UNI-Copter: A portable single-rotor-powered spherical unmanned aerial vehicle (UAV) with an easy-to-assemble and flexible structure


This paper presents the design and modeling of the UNI-Copter, a portable spherical unmanned aerial vehicle (UAV) that is powered by a single rotor. This type of single-rotor spherical UAV has many advantages over other types of multi-rotor UAVs, but the spherical external structure takes up more volume, thereby reducing its portability. We focus on designing and building the UNI-Copter to provide ease of assembly and portability while taking advantage of the existing spherical structure. This paper explains our design concepts and the development process of improving the performance through various prototypes. We also verify flight stability of our new design by conducting several flight tests. To do so, a mathematical model of the UNI-Copter is derived in detail, and then we implement a state feedback controller for hovering flight. As a result, the indoor flight tests show stable performance, and the outdoor flight tests show that stable performance could also be achieved provided that the wind speed is low.

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Corresponding author

Correspondence to Joonbum Bae.

Additional information

Recommended by Editor Ja Choon Koo

Jae-Sung Moon received the B.S. degree in mechanical engineering from Pusan National University, Korea, in 2000, the M.S. degree in mechanical engineering from POSTECH, Korea, in 2003, and the Ph.D. degree in systems and entrepreneurial engineering from the University of Illinois at Urbana- Champaign, USA, in 2011. He was Assistant Research Professor and Postdoctoral Research Fellow with the School of Mechanical, Aerospace and Nuclear Engineering at UNIST (2011-2017). In 2017, he joined Chonbuk National University where he is now Assistant Professor in the Department of Mechanical Engineering. His research interests include dynamics and control of bipedal locomotion and humanoid robots.

Joonbum Bae received the B.S. degree in mechanical and aerospace engineering (summa cum laude) from Seoul National University, Korea, in 2006, and the M.S. degree in mechanical engineering, the M.A. degree in statistics, and the Ph.D. degree in mechanical engineering from the University of California at Berkeley, USA, in 2008, 2010, and 2011, respectively. In 2012, he joined the Department of Mechanical Engineering at UNIST, Korea, where he is currently the Director of the Bio- Robotics and Control Laboratory. His current research interests include modeling, design, and control of human-robot interaction systems, soft robotics, and biologically inspired robot systems.

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Moon, J., Kim, C., Youm, Y. et al. UNI-Copter: A portable single-rotor-powered spherical unmanned aerial vehicle (UAV) with an easy-to-assemble and flexible structure. J Mech Sci Technol 32, 2289–2298 (2018). https://doi.org/10.1007/s12206-018-0440-1

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  • Attitude control
  • Easy-to-assemble structure
  • Portable single-rotor unmanned aerial vehicle (UAV)
  • Spherical UAV