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Module 4 - Autonomy & Paths

Objective: execute reliable autonomous routines.

Prereqs: Command-based project and drive subsystem.

Steps

  • Build autos with command sequences/command groups.
  • Generate trajectories in PathPlanner; export and load in code.
  • Test in simulation; validate odometry and event markers.
  • Use alliance color for mirroring when needed; confirm starting pose and heading.
  • Add fallbacks for odometry loss; timeouts on critical steps.

Deliverables

  • Multi-step autonomous routine tested in sim (and on bot when available).
  • Auto checklist: starting pose, gyro zero, path files loaded, button mapping.

Code example (simple auto command group)

Command auto = new SequentialCommandGroup(
  new DriveDistance(drive, 2.0, 0.5),
  new TurnToAngle(drive, 180),
  new DriveDistance(drive, 1.0, 0.4)
);

Resources

  • PathPlanner: pathplanner.dev
  • Trajectory examples: docs.wpilib.org/en/stable/docs/software/pathplanning/index.html

Instructions (numbered)

  1. Define autonomous goals; plan steps and command sequence/command groups.
  2. Build trajectories in PathPlanner; export and load; set starting pose/heading.
  3. Implement auto selector and button mapping; add timeouts/fallbacks.
  4. Test in Sim GUI; validate odometry and event markers; mirror for alliance if needed.
  5. Test on-bot when available; log results and adjust.

Example

  • Auto: drive 2 m, turn 180, drive 1 m; PathPlanner paths loaded, gyro zeroed at start, button B selects path.

Best practices

  • Include a "safe" auto for reliability.
  • Use timeouts and odometry fallbacks; log auto runs.
  • Confirm paths updated on deploy; version control path files.

Common mistakes

  • Wrong starting pose/heading; forgetting gyro zero.
  • Missing alliance mirroring; stale path files.
  • No timeouts — stuck commands.

Spec notes / data to log

  • Paths: start pose/heading, alliance mirroring, constraints.
  • Autos: timeouts, events markers, button/selector mapping.
  • Data: log odometry, target states, and errors per auto run.

Checklist

  • Paths built/exported and committed
  • Starting pose/gyro set
  • Auto selector/button set
  • Timeouts/fallbacks added
  • Sim test passed
  • On-bot test logged

Recommended tools

  • PathPlanner, Sim GUI, logging, field coordinate reference.

Sample log (template)

  • Date:
  • Auto tested:
  • Results (sim/bot):
  • Issues/fixes:
  • Next changes:

Photos/diagrams

  • [Placeholder: path diagram from PathPlanner]

Numeric Example​

Example drivetrain path constraints:

  • Max velocity: 3.0 m/s
  • Max acceleration: 2.5 m/s²
  • Max angular velocity: 6.0 rad/s
  • Max angular acceleration: 8.0 rad/s²

Sample waypoint path:

  • Start: (x = 0.0 m, y = 0.0 m, heading = 0°)
  • Waypoint 1: (x = 1.5 m, y = 0.3 m, heading = 15°)
  • Waypoint 2: (x = 3.0 m, y = 0.0 m, heading = 0°)
  • End: (x = 4.5 m, y = -0.2 m, heading = -10°)

Expected autonomy behavior:

  • Pose error at end of path: < 0.10 m, < 3°
  • No wheel slip (no sudden spikes in accel beyond limits)

Data to Log​

For autonomous path tests, log:

  • Timestamp
  • Desired pose (x, y, heading)
  • Measured pose (x, y, heading)
  • Path progress (0–100%)
  • Wheel speeds
  • Controller outputs
  • Error in x, y, and heading
  • Any events (brake mode, stop conditions, failsafes)