Hybrid Shape Memory Alloy and Elecromechanical actuator systems

Today, Shape Memory Alloys (SMA) based on Nickel Titanium are mostly known for medical applications, using the superelastic behaviour, good biocompatibility and excellent mechanical and functional properties of NiTi. For actuator applications, two geometries are predominant, tensile wires and compression spring actuators, which are both already used in mass production for automotive applications.

In this work, an example is demonstrated how SMA actuators and electromechanical components can be combined to establish a hybrid actuation system for resource-efficient lightweight applications. Usually, SMA actuators are used to replace conventional electromechanical drives. However, a direct replacement can result in needs for compromises based on SMA specific requirements, such as the precision of position control.

Our research focuses on the definition of the requirements for a hybrid actuation system and classification of desired requirements to the different system components. A special attention is paid to the interconnection of the electromechanical and SMA components. The requirements differ strongly depending on the application area. An example is demonstrated based on a clamping system for components with different geometric dimensions.

Furthermore, a thorough analysis of the advantages and disadvantages of electromechanical, material-mechanical, and hybrid solutions is conducted. This comparison identifies potentials for the integration of SMA actuators into conventional actuation systems, leading to benefits concerning weight, installation space and energy consumption.

Finally, various implementation variants of the presented hybrid actuation application are highlighted to show the diversity of potentials and solutions, as well as challenges in the selection of SMA actuators for universal and application-specific systems.