Localized generation of a vibration pattern on a thin plate by using traveling wave control with periphery actuator array

Abstract

Vibrations are rendered on the display panel of a mobile electronic device to transfer a tactile sensation to users for effective information. Previous vibration control has usually focused on the suppression of an entire area. The only choice for actuator position is the boundary of the panel due to the utilization of central part for other electric components by consideration of the practical application. Traveling wave control is adopted as the basic principle to generate a rendered vibration pattern. Proper weighting for both amplitude and phase for each actuator in the array is determined by applying the general inverse method with the relationship velocity responses and input signals of actuators. Experiments are conducted on a thin the tempered glass panel of a commercial tablet PC employing small moving-coil actuators. Good performance to fulfill the rendered 2x2 and 3x3 grid distribution of vibration magnitude was observed with more than 97 % success ratio. Also, Regularization provides 75% reduction of the control effort. Minimum number and optimum position of actuators for rendering target vibration pattern can be chosen by consideration of the independency of actuator array.