Adam NewtonMechanical Engineering MEng
SMA Linear Actuator
A novel driving mechanism using SMAs
Linear actuators are used in a multitude of applications, ranging from the very large used in heavy lifting equipment to the tiny piezoelectric actuators. In this project, a novel driving mechanism using shape memory alloys (SMA) were investigated and successfully integrated in to a linear actuator. SMAs are metals that remember and return to their original shape after being deformed. A design was chosen based on a scissor action due to its simplicity and adaptability. A thin Nitinol wire was strung across the bottom scissor set and, when heated via an electrical current, it contracts closing the scissor arms and extending the actuator pin. A mechanical advantage is achieved by the asymmetric scissor configuration that has been designed so that a small contraction in the SMA wire will allow for a larger movement in the actuator.