3588 the Talon - 2023 Build Thread

Kickoff

Happy Kickoff! Our team has been working hard over the weekend coming up with ideas of how our team can tackle this year’s challenge. Right now, we are developing prototypes of the ideas we came up with, but here’s a brief overview of how we got here:

Game Animation

Right after watching the game animation, we looked at the rulebook and answered the following questions:

  • How can our robot move?
  • How can we interact with game pieces?
  • How can we interact with the arena?
  • How can we interact with other robots?

And using those questions, we went into making a priority list of what we wanted OUR robot to do.

Mechanism Brainstorming

Once we have our priority list, we start thinking of HOW to do those actions. We took our priority list and figured out what we would need to have in order to do what we want it to do (ex: Claw, lift, arm). Some of the ideas we tested out by grabbing some scrap pieces and using people to act as the “mechanism”, which we used to eliminate or further understand some of the mechanism concepts we came up with. The biggest things we learned from this were:

  • One axis arms were more complex than we originally thought
  • A flat claw makes it hard to pick up cones
  • Center of Gravity is very important and heavily impacted by any lifting mechanism

Prototyping

Now we have reached our prototyping phase, where we took the ideas from our brainstorming and made them more accurate. We have started prototyping four different types of claws (Flat, curved, roller, and passive/reverse piston). We have yet to test any lifts or arms.


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Week 1

So far, our team has successfully prototyped several claw designs, held both an open and team-only PDR, finalized our overall robot concept, finished the master sketch, and began assembling the full robot 3D model.

Prototyping

For prototyping, we settled on replicating four “unique” claw designs, and one extra claw design similar to one we were already working on.

Roller Claw: Similar to 2018, our roller claw uses wheels to pull both cubes and cones in and “hug” them by pulling the arms together passively. After testing, we realized this design was extremely heavy, did not work very well when picking up cones, and was more complex than our other designs.

Round Claw: The concept of our round claw was to create a curved grip with arms/pinchers that rotate around an axis to better grip cones, but also pick up cubes. Testing revealed that this design would take some trial and error to figure out the best curve or curve+flat combo to pick up both game pieces, but it could be made light and with few materials.

Flat Claw: Our flat claw’s concept was to use a flat gripping surface with two arms, with one arm fixed and the other arm free to slide, to pick up both cones and cubes while being actuated with a piston. We were unable to successfully prototype with truly “flat” claws, and we had to add lumps to the claw to grip the cone. Further testing showed the claw was no more effective than the Round Claw and was more vulnerable to damage.

Reverse Piston w/ Rotating Grips: Based on a design from a Ri3D, our reverse piston design uses arms with wheels or hubs on a freely rotating axis to grab a cone or cube and orient cubes upright when grabbed+lifted. Our testing proved this design was very effective, however, it would require more weight than the Curved design while achieving the same goal (pick up from shelf, dropped cones aren’t a priority)

Scissor Claw: Essentially a different version of our Flat Claw, the Scissor Claw would rotate two flat arms around an axis like scissors to grab both cones and cubes. After adding pool noodles and grippy tread to the arms, the arms were able to pick up both game pieces, however the grip was not all that strong.

PDR

Although our open PDR may not have had as many attendees as last year, we received quite a lot of good input. After presenting our overall game strategies and robot concepts, we received the following from our audience:

  • Using pistons for all of our designs would be more efficient and weigh less
  • Motors are more reliable than pistons when it comes to claws
  • Use bungines with motors to reduce stress
  • Keep efficiency and cycle time in mind for overall strategy and replacements

While this is not all we received, these were the most relevant pieces of criticism and advice we received.

Team Only PDR

During our team only PDR, we went into more detail on the criticisms and advice we received during our open PDR. We then used that feedback to decide on our overall strategy and robot concept. In terms of strategy, we thought through the most efficient way to earn points and the best way to avoid being defended against, as well as the best way to defend, which landed us on two drivetrain concepts:

  1. Mecanum Drive: Pros are that it can move side to side, which would help us align. Cons are that we are easy to defend against, and won’t have much grip on the charging station.
  2. Tank/Drop Center: Pros are that it is not easily moved, and has more grip and “tilt” for getting onto the charge station. Cons are that it isn’t as maneuverable and could make our robot too big to fit three robots on the charging station.

Considering all of these pros and cons, we ended up settling on Tank/Drop Center because it provided the ideal balance of speed to defense that we were looking for.

We also went over our lift mechanisms, which after PDR were:

  • Elevator+Telescoping Arm: This combo makes scoring fast and adjustable for the driver, but is also heavier and more complex than-
  • Rotating Arm: Which essentially uses a single arm with an axis above the robot that allows the arm to rotate back and forth over the robot to grab game pieces. While this would allow us to grab from the ground and would make our lift mechanism more simple, it would also create a large torque issue on that single axis that we would have to deal with.

With that being said, we ended up going with the Elevator+Telescoping Arm. The team decided that the elevator and arm would cover a wider range of possible points we would need to reach, as well as be quicker overall (plus it looked kinda cool).

Finally, our team discussed which claw mechanism would fit us best, and after some tips from our mentors we discovered that:

  • Scissor arm and Flat claw are the same, just rotating on a different axis
  • Rotating vs. Sliding doesn’t matter because as the claw gets closer to grabbing the game pieces they are moving in the same direction, the only thing that would affect is spacing and implementation.
  • Pistons would allow us to put less weight onto the telescoping arm
  • A rotating grip wouldn’t benefit us because we plan to grab from the shelf, where all of the pieces are already oriented correctly.

Taking that into consideration, we decided that the best design for us would be our Curved Claw design with a Piston to actuate the motion. This would allow for quick pickup of both game pieces as well as easy replaceability if the claws were to ever break.

Thank you all for reading over our post, and unfortunately, the post was a bit delayed. Nevertheless, we’re heading into our 3rd week of the build season with a plan of action. We’ll make sure to keep this thread updated with significant developments in the coming weeks. The week two recap will be posted early next week, so be on the lookout!

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