Piezoelectric print-head drive-waveform optimization method based on self-sensing

Abstract

The piezoelectric print-head, which controls the droplet formation process by regulating the pressure wave in the tube with a voltage drive waveform, is an important device for droplet deposition. However, the structural deformation caused by the voltage-drive waveform is generally accompanied by structural vibration owing to the dynamic characteristics of the piezoelectric print-head. To precisely control the deformation of the print-head structure, this paper proposes a structural deformation control method for the piezoelectric print-head, based on self-sensing. This self-sensing principle is analyzed, and its measuring circuit is presented. A lumped-parameter model for the structural deformation of the piezoelectric print-head is established and its parameters are identified, based on self-sensing. An iterative learning control method for the structural deformation is presented, based on the identified system model. To verify the control effect of the proposed method, the radial displacement of a coaxial extruded piezoelectric print-head is controlled along a standard trapezoidal trajectory. The experimental results demonstrate that the structural deformation control precision of the piezoelectric print-head with the optimized drive waveform is considerably higher than that without the optimized drive waveform.