Posts Tagged ‘aerial’

December 8th, 2010

Flying robot actors - article


A Midsummer Night’s Dream (with flying robots)
Robin Murphy, Dylan Shell, Amy Guerin, Brittany Duncan, Benjamin Fine, Kevin Pratt, Takis Zourntos

Around a year ago, theater-goers at Texas A&M discovered Shakespeare’s play “A Midsummer Night’s Dream”. The plot unfolds in a magical forest inhabited by fairies. To add to the otherworldly feel of the play, one large remote controlled quadroter and six palm sized helicopters, in their LED costumes, were used to complement the performance of “human fairies”.



Cooperating with people from theater is interesting because of their expertise in predicting how spectators will interpret the behavior of agents and what to do to make the agents believable. Furthermore, the theater is an ideal large-scale testbed to study the response of “untrained” humans (the audience and actors) to robots.

After four weeks of practice and eight performances, Murphy et al. came up with an impressive analysis of how robots were perceived. First, they identify three ways robots can generate emotional or cognitive impact (affect):

  • 1) The audience interprets the motion of robots as if they were living creatures (animacy). In one example, helicopters flying in rhythm to the music were deemed “excited by the music”.
  • 2) Actors, through their theatrical interaction with the robots, give them a meaning. Fairies scolding or cooing helicopters, and the fact that the robots would land in their hands, made the audience interpret them as “baby fairies”.
  • 3) Robots, through their behavior, are able to convey meaning. In the play, helicopters were able to play sounds and perform easy to interpret motions that were assimilated to mocking or joy.

Furthermore, the paper is a beautiful account of how people react to robots and assume they are safe and robust. Examples include approaching 1m quadrotors up close, throwing helicopters like a baseball to make them take off or assuming small helicopters will stay in the air if you waive your hands around them. The work also provides a nice summary of all the unintended situations that can arise (see table below) and the need of improvisation to deal with them.

For the future, Murphy et al. are planning new productions where robots have key roles!

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November 18th, 2010

Cooperative payload transport with quadrotors - article


Cooperative manipulation and transportation with aerial robots
Nathan Michael, Jonathan Fink, Vijay Kumar

Just the other day, a noisy helicopter was flying above campus, carrying large batches of solar panels to hard to reach rooftops. You might have also seen people dangling from helicopters in rescue missions or the transportation of materials in military, industrial and construction applications. Pushing the limits of aerial payload transportation this spring, the Alinghi catamaran was “shipped” to sea using a Mil Mi-26 helicopter, the biggest and most powerful in the world (see picture below).

AP Photo/Keystone/Jean-Christophe Bott

Rather than going for large helicopters with experienced pilots, Michael et al. explore the possibility of using multiple autonomous quadrotors. By working together, the robots can potentially lift heavy objects and can position themselves in such a way that the pose of the object can be controlled. Simply put, in the image above, there is no way to tilt the catamaran sideways by 45 degrees whereas a system with multiple robots could do the trick.

More specifically, the researchers consider the problem of controlling multiple robots manipulating and transporting a payload in three dimensions via cables. To do so they derive a mathematical model that ensures static equilibrium of the payload at a desired pose while respecting constraints on cable tensions.

Experiments shown in the video below were conducted with three AscTec Humming-bird quadrotors from Ascending Technologies GmbH. Localization information was provided by a Vicon motion capture system that consists in a set of cameras in the room that monitor the robots at high speed. The robots are able to lift a triangular payload, change its pose and transport it while avoiding inter-robot collisions.

In the future, Michael et al. hope to find a way to make the robots damp out oscillations that occur when the payload moves.

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