A multilink manipulator with IPMC joints

Abstract

IPMC (Ionic Polymer Metal Composite) is a class of electroactive polymers (EAP) that bend when electric field is applied to the material. From our theoretical studies of the material it appears that IPMC can be modelled as a lossy transmission line. From simulations it appears that IPMC reaction time depends on length of the strip used. Also the shorter the transmission line the less complex it is to model. We have also mechanically modeled an IPMC. It appears that the output force does not depend on length on IPMC but on width. Also the shape unpredictability is the larger the longer the strip is. Based on these results the concept of a short IPMC with rigid extension was created. From simulations and experiments it was seen that there exists a certain length of IPMC at which output force and deflection angle remain close to those of a long IPMC while precision increases. Also, the material becomes easier to model and its short-term stability appears to be sufficient to be controlled. A manipulator was built to verify IPMC compatibility as links, tested for accuracy and compared with a long sheet of IPMC. The manipulator appeared to be 314% more accurate and twice as fast compared to the long strip of an IPMC and thus confirming the usability of the described design.