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VR Interfaces: Levitating Haptic Stick


Overview of Levitating Haptic Stick
One of the severe problems with haptic input devices (other than the very, very basic type that jack directly into the nervous system) is that the mechanics of hand-held systems only bend or push so far, then they hit engineered limits and the feeling dissipates.

Even worn systems have problems. A haptic bodysuit can give you the feeling of touch on your tummy, chest, and back. However, they are weighty things, and make you feel like a small, bulky elephant when you are wearing one. This increased weight and restriction of movement, hardly makes them feel natural.

A new approach, being undertaken by , Ralph Hollis and colleagues at Carnegie Mellon University, us hoping to change that. They are using magnetically guided haptic elements, and have completed a prototype system.

When the controller is levitated by magnrtic impulses, both from underneath and the sides, it can provide a real feeling of force against you ? and potentially enough to push back.

A bowl with electromagnets concealed below its base contains a levitating bar that is grasped by a user and can be moved in any direction. The magnets exert forces on the bar to simulate the resistance of a weight, or a surface's resistance or friction. LEDs on the bar's underside feed back its position to light sensors in the bowl.

The prototype can resist up to 40 newtons of force before it shifts even a millimetre. To put into perspective that is stronger than the force required to open most doors. Of course, it can also move as gently as a baby, if required.

Already a leap ahead of anything else currently available in physical haptic interfaces, the prototype can track movements of the bar as small as two microns. Or, putting that into English, one fiftieth of the width of a single human hair. In other words, it is sensitive enough to create textures as well as pressures ?more sensitive than we can even feel.

To put the final nail in, it is a 6DOF device ? all six dimensions of freedom. Up and down, left and right, forward and back, pitch, yaw, and roll.

After working on a series of prototypes since 1997, Hollis has started a company called Butterfly Haptics to market the technology. The first six second-generation versions of the device will soon be shipped for testing to a consortium of several US and Canadian universities.

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