Camera fixed, Straight lines I haven't gotten a whole lot of vision work done in the past couple of days, mostly because the camera's been producing bad output. We finally tracked it down to a corroded cable last night, and have replaced it with a new camera, hopefully with a better connector. The compass is still not behaving, but its output is looking a lot better. We can probably fix it by recalibrating it; if not, it is usable over about 3/4 of its range. Even without the compass, we can make it through the gate on the IMU alone (and maybe hit the docking station). Time to go down to the pool and get this vision thing done.  ¶ kd5bjo @ 11:34, 0 comments

  Vision, Sonar, and Compass Sunday night, I swam laps with the sub for about an hour, and it only ever lost the line three times. Whenever it did that, though, it always picked up the adjacent one successfully. At the same time, Wes and Ian were unsuccessfully fighting with the sonar boards trying to read the time differential between two channels. Once they get that worked out, it looks like the sonar will be working properly.

The compass has also started reporting bad values, and we haven't been able to fix it yet. If the values were consistent, then we could probably use the compass, but at reduced effectiveness. The compass seems to have several different transfer functions and there is no way for us to know which one it is using this time. We also don't know if the problem is the compass reporting the value incorrectly or the AVR reading it incorrectly.

I was at the pool for about three hours yesterday, and discovered that the handheld PC that was loaned to us doesn't have a daylight-readable display, so it is mostly useless in the Texas sun. In the evenings, however, it is quite invaluable. I did some work on the compass yesterday, and it seems to be better. Unfortunately, that does not necessarily mean "useful". I also had trouble getting the vision system to recognize the test bins, but I believe that is because the pool is so shallow that it could never get the entire bin in frame at the same time.

Today's adgenda (for me) at the pool is:

1. Get the sub travelling straight by any means necessary. This probably means using the IMU's rate gyro to control our yaw speed to 0, independent of our heading.
2. Train the vision system on our test course elements in daylight. See how long it takes and how dificult it is with a washed-out screen.
3. Follow the orange pipe. This should just work, but it will be the first time the sub has followed a non-straight line.
4. Identify a bin in the camera frame. If necessary, use a surrogate bin that is a smaller target due to the shallowness of the pool.
5. Get the bin-seeking control system working.
6. Follow the orange pipe to a bin and stop at the bin instead of continuing along the line.
7. When sufficiently centered over a bin, dive to the bottom, remaining centered over the bin.
8. Drop markers on the bin.
9. Automatically abort the vision system when we have no more markers to drop.

I probably won't get all of this done today, but I will try. Once all of these steps happen, the vision system will be completely working, and we will be able to make it through the validation gate (and hopefully hit the docking station in the process). It also sounds like sonar is coming along nicely, so we should have a real contender here in a few days. Now the real question is whether "a few days" is before or after the competition.  ¶ kd5bjo @ 12:02, 0 comments

  Hectic Week I'm sorry that I haven't posted something up here for a week, but we've all been running to get problems fixed. As I was doing that, Wes was testing the new faceplace for leaks, of which it had plenty. It took us several days to find and fix all of them. At some point, the computer decided to stop working. We still have no idea why, but something failed and it doesn't power up anymore. We put our replacement board in, and everything worked great, in the lab. Once we got all of the leaks worked out, we put the electronics back in, and the computer refused to stay up for more than 10 minutes. We didn't get that figured out until Friday night, when we did a successful depth control run.

Yesterday, we didn't get into the pool, but we did get a lot of work done. We fixed the camera cable (which still needs to be tested); we installed the kill switch; we got the marker dropper working; we fried a servo; we fixed a communications problem between the sub and the buoy; we got the hydrophones mounted to the sub. Today, we need to verify all of that, and do something that looks a little like a mission run.  ¶ kd5bjo @ 10:36, 0 comments