**2.1.1 Mediated contact interaction**

During haptic interaction mediated by a tool the subject holds a tool in his hand and the haptic information regarding the interaction is practically contained in the motion and the forces that are acting on the tool. An ideal device able to perfectly reproduce the haptic interaction can be equipped with a toll moke-up that is a faithful reproduction of the real tool. The problem of perfectly reproducing the tactile and kinesthetic sensory input is then reduced to the problem of imposing to such moke-up the same static and dynamic behavior of the real tool.

For this kind of interaction kinesthetic haptic interface are theoretically very efficient but in many cases their mechanical performance in terms of frequency response, fidelity in force reproduction and force resolution are still insufficient for high fidelity reproduction of the real feelings.

A lot of research efforts has been applied for improving and optimizing kinesthetic haptic interfaces specifically developed for mediated tool interaction and many systems are already commercialized and available as an off the shelf product.

For example, in the field of surgical simulators for training of laparoscopic surgery, catheter insertion, phlebotomy, or, in the domain of Virtual Prototyping and Assembly, mediated contact device have been successfully employed.
