During mechanical interaction with our environment, we have a perceptual experience that can be compared to that of audition or vision. The tactile modality is based on mechanics and on its infinite complexities. Feeling objects, like in vision and audition, relies on the solution of a vast inverse problem, which is at the root of many ambiguities.
To make matters more interesting, there is mounting evidence that many percepts, such as shape, texture, rigidity, speed, size, and so on, can be elicited through multiple sensing modes that blur the boundaries traditionally, and probably incorrectly, erected between touch and kinesthesia. From these ambiguities many illusions can arise when provoked by staging the proper conditions.
In our group, we strive to build equipment to study them and take advantage of them for practical purposes. Sometimes, we can come up with informative, or even predictive explanations.