| Abstract | The paper describes the design phase of an intelligent controller for a new morphing mechanism using smart materials made of Shape Memory Alloy (SMA) for the actuators. After a brief presentation of the morphing wing system, the controller purposes are discussed. The morphing system requirements and the behaviour of SMA actuators lead to a fuzzy logic Proportional-Integral- Derivative for the controller architecture. The output error and the change in error are used as controller inputs, while the electrical current is used as command variable (controller output). In the chosen architecture, the inputs and outputs designed membership functions, and the inference rules allow the control of both cooling and heating SMA phases. In this way, the electrical current given by the controller is approximately 0 A for the cooling phase, and have higher values for the heating phase depending by the values of controller inputs. In the fuzzy logic controller input-output mapping, [-1, 1] interval is chosen as the universe for all inputs signals, while the [0, 2.5] interval is used for output signal. Numerical simulations impose a number of three membership functions for each of the two inputs, three membership functions for the output, and five inference rules. The shapes of the inputs membership functions are s-function, π-function, respectively z-function, while the product fuzzy inference and the center average defuzzifier are applied (Sugeno). |
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