Fluidic haptic interface for mechano-tactile feedback.

Notable advancements have been achieved in providing amputees with sensation through invasive and non-invasive haptic feedback systems such as mechano-, vibro-, electro-tactile and hybrid systems. Purely mechanical-driven feedback approaches, however, have been little explored. In this paper, we now created a haptic feedback system that does not require any external power source (such as batteries) or other electronic components (see Fig. 1 ). The system is low-cost, lightweight, adaptable and robust against external impact (such as water). Hence, it will be sustainable in many aspects. We have made use of latest multi-material 3D printing technology (Stratasys Objet500 Connex3) being able to fabricate a soft sensor and a mechano-tactile feedback actuator made of a rubber (TangoBlack Plus) and plastic (VeroClear) material. When forces are applied to the fingertip sensor, fluidic pressure inside the system acts on the membrane of the feedback actuator resulting in mechano-tactile sensation. Our $\varnothing 7\,\mathrm{mm}$ feedback actuator is able to transmit a force range between $0.2\,\mathrm{N}$ (the median touch threshold) and $2.1\,\mathrm{N}$ (the maximum force transmitted by the feedback actuator at a $3\,\mathrm{mm}$ indentation) corresponding to force range exerted to the fingertip sensor of $1.2-18.49\,\mathrm{N}$ .