The DEtune project pursued a multidisciplinary approach, combining base research aimed at understanding and describing the driving principles behind DE loudspeakers, and application-oriented prototyping of technological demonstrators. Base research activities were approached in a holistic manner, by combining experimental analyses and numerical models.
The main results of the project can be summarized as follows:
- Experimental characterization of voltage-driven vibrations in DE membranes were performed, using a 3D laser Doppler vibrometer (one of the most advanced tools for measurement of mechanical vibrations). This allowed understanding and visualizing the deformation patters that DE membranes produce when subject to high-frequency voltage excitation, and gaining precious information/data for the validation of numerical models.
- Multi-physics models, able to describe DE loudspeakers’ response (dynamics, sound pressure output), were developed. The proposed models rely either on analytical formulations, or numerical codes based on the finite element method. These models merge different physical domains (namely, nonlinear elasticity, electro-elastic interactions, elasto-acoustic interactions) so as to consistently describe the complex and nonlinear response of DE speakers.
- The observations brought up by modelling/characterization activities allowed developing a completely new principle to develop multi-function devices, capable of performing multiple tasks by using different deformation modes of a same DE membrane unit. The project team proved that some specific topologies of DE membrane actuators can concurrently work as linear actuators (i.e. producing a force/displacement in a given direction) and loudspeakers. This is achieved by exciting a single DE membrane with a multi-chromatic voltage input, that concurrently excites different vibration modes of a same membrane and allows producing two independent output at the same time. Among other, this principle can be used to build audio-tactile devices, that make use of a single active membrane to provide users with complex combined vibrotactile and acoustic feedbacks.
- Prototype demonstrators were built, including coil-free DE loudspeakers, and an audio-tactile user interface (smart button) that is able to recognize a user’s touch via capacitive sensing and produce combined audio-tactile stimulations in response.
The activities and results of the project were disseminated through scientific publications (5 journal papers + 7 conference papers) and presentations in international scientific events (e.g. 7 presentations at conferences in the field of mechatronics). Actions aimed at reaching the general public were also undertaken, including the creation of social pages for the project (Youtube, Twitter channels), and the participation in public events (e.g. University’s open-door days).
