CAD-ing and Path Planning

Phase 3: Theoretical Work

Sprint 6, February 7 — February 21

The goal of this sprint was to work off of the high-level decisions made last sprint and to create the first stage of the Hawsepiper design. For most of the mechanical team, this meant basic CAD of the different parts of the boat. For the software team, this meant refining the path planner, writing a heading controller, and documenting stuff.

A quick mockup of what Hawsepiper should roughly look like. A trimaran design and wing sail set it apart from the other boats we’ve built in the past.

The mechanical team had a very productive sprint composed of several meetings devoted entirely to creating Hawsepiper in SolidWorks. The CAD was completed for a basic design of the hull, the outriggers, the keel, the rudder, the mast, and what we are calling the spanker — a small aerofoil attached to the back of the sail that allows us to adjust its position more easily and functions like a sort of “wind rudder.” The CAD is by no means final, but it is a very useful base to be able to work off of.

The support for Hawsepiper’s wing sail.
Our path planner can solve mazes! The planner was told the wind was coming from the top of the image, so it preferred traveling at diagonals when possible to maximize speed. (It doesn’t know that it takes time to tack yet, though.)

This past sprint was an exciting one for Software. They gained a new member and continued to make good progress on the path planner. The latter included testing on maze images (mazes being a fun way of testing complex “terrains”) and turning the output of the planner into a list of waypoints to navigate.

The new member also implemented a proportional-integral (PI) controller for maintaining boat heading (the input being how far off of the correct heading the boat is and the output being a rudder position).

Additionally, the Software team implemented data reporting to a telemetry server running on Heroku, which then enabled viewing the boat’s position and heading in the remote monitoring web app.

A portion of the web app created to monitor the boat. Data is broadcast over ROS, picked up by a telemetry node, broadcast to a Node.js server, and finally relayed to a React frontend.

Lastly, a much-needed system diagram was drawn up, disseminated, and posted in the workspace.

Electrical wired up the Airmar using the new waterproof connectors.

The next step for Hawsepiper is refining our design. The rough CAD was made with a lot of estimates, so we will need to do more exact calculations for the dimensions of the boat’s components. The mechanical subteam will be dividing into a hull sub-subteam and a sail sub-subteam to focus on each of those in more detail.

~ Eric Elder Jacobsen (Mechanical Subteam) and Kyle Combes (Software and Electrical Subteams)