Adaptive Planning and Control with Time-Varying Tire Models for Autonomous Racing Using Extreme Learning Machine

Autonomous racing is a challenging problem, as the vehicle needs to operate at the friction or handling limits in order to achieve minimum lap times. Autonomous race cars require highly accurate perception, state estimation, planning, and control. Adding to this complexity is the need to accurately identify vehicle model parameters governing lateral tire slip effects, which can evolve over time due to factors such as tire wear and tear. Current approaches to this problem typically either propose offline model identification methods or rely on initial parameters within a narrow range (typically within 15-20% of the actual values). However, these approaches fall short in accounting for significant changes in tire models that can occur during actual races, particularly when pushing the vehicle to its handling limits. We present a unified framework that not only learns the tire model in real time from collected data but also adapts the model to environmental changes, even when the model parameters exhibit substantial deviations. The friction estimation, obtained as a byproduct from the learning results, facilitates the selection of the optimal racing line from a library for adaptive speed planning. We validate our approach through testing in simulators, encompassing a 1:43 scale race car and a full-size car, and also through experiments with a physical F1/10 autonomous race car.