Colony Scout: Obstacle Avoidance with a Scanning Sonar

The Colony Scout sports a new chassis in its third major revision, with faster motors, a scanning sonar turret, and an upgraded sensor suite.

The Maxbotix EZ line of ultrasonic distance measurement sensors affords over 20 feet of ranging. A 7.5deg/step stepper motor positions the sonar for measurement. Each cycle takes ~50ms.

Several obstacle avoidance algorithms have been implemented: from a random deflection approach to a more calculated response dependent on sensor reading. All the techniques so far have used a fixed threshold, although I'm exploring adaptive thresholding based on the environment surrounding the robot.

As you can see, the sensor positioning needs a little work yet so the robot can detect lower obstacles. There will also be a rear facing sonar for full 360deg coverage.

The clips here show 3 position panning-- 45deg left, center, and 45deg right. I've also ran some tests with 13 positions from 90deg left to 90deg right. This takes longer to gather data, but gives a truer picture of the surrounding environment.

There's lots of work left to do, but we're off to a great start!

See danshope.com/blog for more details about the Scout!

Category:

Science & Technology

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• carnegie mellon
• swarm robotics
• robot
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• demo
• atv
• ugv
• rugged
• autonomous
• robotics
• CMU
• robotics club
• sonar
• sensor
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