Mechanical Properties Analysis Of Polypyrrole Conducting Polymer Actuator

Conducting polymers(CPs) are one group of smart materials with unique electrical and mechanical properties. Conducting polymers are one of the electroactive polymers which have many promising features including small energy consumption, light weight, low power consumption, biocompatibility, good flexibility, and they are widely used in the fields of the bionic robot and biomedical devices. In this paper, the research object is CP made of polypyrrole(PPy) used to make multilayer bending CP actuators. With reference to the operation principle of the actuators, and given its own physical dimension, the experimental system has been set up by home-made bending polypyrrole conducting polymer actuator to study the bending motion characteristics.Research contents that the paper obtained are as follows:1. Two modeling approaches are proposed. linear beam theory(analytical approach) and a finite element analysis based on a thermo-mechanicalanalogy(a grey-box approach). And by these two methods respectively established the equivalent cantilever beam model and finite element analysis model of conducting polymer actuators.2. The bending deformation is measured when applying the low voltage(0 V~1.0 V) to the actuator with different lengths, through researched the relationships between the bending displacement and the voltage and the bending force, the linear function relationship between the voltage and the uniformly distributed load and strain are established, and the exponentially functional relation between the voltage and the radius is established. Furthermore, the numerical values of uniformly distributed load is calculated. Besides, the displacement deviation between the theoretical deflection value and the measured value of the actuator is calculateed by dividing the actuator into ten parts and the normal work of the actuator will not be affected by these deviations. The electric-mechanical transfer model was established based on the relationships between the bending displacement and the voltage and the voltage frequency, and it is concluded that electrostrictive properties of conducting polymers actuator with low frequency connectivity.3. The experimental validation method of mechanical model is proposed. It was verified by the fact that the tip of the actuator can support a certain load and the actuator can move 2.71 mm with something weighted about 5 times of itself on it.4. An analogy between the thermal strain and the real strain in the PPy actuators is draw to set up a coupled thermal-structure model. The Finite Element Method(FEM) is used to solve the model. Theoretical and experimental results demonstrate that the model is practical and effective enough in predicting the bending motion of the PPy actuators quite well for a range of input voltages.5. A flexible gripper with simple structures, low power consumption,light weight is designed and manufactured.