Written/Compiled by Strummer and William
Edited/Formatted by Tristan and Strummer
Hello everyone!
This Thread will be a brief recap our season so far and the development of our robot for the 2023 season, as well as media and business activities in preparation for this season.
Prototyping Groups
Considerations:
- Start simple, explore more complex mechanisms later on
- Avoid systems that require weird parts that need to be ordered
- Gripper is going to be the main focus as there are more ways to do it
- Don’t need a cube only gripper unless decided otherwise - less strategic
The Groups:
Elevator Group:
This group split into two with one looking into a telescoping arm on its own, and another looking into a telescoping arm on an elevator.
Elevator + Telescoping Arm Group
Pros:
- Simple
- Two degrees of Freedom
- “Among us luxury design”
Cons:
- Harder to pick up pieces from the ground
- Hard to keep in frame perimeter
- Unbalanced “Rip Bozo”
- Geometry!!
- “Not enough Amongus’”
- Motor Mounting could get complicated
Ideas for improvement:
- Adding a third stage
- Counterweight
- Actual elevator
Pivoting Telescoping Arm Group
Pros:
- Fast
- “Good” degrees of freedom
- Can pick up from both sides of bot
- Less likely to destroy telescoping arm compared to last year
Cons:
- May be beyond our team’s capabilities
- Can’t pick up cone from both sides
- Claw has to work at an angle
Cone Only Intake Group:
Grabber Group
First Iteration
4 inches from base with a slope from end of the cut to the end of the wood
Pros
- None listed
Cons
- easy to fall out
- not quick
- needs a little messing with to get on
Second iteration
Cutting extra circle in the slope for easier grabbing
Pros
- Quicker and easier than last design
- Can pick up from left/right/top sides
- Can pick up cubes with 2 on either side
- Can push the cones to the hybrid nodes
Cons
- Might get in the way of the cone going on
- Going to the third level it will run into the second pole
- Little tight stretch to reach the third level
- The cone must be tipped over to pick up
- Hard to see which way your oriented to pick up the cone
- Not very efficient for going fast
- Not very easy to push so you can fit the hook in
- Only able to fit in on one side,
Ideas and Thoughts:
- New types of grip being put onto the hooks that will hopefully provide a better grip and allow the cone to go on and stay on easier and allowing for new types of claw designs without worry of the cone slipping out
- Friction is not an issue
- Maybe adding another arm on the side for extra stability
- Maybe rotate 90 degrees
- Tried shelf liner, shoe grip, non-slip kitchen table mat,
- The cone jumps out of the grip
- Too small of a grip for the cube and needs to be bigger
Single Substation Funnel
Pictured: 2412 figures out how gravity works
- Maybe poles on the chute
- Trouble dropping through the chute
- Adjust the angle of the chute so we can catch the cones
- Drop the cone nose first AND land nose first and tell the droppers to do it that way to be able to get the same fall every time and face the wall. Works every time even if the robot is not in perfect spot
- Sides should be transparent so we can see through it and see easier
- Conveyer belt on the funnel or wheels to get it into the hole
- Putting cubes in a 45 degree angle it will get stuck and it’s hard to pick it up so tell the dropper to keep it parallel to the wall
- Current design cubes aren’t going to work too well and will only really work with cones
Passive Hook to Right Cones
Lacking Notes
One-Sided Pneumatic Claw
Lacking Notes
Cone And Cube Intake Groups
Grip Claw
This one seems to hold in cones and cubes well, even with a lot of forward or side to side force
Motorized tests
https://photos.app.goo.gl/TSZPS6LNVdXe35SYA
2 Neos on ~3:1 reductions
On actual robot we might use high enough gearing ratio to use just one motor (and use gears to make it run both arms)
5 amps: gripped cube well
8 amps: cube didn’t have any issues
15 amps: gripped cone, shook loose though. No deformation of cone.
Ideally would do more testing to see if we could use same current for cube and cone, seems unlikely though
Ran motors at 0.2 speed, that seemed to work fine
Calculations:
Need around 6 pounds of force to grip cone
- Distance is 8.5" from pivot
- About 5.5 Newton meters
Neo brushless stall torque is 2.6 Newton meters
- Probably need a roughly 5:1 ratio (5.5/1.3 = 4.2308)
- Free speed is ~5500 RPM
- Actual speed around 4000 RPM?
- Running through 5:1 leads to 4000/5=800 RPM
- 0.25 / 800 * 60 = 0.0188 seconds (19 ms) for a quarter turn
- Speed is not a concern
Neo 550 stall torque is .97
- Need roughly 12:1 ratio (5.5/0.5 = 11)
- Free speed is 11000 RPM
- Actual speed around 8000 RPM?
- Running through 12:1 leads to 8000/12=666.6667 RPM
- 0.25 / 666.6667 * 60 = 0.0225 seconds (22 ms) for a quarter turn
- Speed is not a concern
Compliant wheel intake
Pros
- Touch it own it
- Doesn’t use pneumatics
Cons
- Might not be as precise when outputting cones
Notes from first active prototype:
6 in c2c cone
11.75 in c2c
Approx 9 c2c inner to outer
Center of back wheels to wall is about 5 inches
Cube popped when at a diagonal in cone area
6.75 colson to compliant
Green compliants work good (as to be expected)
Colsons are too far apart
Compliants worked ok but didn’t hold it in super well
Final choices by robot design team:
Virtual 4 bar arm
- Simple and effective
- Allows game pieces to be protected inside frame perimeter
- Lower cg while retracted
Compliant wheel intake
- Think it will be effective
- Touch it own it
- Possibly switching to a more complex design later in season
Swerve drivetrain(mk4i, L2)
- We have it, so let’s use it
- Fast
CAD complete
