Dynamically Adaptive Feed Drives for High Performance and Energy Efficient Manufacturing

Background and Motivation

Linear motors are used for fast and accurate motion delivery in a wide range of precision manufacturing machines. They however consume a lot of energy and generate a lot of heat in the process. In this project, we explore a mechatronic design concept where the electro-mechanical structure of linear motor driven machines is designed much like the power train of hybrid electric vehicles; i.e., their structure is designed to intelligently vary in real-time as a function of the manufacturing operation being performed, so as to simultaneously  achieve high performance and improved energy efficiency.  Two specific cases are studied within this project:

• Design and control of a hybrid feed drive for high performance and energy efficient machining
  
• Design and control of a magnet assisted wafer scanner for vibration and heat reduction in (wafer) scanning

Highlights (Hybrid Feed Drive)

• A novel hybrid feed drive which switches rapidly between two modes of operation has been designed (see on right). It consists of a linear motor and a screw drive that work together to achieve up to 80% reduction in energy consumption while achieving similar speeds and precision as a linear motor.
• A energy efficient controller design approach has been developed for the hybrid feed drive; it optimally allocates control effort to its two actuators in order to achieve the best positioning performance and energy efficiency during machining.
• Future work will develop fast switching techniques that guarantee stable and smooth switching between its two modes of operation

Highlights (Magnet Assisted Scanning Stage)

• A patent-pending magnet assisted stage (see on left) has been developed. It uses magnetic repulsion to store and release kinetic energy during acceleration and deceleration thereby reducing the heating of the linear motors by over 75%. It simultaneously reduces residual vibration by over 50% during high-speed scanning by channeling the assist forces from the magnets to the ground
• Control techniques are currently under development for actively controlling the stage to achieve larger reductions in heat and vibration
• Stage can be used for wafer scanning, 3D printing, laser patterning and other processes which require precision scanning motions

Project Team and Collaborators

• Molong Duan (Ph.D. candidate, U-M)
  
• Deokkyun Yoon (Ph.D. candidate, U-M)

Related Publications/Patents

• Yoon, D., Okwudire, C.E., 2015, “Magnet Assisted Stage for Vibration and Heat Reduction in Wafer Scanning,” Annals of the CIRP, Accepted (pdf)
• Yoon, D.,  Okwudire, C.E., 2015, “Active Assist Device for Precision Scanning Stages,” Accepted for presentation at the 2015 ASPE Annual Meeting, November 1-6, 2015, Austin, TX
  
• Duan, M., Okwudire, C.E., 2015, “Energy Efficiency and Performance Optimized Control of a Hybrid Feed Drive,” Accepted for presentation at ASME International Manufacturing Science and Engineering Conference (MSEC), June 8-12, 2015, Charlotte, NC.
• Yoon, D., Pan, Y., Okwudire, C.E., 2014, “Magnet Assisted Stage for Efficient Wafer Scanning,” ASPE 2014 Annual Meeting, November 9-14, 2014, Boston, MA. (pdf)
• Kale, S., Dancholvichit, N., Okwudire, C.E., 2014, “Comparative LCA of a Linear Motor and Hybrid Feed Drive under High Cutting Loads,” 6th CIRP High Performance Cutting Conference,June 23-25, 2014, Berkeley, CA. (pdf)
• Okwudire, C.E., Rodgers, J., 2013, “Design and Control of a Novel Hybrid Feed Drive for High Performance and Energy Efficient Machining,” Annals of the CIRP, Vol.62, No.1. pp. 391-394. (pdf)
• Okwudire, C.E., Yoon, D., Active Assist Stage for Scanning Applications. U.S. Patent (Pending).
  

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