Realistic Brake Pedal Feel in the Driving Simulator by Combining HiL and DiL

Abstract 

The increasing demands of modern vehicle development require earlier and more integrated validation methods. Driving simulators have become essential for front‑loading test activities, yet realistic brake pedal feedback has remained a limitation. While steering feel can already be reproduced convincingly through remote Hardware‑in‑the‑Loop (HiL) integration, braking systems introduce additional complexity due to hydraulic nonlinearities, ABS/ESC dynamics, and the strong influence of brake pedal feel on driver perception.

This paper presents the MXbrakeLink, a low‑latency haptic coupling that connects a complete brake system on a MXbrakeHiL with the MXbrakePedal inside a Driver‑in‑the‑Loop (DiL) driving simulator. The system enables drivers to experience authentic brake pedal behaviour, including force–travel characteristics, ABS pulsation, and nonlinear hydraulic effects, while the physical brake hardware remains stationary in the laboratory. This minimizes added driving simulator mass, maintains mechanical simplicity, and ensures high physical fidelity. An alternative mode allows software‑generated brake pedal forces when independent HiL and DiL operation is required.

The paper

• describes the architecture of the MXbrakeHiL, MXbrakePedal, and MXbrakeLink,
• evaluates their performance with emphasis on bandwidth and end‑to‑end latency,
• and demonstrates how the system supports a closed workflow between HiL and DiL.
• Finally, modularity and scalability are discussed, highlighting applicability across hydraulic and brake‑by‑wire systems, driving simulator classes, and real‑time environments.

English abstract published with the kind permission of the authors. Original work: Groß, R., Tworek, A., Riegert, B., Pfeffer, P. E. (2026). A HiL-Driven Brake Pedal Feedback Architecture for Driver-in-the-Loop Simulation. Presented at the Driving Simulation Conference Europe XR 2026, Antibes, France. The full paper will be published in the Proceedings of the Driving Simulation Association; link to follow upon publication.

What questions does the paper address?

How can realistic brake pedal feel be reproduced in a Driver-in-the-Loop simulator?

By coupling a real brake system on a HiL test bench with a haptic brake pedal in the driving simulator in real time. This allows force-travel characteristics, hydraulic nonlinearities, and dynamic effects such as ABS pulsations to be experienced directly by the driver, without integrating the complete brake system into the driving simulator.

How can objective HiL testing and subjective driver evaluations be combined?

HiL and DiL are used as an integrated development workflow: On the HiL test bench, brake system functions, control strategies, and calibrations can be evaluated objectively and reproducibly. In the DiL simulator, it can then be assessed how this system behavior actually feels to the driver. Findings from both environments can be directly compared and fed back into the development process.

What requirements must the coupling of HiL and DiL meet to enable realistic driver evaluations?

Key requirements include precise transmission of pedal position and pedal force, sufficient bandwidth for fast dynamic events, and the lowest possible end-to-end latency. In the system investigated, position latency is below 1 ms and the end-to-end latency of the brake pedal force is typically below 7 ms. This enables even fast transitions and subtle differences in brake pedal feel to be reproduced realistically.