Experimental characterization and model validation of the quasi-static performance of piezoceramic telescopic actuators

The piezoelectric telescopic actuation architecture capitalizes upon an internally leveraged amplification technique to produce large actuation forces with amplified displacements. This building-block type actuator consists of interconnected concentric, cascaded cylinders with end cap joints that allow for a telescopic type motion. The internal amplification scheme and building-block nature of the telescopic design allow for efficient, densely packed actuators that yield a high work output for a given volume. This paper presents an experimental investigation of the quasi-static force-deflection performance of three unique telescopic prototypes, each manufactured by different means, from various materials, and in distinct geometries. To accurately predict the observed behavior of this architecture, a full three-dimensional numerical model was constructed for each prototype and was used to revise a previously derived analytical model. These models were refined to include extra compliance factors to account for observed actuation losses, focusing primarily on the bonding layer effects. The revised models captured more accurately the complex actuator behavior observed in the experiments and characterized better the loss mechanisms in the telescopic actuation architecture.