Ready for Testing!
Phase 1: Damn Yankee Usability
Sprint 2, October 25 — November 8
The goal of this sprint was to finish all of Damn Yankee to get it ready for testing, and then to test it. We did not end up getting to test during this sprint, but we were able to finish all the construction, so that we will be able to test during sprint 3.
The mechanical subteam worked on revitalizing Damn Yankee. In sprint 1, the team was held back by having too general of a goal, so in this sprint they broke the project down into more specific components: the hatch, the rigging, the rudder, and the servos. The hatch had already been laser-cut, so the subteam attached it and made a silicone seal to make it watertight. The rigging was sorted out, and new hooks and swivels were added to keep it from getting tangled or slipping off. They also drilled a new hole in the jib club, which allowed it to be attached backwards from the way it was — which should result in a more stable jib, although this remains to be seen in testing. The rudder key was resolved fairly easily, and it was found that the rudder works as-is with hardly any modification. The only issue surrounding the rudder is that the hole it mounts in may not be watertight, which, again, must be investigated further. The mechanical and electrical subteams worked together to install the servos that will control the sails and rudder. The servos were mounted into the boat and connected to the belts that attach them to the thing they are supposed to operate. The only task besides testing that the mechanical team didn’t get to this sprint was making and mounting a waterproof box for the electronics to go in. The team already has a waterproof box, but some holes must be drilled in it so that wires can run in and out, and then the holes must be resealed with the wires in them. On the last day of this sprint, the team sealed these holes with silicon, but the box has not yet been mounted in the boat. Looking forward at next sprint, the mechanical subteam will be focused first on testing, and then on making any modifications or repairs that come up as a result of the testing.
Software finished fixing the Dynamixel motors and wrote Python modules to control them via the Spektrum RC controller. All the motors work when plugged into a laptop running Linux, but they are experiencing trouble communicating with the Dynamixels on the embedded ODROID computer running Linux on an ARM processor. Software also began learning ROS by controlling a Neato robot. By the end of the sprint, they were able to control the Neato with the RC controller. Electrical finalized all the components that needed to go in the waterproof box and handed it off to Mechanical to seal with silicone.
This sprint was much more productive than the last one, largely due to better planning on the part of both subteams and the team as a whole. As of the end of the sprint, we have a finished “first draft” from each subteam: the boat is built but untested, and the RC control is functional but only tested on the vacuum, not the boat. For both subteams, testing is the next step, so that will be the focus of the third sprint. This testing can happen in a few different ways. Some parts can be tested on their own, for example the watertight box can be submerged to test the seal, but other parts, such as the rigging, can only be tested with the entire boat. The main goal of next sprint will be to do a test of all the systems together, which would mean putting the boat in the water and sailing around. We will probably use Babson’s pool for this, with some sort of fan system to simulate wind.
~ Eric Jacobsen (Mechanical subteam)