Our engineering team, through our Center of Excellence (CoE), developed a dual-mode, software-defined Brake-by-Wire (BbW) system for an E-Buggy platform, demonstrating our SDV-ready, safety-critical vehicle control system design and development capabilities.
The solution is developed as an electro-hydraulic and software-controlled architecture, an alternative to conventional hydraulic-only braking, to enable precise, real-time deceleration control for Level 3+ autonomous operations. By combining closed-loop control, deterministic execution, and functional safety engineering, we delivered a braking system that enhances vehicle dynamics, improves passenger comfort, and ensures ASIL D-compliant performance.
Business Objectives
Key objectives included:
- Develop a software-defined electro-hydraulic Brake-by-Wire architecture, reducing dependency on conventional hydraulic systems
- Deliver deterministic, high-resolution deceleration control using multi-sensor closed-loop feedback
- Enable dual-mode braking supporting both autonomous control and real-time manual override
- Engineer an ASIL D-ready functional safety architecture with redundancy and fail-operational capability
- Eliminate braking jerk and optimize NVH through advanced control strategies
- Enable seamless integration with Autonomous Driving Control Units via CAN
- Enhance system reliability through diagnostics, anomaly detection, and safe-state transitions
- Reduce lifecycle maintenance effort and improve MTBF through robust system design
- Support SDV principles and scalable deployment for Level 3+ autonomous vehicle platforms
Solution
The system leverages a closed-loop control approach to align commanded deceleration with real-time braking response, enabling precise and stable braking performance across varying driving conditions. It supports seamless interaction with the Autonomous Driving Control Unit, allowing both autonomous braking commands and manual inputs within a single, coordinated system.
Built for deterministic performance and safety, the architecture incorporates real-time control execution, continuous diagnostics, and fail-operational capability through mechanical override. This ensures reliable braking behavior while meeting ASIL D functional safety requirements and supporting Level 3+ autonomous operation.
Key Highlights
Dual-Mode Electro-Hydraulic Brake-by-Wire Architecture
- Engineered a dual-mode braking system integrating autonomous commands and manual input, enabling seamless control transitions with instant override prioritization for safe operation under all conditions.
High-Precision Multi-Sensor Closed-Loop Control
- Integrated pedal position, fluid pressure, and wheel speed sensors within a closed-loop control framework, ensuring deterministic deceleration and precise correlation between commanded and actual braking force.
PID-Controlled PWM Actuation
- Developed a PID-based PWM control framework for electro-hydraulic actuation, delivering smooth ramp-up and ramp-down of braking force while eliminating transient jerk and oscillations.
RTOS-Based Deterministic Execution
- Implemented multi-threaded RTOS scheduling across control, sensing, and communication layers, ensuring predictable real-time execution and synchronized system behavior.
ASIL D-Ready Functional Safety Architecture
- Designed a multi-layer safety framework with redundancy, diagnostics, and safe-state transitions, enabling fail-operational performance and compliance with ASIL D requirements.
Mechanical Override Redundancy
- Retained a parallel mechanical braking linkage, guaranteeing immediate manual control and uninterrupted braking during electronic or system-level failures.
CAN-Based Real-Time Control Integration
- Enabled high-speed CAN communication with the Autonomous Driving Control Unit, supporting accurate and real-time execution of autonomous braking commands.
Advanced Diagnostics and Fault Handling
- Embedded signal validation, anomaly detection, and fault isolation mechanisms improve system reliability, fault tolerance, and Mean Time Between Failures (MTBF).
NVH Optimization through Controlled Deceleration
- Engineered controlled braking profiles through precise actuation, reducing noise, vibration, and harshness while delivering smooth, human-like braking behavior.
SDV-Ready Modular Software Architecture
- Built a modular, software-defined braking platform with clear hardware-software separation, enabling reuse, faster validation cycles, and scalable deployment across autonomous vehicle programs.
Outcomes
- Delivered precise, software-controlled deceleration, improving vehicle stability and braking performance
- Eliminated transient braking jerk, enhancing passenger comfort and ride quality
- Enabled reliable Level 3+ autonomous braking through seamless ADAS integration
- Strengthened safety with an ASIL D-ready architecture and fail-operational capability
- Increased system reliability and reduced operational risk through diagnostics and fault-tolerant design
- Reduced lifecycle maintenance effort and improved MTBF through a robust, software-centric approach
- Improved cost efficiency and accelerated development through modular, reusable system architecture
Technologies Used
- Microcontroller: NXP S32 Series (automotive-grade)
- Development Environment: S32 Design Studio
- Operating System: RTOS
- Sensors: Pedal position, fluid pressure, and wheel speed sensors
- Actuation: Electro-hydraulic actuator
- Control Algorithm: PID control framework
- Communication Protocol: CAN network
