• curvature rendering
• design of haptic device
• finite element method
• haptic invariants
• haptic rendering
• SOFA framework
• soft robotics
• tactile perception

This master's thesis aims to design and control a haptic device, which exploits the transparency characteristic of a fabric to return the stimulus of curvature to the user’s finger. A first phase of extraction of the references associated with Hayward’s tactile invariant theory is distinguished, since it is necessary to provide a "skin-like" trend to the mechanical transient of the fabric. The second phase regards the designs of the haptic device and the transmission and control system of the fabric, which is realized by means of three non-deformable cables, attached to the fabric. The tissue control is carried out by means of FEM modeling within a simulation of contact between the user’s finger and the tissue, returning, in a closed loop, the computed force to the simulated cables. Finally, the proposed approach is tested through a Sim-to-Real control loop, in which the real-time simulation generates the torque sent to the real device, until the convergence of the specified curvature. Different concavities, generated by the device, are then compared with specimens with known curvature and a validation of the shape returned by the simulation is performed using a depth camera, able to return the profile of the real fabric through the point-cloud method. The geometries of the real and simulated fabric are compared.