Bending actuators

O Brien B, Calius E, Xie S, Anderson I (2008) An experimentally validated model of a dielectric elastomer bending actuator. Proc SPIE 6927 69270T... 

A single-layer PPy film, capable of bending actuation due to its intrinsic anisotropy, but without delamination problems, was constructed by electrochemical synthesis on a steel... 

B. Shapiro and E. Smela, Bending actuators with maximum curvature and force and zero interfacial stress, J. Intell. Mater. Syst. Struct., 18 (2), 181-186 (2007). 

W. Takashima, S.S. Pandey, and K. Kaneto, Investigation of bi-ionic contribution for the enhancement of bending actuation in polypyrrole film. Sens. Actual. B, B89 (1-2), 48-52... 

Chen, L., Liu, C., Liu, K., Meng, C., Hu, C., Wang, J., Fan, S., 2011. High-performance, low-voltage, and easy-operable bending actuator based on aligned carbon nanotube/polymer composites. ACS Nano 5, 1588-1593. 

PPy layers that forms the outside layers on either side of a polymer electrol5de layer in the middle. The pol5mier electrolyte layer could be solid state electrolyte or electrol5de saturated media (i.e., porous PVDF film). Once a voltage is applied, one PPy layer performs as cathode and the other performs as the anode. Since oxidation and reduction occur separately at both sides, expansion and contraction on each side will cause bending actuation (Fig 4.9). 

FIGURE 8.85 Video images of the bending actuation of the doped film with the wrinkled PPy electrode and the conventional gold electrode. The applied voltage was 1000 V (the electric field was 5 MV/m). (From Watanabe, M., Shirai, H., and Hirai, T., /. Appl. Phys., 92, 4631, 2002. With permsission.)... 

Pugal, D., Kim, K. J., Punning, A., Kasemagi, H., Kruusmaa, M. and Aabloo, A. (2008). A self-osciUating ionic polymer-metal composite bending actuator. Journal of Applied Physics 103, 8, p. 084908. 

Wu, Y., Alici, G., Spinks, G. M. and Wallace, G. G. (2006). Fast trilayer polypyrrole bending actuators for high speed applications, Synthetic Metals 156, pp. 1017-1022. 

It is important to note that the unimorph (a piezoceramic plate and a metal plate bonded together) bending actuation cannot provide high efficiency theoretically, because the electromechanical coupling factor k is usually less than 10%. Therefore, instead of the unimorph structure, a simple disk was... 

Early investigations on CNT bending actuators showed active strains of the order of 0.2%, depending on the experimental conditions, when an applied voltage was limited to the electrochemical stability of the electrolytes... 

Figure 18-1. Configuration of EAPap bending actuator (Kim et al. 2006c) [Courtesy of ACS] (See Color Plate of this figure beginning on page 355)...

Figure 13.19 Inchworm like motion of a bending actuator utQising a similar architecture to IPMC artificial muscles.

The application of IPMC bending actuators to hand exoskeletons has been considered in detail and the blocked forces from individual IPMC actuators were found to be too small to match human hand grasp. Stacked actuators have been proposed as a solution to increase force, but not yet demonstrated. 

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