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.

Polymers labeled as EAPs (Electro-active Polymer) have a mechanical response to electrical stimulation and produce an electric change in response to mechanical stimulation. The high strains of ionic polymer metal composite (IPMC) make them attractive as mechanical actuators for applications requiring large motion but little force. This paper describes the results an application of IPMC as active damper for a flexible link. IPMC is studied experimentally to find out material loss factors and damping characteristics. A single link rotary flexible manipulator with IPMC as smart patches was studied for attenuation of vibration actively. Modeling of the flexible rotating beam with IPMC has been done using modal approach to determine the fundamental modes of vibration. The end effector position of link was controlled by generating localized bending by giving input current to the IPMC in a phase opposite to the excitation. The results prove that IPMC can be used as an active damper for suppressing vibration in a flexible link.

Ionic polymer metal composites (IPMC) are a class of electro-active polymers (EAP) that produce mechanical strain in response to electrical stimulation and vice versa. The property of generating high strains with low actuation voltage makes IPMC suitable for mechanical actuators in applications involving control of high-amplitude vibration. This article describes results on an application of IPMC as an active damper for large deflection vibration control of a single link rotating flexible manipulator. Modeling of the flexible rotating link has been done using modal approach and it was found that the first two modes of vibration take the maximum amount of energy. Based on this, two IPMC actuators were fixed at suitable positions on the link to suppress vibrations. A dynamic model of the link with IPMC was derived and a distributed PD controller designed to actuate the IPMC to control the vibration of the flexible link. Simulations were first done to demonstrate the effectiveness of IPMC and then experiments are conducted to validate the results. The results prove that IPMC can be used as an active damper for suppressing vibration in a flexible link manipulator.

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In this article bending resistance of IPMC has been estimated following a newly proposed Variable Parameters Pseudo-rigid Body model. First an experiment is conducted to study the voltage verses bending characteristics of IPMC and based on the experimental data the IPMC has been modeled through the proposed technique. Simulation has been performed and estimation of bending resistance has been made based on experiment results. It is observed that bending resistance of IPMC increases with input voltages although the changes remain insignificant after certain range.