Haptics: Material Identification

Haptics. Our sense of touch. It’s how we interact with our world, and soon it might be part of the way we interact with virtual worlds. Think about this, our hand typically has a resting temperature between 25 and 36 degrees Celsius (That’s 77 to 97 degrees Fahrenheit). Usually warmer than the world around us. Because of this, when you touch an object heat is conducted away from your hand, causing what is a measurable temperature change.

H- Ho and L.A. Jones at the department of Mechanical engineering at MIT attempted to replicated this heat flux that we experience through what we can call a thermal display.

If you can mimic the same temperature change on this display as one would experience from touching the real world material then an accurate virtual representation of touch can be created

In this case a peltier device was used to cool a surface down to an exact temperature in an attempt to mimic the thermal properties of a given material. in order to test their display H. Ho LA jones asked test subjects to familiarize them selves with real world objects such as copper, steel, granite and foam. They would then attempt to identify said objects on a thermal display . Results were promising, showing that the identification of real world objects was very similar to that of the display.

If you remember from a previous video, or sense of temperature is spatially low resolution – one finger is not capable of detecting multiple simultaneous changes in temperature – Therefore there is little advantage to building higher resolution temperature displays. You might also remember that our sense of pressure is reacts far faster than our sense of temperature. Case in point that it took users about half a second to identify objects based on roughness, in contrast to roughly a full second when relying on temperature alone.

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