After some last-minute hacking to get my s/w to smoothly integrate 3-point turns plus smooth PID-type turning, the Ford truckbot was sent out Wed night to circle the block.

The mission met with "mixed success". While the turning code worked OK, the bot lost contact with the base AP at a range of only 50 m, so executed an "abort" and shut down on the nearest of the 4 corners on the block.

Like most of my robot s/w, the ultimate controlling is done by some goal-oriented Prolog. And one of the (several) great things about Prolog programming is the ease with which you can hack in a correction to a complex set of instructions. (I.e. "clauses" nearer the top of the source file take precedence over those later in the code; you can also ensure a given "hack" clause causes later alternatives to be simply dropped. This is all pretty much a hacker’s dream and a maintance programmer’s nightmare .

So it was only a matter of seconds before the idea of simply "aborting" was short-circuited unless there was REAL trouble (i.e. none of a shortlist of things that could actually be ignored for the night).

Mission 3.2 met with another problem that saw much the same result. After driving up-hill along my driveway, turning left at the gate, and moving to the nearest corner, truckbot decided something didn’t smell right about it’s inertial positioning, and executed a return-to-base. Which it actually managed to perform accurately by simply backtracking on its course — it didn’t rely on the it-assumed-faulty position estimating. (The GPS positioning data wasn’t much help in soothing truckbot’s estimated location problems since the entire mission track was not much longer than the Trimble board’s location error).

During the 60 mins or so all this took I managed to record images from the on-board IR camera. However, even the 200 mw TX attached to the camera didn’t seem to reliably connect to the purpose-built AP I’d attached to the top of a pole PoE-style.

Beside learning a few things about internal status monitoring (is is worth it, or should you just accomplish the mission regardless of how well the bot thinks it’s doing? , I did finally managed to decode the vid the AP was stashing on a DVR. I’d always wondered how to decode those .VOB files — now I think I know.

In the 60 mins of vid, there is — however — only a few 1000 monochrome frames that actually show anything recognisable. (Shots of local streetlights against a night sky are not counted in the definition of "recognisable").

I have the converted MPEG4 on a laptop, and will try to fish around in it to get some sample shots.

The DVR footage also seemed to catch a bit of experimenting with using the IR cam as a cat-spotter. (I’ve had trouble with neighbourhood cats sneaking into my kitchen at night and stealing *my* kitten’s foot — as well as beating it up). I’ll add a bit of that to the YouTube item, too.

I’ll attach the YT ref tomorrow, when the fishing & uploading are done.

UPDATE:

The other attached vid is from the Chicago bot club’s robomagellan contest. My cat vis is elsewhere, and processing of my truckbot’s vid is on-going. :{

UPDATE 28 Aug 2008:

Yes, I finally managed to process the 12 min of .vob file into something you can see. But only just. The other 11 mins is just static. So much for 200 mw TX on the robot; it looks like it needs a much better mobile antenna!