How is lateral control implemented for lane keeping systems?

Lane keeping lateral control: Perception provides lane position (lateral offset, heading error, curvature). Control approaches include: Pure pursuit - geometric controller following a point ahead on path; Stanley controller - uses heading error and cross-track error with proven stability; LQR (Linear Quadratic Regulator) - optimal control minimizing deviation and effort; MPC - handles constraints and preview. Implementation considers: Look-ahead distance (speed-dependent), steering actuator dynamics, driver steering input handling (torque overlay versus position control), and smooth transitions when activating/deactivating. Tuning balances responsiveness (safety) versus comfort (avoiding harsh corrections). Validation covers lane geometry variations and degraded lane marking conditions.