Project History

Autonomous helicopter development through incremental research platforms.

September 1991

Initial attitude control experiments

  • Attitude control testbed developed.
  • Used to test and tune attitude control system.
  • Electrical model helicopter mounted on a swiveling arm platform.
  • Optical encoder mounted with a frictionless bearing measures ground-truth angles in real time.
  • Configurable for roll, pitch, and yaw.

February 1992

Free flight and vision-based state estimator

  • Six-degree-of-freedom testbed developed for evaluating various position estimation and control systems.
  • Electrical model helicopter attached to poles by graphite rods for safety and helicopter ground-truth position estimation.
  • Lightweight composite material and custom designed frictionless air bearings allow unobtrusive helicopter free flight in a cone shaped area.
  • Mechanical stops prevent the helicopter from crashing or flying away.

September 1994

First autonomous platform

  • Indoor testbed developed as an intermediate step towards autonomous operation.
  • Used for testing the vision system, control system, sensor platform, power system, RF interference, and overall system integrity.
  • Allows relatively large (1.5 meter) longitudinal travel.
  • Severely limits helicopter travel laterally and vertically.
  • Helicopter is tethered with ropes which are fastened to the ground and two poles positioned on either side of the platform.
  • Steel rod with hooks on either end connects the ropes to the helicopter.
  • Steel rod is secured to the helicopter's center of gravity to eliminate any torques from restraining forces which could cause dangerous rotations.
October 1995

Autonomous Helicopter #1

  • Visual odometer (4 cm accuracy, 60Hz update), tracks image patches and templates with helicopter motion.
  • Initial computer control trials performed at relatively high (~15m) altitudes to allow safety pilot time to override computer.
  • Latitudinal and longitudinal controls were tested first by mixing human control for height and heading with the computer commands.
  • Heading and height control were enabled as the computer control proved effective in stabilizing the helicopter
  • GPS used for ground-truth measurements.
  • CNN coverage.
August 1996

Autonomous Helicopter #2

  • Control system for autonomous takeoff, landing and smooth trajectory following.
  • System tested in harsh conditions (40-45 mph wind gusts).
  • State estimator fusing data from a dual-frequency carrier-phase GPS receiver, 3-axis angular rate and inertial sensors, and field-rate vision-based odometry.
  • Custom-designed vision system capable of field-rate position sensing, multiple object tracking, color discrimination, and aerial intensity map building.
  • Custom-designed camera stabilization system.
  • 3D laser line scanner.
  • Power system for up to 33 minutes autonomous operation.
  • Winner of the 1997 Unmanned Aerial Robotics Competition
  • .
  • Journal of Robotics and Autonomous Systems (Oct 1997) article about the competition.
July 1998

Autonomous Helicopter #3

  • On-board laser mapping system
  • Deployed in Haughton Crater, Devon Island NWT Canada
  • Haughton Mission details

© 1998 Carnegie Mellon Robotics Institute