersion modeling system, which provides fast simulation of the flow field around buildings and the concentration fields of chemical plumes. One experimental application will relate to developing methods for tracing the source of noxious chemicals released into the environment. With a real-time wind and plume dispersion simulation, response and training scenarios can be developed. Small mobile robots with chemical sensors can be placed on the treadmill to track plumes using algorithms that take into account wind direction, wind speed and local concentrations.
Broader Impacts. The generation of 3D airflow is a new research topic, which will allow realistic wind and olfactory displays for virtual environments, and offer an alternative to traditional wind tunnels by placing airflow at a local region of interest without immersing a whole structure, and by simulating meandering wind. By simulating plume dispersion of chemicals around city structures, training and emergency response scenarios can be developed for the release of chemical agents into the atmosphere. The research adds fluid mechanics and control to the already highly interdisciplinary Treadport project that also includes psychology, biomechanics, robotics, and computer graphics, and will result in the training of a sizable number of graduate students competent to conduct interdisciplinary research.
