The Drivetrain

Introduction

The tank drivetrain is tried and tested, even by us! During Prototyping we experimented with our kitbot drivetrain and used it as a solid base to train new members with.

The drivetrain is a 3x3 tank drive base, with all wheels powered, and the first two being omnidirectional.

The drivetrain’s top speed is estimated to be 45kts. Although it has not yet been in wide enough area to confirm.

Prototyping

In the pre season we prototyped using our kitbot and counterweights.

Software

The drive base uses simple two wheel steering kinematics and an odometry with encoders, gyro and accelerometers to detect robot position.

Config Files

drivetrain:
  max_velocity: 1.5               # Updated Never by Nobody
  encoderConversionFactor: 21.43  # Updated 1/27 by Joe

  # All pose coordinates are in meters.
  leftMotor:
    Motor1Port: 2                # Updated 1/12 by Keegan
    Motor2Port: 1                # Updated 1/12 by Keegan 
    EncoderPorts: [2, 1]         # Updated 2/12 by Keegan
    EncoderReversed: False       # Updated Never by Nobody
    Inverted: False              # Updated Never by Nobody

  rightMotor:
    Motor1Port: 3                # Updated 1/8 by Keegan
    Motor2Port: 4                # Updated 1/8 by Keegan
    EncoderPorts: [3, 4]         # Updated Never by Nobody
    EncoderReversed: True        # Updated Never by Nobody
    Inverted: True               # Updated Never by Nobody

  navX: # NavX ids
    can_id: 0                    # Updated 1/13 by Keegan
    yaw: 0                       # Updated 1/13 by Keegan
    pitch: 0                     # Updated 1/13 by Keegan
    roll: 0                      # Updated 1/13 by Keegan

drive:
  # Diff lock
  kStabilizationP: 0.011
  kStabilizationI: 0.0001
  kStabilizationD: 0

  # TurnToAngle
  kTurnP: 0.007
  kTurnI: 0.006
  kTurnD: 0.001

  kMaxTurnRateDegPerS: 100
  kMaxTurnAccelerationDegPerSSquared: 300

  kTurnToleranceDeg: 5
  kTurnRateToleranceDegPerS: 10 # degrees per second