Control systems

Our chassis followed paths with pure pursuit: aim at a point a fixed distance down the path and ramp the speed up toward it. The robot's accelerations stay implicit in that, so it has no idea how hard it can brake or how fast it can take a corner, and at speed it swings wide of turns and overshoots where it should stop. I proposed replacing it with path tracking that models those accelerations explicitly, and led the feature from idea to implementation: I wrote the design and gathered the resources behind it, from spline fitting and arc-length reparametrization to the Riccati equation and a study that found LQR tracks more accurately than pure pursuit. First, a cubic spline through the waypoints is reparametrized by arc length, the speed at each point is capped by its curvature, and a forward and a backward pass keep every speed-up and every stop within what the robot can deliver. Then an LQR tracks that profile on a world-frame model of the chassis, where its dynamics stay constant, and its force is rotated into the robot's frame. I designed it and built the framework; the comparison here runs the finished MVP against our pure pursuit in simulation.