A bio-inspired EAP actuator design methodology

Current EAP actuator sheets or fibers perform reasonable well in the centimeter and mN range, but are not practical for larger force and deformation requirements. In order to make EAP actuators technology scalable a design methodology for polymer actuators is required. Design variables, optimization formulas and a general architecture are required, as it is usual in electromagnetic or hydraulic actuator design. This will allow the development of large EAP actuators specifically designed for a particular application. It will also help to enhance the EAP material final performance. This approach is not new, it is found in Nature. Skeletal muscle architecture has a profound influence on muscle force-generating properties and functionality. Based on existing literature on skeletal muscle biomechanics, the Nature design philosophy is inferred. Formulas and curves employed by Nature in the design of muscles are presented. Design units such as fiber, tendon, aponeurosis, and motor unit are compared with the equivalent design units to be taken into account in the design of EAP actuators. Finally a complete design methodology for the design of actuators based on multiple EAP fiber is proposed. In addition, the procedure gives an idea of the required parameters that must be clearly modeled and characterized at EAP material level.