Haptic device using flexible sheet and air jet for presenting virtual lumps under skin

A haptic device using flexible sheet and air jet is proposed. This device presents haptic sensation of virtual lumps under skin to user´s finger. A tensioned flexible sheet is regarded as virtual skin. A user touches the sheet directly with his finger. Then he feels the softness of normal skin as the sheet compliance. A nozzle fires thin beam of air jet to the sheet from its back, when the user touches the sheet at the location of a virtual lump. The fingertip feels the small hard part made by the air jet through the sheet. This can be the virtual lump. In order to present multiple virtual lumps, the nozzle is attached to a manipulator. A camera measures the fingertip motion, and the manipulator moves the nozzle together with the fingertip. The nozzle fires the air jet when the fingertip is on the virtual lumps. We can vary the hardness of a virtual lump by controlling the flow rate of air. We can also vary the size of the virtual lump by controlling the distance between the nozzle and the sheet; the shorter distance makes the virtual lump smaller. This is because the air jet radiates out from the nozzle. Some experiments of presenting multiple virtual lumps and varying the hardness and size of a virtual lump are performed.