ECE5320 Mechatronics Assignment#01: Literature Survey on Sensors and Actuators Topic: MAGNETOSTRICTIVE ACTUATORS

1. ECE5320 MechatronicsAssignment#01: Literature Survey on Sensors and Actuators Topic: MAGNETOSTRICTIVE ACTUATORS Prepared by: Deepti R Patlolla Dept. of Electrical and Computer Engineering Utah State University E: ; T: (435)797-; F: (435)797-3054 (ECE Dept.) 02/24/2007

2. Outline • Reference list • To probe further • Major applications • Basic working principle illustrated • A typical sample configuration in application (application notes) • Major specifications • Limitations • And many more relevant issues in applications (such as, how to choose, cost information, where to buy etc.) ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

3. Reference list • http://www.mide.com/pdf_html/Magnetostrictive_Actuators.htm • http://www.energeninc.com/pdf/Actuator2000June2000.pdf • http://www.lpa.uni-saarland.de/pdf/Sens03arteng_final.pdf • http://www.me.sc.edu/research/AARG/magnetostrictive_actuators.htm • http://www.cedrat.com/applications/hardware/doc/ASSET2002_MAGNETOSTRICTIVE_vs_PIEZO_ACTUATORS.pdf • http://www.public.iastate.edu/~terfenol/homepage.html ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

4. To explore further (survival pointers of web references etc) • http://www.energeninc.com/pdf/Cryogenic%20Magnetostrictors.pdf • http://ieeexplore.ieee.org/iel5/8980/28507/01273841.pdf • http://adsabs.harvard.edu/abs/1996SPIE.2721..385K ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

5. Major applications • Ultrasonic cleaners • High force linear motors • Positioners for adaptive optics • Active vibration or noise control systems • Medical and industrial ultrasonics • Pumps • Sonar ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

6. Magnetostriction • Magnetostriction is the material property that causes a material to change its length when subjected to an electro-magnetic field. • Magnetostriction properties also cause materials to generate electro-magnetic fields when they are deformed by an external force. • The magnetostrictive materials are referred to as the Rare-Earth's. ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

7. Terfenol-D is a commercially available magnetostrictive material that has high magnetostriction at room temperatures • The difference between traditional magnetostrictive materials and giant magnetostrictive materials is the amount of strain per unit volume of the material.  Giant magnetostrictive materials undergo large amounts of strain (i.e., large deformations) for a given applied magnetic field.  Terfenol-D and Metglass come under the giant category. ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

8. . Typically a magnetostrictive rod is placed inside a coil They exhibit large output forces and quick dynamic responses. ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

9. Magnetostrictive Actuator • A coil is located around the rod which produces the necessary magnetic field for actuation operation. For a defined field production and field reduction the coil is driven with a given driving current I. ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

10. Working Principle • The basic idea is to squeeze a rod of Terfenol-D into a metal tube whose bore size is just slightly smaller than the rod's diameter, wrap a series of electromagnetic induction coils around the tube (or stator), and use the coils to generate a moving magnetic field that courses wavelike down the successive windings along the stator tube. ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

11. As the traveling magnetic field causes each succeeding cross section of Terfenol-D to elongate, then contract when the field is removed, the rod will actually "crawl" down the stator tube like a worm. Repeated propagating waves of magnetic flux will translate the rod down the tube's length, producing a useful stroke and force output. ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

12. Magnetostrictive Actuator Schematic ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

13. Specifications • Ref:http://www.mide.com/pdf_html/Magnetostrictive_Actuators.htm ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

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15. Other actuation materials, such as piezo-electric crystals, require high voltages (200 - 300 Volts) to produce desired mechanical deformations, whereas magnetostrictive materials respond to significantly lower voltages. Magnetostrictive materials do not decay over time—experience less hysterisis. A magnetostrictive device is fairly robust as far as wear and tear are concerned. Advantages ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

16. Giant Magnetostrictive Materials have very low Young’s Modulus which is an advantage for producing low-frequency resonators of compact size. • It exhibits higher dynamic strain at resonance. ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

17. Limitations • Usually temperature dependent. • These actuators can have problems when overheated. However, they can be made functional again at reasonable temperatures. • Exhibit small displacements. ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

18. Research Areas and Trends • Energen, Inc. developed compact actuators based on magnetostrictive materials. These actuators are designed to provide precision positioning and active control of adaptive optical surfaces. • Magnetostrictive actuator-based micropositioner and its application in turning. ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

19. Design of a smart magnetostrictive actuator by sensing the variation of magnetic fluxtofavor a miniaturized, simpler and cheaper mechatronic system design. ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

20. Manufacturers Some of the manufacturers of Magnetostrictive Actuators: • Energen, Inc. • Etrema Products • HoneyBee Robotics University of South Carolina Department of Mechanical Engineering has intensive research going into this. ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators