to control flying robots for physical interaction

Aerial Inspection at Close Proximity

An autonomous quadrotor system equipped with a winch-tethered magnet that is capable of perching on and sliding along a vertical surface for inspection at close proximity. The first realization of a tethered quadrotor that can hover and perch vertically near infrastructure elements, enabling a variety of surface manipulation and repair tasks.


H. Nguyen, B. Stephens, M. Kovac "Aerial inspection at close proximity: a multi-modal mobility approach", ICRA, 2019. (Video Contribution)
[featured in Reuters TV] [on Imperial College] [on EMPA]

Adaptive Tensile Perching

An autonomous quadrotor system equipped with a passively adaptive perching mechanism which allows an aerial vehicle to stably attach to a variety of surfaces including tree branches and pipelines. A hybrid force-motion controller is developed to ensure the cable tension to be regulated as the vehicle achieves the desired attitude. The hybrid control approach exploits the mechanical compliance of the system to ensure reliable, stable attachment to irregular natural structures, and the addition of a winch allows the robot to stably orient itself in any position or orientation relative to the branch.


H. Nguyen*, R. Siddall*, B. Stephens, A. Navarro-Rubio, M. Kovac "A passively adaptive microspine grapple for robust, controllable perching", RoboSoft, 2019. (* equal contribution)

Spherically-connected multi-Quadrotor Platform (SmQ)

SmQ platform is a new platform for aerial manipulation, which consists of a tool (or frame) with multiple quadrotors connected to that by spherical joints, acting as distributed rotating thrust generators. Lyapunov control design is performed while taking into account the spherical joint limits in a form of real-time constrained optimization.


H. Nguyen, S. Park, J. Park, D. J. Lee "A novel robotic platform for aerial manipulation using quadrotors as rotating thrust generators", IEEE Transactions on Robotics, 34(2), 353-369, 2018. (IF: 4.264, SJR: 100/6810 in Engineering)
[S3Q-Platform] [S2Q-Platform] [featured in IEEE Spectrum] [in Interesting Engineering]

H. Nguyen, S. Park, D. J. Lee "Aerial tool operation system using quadrotors as rotating thrust generators", IROS, 1285-1291, 2015.
[manuscript] [slides] [video] [featured in IEEE Spectrum]

Quadrotor-Tool System (QT)

We propose a novel control framework to enable a quadrotor to operate a tool attached on it. We fully characterize the internal dynamics of the spatial quadrotor tool operation, which arises due to the quadrotor’s under-actuation, and elucidate a seemingly counter-intuitive necessary condition for the internal stability, that is, the tool-tip should be located above the quadrotor’s center-of-mass. We further manifest that this internal dynamics can exhibit finite-time escape and propose a stabilizing action to prevent that.


H. Nguyen, C. Ha, D. J. Lee "Mechanics, control and internal dynamics of quadrotor tool operation", Automatica, 61, 289-301, 2015. (IF: 6.126, SJR: 20/6810 in Engineering)
[manuscript] [video 1] [video 2]

H. Nguyen, D. J. Lee "Hybrid force/motion control and internal dynamics of quadrotors for tool operation", IROS, 289-301, 2013.
[manuscript] [slides]