Robo-blog

Cliff Avoidance

Very simple code, this- at startup the sensor is tilted down in such a way that it’s taking distance readings from the point about 12cm in front of the robot, which is normally just the table surface. If the sensor reading ever drops significantly (i.e., distance to nearest object increases substantially) it’s interpreted as a cliff and the robot does an about face to avoid driving in to thin air. Terrifying to watch it in action though, as several hundred quid worth of robot slowly and seemingly obliviously trundles towards the edge, green ‘happy’ light lit…

The straight line performance isn’t particularly straight, and the 180 degree turn is a bit off; I don’t have any way to determine how far its turned, such as a compass, landmark recognition or quadrature encoders on the wheels. The plan was to mix this code in with collision avoidance, scanning alternately for obstacles and cliffs- but given how close to the edge it gets even when constantly monitoring the ground, I think I want a dedicated sensor for this job. A cheaper, digital rangefinder should do the trick, and a regular check for cliffs should be easy enough to build into other projects. It might not ever be able to climb stairs, but at least it won’t fall down them now!