From initial impressions Stronghold 2 looks like a fun game with some interesting design challenges! Shooting seems very similar to 2016 with the added challenge of indexing and rapidly shooting 5 balls. Ranking could be interesting this year as the RP challenges seem more difficult than previous years and climbing points could shift the outcome of many matches. Overall the team is excited for a shooting challenge. The team sat down after the initial game release on Saturday to go over all the rules and break down the points structure.
We structured the students to break up into 5 different subteams that they will stay with throughout the course of the first week for prototyping. After getting a good understanding of the rules, RP points structure, and points structure, the team decided on some high level priorities to drive our prototyping efforts.
- Shoot balls high
- Climb solo
- Climb with one partner
- Intake balls from the floor
- Intake balls from the HP station directly
- Wheel of doom
After we figured out these priorities, we broke up into prototyping subteams and each team was assigned a priority. We made the decision to not prototype a drivetrain and instead have the 2 of the teams focus on building a shooter, two teams work on developing and hanger, and one working on developing an intake.
For a shooter, the prototyping subteams looked at a few teams to base their prototypes off, 228, 118, and 1717 from 2012, 2056 from 2016(specifically their hood). We believe shooting will be fairly straight forward this year and this biggest questions we will need to answer is how fast to spin the shooter wheel, which wheel to use, how much compression, and launch angle to hit our ideal shooting spots on the field. We believe it makes the most sense to try to shoot from your protected zones, the trench and up against the driver station. We made the decision to run a hooded shooter so the team got to work to develop a simple shooter prototype.
The students quickly got to work CADing up an initial design and cutting it on our router, here is a picture of the final product.
The first revision had 4inch fairline, “marshmallow” wheels, with an inch of compression and a direct driven NEO. Below is a video of this rev;
The next revision we threw on a 6in Colson wheel, now with two inches of compression and still direct driven at 1:1 with a NEO;
We’re super happy with how this first revision came out, we could toss the ball about 43ft. The next step is to hard mounting the shooter, extending the hood(to add more time for the wheel to energize the ball), adding a weighted flywheel(less recovery time), shrinking to a 4in wheel(we have these two wheels,2477K37 and 2476K37 on order, pushing for 4” for packaging reasons), and keeping compression at 2in.
The team believes that climbing is both the easier extra RP and a significant source of points, especially in the early weeks (we are competing week 1). To ensure the extra RP we believe making a buddy climber to lift one robot is the most consistent option. Climbing with a partner behind the robot allows for balance with two robots by being directly in the center, and 3 if another partner can solo climb by attaching close to the center but slightly offset. To accomplish this within the extension limit we believe a system similar to the 148 2018 Robot Wrangler would work best. There are some questions about the legality of adding a velcro strap due to the new rules on major mechanism. If a strap more than a COTS piece of velcro is required this may require more work to be legal.
We believe this task will be high risk but high reward. Due to the possible points and RP, size constraints, and need to be strongly attached to the frame this mechanism is very high on our priority list. Initial prototypes and potentially Q&A clarifications will show the viability of this design.
For the intake, the prototyping team decided they wanted to mainly focus on trying to replicate 254s intake for 2017, with a roller than slides out above the frame to intake the ball over the bumper. I didn’t get a chance to take any pictures of this but will have more info in tomorrows post.
High Level Design Sketch
In order to get a quick look at packaging, some of the mentors sat down and started to draw up a simple 3D block design to get a better picture of how the robot might look. I’ve attached that picture below.