Timing is Everything

In order to have an exact strategy planning, we also needed to time ourselves on the playing field. An average time can help a lot, especially when many of the tasks are time-dependent, and an average level of reliability when doing tasks is also great to see where we can still improve as drivers.

As such, we have constructed an Excel spreadsheet where we can enter the time we needed for the task. We also practiced tasks for a long time in a row, which is how we learned to optimize the controls. Knowing exactly how to solve a task with as few steps as possible really cuts down on time needed, and like this we were also able to track our progress.

 

In case you are also interested in tracking your times like this, we have published our spreadsheet in an empty version right here:

https://docs.google.com/spreadsheets/d/10Uuz5GbwugIdwqXxlWz1Ypfb8hgA_dz2eS-PKiI38ko/edit?usp=sharing

Cable Management <3 and Sheets

Our robot is looking more and more like it is finished, and starting to work reliably. That means it’s time to clean everything up, and fix the cables permanently (with zip ties of course) to the frame.

Fortunately Robert loves doing cable management. With that I mean he can spend hours upon taping cables in exact right angles to the ground. An

Control and Expansion Hub with cables wired neatly
Cables along a extrusion

Another thing was cutting a sheet for the front of the robot. This is also where we later want to put the sponsors. Also we fixed the sheets to the frame using velcro

Robot from front

Let’s talk Strategy

Strategy is vital in this game. Mechanisms might work wonderfully on their own, but in the end it will be strategy and coopertition with your alliance that will decide the winner.

This is where our strategy sheet comes in. The sheet makes it a lot easier to discuss strategies with your alliance partners and decide who will do what and when. Filling every field ensures that  you forget nothing and play a smooth and fun match with your partners! We hope this not only helps you guys plan a match but also gives a very quick overview of everything that must be done for team discussions.

Download the Sheet here: https://drive.google.com/open?id=1enKQFLxQ7GaED9P8_NWc33kZGkq-Jcbkelel3T_9LSc

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Improving our Conveyor and Launcher – Friction, Elasticity and Automation

Test driving our robot we noticed a few things. One of them was the shooter launching the cubes better when they were not pressed against the cardboard. This led us to the conclusion, that the friction between the cubes and the cardboard was preventing them from flying consistently. That is why we decided to remove the cardboard and let the cubes slide on two parallel extrusions instead.

Conveyor with extrusions instead of cardboard/sheet in the back of the conveyor

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Programming

Our focus in programming our robot was efficiency, which is why we spent a lot of time planning what function of our robot was to go with which button on the gamepad. As such, we have planned our most important functions beforehand. For driving, we have decided to add a toggle named “slow-mode”, where the robot drives with less than full capacity, so we can drive with more precision. That might come in handy when repositioning the robot in front of the atomic plant for example, or the wind turbine, where precision matters a lot.

For our driving system, we have decided on a tank drive, that will be controlled with the gamepad sticks, since it is the method our two drivers prefer.

While programming, we have also changed quite a few hardware aspects, since it has shown us a few issues we still had to solve. While we wanted to leave our omnom running for most of the time while collecting, we have also toggled this mechanism. The elevator runs on a toggle as well, but as we discovered, we had to build in a stopper so the cubes wouldn’t fall out over the top of the robot while the shooter isn’t running. The shooter itself isn’t toggled, as we don’t spend a lot of time shooting the cubes.

To avoid shooting the cubes one after another too fast, which might reduce our precision and lead to cubes falling short of the goal or missing in case of the atomic plant, we have built in a touch sensor that measures the pull on the frame that happens during shooting. Like this, the elevator is stopped shortly so the mechanism can fully recover before shooting the next cube, and the drivers can steer the robot with more precision to avoid misses.

As for the rest of the mechanisms, we used servos, as we rely on positioning rather than power. As such, our solar panel picker has four main positions, not counting the one at the start. They are up, mostly up, hovering just above the ground and pressing down, which are the results of trial and error runs. Like this, our solar picking works pretty well. The opening and closing of the solar picker is a programmed servo as well, since it takes precision rather than power.

We are using two servos for the wind turbine mechanism as well, one of them to move the mechanism out of the main robot body, and the other one to twist.

Discussing T-Shirts, Buttons and our Pit Design

Mexico is moving ever closer and it’s time to start thinking about other things than our robot.

T-Shirts

The first thing we discussed was our costumes and our t-shirts on which we will print our sponsors.

As for costumes we want to go for something traditional. And tradition means Oktoberfest (a festival particularly famous in Southern Germany, especially Stuttgart and Munich!), and Tracht. Tracht is the German word for traditional clothes, which in our region are Dirndl and Lederhose, a special type of dress and pants made of leather. While the tradition of Tracht reaches back a long time, they are still worn today to special occasions like the Oktoberfest.

During the competition we want to wear one of two styles: Either golden suspenders with red bowties and a black t-shirt. Or we’ll wear a golden fedora hat. Additionally we want to put our sponsors on buttons.

 

Our Pit

Since FIRST Global offers us the chance to decorate the pit after a few guidelines, we were thinking of putting up a few informational posters. We wanted to have one explaining our robot design and the way it functions, another one about Germany, our school and our team. There will also be a poster dedicated to our supporters, without whom we wouldn’t have been able to participate!

As for decoration, we were thinking of a chain of lights for a bit of a highlight on our robot box, where our robot will spend its time away from the training fields and actual matches.

We also want to bring an assortment of cultural food and various buttons for other teams to collect, since sharing has been a major part of last year’s competition. Especially the diverse food of all the different teams is always a highlight!

 

Organization

Since our school is closing down for the summer holidays, we will have to move our entire workspace by the end of the week. While it will be quite a challenge to move our entire equipment plus our robot through the public transportation system of Stuttgart, we will also be packing the essentials we will be bringing to Mexico City in August already.

Improving the Conveyor, Adding Structural Support and Building the Wind Turbine Rotator

Improving the Conveyor

After testing a few days ago, we saw a few things that were not going as well as we want them with the fuel cube conveyor. One thing was the conveyor pressing the cubes into the shooter when it was not supposed to do this. That is why we decided to put a stopper into the conveyor. It is a servo with a rod attached to it. At first we had a problem with the cubes being pushed over the rod but we solved it by lowering the bar (in the U) above the conveyor.

Servo with rod attached
Shooter and conveyor from the top with the stopper servo behind it

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Building a Prototype of the Shooter

We went back to our calculations, and noticed that the torque of the motors should suffice after all. (They are three times as strong as we need them to be).

Now we need a gear ratio of about 30:1 (see the calculations). To see which gear combinations might work, we made an excel table that calculates the ratio for each combination of wheels. By combining two pairs and multiplying their ratios we strove to get to the 30:1.

Ratio of different gearing combinations

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