Levitating joystick improves computer feedback – tech – 04 March 2008 – New Scientist Tech:

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. This approach has “huge potential”, says Anthony Steed, a haptics researcher at University College London, UK. “This system gets rid of the mechanical linkages that are a major constraint on most haptic devices.” Six degrees of freedom The maglev interface can exert enough force to make objects feel reassuringly solid, says Hollis, resisting as much as 40 newtons of force before it shifts even a millimetre. That’s enough to feel the same as a hard surface and better than most existing interfaces, he says. “Current devices feel very mushy, so it’s hard to simulate a hard surface.” The device can track movements of the bar as small as two microns, a fiftieth the width of a human hair. “That’s important for feeling very subtle effects of friction and texture,” says Hollis.

That stiffness is good — 40 newtons is about the force of 4 kilos, and your fingers deform more than a millimeter under that kind of force. The resolution is also great, although I blench to think about the level of detailed model information that would have to be processed to make use of it.  A  10-cm-square patch at two microns would be something like 2.5 billion data points.

It’s pretty easy to distinguish textures on the 50-100 micron level, but relatively few large objects have interesting structure throughout at that level, so I bet you could get away with the equivalent of shaders and voxel maps to generate it on the fly…


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