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Polymer and elastomer actuator concepts for engineering

Final Activity Report Summary - PEACE (Polymer and elastomer actuator concepts for engineering)

Electro-active polymers are able to convert an amount of electrical energy into a physical output in its surroundings. Since the observed motions are large, and the actions achieved are soft, the electro-active polymers are often described as artificial muscles.

In this project it was sought to find new principles for the conversion of electrical energy into controlled mechanical motion, through the combination of stiff polymer actuators with soft polymer actuators. A very general principle was discovered through the project. It was found that if a piece of elastomer material is stretched over a frame of intermediate stiffness, the resulting highly deformed 3-dimensional out-of-the-plane shape can be defined with high precision. Further, when electro-active polymers are used as the building materials, polymer actuators can be achieved with strain-amplified motion highly beneficial to actuation.

These novel polymer actuators are best described as active structures, and a term 'minimum energy structures' was coined to describe their structure and their motion under applied voltages. These active structures can display linear or bending motion, depending upon the chosen shape of the frame. It is a simple matter to embed several actuators within a certain structure, to allow such applications as self-organised robotics. In particular, special structures that display novel actuation modes can be made. For instance, a three-clawed grabber was demonstrated, which was manufactured by simple procedures. Finally, the minimum energy structures should allow easy combination of various electro-active polymers into active structures relying on piezoelectric or thermal activation.