Day 8 - January 15 2022
It has been a few days since we posted. In this update we’ll discuss the following topics.
- Robot and Game Play Technical Profile
- Intake prototype #3
- Calibrating our Ballistics Model - Measured exit velocity
Robot and Game Play Technical Profile - LINK TO PROFILE
This will be a document in evolution for a week or 2, but this is what is looks like today. Here are the top 10 must do:
- Must Taxi in Autonomous
- Minimum 1 Shot in Autonomous
- Target Autonomous script
-Pickup (Different autons for different CARGO pickup positions)
- Need a Human Player with better than 25% capability
- High Hub capability
- Must make from the Fender
- Make a shot from Launch Pad
- Floor CARGO Pickup
- Hold 2 CARGO
- Climb to MID HANGER
Intake Prototype #3 - VIDEO
This video shows a fast moving intake over a 5" bumper with 1" of ground clearance.
NEO - 2000 rpm
48/65 gear reduction on first shaft
Belt reduction 18/24 pulley reduction for 2nd shaft
We’ve tried, Thrifty 2" squishy wheels, 4" Andy Blue Intake wheels, 2" VIW, and we think this setup works pretty well with the 3" AM green wheels and minimal compression ~0.25" It is time to take it to CAD and hook it up to some motors to deploy and stow it!
Launcher Calibration -
This was hard but fun. Our setup is shown in this image. 6" Hi-Grip Wheels on both sides.
We adjusted CARGO compression in this setup at 0.25", 0.75", 1.25", 1.75"
We got nothing at 0.25" - the ball just spun on the wheels!!
0.75" - 1.25" - 1.75" all gave us VERY SIMILAR EXITS speeds measured looking up as the ball leaves with THIS
We had never used a radar gun and you need to measure in line with trajectory, so we measured from below the ball, but above the wheels so the gun did not see the wheels. We set the wheel speed to give a theoretical exit speed of 26.5mph, and we measured 17, 18, and 17mph through multiple trials at 0.75", 1.25", and 1.75" respectively. Basically that launcher is 65% efficient at converting wheel speed to launched speed. So, here is a plot of the Theoretical Trajectory and the Empirical Trajectory calculated by reducing the exit speed to the measured value.
Side view of a 1480rpm shot - ~11ft peak height. It matches our calibrated model nearly perfectly! I was very happy with that, but not with a launcher that only gives 65% of the wheel speed! There must be better versions that convert more speed to CARGO. Maybe we’ll add some primer wheels to get the ball moving faster prior to the main launcher wheels. People seem to use those a lot and now we see why! Good Luck everyone!