Real-Time HIL Testing and Validation for Multi-ECU Smart Brake Systems: Design, Implementation, and System Optimization

This paper presents applied methodologies and results from real-time Hardware-in-the-Loop (HIL) testing of smart braking systems, based on experience gained during European Tier-1 supplier development programs. It outlines how HIL accelerated control software validation, enhanced fault coverage, and improved development cycles for emerging technologies like brake-by-wire and regenerative braking systems. As braking systems evolve to meet the demands of electrification and autonomy, their complexity has grown significantly requiring robust, scalable, and safety-focused validation techniques. Modern smart braking architectures often employ decentralized control, with individual ECUs managing each brake corner. To ensure safe and reliable operation of such systems, a real-time HIL test bench was developed to simulate a wide range of driving conditions and validate critical functionalities including Anti-lock Braking System (ABS), Vehicle Dynamics Control (VDC), and regenerative braking coordination. The test bench also supports fault injection and scenario-based testing, allowing engineers to observe system behavior under emergency maneuvers, sensor failures, and road surface variations—all without the need for a physical vehicle. By replacing the main vehicle controller with a real-time simulator, this setup enabled efficient closed-loop validation of both individual ECU functions and their interactions. This methodology helped accelerate development timelines, identify potential integration issues early, and ensure compliance with safety and performance standards. The paper details the design, implementation, and benefits of the HIL test approach, emphasizing its importance in advancing next generation braking systems for electric and autonomous vehicles.