25-01-2012, 12:06 PM
Electroactive Polymer (EAP) Actuators
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Electroactive Polymer Technology
Electroactive polymers (EAP) are promising as actuators in intelligent material
systems, where large deformations are required. Electromagnetic, piezoelectric
or shape memory alloy actuators are either too heavy, too complex or too slow
for such applications. EAP however are relatively lightweight, rather simple and
fast enough.
In particular, dielectric electroactive polymers were shown to have good overall
performances. Since their capabilities correspond to the performance of natural
muscles, dielectric EAP actuators are often referred to as „artificial muscles“.
Working Principle of Dielectric Electroactive Polymers
Electroactive polymers (EAP) are promising as actuators in intelligent material
systems, where large deformations are required. Electromagnetic, piezoelectric
or shape memory alloy actuators are either too heavy, too complex or too slow
for such applications. EAP however are relatively lightweight, rather simple and
fast enough.
In particular, dielectric electroactive polymers were shown to have good overall
performances. Since their capabilities correspond to the performance of natural
muscles, dielectric EAP actuators are often referred to as „artificial muscles“.
Working Principle of Dielectric Electroactive Polymers
A dielectric EAP actuator is basically a compliant
capacitor, where a thin elastomer film is sandwiched
between two compliant electrodes. When a high DC
voltage (kV) is applied to the electrodes, the arising
electrostatic pressure squeezes the elastomer film in
thickness and thus the film expands in planar directions.
When the voltage is switched off, the elastic film returns
to its original shape.
Configurations and Characteristics of Dielectric Electroactive Polymers
Possible Actuator Configurations
Various actuator designs are possible such as:
• Single-layer or multilayer planar actuators
• Spring roll actuators (electroactive polymer
wrapped around a coil spring)
• Shell-like actuators (bending actuators)
