Gregory D. Buckner Assistant Professor Department of Mechanical and Aerospace Engineering

1. Electromechanics: Integrating 19th Century Theory with 21st Century Technology – Applications to Aerospace Systems Gregory D. Buckner Assistant Professor Department of Mechanical and Aerospace Engineering September 4, 2003 GDB 090403-1

2. PRESENTATION OVERVIEW • Electromechanics • What is Electromechanics? • Bridging 19th Century Theory with 21st Century Technology • Electromechanics Research at NCSU • EM Research Laboratory • Active Magnetic Bearings • Automated Chatter Prediction on HSM Centers • Semi-Active Vehicle Suspensions • Other Projects • Conclusions GDB 090403-2

3. WHAT IS ELECTROMECHANICS? • Electromechanics explores the interactions of electric and magnetic fields (electromagnetism) and how these interactions can be harnessed to produce mechanical work • An inherently multi-disciplinary engineering field • The design, analysis, and control of electric machines: GDB 090403-3

4. WHAT IS ELECTROMECHANICS? • Electromechanics is a “mature” engineering discipline • Principles unchanged since the 19th century (Maxwell’s equations) • The design of many industrial machines (motors, generators) has changed little in the past 25 years • Once a core component of the Electrical Engineering curriculum, now few engineering undergraduates are exposed GDB 090403-4

5. WHAT IS ELECTROMECHANICS? • Electromechanics  Mechatronics (though the two are highly related and complimentary) GDB 090403-5

6. WHAT IS ELECTROMECHANICS? • Recent advancements in technology have renewed interest and extended applications • Materials • High-energy permanent magnets • “Smart materials” – SMAs, MR fluids, magnetostrictives, etc. • Superconductors, hi-mu alloys • Manufacturing Processes • Precision machining – DTMs, ultramills • MEMS fabrication - silicon micromachining, LIGA, etc. • Computational Advancements • Microcontrollers • Design software – FEA, BEM • Simulation software – MATLAB, Simulink • Control algorithms – adaptive and intelligent control GDB 090403-6

7. ELECTROMECHANICS RESEARCH AT NCSU • Electro-Mechanics Research Lab (EMRL) • Research focus: development and transfer of enabling technologies (a bridge between 19th century theory and 21st century technology) • Over $1.2M in research grants • $725K federal: NSF CISE, NSF DMII, NASA NIA, DOE NNP • $450K industrial: Ethicon (J&J), Gillette, Vulcancraft, Carrera, AO Smith, Hyster/Yale • $35K non-profit: Doris Duke, NCIIA • Supported 26 student researchers • 6 PhD (4 current) • 11 Masters (2 current) • 9 Undergraduate (2 current) • Resulted in 21 papers, 5 patent disclosures GDB 090403-7

8. ELECTROMECHANICS RESEARCH AT NCSU • Intelligent Controllers for Active Magnetic Bearings • Sponsor: NSF (CISE) • Research Objective: Develop self-learning (“intelligent”) AMB controllers that will enable the development of practical flywheel battery systems for automotive and aerospace applications NASA Graphics from website GDB 090403-8

9. ELECTROMECHANICS RESEARCH AT NCSU • Intelligent Controllers for Active Magnetic Bearings • Motivation: Flywheels for space applications • Motor when solar panels are active • Generate when panels are inactive • AMBs provide non-contacting support, reduce friction and wear, and eliminate lubrication concerns • Have higher power and energy densities than batteries • Longer life! NASA Graphics from website • CONs • AMBs are inherently unstable, highly nonlinear • Gyroscopic and bending effects, model uncertainty GDB 090403-9

10. ELECTROMECHANICS RESEARCH AT NCSU • Intelligent Controllers for Active Magnetic Bearings • Approach: • Artificial neural networks are used to characterize (“learn”) model uncertainty • These intelligent uncertainty bounds are fused with robust control synthesis • Resulting controller adapts for improved performance, responds to parameter variations • This fusion of intelligent and robust control is both innovative and applicable to a wide range of problems GDB 090403-10

11. ELECTROMECHANICS RESEARCH AT NCSU • Intelligent Controllers for Active Magnetic Bearings • Results: • This intelligent approach has been successfully applied to single-input, single-output magnetic bearings • Application to a 5-axis, flexible rotor AMB test rig is underway GDB 090403-11

12. ELECTROMECHANICS RESEARCH AT NCSU • Integrated Chatter Prediction on High Speed Machining Centers • Sponsor: Vulcancraft, Inc. • Research Objectives: • Increase High Speed Machining (HSM) productivity by predicting the onset of regenerative chatter on milling centers • Design non-contacting EM actuators, sensors, and algorithms for modal testing of HSM centers Boeing Graphics from website GDB 090403-12

13. ELECTROMECHANICS RESEARCH AT NCSU • Integrated Chatter Prediction on High Speed Machining Centers • Motivation: • HSM advantages: • Very high material removal rates (MRR) in aluminum • Tooth passing frequency approaches or exceeds first natural frequency • Parts simultaneously lighter, stronger, cheaper • Embraced by aircraft industry • HSM disadvantages: • Limited by unstable self-induced vibration… ‘regenerative chatter’ • Poor part surface finish • Tool wear/breakage GDB 090403-13

14. ELECTROMECHANICS RESEARCH AT NCSU • Integrated Chatter Prediction on High Speed Machining Centers • Approach: • Develop non-contating EM actuator, tool, displacement sensor • Use modal testing to identify the combined tool/toolholder/spindle dynamics • Use RCSA to identify the toolholder/spindle dynamics • Combined response for any tool can be computed GDB 090403-14

15. ELECTROMECHANICS RESEARCH AT NCSU • Integrated Chatter Prediction on High Speed Machining Centers • Results: • Developed non-contacting EM actuator, displacement sensor, tool • Currently validating RCSA to identify toolholder/spindle dynamics GDB 090403-15

16. ELECTROMECHANICS RESEARCH AT NCSU • Optimization and Control of MR Dampers for Semi-Active Vehicle Suspensions • Sponsor: Carrera, Inc. (Atlanta) • Research Objectives: • optimize the electromechanics of a commercial semi-active shock absorber • develop and demonstrate real-time actuation and control to improve ride quality and vehicle handling GDB 090403-16

17. ELECTROMECHANICS RESEARCH AT NCSU • Optimization and Control of MR Dampers for Semi-Active Vehicle Suspensions • Motivation: • Ride quality and vehicle handling represent design tradeoffs • Off-road suspensions require large displacements, peak forces • Active vehicles suspensions are COMPLEX, expensive, durability is questionable • Semi-active suspensions, particularly MR dampers, have fewer moving parts, are cheaper, more durable GDB 090403-17

18. ELECTROMECHANICS RESEARCH AT NCSU • Optimization and Control of MR Dampers for Semi-Active Vehicle Suspensions • Results: • Carrera’s Magneshock was redesigned using FEA for optimal EM performance • Efficiency, damping characteristics were significantly improved • FL controllers were developed and demonstrated on a vehicle equipped with Magneshocks • Ride quality was significantly improved vs. passive shocks GDB 090403-18

19. ELECTROMECHANICS RESEARCH AT NCSU • Other Ongoing Research Projects • AMBs for Tool Deflection Compensation in Precision Milling Operations • Sponsor: NSF (DMII) • Co-I: Dr. Tom Dow, NCSU Precision Engineering Center • Development of a Low-Frequency MEMS Vibration Sensor • Sponsor: DOE (NNP Fellowship) • Collaborator: Dr. Angus Kingon, NCSU Thin Films Lab GDB 090403-19

20. ELECTROMECHANICS RESEARCH AT NCSU • Other Ongoing Research Projects • Reliability Analysis and Life Prediction of Aircraft Structures • Sponsor: NASA (NIA) • Co-I: Dr. Mohammad Noori, NCSU MAE • Technology Development for Robot-Assisted Cardiac Surgery • Sponsor: CardioVations (J&J) • Collaborator: Dr. Randolph Chitwood, ECU Brody School of Medicine GDB 090403-20

21. ELECTROMECHANICS RESEARCH AT NCSU • Conclusions • Electromechanics research at NCSU focuses on the development and transfer of enabling technologies (a bridge between 19th century theory and 21st century technology) • A broad range of research projects are underway, funded by federal agencies and industries and conducted at the EMRL • Aerospace applications are obvious in many of these projects • Ideas for specific NIA projects are being explored GDB 090403-21