sunnypilot/docs_sp/features/nnlc.md

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Neural Network Lateral Control

Neural Network Lateral Control (NNLC)

What It Does

NNLC replaces the traditional PID or torque-based steering controller with a neural network trained on real driving data. This can provide smoother, more natural-feeling lane keeping that adapts to your vehicle's steering characteristics.

How It Works

Instead of using fixed mathematical formulas (PID controller), NNLC uses a machine learning model to calculate steering commands. The neural network has been trained on real-world driving data and can handle a wider variety of driving scenarios with smoother output.

!!! note "Evolution from NNFF" NNLC evolved from Neural Network FeedForward (NNFF), an earlier approach that used a neural network as a feedforward component alongside traditional controllers. NNLC builds on this foundation by giving the neural network full lateral control authority, resulting in improved steering smoothness and adaptability.

!!! info "Vehicle-Specific Training Data" The neural network models are trained on real driving data collected from specific vehicles. Because each vehicle has unique steering characteristics, a dedicated model must be trained for each supported make/model. Over 70 vehicle models currently have trained NNLC models available. If no model exists for your vehicle, the NNLC toggle will not appear in settings.

Model Matching

When NNLC is enabled, the system matches your vehicle to the best available model using a 3-tier fallback:

Tier	Match Criteria	Confidence	Description
1. Exact	Fingerprint + firmware version	≥ 0.99	Best match — a model trained on your exact vehicle and firmware combination
2. Valid	Fingerprint only	≥ 0.9	Good match — a model trained on your vehicle platform, regardless of firmware version
3. Substitute	Substitute table lookup	Fallback	A model from a similar vehicle platform is used as a substitute (configured in substitute.toml)

Requirements

!!! info "Requirements" - Vehicle must not use angle-based steering (steerControlType must not be angle) - A trained NNLC model must be available for your specific vehicle - Mutually exclusive with Torque Control — only one can be active at a time - Device must be offroad to enable/disable

How to Enable

Settings → sunnypilot → Steering → Neural Network Lateral Control

!!! tip Not all vehicles have NNLC models available. If the toggle does not appear, your vehicle may use angle-based steering which is not compatible with NNLC, or a trained model may not yet exist for your vehicle.

NNLC vs. Torque Control

Feature	NNLC	Torque Control
Approach	Neural network (learned)	Mathematical formula (tuned)
Customization	Automatic	Manual tuning available
Best for	Smooth, adaptive steering	Precise, configurable steering

These two features are mutually exclusive — enabling one automatically disables the other.

Settings Reference

See Steering Settings for configuration details.