Cleverly using physics

“Cleverly using physics”,, is the title of the current issue of antriebstechnik, which features the GMI Encoder technology from FLUX GmbH on page 20 onwards. We appreciate Miles Meier‘s interest in our new positioning technology and his visit to our booth at SPS 2022.

antriebstechnik 2023/01-02
Text excerpt and summary:

CLEVER USE OF PHYSICS

Special applications require special solutions. For precisely these cases, a company from Austria has innovative sensor technology with interesting properties in its portfolio – thanks to a physical effect. The encoders for position determination are also used where usual devices are too large and heavy.
Long before its founding in 2017, FLUX from Austria was already a self-confessed specialist in sensor technology, with decades of experience and great know-how in the field of magnetic, inductive and optical technologies. At a certain point, however, it became apparent that it was time for new developments, especially in the detection of rotational and linear motion sequences. The reasons for this were far-reaching innovations in automation and robotics, which were also taking place ever faster. Ultra-fast, ultra-light and ultra-flat sensors and encoders that could keep pace with the rapid development of Industry 4.0 applications were in demand.

GIANT MAGNETO IMPEDANCE

The Austrian answer is the patented GMI technology (Giant Magneto Impedance). The principle behind it is well known: The GMI effect is that certain materials change their impedance, i.e. their AC resistance, as soon as they are exposed to an external magnetic field. This in turn affects the so-called skin effect, which is caused by applying an alternating current in the GMI material. In this way, a signal can be generated depending on the position between the sensor (GMI foil) and the measuring tape (external magnetic field). This is a novelty, because the GMI effect had never been used for position determination before. If this knowledge is transferred to the production of an encoder, as FLUX has succeeded in doing, it results in enormous added value: applications are now conceivable that previously seemed impossible because conventional sensors and encoders were simply not suitable due to their size or inertia. The GMI encoders combine the high-precision performance of an optical encoder with the robustness of an inductive encoder and the large mounting tolerance and operating range of a magnetic encoder. In addition, the GMI encoders operate hysteresis-free and offer real-time position detection; that is, the current position is available at any time without delay. They combine the features and functions of previous encoder systems in one device – saving costs for energy, installation, integration, operation and maintenance.

DISTRIBUTION AND COOPERATION PARTNERS

Paul Tutzu, FLUX founder and CEO, sums it up like this: “Rapid technical progress and constantly changing framework conditions require a high degree of flexibility. By using our encoders, we enable our customers to achieve maximum adaptability and reliability while offering added value through superior technical performance.” Servotecnica has benefited from this important know-how since 2021, on the one hand as the exclusive distributor for FLUX’s products for Germany and Italy, and on the other hand as a cooperation partner for further developments in the field of encoder technology and slip rings. The current product portfolio of distributed encoders with GMI technology includes GMI angle encoders (GMI Angle series) as well as GMI rotary encoders (GMI Rotary series) in various sizes and designs. The range is additionally complemented by a series of particularly compact and lightweight encoders based on induction. In addition to the advantages already mentioned, the GMI encoders have numerous other advantages over conventional absolute encoders. For example, their measuring principle works in a larger operating range and they have a very good signal-to-noise ratio. As a result, this leads to comparatively large mounting tolerances in combination with high resolution and accuracy over the entire operating range. The frameless design of the GMI encoders prevents additional, parasitic friction from being introduced into the system, as often happens with encapsulated systems that introduce additional static and rolling friction into the rotary axis.

ADVANTAGES OVER CONVENTIONAL ENCODERS

GMI encoders also work holistically: the sensor does not scan the scale tape selectively, but over the entire 360 degrees of a revolution. This makes it largely insensitive to inaccuracies such as eccentricities or an offset between sensor and scale tape. As a real-time encoder, it also provides an initial position that is independent of a calculation time: it can transmit the current position to the controller immediately and without time uncertainty (jitter) with every query. This means that GMI encoders have consistently high precision at both low and very high speeds and are particularly suitable for applications that require speed or torque control. FLUX encoders are used, for example, as load and motor encoders in joints of industrial robots and cobots, as well as in the latest generation of machine tools or in torque motors. With their outstanding accuracy and repeatability, they also play a major role in demanding manufacturing processes, for example in the production of semiconductors. With their low mass, they are also ideally suited for applications in gyro-stabilised, gimbal mounts for cameras or measuring instruments, so-called gimbals, which can be mounted on drones or manned aircraft. To find the right solution for drives, sensors and automation in each case, Servotecnica is one of the right contacts. The GMI and induction-based encoders from FLUX open up another field for users with numerous new possibilities, some of which are pioneering.

THE IDEA

“Automated applications are becoming more and more demanding and faster. When it comes to detecting rotational and linear motion sequences, conventional sensor technology is reaching its limits. FLUX’s patented GMl technology opens up completely new possibilities: GMl encoders from FLUX combine the precise performance of an optical encoder with the robustness of an inductive one. They operate hysteresis-free and provide position data i real time – a superior technical performance. Sales partner for FLUX’s GMI encoders is Servotecnica.”

Paul Tutzu, CEO, FLUX, Braunau am Inn, Austria