Marker Dropper – Design Changes

This entry is part 2 of 2 in the series Marker Dropper

During testing, we noticed that replacing the markers took quite a long time, as the front plate needed to be completely unscrewed and then screwed back in. To resolve this, we cut two large holes into the top of the marker enclosure for dropping the markers in. As we plan to do a barrel roll …

Torpedo Launcher – Overall Design

This entry is part 1 of 1 in the series Torpedo Launcher

The torpedo launcher we’ve been constructing features two cylindrical tubes containing torpedoes that compress a spring and are released by a trigger mechanism. Our design process has led to various alterations, particularly to the barrel, torpedo, and trigger mechanism. For the barrel, we added holes to facilitate water escape making it easier for the torpedo …

Adjustable Buoyancy – Rod-Based System

This entry is part 4 of 4 in the series Adjustable Buoyancy

Our new system was designed to be just as flexible as our old system while retaining the stability and reliability of the capsule system. This system is composed of two rods mounted on the system and uses the same foam blocks as the original design. This system is analogous to adding weights to a barbell: …

Marker Dropper – Overall Design

This entry is part 1 of 2 in the series Marker Dropper

Marker Enclosure For our marker enclosure, we chose a crescent-shaped design. This allows us to fit two markers, one in each half of the enclosure. Moreover, the crescent shape will allow the markers to naturally roll towards the center, where there is an opening for the marker to drop through. The markers are then kept …

Battery & Camera Mounts – Improved Battery Mount

This entry is part 3 of 4 in the series Battery & Camera Mounts

The main point of failure here was also the interface between the ring and the frame mount. However, because we require the rings to be able to rotate when replacing the battery, we were unable to mold these into a single mount. However, we were still able to make several improvements. First, we made the …

Adjustable Buoyancy – Capsule-Based System Update

This entry is part 3 of 4 in the series Adjustable Buoyancy

During testing, we noticed that the capsule system is much bigger and cumbersome than our old design. The weight from the acrylic and metal mounting brackets was many times that of our simple 3D-printed mount. This also means that there are fewer places it can be mounted on the robot and it is overall less …

Adjustable Buoyancy – Capsule-Based System

This entry is part 2 of 4 in the series Adjustable Buoyancy

To improve the adjustable buoyancy system, we decided on a new design with an old, damaged camera capsule we had on hand. We want to create a piston-like system that allows the volume of air inside the capsule to be adjusted when needed. This principle is similar to a syringe: when the piston retracts, the …

Hydrophone Mounts

This entry is part 1 of 1 in the series Hydrophone Mounts

As the acoustics team continues development this year, the main priority for the hydrophone mount is modularity: the hydrophones may need to be moved around the robot for tests and the mounts may need to be quickly reprinted to accommodate different designs.  Therefore, the hydrophone mount uses a two-part design. The first part is the …

Adjustable Buoyancy – Old System

This entry is part 1 of 4 in the series Adjustable Buoyancy

Pros Our old design is minimal and compact, allowing it to be easily 3D-printed and assembled quickly. This design allows high adjustability as well: we can add as many buoyancy blocks as we want atop the mount. Moreover, we could easily mount this design on many parts of our robot because it simply wraps around …

Main Capsule – Metal Plate

This entry is part 3 of 3 in the series Main Capsule

The first step to secure the metal plate was to drill four additional holes into our stack plate. These will allow four additional standoffs to be mounted to hold the plate securely onto the capsule. We used a laser-cut jig to line up a hand drill and manually drilled each one.  Then, we cut four …

Main Capsule – Design Candidates

This entry is part 2 of 3 in the series Main Capsule

We have several candidates right now for a permanent solution to our capsule problem: We ended up choosing the metal plate solution for several reasons. First, it was easiest: ordering a metal plate is relatively cheap, and we have experience making similar designs in-house. Moreover, this can be easily prototyped out of cheaper materials like …

Battery & Camera Mounts – Problems with the Old System

This entry is part 1 of 4 in the series Battery & Camera Mounts

The current battery and camera mounts frequently broke during competition, as the 3D printed mounts were put under a large weight continuously. The battery mounts in particular were prone to failure as they would be jostled around when we replaced the battery. In fact, during competition, we had to ask another team to print us …

Main Capsule – Problems with the Old System

This entry is part 1 of 3 in the series Main Capsule

Last year, we used a standard Polycase™ waterproof enclosure to house our electrical stack and keep water out. This capsule came with four brass inserts in the corners to press the capsule into the O-ring. Despite working initially, wear and tear from a year of use eventually degraded the plastic-brass bond, causing the brass inserts …

Reflections on Mechanical Leadership

As a freshman, I knew I wanted to join a project team where I could learn engineering skills, take on a complicated design challenge, and build something real. That’s exactly what I’ve been doing in the Duke Robotics Club (DRC). The club’s primary focus is designing, building, and programming an autonomous underwater vehicle (AUV) for …

3/22/16 – Frame Assembly

The sub is coming together! We have mounted the horizontal thrusters and attached the pressure hulls to the frame. Mechanical is now working on attaching the hull connectors. We aim to do our first swim test next week and begin tuning our PID controllers.