One of the first tasks our team worked on was buoy detection. Most of the navigation courses in Roboboat require us to identify buoys and then figure out how to navigate them. Using a ZED camera, we developed the following algorithmic steps to properly identify buoys on the course:

Performs erosion with a segmentation kernel

Performs dilation with the same segementation kernel

Converts the image to HSV

Gets the mask for each color range we are looking at(red, green, yellow)

Generates a bounding box for each disjoint blob in the color range mask

Our controller is a Pixhawk 4 running Ardupilot. It takes in GPS waypoint coordinates and headings and handles the motor commands to achieve the desired position and heading. For the two main navigation tasks, we plan to first identify them and head to the position shown in each of the above figures on the left. Then, we will run through pre-planned paths that are adjusted in realtime by a local planner for obstacle avoidance. The preplanned paths are shown visualized in RVIZ in the above figures on the right.

Current Status

For those who are unfamiliar with the structure of MIT Arcturus, we split up into subteams to complete tasks and work on our competition boat in an efficient manner. One of such subteams solely focuses on the boat itself and in doing so, plays an integral role in creating a foundational structure to support the work being done by the other subteams. As the primary focus of this team is the hardware of the vessel itself, like the hull and the integrated electronics that allow it to function, we have merged these two elements into the wonderful field of engineering known to us as Hullectronics.

So far, we have fully assembled the frame of our test boat (coined CatamaROV) and are starting to install azimuthal thrusters, which we usually will call azipods. The design of this thruster implementation has been an entire subteam effort. We have each been taking on separate tasks as well as one component of the azipod design, which we hope to test ASAP on CatamaROV.

Val and Sebastian have been working through the kinks on our azipod-to-hull mount this week among other things. While doing that, Val has been looking ahead and ordering parts we will soon be needing to finalize CatamaROV and Sebastian has been preparing our waterproof “dry boxes” which house all of the electronics for the boat. Penelope finished fabricating the bearing attachments for the azipods, which are responsible for transferring all the thrust from the azipod to the boat itself. Meanwhile, Ansel finished mapping all of the controls with the Ardupilot and wired up all the components in the dry boxes that Sebastian helped to solder.

Next Steps

With most of CatamaROV coming together, we have to coordinate with our Navigations subteam to determine a testing schedule so that we can test some of the experimental elements of our design while also making sure they have the most useful testing platform possible so that we can start focusing on the design and fabrication of our final boat.

Recent Developments

We just completed our first field test with CatamaROV this week! This was one of the first times we were able to get it out on the water to test its speed and maneuverability. Testing in our two tanks are great for some aspects, but out on the Charles we confirmed that our three azipod layout would indeed give us the flexibility we need to make complex maneuvers like tight turns at both low and high speeds. We also confirmed what we already knew about our preliminary azipod design, that we are going to need to i crease its supporting substructure for our scaled up final hull. Overall, the tests were a success!

Next Steps

Moving forward, we can start applying what we verified in our testing to the design of the final hull. Time permitting (on both the Hullectronics and Navigations side of things), we will fabricate and install three azipods into our final hull after a redesign to compensate for our larger final vessel. We already have some ideas for the new azipod design and after some conversations between subteams (and some calculations we ran around buoyancy to ensure we can reuse this boat for future projects) we have decided fully on a catamaran structure going forward.

Current Status

After successful trials with our test boat (CatamaROV), we are finalizing our designs and are looking to fabricate our final hull. With sustainability in mind, we will try and repurpose a foam-fiberglass hull that we had built previously to meet our design specifications.

Recent Developments

Our new catamaran hulls have been cut down to size and are now in the process of getting the epoxy and fiberglass lay-up done. Sebastian and Yasin have been working on the aluminum frame of the boat that will hold the two hulls together and Ansel has been procuring materials for the deck that will hold all of the electronics on the vessel.

Jessica is working on adapting our azimuth thruster design to these new catamaran hulls. Adding several layers of structural support to these thruster elements will ensure this vital component is as secure as possible without sacrificing functionality. While the azipod thrusters will take some time to finish, it is imperative that we complete the hull and deck fabrication in a timely manner to allow our Navigations subteam the necessary time to mount the sensor suite for calibration.

Goals and Timeline

After finalizing our azipod thrusters and finishing the hull retrofit, we will start to look at finishing the fabrication of the deck between our hulls at the start of next week. We will be modifying this bridge heavily in the coming weeks as we go in order to suit the specific challenges of this competition and provide a strong structural foundation for the Navigations and Task Force subteams\' components.

Let's Get This Drone to Fly

This week welcomed a new member of Drone Zone, Erin! At the beginning of this week we had our drone physically assembled, but it needed a lot of work to get the electronics finished. Ita and Audrey created some monster wires to send consistent and equal power to all four of the motors. Once that was done, Erin was immediately working on the computer. Our drone was set up with a Pixhawk autopilot, but for unknown reasons we did not pass half of the flight checks to get the motors to start spinning. We turned all of them off, and one by one turned the checks back on, troubleshooting until we got the drone to fly consistently.

At the same time, the Landing Gear team was just finishing up their prototype to allow the drone to land on the boat. They had a series of mag jigs connected together by a timing belt to turn the magnets “on” and “off” at once. With their new design, the drone should be able to land consistently, but we will have to switch our landing gear from regular legs to a thin metal ring.

Currently on track with our timeline, we should have the two parts working together by the end of the month. We will be handing off the two prototypes to navigation so they can start programming them autonomously.

Bad News

We have just discovered there is no drone in this year's competition. To accommodate these changes, Drone Zone and Landing Gear will be merging teams into Task Force. Task Force will be working on the water gun and skeeball portions of the competition. We will be focusing the upcoming week on creating a new timeline, and deciding how we want to approach the new tasks.

Prototypes Prototypes Prototypes

After finishing our prototype session for the water gun and deciding on an aiming system, we are looking forward to the skeeball shooter. Since we do not yet know the exact dimensions for the skeeball shooter, we want to be a module as possible for the design. We are splitting Task Force into 3 teams, one will work on a flywheel (Audrey, Isa), one will work on an extending arm (Jessica, Richard), and the final will be working on a crossbow design (Erin, Via).

Flywheel: The flywheel will be a wheel attached to the motor, close to a solid wall. As a ball is fed through, it will be shot ahead by the wheels. We like this idea because there are lots of examples of it from FTC, and it's pretty easy to build.

Crossbow: The crossbow design uses a spring to shoot the ball. The ball will be loaded in, and the spring slowly cranked backwards until it's ready to shoot. This idea looks good because it should be very consistent with every throw, and we have a lot of modularity with a single design by changing the size of the barrel, and the spring.

Extending Arm: The extending arm would be paired with one of the other two designs. It will extend beyond the initial measurements of the boat to accurately deliver the balls.

All of these designs need to be compatible with the hull, in terms of power consumed as well as size.

Upcoming Goals

We need to finish up these prototypes as soon as possible. A finished product will be given to the Navigation team so they can begin to plan for and program the aiming system. This week we plan to have a CAD model for each of the designs, and order any required materials.