Characteristics of Dielectric Electroactive Polymer Cylindrical Actuator under Voltage Activation

The dynamic and static characteristics of a dielectric electroactive polymer (EAP) actuator is the foundation for its reasonable operation and optimizing design. The geometrical deformation of the cylindrical actuator can be depicted through constructing a geometry model; furthermore, the dynamic formulation for the axial linear movement is also deduced based on the electromechanical coupling equations of EAP. The relation curve between the displacement and voltage of the cylindrical actuator, obtained through numerical calculation, reveals that the coating method for the outer and inner layer of the flexible electrodes can influence the actuator displacement. Based on the relationship between voltage and displacement, the main failure forms of the actuator are also discussed. Modifying the one-time-constant viscoelastic model, based on the neo-Hookean springs, to two-time-constant model, the two models are applied to study the dynamic responses of the actuator excited by step and periodic voltage. Comparative analysis of theoretical calculation and experiment results shows that the two-time-parameter viscoelastic model can describe the dynamic displacement more accurately. The displacement amplitude of actuator, under periodic voltage excitation, will be significantly reduced through increasing frequency, while the vibration center offset and vibration amplitude reduced due to "excitation dead zone".