port: (2025 Ioniq5) HKG Angle Steering LFA2

[devtekve]

Note

Depends on

• HKG: Add hands-on detection signal for LFA2 vehicles #2420
• HKG: Update angle steering signal definitions #2422

This PR introduces the minimum required changes to safely support angle-based steering control on HKG vehicles, starting with the 2025 Hyundai Ioniq 5, which I personally own. This vehicle serves as the initial reference platform for the “official” port.

Although the current implementation works across all HKG angle steering vehicles we've tested so far, additional safety-related data needs to be gathered on a per-model and per-region basis. Merging support for this vehicle now enables faster iteration and testing for the remaining variants.

---

✅ What’s Included

• Lateral control via angle steering for HKG platform.
• Safety-critical enforcement of steering angle rate limits, maximum lateral acceleration, and jerk.

---

❓ Remaining Unknowns

We do not yet fully understand how the Torque Reduction Gain setting behaves across different HKG vehicles. This parameter, used by the EPS controller, appears to differ by model and region (so far US vs. Rest of the World). While it does not affect core safety constraints, it may influence driver comfort and perceived steering responsiveness.

• The safety code assumes that requested steering angles are applied immediately, regardless of the vehicle's internal smoothing or delays. Therefore, “Torque Reduction Gain” does not factor into the safety model for enforcing lateral acceleration or jerk limits.
• Despite this, the parameter may still influence how the EPS modulates assist during continuous control or how it blends driver and system input.

We could implement additional checks to ensure the driver can always override the system, but this might be redundant: the EPS controller already disables assist when the driver applies more than approximately 10 Nm of torque, ensuring manual control takes precedence when needed, although requiring significant override force.

---

🔍 Observations on Torque Reduction Gain

This parameter has been observed to fluctuate during live drives with Lane Following Assist (LFA) enabled. It tends to settle to a steady value when driving on straight roads, but:

• For EU Ioniq 5 models, the steady-state value has consistently been 0.384.
• For US Ioniq 5 models, we’ve observed it stabilizing around 0.92.
• The maximum observed value is 1.0.

These differences suggest regional or model-specific EPS tuning. However, the impact on steering feel and override responsiveness still requires further study. There is currently no evidence that these values compromise safety enforcement, but we intend to gather more structured data as we expand support.

Testing

• Route: e1107f9d04dfb1e2/00000281--d21e3d98e5