Distributed actuators

Prahlad, H., Kombluh, R., Pelrine, R., Stanford, S., Eckerle, J., and Oh, S. Polymer power Dielectric elastomers and their applications in distributed actuation and power generation. Proceedings of ISSS International Conference on Smart Materials, Structures and Systems, Bangalore, India, July 28-30, 2005, SA-13, pp. 100-107. 

Figure 22.1 Schematic of feedback control system with distributed actuators...

The formulation of combustion dynamics can be constructed using the same approach as that employed in the previous work for state-feedback control with distributed actuators [1, 4]. In brief, the medium in the chamber is treated as a two-phase mixture. The gas phase contains inert species, reactants, and combustion products. The liquid phase is comprised of fuel and/or oxidizer droplets, and its unsteady behavior can be correctly modeled as a distribution of time-varying mass, momentum, and energy perturbations to the gas-phase flowfield. If the droplets are taken to be dispersed, the conservation equations for a two-phase mixture can be written in the following form, involving the mass-averaged properties of the flow ... 

The control source he arising from combustion of the injected fuel can be treated as a distributed actuator, with its spatial distribution approximated by an array of M discrete sources [1]. If a generalized time-lag theory of Crocco and Cheng is used to model the process of the control fuel from injection to complete combustion, then h can be written as... 

Fung, Y. T., V. Yang, and A. Sinha. 1991. Active control of combnstion instabilities with distributed actuators. Combustion Science Technology 78 217-45. 

Prahlad H, Kombluh R, Pelrine R, Stanford S, Eckerle J, Oh S (2005) Polymer power dielectric elastomers and their applications in distributed actuation and power generation. In Proceedings of ISSS 2005 international conference on smart materials structures and systems, pp SA-lOO-SA-107... 

The adaptronic approach would be one that would borrow directly from the biological world. Materials that behave more or less like muscles can be used in adaptronic structures and are called induced strain actuators. When energy is applied to the actuators, they attempt to expand/contract and work against any load that is applied to them. The actuators are typically bonded to the surface of a structure, or embedded within the material. This means that the artificial muscles must now work against the inherent structural impedance of the component, just as hmnan muscles are parallel to the skeletal structure or bone. However, whereas the arm has discrete joints about which rotation occurs, the adaptronic structure may be a continuum, thereby necessitating a distributed actuation system. For example, the tip motion of a beam will not occur by rotating the beam about a joint but by inducing its deformation by means of induced strain actuators placed on the beam. 

Tadokoro, S., Fuji, S., Fushimi, M., Kanno, R., Kimura, T., Takamori, T., Oguro, K. Development of a distributed actuation device consisting of soft gel actuator elements. In Proceedings of IEEE International Conference on Robotics and Automation, pp. 2155-2160 (1998)... 

Tadokoro, S., Fuji, S., Takamori, T. and Oguro, K. (1999) Distributed actuation devices using soft gel actuators, Distributed Manipulation, K. F. Behringer, H. Choset (Eds), Springer London, 217-235 (2000). (Kluwer Academic Publishers was absorbed by Springer). 

Figure 11.4 Schematic of the device (a) first design consists of CP/SPE/CP sandwich structure Inserted Inside the catheter wall [39] (b) distributed actuator fibre + SPE (c) functioning device (adapted from [12]).

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