Research and Application of New Inserted Shape Memory Alloy Actuators

More and more people prefer a new inserted shape memory alloy actuator (ISMAA) to a traditional SMA actuator because there are some advantages in ISMAA, such as precise control abilities, high response, broad range of performance, and so on. An elastic rod and two SMA wires, which are inserted in parallel with the axis of the rod, make up the actuator. The actuating wire, which is one of the two wires, is superposed along the rod´s axis and set to memorize a “U” shape. The restoring wire, which is the other of the two wires, is placed off-axially and memorizes a straight shape. In the actuator, there are also two differential stain meters, which are placed at an apt location referring to the actuator´s bending direction. By making use of these two meters, accurate position control comes true. Taking advantage of the coordinating martensite fraction coefficients appropriately, the presence of major and minor hysteresis loops can be explained in detail when the analytical model was established. The actuator can be optimized by combining the analytical model with the experimental results, particularly the structural parameters, such as the wire´s recoverable curvature, wire´s radius, rod´s radius, and offset distance. In order to take into account the basic performance, there is an example of an anthropopathic robot hand, which is composed of six ISMAAs.