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Shape Memory Alloy (SMA) wires are currently employed in robotics, as well as prosthetic limbs and medical equipment. Due to advantages such as reducing the size in the application, high power-to-weight ratio, elimination of complex transmission systems and noiseless actuation, and humanmachine interface, these materials are used as actuators in the prosthesis limb. Because of hysteresis property and nonlinear behavior of SMA, control of these actuators is very complicated. In this paper, the design of control algorithms has been discussed for SMA actuators in the artificial fingers with 3 DOF, which includes PID-fuzzy controller. Gains of controllers are set so that the current applied to SMA wires has minimum overshoot and output of system has minimal time to achieve stability. The simulation results compared with actual measured data show how well the controllers decrease the overshoot and time of stability of input signal to SMA wires.

In this article, bending behavior of the sandwich plates with embedded shape memory alloy wires in their face sheets is studied. Three-dimensional finite element method is used for constructing and analyzing the sandwich plates with flexible core and two stiff face sheets. Some important points such as continuity conditions of the displacements, satisfaction of inter-laminar transverse shear stresses, conditions of zero transverse shear stresses on the upper and lower surfaces and in-plane and transverse flexibility of the soft core are considered for the accurate modeling of the sandwich plate. Solutions for bending analysis of shape memory alloy wire-reinforced sandwich plates under various transverse loads are presented and the effects of plate dimensions, shape memory alloy wires diameter, boundary conditions and shape memory alloy wires embedding positions are studied. Comparison of the present results in special case with those of the three-dimensional theory of elasticity and some plate theories confirms the accuracy of the proposed model. According to the obtained numerical results, the local behavior of the sandwich plate in bending against various loading conditions was significantly improved by employing the shape memory alloy wires in the face sheets.

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