Using tethered robotics to launch flying and hovering robot agents for tactical airsuperiority in la

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Using tethered robotics to launch flying and
hovering robot agents for tactical
air-superiority in land warfare and
anti-terrorist activities
SPIE2004
Dr. Danny Ratner, A/Prof. Phillip McKerrow -
School of Information Technology and Computer
Science - University of Wollongong Australia
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Inspiration from marine tethered robotics -
creating global X-Y-Z manipulator
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Similarities and differences

• Robot is connected via cable to a stable host
  platform
• Both are stabilized by gravity
• Both have localized self-maneuverability
• Aerial tethered robot is fully supported by the
  cable, while marine robot is almost balanced
  self-floating
• Air damping much smaller than water damping

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Gravity stabilized sensing head

• Each tethered robot is equipped with a sensing
  head that includes mono/stereo vision on pan
  tilt unit and additional sensors.
• Vision provides
• visual servoing to correct the position of the
  robot with respect to images of the
  targeted environment,
• recognition of specific landmarks for navigating
  the robot, and
• data to the operator about operational
  conditions.
• Line of sight is controlled by moving the light
  camera against the inertia of the robot

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Concepts - tethered robot as a sensing head
carried by an electric hybrid robotic host
platform capable of hovering and flying
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Concepts -tethered robot equipped with
manipulator carried by an air-ship
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Concepts - tethered robot with a sensing head and
an airfield for robotics agents
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We are exploring a few concepts of robotic agents
capable of flying and hovering in confined
spaces. Agents will use ducted-fan technology
enabling it to collide with walls without
crashing the blades.
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We conducted many experiments with the
DraganFlyer to learn the fesability of robotic
agents launched near the target from a tethered
airfield. A flight simulator and a dynamic model
will be presented by Phillip McKerrow at
ICRA2004.
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Design issues

• Host can move in 6 dof, while robot is
  constrained by the cable in the vertical
  direction and gravity enables pendulum style
  motion on a sector of hemisphere
• Main concerns are effect of wind and bumpy air
• Host platform must be stable and much heavier
  than robot
• Other issues are effect of air damping, cable
  stiffness and controlling motion relationship
  between host to robot

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Simple model of force control
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Force control considerations

• Movements constraints system degrees of
  freedom
• X,Y and yaw are controllable like a turtle robot
• Z controlled by host
• Roll pitch are constrained by gravity spring
• Cable provides spring constant - which gives
  stability
• Active yaw control requires feedback due to lack
  of spring constant (compass or gyro)
• Design of the propulsion system
• Effect of force application relative to hinge
  point
• Gravity compensation for motor reaction torque
• Gyroscopic effects during yaw and pitch

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Propulsion configuration a
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Propulsion configuration b
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Mounting the wireless camera on custom made
pantilt unit
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LabVIEW control panel and digital video
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RD project - outdoor prototype
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Titan 4WD outdoor mobile robot to be used to tow
a balloon carrying a tethered robot
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Future plans

• Conduct outdoor experiments of the new tethered
  robot by hanging it from a weather balloon and
  towing it by the Titan 4WD outdoor mobile robot
  over a field
• Integrate our ducted-fan based robotic agents
  with the tethered robot and test the launching of
  the agent into a structure with confined space