Electromechanics: Integrating 19th Century Theory with 21st Century Technology – Applications to Aerospace Systems
Gregory D. BucknerAssistant Professor
Department of Mechanical
and Aerospace Engineering
September 4, 2003
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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
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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:
Electrica lSystem
M agneticF ie ld
M echanicalSystem
Electrica l Losses(Coil Resistance)
M echanical Losses(S lid ing Friction)RV BF
i,e v,f
Electrica lInput/O utput
i,V
M echanicalO utput/Input
v,F
Lossless
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• 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
WHAT IS ELECTROMECHANICS?
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• Electromechanics Mechatronics (though the two are highly related and complimentary)
WHAT IS ELECTROMECHANICS?
Electro-Mechanics
Electrical andComputer
Engineering
Mechanical andAerospace
Engineering
Computer andInformation
Science
Mecha-Tronics
ElectricalComputing
MechanicalComputing
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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
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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
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• 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
ELECTROMECHANICS RESEARCH AT NCSU
NASA Graphics from website GDB 090403-8
• Intelligent Controllers for Active Magnetic Bearings
ELECTROMECHANICS RESEARCH AT NCSU
– 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!
– CONs• AMBs are inherently unstable, highly nonlinear
• Gyroscopic and bending effects, model uncertainty
NASA Graphics from website
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• Intelligent Controllers for Active Magnetic Bearings
ELECTROMECHANICS RESEARCH AT NCSU
– 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
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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
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• 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
ELECTROMECHANICS RESEARCH AT NCSU
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Boeing Graphics from website
• 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
ELECTROMECHANICS RESEARCH AT NCSU
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• 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
ELECTROMECHANICS RESEARCH AT NCSU
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• 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
ELECTROMECHANICS RESEARCH AT NCSU
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• 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
ELECTROMECHANICS RESEARCH AT NCSU
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• 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
ELECTROMECHANICS RESEARCH AT NCSU
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• 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
ELECTROMECHANICS RESEARCH AT NCSU
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• 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
ELECTROMECHANICS RESEARCH AT NCSU
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• 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
ELECTROMECHANICS RESEARCH AT NCSU
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• 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
ELECTROMECHANICS RESEARCH AT NCSU
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