Pool Test 06/27/2024

Since the prequal has been completed, our focus has shifted to completing at least one competition task before we leave. This would be either the gate or the buoy. On days that we’re able to get two lanes, we’ll focus on the gate task. Otherwise, we’ll focus on the buoy task.

Today, our main goals were to ensure the gate and buoy props are ready to be used for testing the gate and buoy tasks, and ensuring the robot could survive a barrel roll.

We adjusted the buoy’s mooring line length to ensure the buoy was no more than 4ft from the bottom of the pool, as it will be at RoboSub. We also added a chain of zip ties to the legs of the gate to provide multiple heights for attaching the weights, which we can adjust based on the depth of the pool at the location of the gate.

For the barrel roll, we first had the swimmer manually flip the robot with it turned off. We didn’t observe any water at the top of the capsule, and compared the humidity before and after and found the difference was negligible.

We then barrel rolled a few times using the joystick, which the robot completed successfully. A small note of caution is that the small hat-switch is difficult to keep pointed straight left or right; slight deviations happen, which causes the robot to roll and pitch simultaneously. Again, this did not result in any leaks or humidity increases.

Finally, we wrote a first draft of the code to barrel roll programmatically. The barrel roll itself is done by switching to desired power, publishing a nonzero power for roll, and waiting for a few seconds while the robot completes two full flips. State goes crazy during this, so we don’t have any direct way of determining how much the robot has rolled, so we will just have to tune the duration of the roll. The difficult part, however, is what comes after – stabilizing the robot and its state. This part is still a work in progress.

We did not observe any water inside the capsule after the test. So far, all tests in which we have re-greased the o-ring before the test have not had any leak issues, while the others have had minor leaks (even though they were only one or two pool tests removed from when we did re-grease), so it seems that re-greasing the o-ring frequently is key to avoiding leaks.