The Group of Automatic Control Department of Electrical and Electronics Faculty of Science and Technology is studying the stimulus-response characteristics of various types of materials for use in the generation and measurement of precise movements in electromechanical systems in miniature and in robotics.
A research team from the Department of Electrical and Electronics Faculty of Science and Technology in Leioa (UPV / EHU), led by Professor Victor Etxebarria, is studying the characteristics of various types of material for subsequent use in the generation and measurement of movement accurate.
At the time of taking an egg or a light bulb with a robot arm is essential to do so with as much precision as possible. Therefore, the progress of science and technology of materials have led to the design and control systems equipped with sensors and actuators built with new materials.
Specifically, the studies focus on two types of materials promising features for applications microposicionamiento: shape memory alloys (SMA) and shape memory alloys of magnetic or ferromagnetic (MSM or FSMA). All of them are new materials, classified as intelligent for their ability to memorize the shape or other novel properties.
The shape memory alloys are capable of remembering the original size and shape even after having undergone a deformation process. The most common of these alloys are generically called nitinol, as it is composed of nickel and titanium, almost 50%. There commercially and is frequently sold in the form of threads.
The shape memory alloys are magnetic ferromagnetic materials capable of withstanding large reversible changes in shape and size, under the application of a magnetic field. There are no commercially manufactured and currently only in research laboratories.
The group has built some devices potential usefulness in robotics using lightweight materials such shape memory, and investigates new applications fundamentally aimed at light or electromechanical systems in miniature.
Prototype craft
The use of SMA as actuators in low-precision applications is not something particularly new. However, the investigative staff of the UPV / EHU has developed some experimental devices to radically improve the control of the positioning of these actuators. As a result, has built the prototype of a lightweight grip for a flexible robot of small dimensions, capable of manipulating small objects.
It has placed a nitinol wire between two elastic metal plates, so that if the thread is applied an electric current, the sheets shrink and the claws are closed altogether, picking up small objects they find around. In the absence of such a flow, the claws are opened at all. However, the research group of the UPV / EHU has succeeded in improving the movement to open and close, reaching a position that movement to an accuracy of even one micron. The accuracy of one micron can be enough for many applications, for example, in machine tool.
Regarding the shape memory alloys of magnetic or ferromagnetic, the investigative staff of the UPV / EHU has designed a device with which he has managed to position the objects with an accuracy of about 20 nanometers. Being a handmade device and a simple control system, the researchers do not doubt that can be improved.
In addition, it can be a serious candidate to replace the current arrangements more precise, since the positioning devices made of shape memory alloys are ferromagnetic the great advantage that once properly positioned do not consume energy. The use of FSMA actuators can become very important in some applications, for example, in large telescopes, which have many mirrors that have to move with high accuracy to focus properly.
All of these devices, for the moment craft, serve to prove the basic characteristics of the materials in the laboratory, but maybe in the future may become prototypes commercial end of robotic devices and micro and nanoposicionamiento.