We built many attachments during the season including this one.
When we first started, Howard and I paired up to do two missions: Oil Platform and Energy Storage. We had just learned about passive and active attachments, and we wanted most of our attachments to be passive, so we made an early passive arm lift for the Oil Platform. However, we realized it was hard to maneuver the robot for both of the missions, so we scrapped that idea and replaced it with an active arm, which looked like this:
We would lift the arm and hang 3 energy units on the axles before starting the mission. The robot would approach the Energy Storage, lower the arm, and dump the energy units inside. Then, it would back up, completely lower its arm, rotate 90 degrees left and lift up the Oil Platform lever.
However, there were reliability issues with this approach. Sometimes energy units would miss the Energy Storage because of inaccurate positioning.
Although the first issue can be fixed by introducing line following algorithm, we also noticed that it wasn’t reliable with the Oil Platform because the arm had to be positioned very accurately or it got stuck.
So we decided to use this arm for Energy Storage only, and we added a bent, sloped passive liftarm to the back of the robot, so that it turns and pushes the Oil Platform lever up. However, that wasn’t reliable as well because the maneuver was too complicated.
We decided to design one slip-on attachment for this run so we have a more efficient transition. We found a way to connect the slope to the attachment base. Plus, we added two beams supporting the slope to add extra stability when the robot is ramming into the Oil Platform.
The robot would do Energy Storage as it did with the previous attachment. After dumping the energy units, it would turn and ram its slope lift into the Oil Platform.
With this design Energy Storage had that same problem as last time: the dump worked perfectly only when the tray goes in between the slopes, when any of the slope hits the tray Energy Units either fell out when being dumped, or flew out when the robot raises its arm quickly.
To fix these problems, we increased our arm’s length and used only one set of liftarms so we could reliably drop energy units from a wider range of distance. This is our final attachment for oil platform & energy storage:
Once we achieved this goal we wanted to grab the tray, since we needed as many points as possible. We decided to use our arm, but programming it was extremely hard and it, again, wasn’t reliable (it would only work once out of 20 tries) since the arm and the tray would never align properly. We gave up on that idea and instead decided to do Solar Farm before the tray. We had an idea for a passive attachment at the back of the robot.
After the robot did Oil Platform, it would back up and attempt to take the energy units and tray with this “hook.”
It was very obvious from the beginning that this hook won’t make it, since it took complex and precise moves to collect the energy units from Solar Farm. Even if it would manage to get hold of an energy unit, the unit would still escape from the opening during the subsequent movement.
We realized it’s more feasible to collect the energy units and tray from the sides of our robot, so we came up with the idea of a rack and pinion with a one-way gate. We had never used this design before, so it was fun to try out. We added a rack to the unused gear, so that when the pinion (gear) spins, the rack would move horizontally to reach out to the side. The rack and pinion steers a one-way gate (which is also seen in many other attachments), so the energy units can go into it, but can’t come out. We were very happy with the results, and we were also able to grab the tray with this approach. We noticed that when the rack and pinion is completely extended, it is very close to the smart grid. We added a simple three-frame extension to the rack so to push the Smart Grid’s hand up.
We further corrected every weak spot we found. And before long, we had our final attachment.
Here’s a description of our run: The robot would line follow to the Energy Storage. The arm would lower to drop the energy units. Then, the robot will do a 90 degree turn left and bump into the Oil Platform three times with its passive slope, freeing all oil units. After, the robot backs up all the way until Smart Grid, where it extends its arm. The three-frame extension pushes the arm in Smart Grid. As the robot moves forward, energy units from Solar Farm are covered collected by the space between the one-way gate and the robot. After it reaches the tray, the rack and pinion will extend again and take the tray. Then, it will return to the left home area.
We had done everything we could do, so we documented our journey and attachment in the Mission Log, where we jot down ideas, pictures, and iterations of our attachments.
And this is our story of how we went from a simple, small passive attachment to one of our most complex and stable attachments.
Files
Oil Platform Mission Log: Google Docs
Energy Storage Mission Log: Google Docs
Attachment Studio File: Google Drive
*Note for Studio File: While we allow you to take inspirations from this attachment, please don’t copy our solution for your table run and missions.
Nicely done!