Differentiated haptic stimulation by modal synthesis of vibration field

To date, Several focusing techniques have been proposed to realize localized stimulation on haptic interfaces: phased arrays of actuators with delayed excitation, or time reversal techniques which require a preliminary learning phase. Additionally, these techniques are sensitive to parameters variation and disturbances. Modal decomposition allows to realize arbitrary vibration fields congruent with the boundary conditions and in this paper, Modal decomposition is proposed to realize a desired vibration velocity field in order to have differentiated stimuli. The experimental results validate the ability of the method to approximate satisfactorily a desired reference form. The psychophysical evaluations show that users can differentiate and localize the stimulation while exploring a surface with two fingers.