Fluids Handling

Self-sensing Actuator based on Magnetic Shape Memory (MSM) Alloy built by AdaptaMat

Phil Black - PII Editor 23/03/2012

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Actuator with built-in MSM element exhibits dual action – motion and position sensing

AdaptaMat Oy, manufacturer of single crystal Magnetic Shape Memory (MSM) smart metals, has built a unique actuator. This self-sensing actuator demonstrates functional properties of MSM alloy by combining two material features in one practical application. Simultaneous proportional elongation in a magnetic field (Magnetic Shape Memory effect) and proportional resistance change of the very same MSM element makes it possible to have a proportionally controllable actuator without any external position sensors or devices. Thus any MSM actuator can be turned into a proportionally controllable and self-sensing device simply by measuring the resistance of the MSM-element within the device.

Magnetic Shape Memory (MSM) Alloy is a smart single crystal alloy with several functional properties. The best known property is the MSM effect. An MSM element elongates 6% of it is length in magnetic field proportionally with the field strength. Besides this MSM effect, the alloy exhibits also several other properties such as variable resistance. When an actuator is built, its movements can be controlled by controlling the strength of the magnetic field, and the position is known by measuring the resistance of the same piece of material. This combination may be used for open or closed loop control of the device. In control mode, the elongation of the actuator can be set accurately in a fraction of a second to any given position within the full operating range of the actuator.

“MSM actuators are low power and high speed devices (hundreds of Hz) with the option of a bi-stable, no-power holding mode. The possibility of turning these devices into proportionally controllable actuators, simply by adding resistance measurement, has been a truly exciting project” said Antti J. Niskanen (PhD), Application Development Engineer, AdaptaMat Oy.

Other functional properties of the MSM alloy are:

1. Villari effect i.e. inverse magnetostriction. When external force presses MSM material placed in a magnetic field, the magnetization field is changed proportionally to the element”s length.

2. Permeability change. Permeability of the material changes proportionally to the element”s length.

3. High Temperature Shape Memory alloy. Besides the Magnetic Shape Memory effect, the material can be used as a traditional Shape Memory Alloy, but up to very high temperatures of 400 ºC

About AdaptaMat: AdaptaMat Oy is Helsinki, Finland based manufacturer of single crystal Magnetic Shape Memory alloys. AdaptaMat has built several devices to demonstrate its material properties, including MSM based Vibration Energy harvesters, displacement sensors, microfluidic devices and actuators. More information on www.adaptamat.com

For any questions or comments please contact:

Jukka Perento
Managing Director
AdaptaMat Oy
Phone: +358 40 5910 419
jukka.perento@adaptamat.com