Behold, Scorppy...

FTC 21-22 Freight Frenzy

Robot Reveal

Vision System Build

We knew from the start that we would use a team scoring element for randomization detection instead of using a duck freight. We initially installed a webcam with Vuforia/Tensorflow so that we can review and reuse the object detection method, like last year’s Ultimate Goal season when we had to detect the number of rings.

However, we quickly realized that if we design our Team Scoring Element big enough to be detected by a distance sensor, it would be much easier than using a camera to detect the TSE. Thus we decided to use a distance sensor in place of the webcam.. Overall, our distance sensor is very reliable in detecting the correct freight level during the autonomous period.

While we’re not using the webcam at the moment, it remained on the robot so that we can continue to learn Vuforia/Tensorflow during off-season, as well as use it to teach our rookie teams and new team programmers.

Team Scoring Element (TSE) Build

As we mentioned earlier, we wanted this year’s team scoring element to be bulky enough to use a distance sensor instead of a webcam. At the same time, we wanted something to show our team spirit. So Puna designed a waffle-looking team scoring element, and it’s exactly what we needed. It also has the capability to be capped during endgame, which is still a work in progress.

Intake System Build

Our intake system build has several parts. First of all, the intake system is built on two linear slides, powered by two continuous servos so that our robot can start within the 18in size limit. Once the game starts, it will expand outward so that we can pick up freight easily.

Our actual intake is built using an AndyMark Entrapption Star with one 20:1 ratio Tetrix motor. It’s also powered using different-sized gears so we can have a faster intake system.

Freight Container System Build

Once the intake picks up a cube/ball, our freight container holds the freight in place. The freight container is built using Tetrix parts that’s built using two 180-degree servos. The first servo (top three images) changes the container angle, allowing the container to raise/lower to prevent a freight from falling out. A second servo (below two images) is the main servo to release freight when we deliver it to the shipping hub.

While the container is big enough to pick up any type of freight (cubes, balls, ducks), we prefer to pick up cubes mainly, as balls may get stuck or roll out, and a duck freight isn’t worth picking up with the amount of time in an FTC game.

Linear System Build

In order for us to place freights to level 3 (the most points), a linear system is necessary. We decided to use a Gobilda linear actuator with a 5.2:1 gear ratio Gobilda motor to have the fastest possible speed that’s still stable and has enough torque to power the actuator. The linear slide system only takes about 1.3 seconds to move the full 201mm (7.9”) that can be achieved in the image shown.

The linear actuator also allows us to not worry about the overall weight when it’s attached to our Crane System, as the motor is towards the end of the linear system, most of the weight is towards the back of the system, and it assists the crane with raising and lowering.

Crane System Build

Our crane system is something we are really proud of, but also the portion of our robot that gave us the biggest headache. It is powered by two 20:1 gear ratio Tetrix motors, combined with two worm gears that minimize backlash and greatly reduce the chance of a back-driving gear motor, so the crane position can be held even when power is not applied, regardless of our heavy crane that contains our linear slide, container, and freight.

Initially, we tried powering these two worm gears with chains, we quickly realized that chains did not carry the power that we needed, so we used gears instead. This is also the portion of our robot that requires the most maintenance in-between games, so we have to check regularly to make sure that all gears are still aligned and working properly.

Carousel Spinner Build

The carousel spinner is simple but important to the gameplay, as each duck delivered during the endgame gives us 6 points. By the time we were done with everything else on the robot, we had maxed out the 8 motor limit, thus we had to use a continuous servo instead, using an AndyMark Compliant wheel that allows us to easily spin the carousel. It’s not as fast as we hoped it would be compared to a motor, but a GoBilda speed servo is fast enough to deliver a duck within 3-4 seconds, which gives us an average of 7-8 ducks during endgame, giving us 42-48 points in endgame alone.

Overall Build

From the initial design process to the end product, we followed our plan from the start and were able to deliver a reliable robot for this year’s Freight Frenzy season.

Of course, as we went along, there were many problems that we had to solve and improvise on. Some were mentioned above and others were too painful to tell in this portfolio. For example, we decided to not pursue capping during endgame, as we realized that even though it gives us the most points potentially (15 points), it takes time to pick up our team scoring element, and we risk moving the shipping hub, which would give us a major penalty. We decided that it’s safer to do duck delivery instead, which gave us a pretty consistent score. All other problems that we encountered and solved can be found in our Team Engineering Notebook.

Robot Hall of Fame

Froggy - Skystone

Retired Bot 2019-2020

Crabby - Ultimate Goal

Retired Bot 2020-2021