Dobby Got Stuck Again

My roomba, Dobby, got stuck again.

This is the second time he’s gotten trapped in some chair legs.

I haven’t seen him get through the chair legs, but I have fished him out of them twice. Apparently, he just barely fits, and has to approach the chair legs at some precise angle to fit through, because he doesn’t get through them every time he vacuums the dining room.

The iRobot algorithm for bumping into something involves

1. Stopping
2. Backing up a little
3. Rotating a little
4. Proceeding forwards

I hypothesize that step 2, rotating a little, isn’t random, or at least has too big of an angular increment, so once Dobby gets between the chair legs, the algorithm doesn’t hit the precise angle to let him slip out. If I don’t notice he’s stuck, he uses all of his battery energy executing the iRobot bumped into something algorithm.

Poor, poor Dobby.