Application of Ni-Ti shape memory alloy actuators in a walking micro-robot

As walking robots are requested to perform tasks in rough terrain, the development of actuators capable to flexibly adapt to the unstructured environment becomes more and more necessary. The conventional mechanisms with stiff joints make the robots more complex, heavy, large and expensive. Shape Memory Alloys are a category of artificial muscles which can be used as actuators for a walking robot. Even if they can exhibit large changes in shape when heated and cooled, only one part of their deformation can be used, if we want to maximize the actuator life. This is why smart mechanisms that can convert the small strain of the wire into large motion are necessary. In this paper, an example of using Shape Memory Alloys as actuators for a hexapod walking micro-robot is presented. A leg mechanism that can convert the small strain of these actuators in large motion is also discussed.