Electro-active polymers as a novel actuator technology for lighter-than-air vehicles

In this paper the worldwide first EAP actuated blimp will be presented. It consists of a slightly pressurized Helium filled body of a biologically inspired form with Dielectric Elastomer (DE) actuators driving a classical cross tail with two vertical and horizontal rudders for flight control. Two versions of actuators will be discussed: The first version consisted of "spring-roll" type of cylindrical actuators placed together with the electrical supply and control unit in the pay load gondola. The second version consisted of a configuration, where the actuators are placed between the control surfaces and the rudders. This novel type of EAP actuator named "active hinge" was developed and characterized first in the laboratory and afterwards optimized for minimum weight and finally integrated in the blimp structure. In the design phase a numerical simulation tool for the prediction of the DE actuators was developed based on a material model calibrated with the test results from cylindrical actuators. The electrical supply and control system was developed and optimized for minimum of weight. Special attention was paid to the electromagnetic systems compatibility of the high voltage electrical supply system of the DE actuators and the radio flight control system. The design and production of this 3.5 meter long Lighter-than-Air vehicle was collaboration between Empa Duebendorf Switzerland and the Technical University of Berlin. The first version of this EAP blimp first flew at an RC airship regatta hold on 24 th of June 2006 in Dresden Germany, while the second version had his maiden flight on 8 th of January 2007 in Duebendorf Switzerland. In both cases satisfactory flight control performances were demonstrated.