Abstract: A haptic interface system comprising: a shell which is moved on a reference surface by a user; an actuator mechanically coupled to the shell, which provides a haptic stimulus on a fingertip of the user; and a motor assembly, which moves the actuator with three degrees of freedom. The haptic interface system also includes: a localization system, which determines the position and orientation of the shell with respect to the reference surface; and a control stage, which controls the motor assembly so as to move the actuator as a function of the position of the shell, in an invariant manner with respect to the orientation of the shell.