Denis Hoornaert

Raphael Trumpp, Denis Hoornaert, Marco Caccamo

The development of vehicle controllers for autonomous racing is challenging because racing cars operate at their physical driving limit. Prompted by the demand for improved performance, autonomous racing research has seen the proliferation of machine learning-based controllers. While these approaches show competitive performance, their practical applicability is often limited. Residual policy learning promises to mitigate this drawback by combining classical controllers with learned residual controllers. The critical advantage of residual controllers is their high adaptability parallel to the classical controller's stable behavior. We propose a residual vehicle controller for autonomous racing cars that learns to amend a classical controller for the path-following of racing lines. In an extensive study, performance gains of our approach are evaluated for a simulated car of the F1TENTH autonomous racing series. The evaluation for twelve replicated real-world racetracks shows that the residual controller reduces lap times by an average of 4.55 % compared to a classical controller and even enables lap time gains on unknown racetracks.

Denis Hoornaert, Cole Strickler, Manos Athanassoulis et al. · harvard

The shift to data-intensive processing from the cloud to the edge has introduced new challenges and expectations for the next generation of intelligent computing systems. As the memory wall continues to grow, modern systems can only meet these performance expectations by displaying data access patterns that exhibit ideal layouts in memory and ideal spatiotemporal locality in caches. However, only a few data-intensive applications are characterized by ideal locality. Instead, most applications exhibit either (i) poor locality when naively implemented and must undergo costly redesigns and tuning or (ii) inflated memory footprint to offer proper locality. To address the aforementioned challenges, we propose a hardware/software co-designed approach that can be implemented on commercially available SoC/FPGA platforms. Our approach seamlessly inserts in the CPUs' data path a Tensor Memory Engine that provides data with an ideal cache locality to running applications by (i) accessing the memory on behalf of the CPUs and (ii) composing a re-organized view of the memory layout. Unlike in- and near-memory computing approaches, it sets itself apart by clearly decoupling computing and memory accesses; computation is still performed on CPUs while the data re-organization is delegated to the Tensor Memory Engine.

Raphael Trumpp, Denis Hoornaert, Mirco Theile et al.

Residual policy learning (RPL), in which a learned policy refines a static base policy using deep reinforcement learning (DRL), has shown strong performance across various robotic applications. Its effectiveness is particularly evident in autonomous racing, a domain that serves as a challenging benchmark for real-world DRL. However, deploying RPL-based controllers introduces system complexity and increases inference latency. We address this by introducing an extension of RPL named attenuated residual policy optimization ($α$-RPO). Unlike standard RPL, $α$-RPO yields a standalone neural policy by progressively attenuating the base policy, which initially serves to bootstrap learning. Furthermore, this mechanism enables a form of privileged learning, where the base policy is permitted to use sensor modalities not required for final deployment. We design $α$-RPO to integrate seamlessly with PPO, ensuring that the attenuated influence of the base controller is dynamically compensated during policy optimization. We evaluate $α$-RPO by building a framework for 1:10-scaled autonomous racing around it. In both simulation and zero-shot real-world transfer to Roboracer cars, $α$-RPO not only reduces system complexity but also improves driving performance compared to baselines - demonstrating its practicality for robotic deployment. Our code is available at: https://github.com/raphajaner/arpo_racing.