Biomimetic actuators

The strain in electric field-associated bending of a PVA-PAA gel is given by the equation g = 6DY/L2 (see Eq. 21). The strain depends on the electric power applied to the gel. Thus, the deflection increases as the thickness becomes small even if the electric power remains constant. The PVA-PAA gel rod of 1 mm diameter bends semicircularly within 1 s under both dc and ac excitation. An artificial fish with a PVA-PAA gel tail 0.7 mm thick has been designed, and it has been demonstrated that the fish swims forward at a velocity of 2 cm/sec as the gel flaps back and forth under sinusoidally varied electric fields (Fig. 13b). This prototype of a biomimetic actuator shows that translational motion may be produced using bending deformation [74],... 

The three biomimetic actuator models mentioned above are driven in a solution. The next target of the advanced model is an actuator electrically driven in air. A mechanical hand composed of two smart gel fingers working in... 

Fig. 13a, b. Biomimetic actuators using electric field-responsive gels a robot hand having four smart gel fingers which can hold a quail egg, and b artificial fish with a tail of gel film which can swim under ac electric fields... 

Acknowledgements I would like to thank Professor M. Doi of Nagoya University for stimulating discussions. I am also very grateful to Y. Hirose and Dr. T. Kurauchi of Toyota Central Research and Development Laboratories, who helped me to fabricate biomimetic actuators. 

Choi H, Ryew S, Jung K, Jeon J, Kim H, Nam J, Takanishi A, Maeda R, Kaneko K, Tanie K (2002) Biomimetic actuator based on dielectric polymer. Proc SPIE 4695 138... 

Actuators that generate movements and forces, such as bending, expansion and contraction driven by stimulation of electrical, chemical, thermal and optical energies, are different from rotating machines such as electric motors and internal combustion engines. There are many sorts of soft actuators made of polymers [1-3], gels [4] and nanotubes [5]. Particularly, biomimetic actuators are interesting because of the application to artificial muscles that will be demanded for medical equipment, robotics and replacement of human muscle in the future. 

The dielectric synthetic elastomers were studied in multi-stacked configuration. In addition to relative simplicity, it produces notably high strain. In order to control it, a PWM-PID controller was designed. The designed actuator has very high force-to-weight ratio, is cost effective and easy to fabricate. Furthermore, it serves as a biomimetic actuator due to soft musclelike characteristics. 

The stable dispersed CNTs by biopolymer set up into biomedical purposes as well as tissue engineering and drug delivery system (Yu and Li 2012). For the bioactivity of biopolymer, their composites with CNTs offer exceptional sensing performance (Liu et al. 2014a, b, c, d, e). The biomimetic actuation founded on CNTs-filled biopolymer devices have as well initially proved to be of large and fast actuation displacement under low voltage electrical stimulation (Chahine et al. 2008). 

Alfiiough in an aqueous solution, a biomimetic actuator using a polymer gel has been demonstrated. In fact the technology has already moved forward— it is now possible to manufacture a robot hand with gel fingers fiiat can operate in air [90],... 

Various prototypes of artificial muscles and biomimetic actuators capable of transforming external energy into mechanical energy have been proposed that use polymer gels. There are still problems with durability and amount of work possible. However, it is highly likely that new actuators will be developed. Because polymer gels are similar to human skin, actuators made from such materials are soft. 

Knoblauch, M. and Peters, W.S. 2004. Biomimetic actuators Where technology and cell biology merge. Cell Mol Life Sci., 61(19) 2497-2509. 

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