George Z.H. Zhu

Professor and Chair, Department of Mechanical Engineering,
York University

Research Interest: Dynamics and control of electrodynamic tether system for space debris removal, autonomous on-orbit service robot for space debris removal, and multifunctional materials for spacecraft structures.  

Speech Title:Computational Control for Suppressing Vibrations of Flexible Spacecraft Induced by In-Space Additive Manufacturing

Abstract:This talk introduces a computational Lyapunov-based control framework for mitigating vibrations in a flexible spacecraft excited by in-space additive manufacturing (ISAM), using a feedback law derived from Sontag’s universal formula. The ISAM platform is modeled as a rigid spacecraft bus carrying a 3D printer that fabricates a flexible truss, resulting in a beam structure with time-varying length (and hence time-varying mass and stiffness). For dynamic model and control design, the system dynamics are represented as a rigid base coupled to a growing flexible beam. To overcome the difficulty to design a control Lyapunov function for the coupled and time-varying rigid-flexible system, we innovatively synthesized a stabilizing feedback law using Sontag’s universal formula for an input-affine representation with finite elements. Base and appendage objectives are handled in a coordinated manner through separable (yet coupled) actuation channels: a base controller regulates translation and attitude, while a tip/appendage controller (or equivalent distributed actuation proxy) damps flexible modes and suppresses manufacturing-induced oscillations. Numerical studies demonstrate that the approach stabilizes both spacecraft motion and structural deformation despite base excitation and ongoing structural growth. Overall, the results highlight the feasibility of combining arbitrary Lagrangian–Eulerian (ALE) finite-element modeling of a morphing structure with nonlinear CLF/Sontag feedback to enable control of future large, flexible space systems that evolve on orbit during fabrication.

Bio

Prof. Zheng Hong (George) Zhu is a Professor and Tier 1 York Research Chair in Space Robotics and AI at York University’s Lassonde School of Engineering. He is also the founding Director of York’s Manufacturing Technology Entrepreneurship Centre and Space Engineering Design Laboratory. 
Prof. Zhu is widely regarded as one of Canada’s leading scholars in astronautics and is internationally recognized for his contributions to spacecraft dynamics and control, space robotics, space-debris mitigation, and space-tether technologies. In addition to his academic career, he brings 11 years of professional experience in the Canadian defence industry. This experience has helped shape a research and leadership approach that bridges fundamental inquiry, mission-oriented engineering, and applied technology development.
Prof. Zhu has published more than 450 peer-reviewed journal and conference papers, with over 8,600 Google Scholar citations and an h-index of 51. He has led major interdisciplinary programs, including two CubeSat missions and large-scale initiatives, e.g., in-space additive manufacturing,  funded by CFI, NFRF, NSERC, and CSA, totaling approximately $16 million. 
Prof. Zhu’s distinctions include election as an Academician of the International Academy of Astronautics and Fellow of the Canadian Academy of Engineering, Engineering Institute of Canada, Engineers Canada, Canadian Society for Mechanical Engineering, American Society of Mechanical Engineers, and Asia-Pacific Artificial Intelligence Association. He is also an Associate Fellow of AIAA and a College Member of the Royal Society of Canada. His honours include the 2024 Ontario Professional Engineers Awards Gold Medal, the 2024 CSME Solid Mechanics Medal, the 2021 Robert W. Angus Medal, and York University’s 2021 President’s Research Excellence Award.
He further shapes the field as Editor-in-Chief of Acta Astronautica, the flagship journal of the International Academy of Astronautics, and Associate Editor-in-Chief of the Chinese Journal of Aeronautics, China’s No.1 aerospace engineering journal.