Air-Vortex Generators for Propulsion and Haptic Feedback in a ZeroG, Week 1

For my MS Thesis, I developed a multimodal interactive interface platform with free-space haptic feedback, which used air-vortex generators for delivering the haptic stimulus. More details about that project can be found in my thesis and in my CHI’18 publication. During this semester, I will be extending the aforementioned project in two ways, which take advantage of the unique gravitational environment offered during a Zero-G flight.

First, I will be testing and quantifying the haptic feedback offered in the unique accelerational conditions offered during the flight. As of this writing, no research exists on the use of toroidal vortices for haptic feedback in a noninertial reference frame. In an inertial reference frame, we know how vortex rings propagate and the kind of haptic feedback they can deliver when the generating device is optimized for this purpose. But in an accelerating frame of reference and especially during the times when there are changes in the gravitational acceleration, the system would behave very differently. During the times of |(dg/dt)| > 0, we don’t know what the trajectory of the rings would be relative to the observer and for how long one would be sustained - because of competing effects.  If we were firing pellets, we could easily calculate what motion those pellets would take because the effects of the air resistance could be largely ignored and only dg/dt needs to be considered. However, because we are firing a ring of air through a medium of air we have to also consider the competing factor that the surrounding air wants to maintain the direction of motion of the ring unchanged relative to the nozzle. To dest these properties, I envision having a box inside of which a vortex generator will be placed on one end of the box, and it will be actuated at a constant rate for at least several minutes, if not during the entire duration of the flight. At the other end of the box, I will have a device that measures the impact force each vortex ring that hits the surface of the device. Moreover, I may introduce a color pigment into the generator or steam, so that the propagation trajectory can be visualized and recorded by a video camera. There will be at least two IMUs, so that we know exactly at which point during the parabolic flight are the events inside the box happening. This part 1 of the project will take full advantage of the conditions afforded during the zero g flight. In particular, observations, data, and experiences will be recorded not only during the moments of microgravity but also of the other three unique moments; namely hypergravity, and the two transition periods - from microgravity to hypergravity, and from hypergravity to microgravity.

Second, I will be developing a vortex generator in a wearable form-factor and testing its viability as a propulsion device. There is a recoil when the vortex ring leaves the chamber, and my hypothesis is that we can use this to propel people or other objects in the microgravity environment, where very small forces are sufficient for this purpose. This would enable the wearer to move in any desired direction by pointing the device such that the nozzle faces in the opposite direction, and rapidly firing the device multiple times per second. Additionally, in the case where tiny generators are affixed to an object, the same recoil principle could be used for remotely moving that object in a risk-free and very finely controlled manner because the duration of each pulse is only a few milliseconds. This method could be used for both translational and rotational motion to enable very fine positioning of objects in an indoor microgravity environment.

There are also several uniquely-zero-g games that could be developed using a wearable air-vortex generator. One such game is 3D soccer, where a ping pong ball and two goals are used. The rules of the game are that one cannot touch the ball, and the ball cannot touch any surface when in the ‘field’. The only way to steer the trajectory of the ball is to shoot at it using vortex generators that are worn by on the players’ hands.