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: Jonathan Meikle Dept. of Electrical and Computer Engineering Utah State University E: ; T: (435)797-; F: (435)797-3054 (ECE Dept.) W: http:// 3/10/2006

2. Outline • Reference list • To probe further • Overview • Major applications • Basic working principle illustrated • A typical sample configuration in application (application notes) • Major specifications • Limitations • Conclusion ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

3. Reference list • University of South Carolina, Mechanical Engineering Dept. <http://www.me.sc.edu/ Research/AARG/ magnetostrictive _actuators.htm> • C.H. Joshi, A. Mavanur, C-Y Tai, Z-X Han, A. J. Rodenbush, Y. Wong. Energen, Inc. “Cryogenic Magnetostrictive Materials and Devices”. • C.H. Joshi, Energen, Inc. “Compact Magnetostrictive Actuators and linear Motors” • Ashley, Steven. Mechanical Engineering Magazine “Magnetostrictive Actuators”<http://www.memagazine.org/backissues/june98/features/magnet/magnet.html.> • Science 501.com Homepage <http://www.science501.com /PTElements.html> ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

4. Reference List • Mide.com Homepage. “Magnetostrictive Actuators” <http://www.mide.com/pdf_html/Magnetostrictive_Actuators.htm> • Telecscope Guider Maintenane Manual “Telescope Guider” <http://rise.hao.ucar.edu/InstDoc/telescope_guider.htm> ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

5. To explore further (survival pointers of web references etc) • Pons, Jose L. “Emerging Actuator Technologies: A Micromechantronic Approach”. • Engdahl, Goran. “Handbook of giant Magnetostrictive materials”. • Niku, Saeed B., Prentice Hall. “Introduction to Robotics: Analysis, Systems, Applications”. ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

6. Overview • “As the trend towards an electromechanical world continues … magnetostrictive materials will be of great benefit to design engineers”1 • A magnetostrictive actuator is classified as any actuator that operates due to the magnetostriction. • Magnetostriction was first identified in 1842 by James Joule ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

7. Major applications Linear Stepper Motors • Some major applications of Magnetostrictive Actuators include the following: • Linear Stepper Motor: This actuator is capable of a stroke of several millimeters • Different variations of this model can provide a long stroke with high resolution.2 Figure 12 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

8. Major applicationsLinear Actuators • Vibration Control • Precise mechanical positioning • Robotics • Switch and Valve Operation • Fine Tuning3 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

9. Major applicationsAerospace • Magnetostrictive Actuators have found place on the Hubble Telescope successor. • The actuators will be responsible to “align various mirror segments and to control and adjust the curvature of each segment”2 • “This will improve image quality and enable remote image correction” 2 Figure 32 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

10. Major applicationsAviation • Change wing profile during flight • This ability will optimize the performance of the wing through different stages of a flight. • Reduce drag, and increase efficiency. Figure 43 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

11. Basic working principle Figure 55 • Magnetostrictive actuators operate due to the magnetostriction effect. • Magnetostriction is the ability of some materials (magnetostrictive materials) to deform when exposed to a magnetic field. • The materials are more commonly known as the Rare-Earth materials. Rare Earth Materials ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

12. Basic working principle • Often Giant magnetostrictive materials are used in place of magnetostrive materials • The difference is the amount of strain per unit volume. • Giant magnetostrictive materials undergo large amounts of strain for a given magnetic field.1 • Terfenol-D is a giant magnetostrictive material that is most commonly used. ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

13. Basic working principleLinear actuator • The rod of Terfanol-D is inserted into a metal tube and wrapped with electromagnetic induction coils. • This produces a stator Figure 66 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

14. Basic working principleLinear actuator • “The coils (stator) generate a moving magnetic field that courses wavelike down the successive windings along the stator tube.”4 Figure 74 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

15. Basic working principleLinear Actuator • “As the magnetic field causes each succeeding cross section of Terfenol-D to elongate and contract, the rod will actually ‘crawl’ down the stator tube like a worm”.4 • Successive iterations of this action will cause the rod to translate and produce and useful stroke and force output. • The amount of force produced is proportional to the applied magnetic flux. ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

16. Sample configuration • Two magnetostrictive actuators are mounted to the rear of this telescope to drive the mirror. • The magnetostrive actuators provide precision positioning and control Figure 7 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

17. Major specifications • Major specifications for a magnetostrictive actuator include6: • Actuator requirements: • Response Time/Timing • Stroke • Force • Temp. Environment • Volume Figure 86 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

18. Major Specifications • Actuator geometry6 • Rod diameter • Rod length • Maximum Magnetostrictive Strain • Coil length • Number of winding • Coil Outer Diameter • Coil Resistance Figure 96 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

19. LimitationsAdvantages • Large strain, and high force compared to piezoelectric materials. • High energy density • Due to the fact that magnetostrictive materials do not decay over time, it is reliable • No permanent damage due to overheating • High Strength to weight ratio ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

20. LimitationsAdvantages • Wide operating temperature range for Giant Magnetostrictive material • Require less voltage to operate than piezoelectric materials • High precision • Extended stroke relative to piezoelectric ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

21. LimitationsDisadvantages • Small stroke relative to larger actuators • Not capable of high forces • Generally temperature dependent (when Giant Magnetostrictive Materials are not used) ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

22. Conclusion • Magnetostrictive actuators are becoming more important as the mechatronic field grows. • The high force to weight ratios prove valuable in many applications. • Continued research looks to advance this field and increase the uses for the actuators. • The small size of these actuators will become more useful as mechatronis grows as well. ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators