Novel genetically optimised high-displacement piezoelectric actuator with efficient use of active material

Abstract

This paper introduces a new type of piezoelectric actuator, Mikbal. The Mikbal was developed from a Cymbal by adding steel structures around the steel cap to increase displacement and reduce the amount of piezoelectric material used. Here the parameters of the steel cap of Mikbal and Cymbal actuators were optimised by using genetic algorithms in combination with Comsol Multiphysics FEM modelling software. The blocking force of the actuator was maximised for different values of displacement by optimising the height and the top diameter of the end cap profile so that their effect on displacement, blocking force and stresses could be analysed. The optimisation process was done for five Mikbal-and two Cymbal-type actuators with different diameters varying between 15-40 mm. A Mikbal with a ∅ 25 mm piezoceramic disc and a ∅ 40 mm steel end cap was produced and the performances of unclamped measured and modelled cases were found to correspond within 2.8 % accuracy. With a piezoelectric disc of ∅ 25 mm, the Mikbal created 72 % greater displacement while blocking force was decreased 57 % compared with a Cymbal with the same size disc. Even with a ∅ 20 mm piezoelectric disc, the Mikbal was able generate ~10 % higher displacement than a ∅ 25 mm Cymbal. Thus, the introduced Mikbal structure presents a way to extend the displacement capabilities of a conventional Cymbal actuator for low-to-moderate force applications.

Bionic Stepping Motors Driven by Piezoelectric Materials

“…In recent decades, numerous types of piezoelectric motors have been developed, which have been widely used in the precision drive systems, such as the manipulation of biological specimens, optical element alignment, semiconductor equipment, insect-scaled robots, and micro-positioning stages [15][16][17][18][19]. Meanwhile, strenuous efforts have been made to address the shortcomings of a small strain of piezoelectric materials [18,19]. First, the piezo-stack with a multilayer structure combined the small strains from many single-layer units into a long output displacement [20,21].…”

Bionic Type Piezoelectric Actuators

“…Although the piezoelectric materials possess so many excellent characteristics, it is difficult to overcome a defect that the deformation of the piezoelectric materials is small [4,5]. Due to the above defect, it is difficult to make use of the strain of the piezoelectric materials under the external electric field in the engineering world [16,17]. Therefore, it has become a hot issue to develop piezoelectric actuators with a long work range and other excellent performance.…”

Meso scale flextensional piezoelectric actuators

“…The second most common technique for amplifying piezoceramic displacements is external leveraging, in which additional passive elements are added in a transmission to trade off force for displacement. These have been predominately produced on the macro scale [7][8][9] but have also been explored on the micro scale [10,11] and to a limited extent on the meso scale [12]. Variations on this approach include using buckling [13,14] or nesting [15,16] to further amplify motion.…”