RoadRunner basics

RoadRunner basics (pre-Center Stage version).

Basic Concepts

Localization: ability to know the robot’s position on the field at any time
Declaring & initialization Java object: Object object = new Object();
Vector2d: (x, y)
Pose2d: (x, y, heading)
Feedback control
- e.g. PID
- update robot behavior (e.g. motor power) from error (target value - sensor value) after the fact
Feedforward
- update robot behavior (e.g. motor power) from anticipated obstacles (e.g. static friction) beforehand
DriveConstants
- TrackWidth: distance between two wheels (measured from the center)
- RUN_USING_ENCODING: set to false; we are not using FTC motor’s builtin PID controller
- Consider not using 100% of the measured MAX_* constants to increase robot stability

Download quickstart
Set up drivetrain
- Rename SampleMechanumDrive to Drivetrain
- Set motor device names in constructor
- Reverse motor directions as appropriate (usually left side)
Set up DriveConstants
- Update TICKS_PER_REV, MAX_RPM, WHEEL_RADIUS, GEAR_RATIO, TRACK_WIDTH, MAX_{VEL_ACCEL,ANG_VEL,ANG_ACCEL} based on robot specifications
- LearnRoadrunner.com has DriveConstants.java for download, but double check just to be sure. The file they have might not be updated.
Follow tuning tests on LearnRoadrunner.com
Record constants measured on tuning tests (if any) in DriveConstants.java
Make RR paths in your Opode
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To access:

Do all of the tuning tests below in order.

NOTE

Skip if not using dead wheels

Goal: To check if dead wheels are working correctly
To pass:
- Move the robot on the field with your hands (make it as varied as possible: forward, backward, turns, etc)
- Check that robot’s position is accurate on RoadRunner dashboard

Skip

We are not using built-in motor PID.

Goal: Tune kV, kA, kStatic coefficients for feedforward control
Steps:
- Go to dashboard
- Start the test
- Use controller to configure test
- Record tuned parameters in DriveConstants

Goal: check if the prior tuning tests are successful
To pass:
- Run StraightTest while the robot is placed like on the field diagram (placed centered on the seam between tiles)
- If the translational error & heading error is low enough, & the robot’s position on field matches what you see on the diagram, then the robot passed.
- If failed, try checking wheel set screws.

Goal: To determine empirical track width to help robot turn better
Steps
- Run angular velocity tuner to set an appropriate MAX_ANG_VEL value
- Run TrackWidthTuner and check the resulting track width. If the number looks normal (within 3 inches of your measured track width) and if the robot turned 180 degrees (+/- 1 degree), then save it in DriveConstants. If not, continue with the steps below
- Manually increase/decrease track width until the robot turns close to 180 degrees. Save the reslting track width in DriveConstants

Goal: To set an initial estimate for HEADING_PID and TRANSLATION_PID.
Steps:
- Turn BackAndForth on
- Increase kP of heading PID slowly until the actual heading (green) matches the target heading (blue)
- Increase kP of translational PID until the green line matches the blue line
- Increase kD of translational PID until there is minimal overshoot while having negligible jitters.