Pseudo-rigid Body Modeling of IPMC for a Partially Compliant Four-bar Mechanism for Work Volume Generation

Conventional four-bar crank rocker mechanisms made of rigid links can generate only one path, at the rocker tip, for one revolution of the crank. However, if the rocker length can be actively changed then its tip can generate a work volume. This study describes an application of ionic polymer metal composite (IPMC) as a partially compliant rocker in a four-bar mechanism for work volume generation. First, an experiment is conducted to study the voltage verses bending characteristics of IPMC and based on the experimental data the IPMC is modeled using a pseudo rigid body model. The model is based on the fix-pin support type of cantilever mode and its derivation is explained in detail. The maximum and minimum length of the rocker is controlled by changing the voltage applied to it and this generates a work volume for one revolution of the crank. Simulation results are compared with the experimentally obtained work volume and the differences are found. The proposed mechanism has the potential for application in micro positioning, compliant structures, etc.