Quadrotor Sim

The quadrotor project is a ground-up flight-dynamics simulator, currently in its 2D simulation phase — there is no physical build yet, deliberately. The simulator models a planar quadrotor in the XZ plane with a six-component state vector — position, attitude, and their rates, as an Eigen matrix — driven by two raw rotor thrust inputs in Newtons and integrated with a fixed-timestep RK4 integrator.

The physics core is written by hand, on purpose. The equations of motion and the RK4 step came from working through the math first — understanding the theory before writing the functions — rather than pasting in a reference implementation. AI assistance is used for scaffolding, build tooling, and rendering code, under a discipline documented in the project's devlog: every generated line gets read and understood before it's kept, and physics stays handwritten.

The roadmap runs in phases: rigid-body physics and a bare renderer, then control, then sensor models with a Kalman filter for state estimation — the full GNC loop in miniature, at which point the noisy-measurement / true-state / estimate distinction becomes the interesting part. Development is active and logged as it happens in the devlog below.