The studies have focused on two types of materials which have shown promising characteristics for micro-positioning and gripping: shape-memory alloys (SMA) and magnetic shape memory (MSM) alloys or ferromagnetic shape memory alloys (FSMA). These alloys are materials that are categorized as "intelligent" as they have the ability to remember a geometric shape after an applied forming mechanism. A common shape memory material is known as nitinol. Nitinol is an alloy made from nickel and titanium. Nitinol is commercially available in the form of wire.

Magnetic shape memory materials are ferromagnetic alloys that realize large changes in geometry and can return to their original shape and size when a magnetic field is applied. Magnetic shape memory materials are not available commercially, however are being developed within many research organizations.

The UPV-EHU team has built and tested several robotic devices using shape memory materials. Laboratory prototypes have included an SMA actuator for a low-precision application test. Additionally, researchers have developed some experimental devices that improve the control and positioning of these actuators. With this, they have built a prototype lightweight gripping claw using shape memory materials that allow for handling small objects. This was accomplished by placing a nitinol wire between two elastic sheets such that when an electric current is applied to the nitinol wire, the elastic sheets contract and the claw gripper closes and grips an object. When the electrical current is removed from the nitinol wires, the gripper claws open.

The UPV/EHU researchers have designed a robot that also uses ferromagnetic shape memory alloys. This robotic device has a precision in positioning objects to within 20 nanometres. All these robotic devices are currently at the research and development stage are used for testing the basic characteristics of the materials and robotic concepts.

Adapted from materials provided by Basque Research.