Overview: Feed drives (i.e., motion delivery systems) of manufacturing machines are currently designed conservatively with fixed electromechanical structures, resulting in undesirable compromises among speed, accuracy and energy efficiency. The proposed research imagines feed drives designed like the powertrains of hybrid electric vehicles; it imagines that they are designed to intelligently vary their electromechanical structure in real time to achieve high performance and energy efficiency as a function of the manufacturing operation being performed. The key challenge with these so-called dynamically adaptive feed drives is that they require a design approach for generating the best combined dynamics (i.e., maximizing synergy) under fast switching. Therefore, the objective of this Faculty Early Career Development (CAREER) award was to investigate the introduction of "fast-varying dynamics" into feed drives and its synergistic exploitation as a means to simultaneously achieve high speed, high accuracy and reduced energy consumption/costs in precision manufacturing machines.

Intellectual Merit: A novel redundantly-actuated hybrid feed drive (HFD) which achieves high speed and precision, but uses up to 80% less feed energy compared the state of the art, has been proposed. The HFD achieves this feat by combining or switching between actuation by a linear motor and a rotary motor depending on the operating condition during machining. Motivated by the HFD, control approaches that enable (near) optimal energy efficiency in redundantly-actuated servo systems without sacrificing positioning precision have also been developed. In particular, a control approach that transforms the energy minimization problem into a standard regulation problem by using a proxy has been proposed. In parallel, a novel magnet assisted stage concept and associated controllers have been proposed. They enable reductions of up to 60% and 40% in heat and vibration, respectively, in wafer scanning applications without sacrificing positioning speed or accuracy. The magnet assisted stage achieves these improvements by adopting an idea similar to regenerative braking used in some hybrid electric vehicles. It switches smoothly between actuation by a linear motor during constant velocity motion and active assist via repelling permanent magnets during acceleration and deceleration. In all, 18 products (8 journal papers, 9 conference papers and 1 patent) have been created.

Broader Impacts: The PI has collaborated with a U.S.-based industrial partner (Aerotech Inc.) in developing the magnet-assisted stage. He has also engaged in commercialization efforts around the magnet-assisted stage through a regional I-Corps program. A graduate course - ME 584: Advanced Mechatronics for Manufacturing - has been developed and enriched with some of the knowledge created through this research project. Moreover, concept maps that connect the core concepts taught in mechatronics-related undergraduate courses at the University of Michigan have been created, and have inspired similar efforts by another faculty. A non-traditional outreach activity aimed at inspiring underrepresented minority middle school students in Detroit towards careers in engineering, using topics that resonate with them socio-culturally, was run over multiple years. Two PhD, one Master's and ten undergraduate students have been mentored through this project.

Last Modified: 03/25/2019
Modified by: Chinedum Okwudire