Team 1538 / The Holy Cows proudly presents our 2015 robot, Daisy Quickstep.
We would like to thank our sponsors, Qualcomm / BlueChip Machine & Fabrication / Nordson Asymtek / Vivid-Hosting / Vinatech Engineering / Anocote Metal Finishing / San Diego County Sheriff’s Department / Advanced Circuits / Quality Powder Coating / Northrop Grumman / Alberts-Worley Family / Lutze Family & HIGH TECH HIGH & HIGH TECH HIGH INTERNATIONAL & HIGH TECH HIGH MEDIA ARTS
Drivetrain Speed: 18.5 ft/sec
6WD using AndyMark 4" Performance Wheels
2 stage elevator, ground to max height in less than 2 seconds
2 x RS775 powered pincher
2 x RS775 powered intake
See you at the Arizona East Regional, San Diego Regional and World Championships!
My did your team find it necessary this of all years to go with a 3 cim gear box? They have been used in the past to go fast with a lot of power. So far this year one of the fastest bots we have seen is 1114 and I don’t think they got any where near 18 feet per second. I guess I am just looking for some reasoning behind the decision. Thank you, the bot looks like it will do very well in Arizona this weekend. Good luck!
What about your ‘pincher’ requires so much power? Does it do more than pinch? What does it pinch?
Do you have any limit switches anywhere on your robot?
Do you guys powdercoat your stock, and then drill into it? It appears that your drive train frame is welded, but the hole pattern for your vertical mount seems very precise for a post-powdercoat drilling. We did this for 2 high-tolerance big rails this year since we hit a time crunch, but I wonder what techniques/changes we could do in order to plan for it next year (after game release, but still in week 1) and then precision drill into it afterwards. Seems like using the blue mill paint and/or scratching the aluminum with calipers would be a big no-no.
Cans, totes, robots, people, etc. Two motors are dedicated to the ‘pinching’ function, the other two power the rollers on the pincher.
Nope. We’ve done a fair amount of control theory work and implementation this year. It’s been a great experience for our students to be exposed to even more practices that are fairly common in the controls industry.
All of our rezeroing, minimum and maximum positions are determined by using a combination of position gathered using a quadrature encoder and monitoring output current and output voltage.
For example, we’d limit the upper end of our elevator travel based on an estimated position and then we’d calculate how much power is going into the elevator to prevent a motor stall condition.
After profiling the current draw, we determined that it requires a little bit of logic to figure out if we’re indeed stalling the gearbox, or lifting a bunch of totes.
We’d also rezero our elevator when it returns to its minimum position. Essentially, we’d allow for the elevator to run past the minimum position. Once we’ve detected that we’re not moving anymore, the position is past the minimum position (our elevator has a spring loaded return cable), and current has trended upward, we can safely say that we’re at the minimum position. We’d then allow the elevator to back drive itself via the spring to its natural state where we’d then reset the encoder.
Finally, we’re using a quad encoder on our pincher gearbox along with two different PIDs. One PID handles position control so that our drivers can quickly acquire game pieces. Once the game piece is kinda-sorta in our possession, we’d switch to a current based PID.
This ensures that we’d be placing almost an equal amount of force on what ever we decide to grab. This configuration works on game pieces in any orientation. Cans fallen over, Cans upside down, totes from the wide side, totes from the long side, totes that are upside down, you name it.
We do not powdercoat our stock and do post machining. It just happened to be on that part, we kind of forgot a few holes. Careful measurements and some patience later along with a handheld drill, we’d have some pretty precise holes.