Abstract-This research creates a steady headwind at a user position in the scaled Treadport Active Wind Tunnel (TPAWT). The TPAWT adds a wind display system to the previously developed Treadport virtual environment, and this research builds upon prior work to provide improved control of headwind angle at the user position. Key to this research is the addition of a negative pressure plenum at the rear of the treadport to improve nominal flow stability. The previous controller based upon the small gain theorem with a dynamic extension is then modified to provide wind angle feedback control. A conditional angular rate-switching controller is added to reduce wind angle oscillations at the user. A vorticity-meter is developed to assure that the wind flow is centered at the user position. As a result, this research reduces wind angle error by 75% compared to previous work.
This paper presents the Treadport Active Wind Tunnel (TPAWT)-a full-body immersive virtual environment for the Treadport locomotion interface designed for generating wind on a user from any frontal direction at speeds up to 20 kph. The goal is to simulate the experience of realistic wind while walking in an outdoor virtual environment. A recirculating-type wind tunnel was created around the pre-existing Treadport installation by adding a large fan, ducting, and enclosure walls. Two sheets of air in a non-intrusive design flow along the side screens of the back-projection CAVE-like visual display, where they impinge and mix at the front screen to redirect towards the user in a full-body cross-section. By varying the flow conditions of the air sheets, the direction and speed of wind at the user are controlled. Design challenges to fit the wind tunnel in the pre-existing facility, and to manage turbulence to achieve stable and steerable flow, were overcome. The controller performance for wind speed and direction is demonstrated experimentally.
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