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Information about Aerobot

Aerobot - An autonomous flying robot

The project Aerobot is developing a semi-autonomous airborne robot for indoor use, which can assist the walking robot AIMEE during exploration missions (like the RoboCup Rescue League). Aerobot should be carried on top of the walking robot and be able to take off and land on it, therefore giving the operator a better view of the surroundings.

The goal is to develop an airborne robot, based on a model helicopter, which can fly autonomously without operator interaction. The tasks for the operator are restricted to easy commands like takeoff or land. All functions needed for a stable flight should automatically be controlled by a ground based computer. Therefore enabling the aerobot to continuously hover above the walking robot and being used a flying eye. To accomplish this the aerobot is equipped with a little camera which transmits its images to the operators graphical user interface. Allowing the operator to get a better overview of the surrounding and to detect obstacles/victims more easily.

Flight stabilization for a helicopter is by no means trivial because a helicopter reacts pretty sensitive to changes of its surroundings, which modify the airflow generated by the helicopter's rotor blades. For instance the flight over a ramp will cause the helicopter to tilt suddenly, destabilizing the flight. A goal is to detect such changes caused by external influences and to compensate by software to always have a stable flight. Furthermore the software should take care of keeping the aerobot above the walking robot continuously.

The stabilization of the flight has to control the following parameters of the helicopter:
  • height
    The helicopter has to constantly keep a given height (relative to the ground)
  • roll
    To roll means the helicopter is tilting sidewards, causing it to fly to that direction
  • nick
    To nick is lowering/lifting the nose or tail of the helicopter, allowing it to fly forwards or backwards
  • gear
    To gear is to turn the helicopter around its own axis. This has to be done controlled, to allow the aerobot to follow the walking robot


Basically the software has to perform the following functionalities:
  • flight stabilisation
    The helicopter has to be kept stable in the air to enable it to follow the walking system.
  • takeoff/landing
    The helicopter has to be able to take off or land autonomously upon operator command. In order to do so the rotor's speed must be in- or decreased in a controlled manner to prevent the system from crashing or uncontrolled lifting. Additionally special requirements to the flight stabilisation occur, because helicopters near ground have to deal with the so called ground effect which destabilises the flight
  • collision avoidance
    To protect the system it has to be able to detect obstacles and their distances, and to avoid them.
  • landmark tracking
    The helicopter should follow the walking system, in order to do so, it is equipped with a camera facing the ground. The walking robot has marks on it allowing it to be tracked and followed.
 
 
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© 2005 - 2007 Universität Bremen - Fachbereich 3
Arbeitsgruppe Robotik - Projekt Rescue Robotics