Modular SMA-Based Bi-Directional Rotational Actuator

State-of-the-art actuators that produce rotatory motion and torsional moment are based on either combustion engines, electro-motors, hydraulic or pneumatic machines. Each of these actuation methods has several drawbacks. All of these systems often come with high initial costs, big weight and need a lot of construction space because of their dimensions. Shape memory alloys are known for their superior energy density. That allows for the construction of very compact and light-weight actuator systems. In this paper, the design and construction of a light weight rotational actuator based on SMA wires is presented. The design is based on a modular concept, with each module contributing to the total rotational radius. This way, the actuator can be custom fitted to specific application needs.