Following a trajectory

Turning a plan into motion: a path is geometry and a trajectory is geometry with a clock, and between them sit velocity profiles, cross-track error, pure pursuit and the look-ahead distance.

Module U10University7 lessons

Start in the simulator
  1. U10.1 A path and a trajectory The same geometry with and without a clock attached, and why the clock changes what you can check.
  2. U10.2 Velocity profiles The trapezoid, the triangle when there is no room to reach cruise, and what jerk costs you.
  3. U10.3 Cross-track error Splitting the error into along and across the path, and a controller for the half that matters.
  4. U10.4 Pure pursuit Chase a point a fixed distance ahead on the path, and choose the one number that decides everything.
  5. U10.5 Feedforward and feedback A ramp leaves a proportional controller permanently behind, and the model knows how to fix it.
  6. U10.6 How far behind Dead band, lag and loop period, measured as the centimetres the robot is behind its own plan.
  7. U10.7 Project: drive the route A full route through waypoints, marked on how closely it was followed and how long it took.