Robot Control #
- Last time we started to vibe code a program to cut down trees.
- Today I want to think a bit more and finish that program manually.
Key idea: Levels of abstraction.
- High level: We’re going to find and cut down trees.
- Low level: Move forward.
What goes in the middle?
To find out, we need to take the high level description and break it down into pieces:
Search area for trees and cut them down.
- Search area for a tree.
- Then cut it down.
- Then return to the search.
- Continue until whole area has been searched.
To search for a tree.
- We need to follow some pattern that covers the area.
- Foward and back, alternating columns.
- Spiral
- Hilbert Curve
- etc
- Stop when we run into a log.
To cut down a tree.
- Chop the log.
- Move to where the log was.
- Chop up until we run out of logs.
- Find any more tree.
Return to the search.
- Problem: Not all trees are the same size / shape.
- Problem: After chopping down a tree we don’t know how to get back.
- Solution: Track what moves we made.
- Three dimensions x is east, z is south, y is up.
- If x is forward, z is right, y is up.
- Every time we move, update variables tracking our position and direction.
- Instead of calling turtle.forward() or other movement functions, make a function that “wraps” that function and also updates position.
- Now we know why we needed dx and dy last time; those are direction.
- To return to the starting point, just make the moves needed to zero out the difference from our starting point. That may even be a more direct path than how we went chopping down the tree.
Continue
- One of the neat things about structuring our programs as functions is that when we return from a function we naturally just keep doing whatever we were doing before.
