RAGE

RAGE

A Tightly Coupled Radar-Aided Grip Estimator For Autonomous Race Cars

Real-time estimation of vehicle-tire-road interaction using FMCW Radar.

Overview

Real-time estimation of vehicle-tire-road interaction and grip level is critical for allowing autonomous race cars to safely and effectively operate at their physical limits. Traditional approaches to measure tire grip often depend on costly, specialized sensors that require custom installation, limiting scalability and deployment. In this work, we introduce a novel real-time Radar-Aided Grip Estimator (RAGE) that jointly estimates the vehicle velocity vector, tire slip angles, lateral tire forces, and tire model parameters, using only standard sensors, such as IMUs and RADARs, which are commonly available on most of modern autonomous platforms. We validate our approach through both high-fidelity simulations and real-world experiments conducted on the EAV-24 autonomous race car, demonstrating the effectiveness of our method in estimating the vehicle lateral dynamics.

Key Contributions

Lateral Dynamics Estimation

Uses Radar measurements to estimate the vehicle lateral dynamics, including tire slip angles and lateral tire forces.

Tire Model Fitting

Online fitting of a non-linear tire model, enabling a more accurate representation of the lateral forces.

Handle delays and aliasing

The proposed method is robust to sensor delays and to Doppler aliasing, which are critical issues in high-speed applications.

Results

RAGE Real-World Results
RAGE outputs compared with reference data obtained from the optical sensor, covering a complete lap of the Yas Marina F1 track. The lateral acceleration estimate is computed combining the front and rear lateral tire forces obtained from the Pacejka model with the online-estimated parameters.
RAGE Real-World Results
Front and rear tire Pacejka model fitted over time. The sequence of model parameters captures the changing tire behavior and lateral dynamics throughout the lap.
RAGE Real-World Results
The estimated tire cornering stiffness shows a correlation with tire temperature and pressure, and exhibits periodic variations aligned with the circuit layout. The color-coded stiffness values correspond to specific segments of the track layout displayed on the right.

Publication