Group leader

Dr. Paolo Stegagno
Phone: +49 7071-601-218
Fax: +49 7071 601-616
Opens window for sending emailpaolo.stegagno[at]
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Recent Journal Publications

Grabe V, Bülthoff HH, Scaramuzza D and Robuffo Giordano P (July-2015) Nonlinear ego-motion estimation from optical flow for online control of a quadrotor UAV International Journal of Robotics Research 34(8) 1114-1135.
Ryll M, Bülthoff HH and Robuffo Giordano P (February-2015) A Novel Overactuated Quadrotor Unmanned Aerial Vehicle: Modeling, Control, and Experimental Validation IEEE Transactions on Control Systems Technology 23(2) 540-556.
Zelazo D, Franchi A, Bülthoff HH and Robuffo Giordano P (January-2015) Decentralized rigidity maintenance control with range measurements for multi-robot systems International Journal of Robotics Research 34(1) 105-128.
Franchi A, Oriolo G and Stegagno P (September-2013) Mutual Localization in Multi-Robot Systems using Anonymous Relative Measurements International Journal of Robotics Research 32(11) 1302-1322.
Lee D, Franchi A, Son HI, Ha CS, Bülthoff HH and Robuffo Giordano P (August-2013) Semiautonomous Haptic Teleoperation Control Architecture of Multiple Unmanned Aerial Vehicles IEEE/ASME Transactions on Mechatronics 18(4) 1334-1345.
Son HI, Franchi A, Chuang LL, Kim J, Bülthoff HH and Robuffo Giordano P (April-2013) Human-Centered Design and Evaluation of Haptic Cueing for Teleoperation of Multiple Mobile Robots IEEE Transactions on Cybernetics 43(2) 597-609.
Censi A, Franchi A, Marchionni L and Oriolo G (April-2013) Simultaneous Calibration of Odometry and Sensor Parameters for Mobile Robots IEEE Transaction on Robotics 29(2) 475-492.
Robuffo Giordano P, Franchi A, Secchi C and Bülthoff HH (March-2013) A Passivity-Based Decentralized Strategy for Generalized Connectivity Maintenance International Journal of Robotics Research 32(3) 299-323.
Franchi A, Secchi C, Son HI, Bülthoff HH and Robuffo Giordano P (October-2012) Bilateral Teleoperation of Groups of Mobile Robots with Time-Varying Topology IEEE Transaction on Robotics 28(5) 1019-1033.
Franchi A, Masone C, Grabe V, Ryll M, Bülthoff HH and Robuffo Giordano P (October-2012) Modeling and Control of UAV Bearing-Formations with Bilateral High-Level Steering International Journal of Robotics Research 31(12) 1504-1525.
Franchi A, Secchi C, Ryll M, Bülthoff HH and Robuffo Giordano P (September-2012) Shared Control: Balancing Autonomy and Human Assistance with a Group of Quadrotor UAVs IEEE Robotics & Automation Magazine 19(3) 57-68.

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Design and Control of Novel Aerial Robots

Click to Enlarge. CAD model of quadrotor with actuated propeller orientation
Common UAVs (Unmanned Aerial Vehicles) are underactuated robotic systems (this is for instance the case of helicopters and quadrotors). As a consequence, only their position and yaw angle can be independently controlled, and the behavior of their pitch and roll angles are completely determined by this choice. This underactuation does not only limit the flying ability of UAVs, it further degrades the possibility of interacting with the environment by exerting desired and arbitrary forces.
This motivates our research to move quadrotors from pure flying vehicles to fully flying service robots which are able to move and exert forces in all directions in space. To this end, we developed a novel concept of a quadrotor UAV with tilting propellers (i.e. the propellers can be rotated along the arm axes).
Research goals:
  • Independent control of position and orientation of the quadrotor main body
  • Ability to apply forces in all directions
  • Gripping and placing objects from arbitrary positions
  • Manipulation with the environment
Visit Markus Ryll's page for additional information.


Click to Enlarge. Red - propeller spinning velocity; green - rotor arm spinning velocity
Thanks to the 8 control inputs (4 propeller spinning velocities, 4 rotor arm spinning velocities) of our novel quadrotor, it becomes possible to obtain full control over the main body configuration space in R3 x SO(3). As a first proof of concept, we derived a physical model based on the actual properties of our prototype (e.g. mass, inertia, communication delays) and simulated the behavior based on a dynamic feedback linearization controller. We could show that our controller is able to track any arbitrary trajectory in R3 x SO(3). It is interesting to note that, as long as the propellers keep on spinning, no singularities in the control action can occur for any propeller-body configurations.


Click to Enlarge. Prototype of the actuated quadrotor on the test bed
We have designed and built an actual prototype of the actuated quadrotor and performed several experimental tests in an indoor arena, thus confirming the validity of our approach. Here we have to tackle different kind of problems from a control point of view:
  • Time delays in the signals and the actuators
  • Control uncertainties at the actuators
  • Coping with unideal actuators
  • Limitations in the computational power
  • Noise in the sensor readings
  • Aerodynamic problems

Essential Publications in this Topic

Ryll M, Bülthoff HH and Robuffo Giordano P (May-2012) Modeling and Control of a Quadrotor UAV with Tilting Propellers, IEEE International Conference on Robotics and Automation (ICRA 2012), IEEE, Piscataway, NJ, USA, 4606-4613.
CiteID: RyllBR2012_2

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Last updated: Friday, 23.02.2018