This repository provides the official simulation framework and validation environment for the research presented in:
A Safe and Robust Control System Architecture for Virtual Coupling
Mario Terlizzi, Luigi Glielmo, Davide Liuzza
🏆 Awarded in collaboration with [Rete Ferroviaria Italiana (RFI)] 🎤 Presented at the World Congress on High-Speed Rail 2025, July 2025 . Session 5.1 - Signalling & control systems - 8 July
The tool supports the development, testing, and safety validation of a next-generation control architecture that facilitates the transition from ETCS Level 3 to Virtual Coupling (VC) operations — a key concept for ETCS Level 4. The parameters used for the simulation for the aforementioned paper are reported in "Table I - Simulation parameters.png".
✅ Modular simulation framework for two-train VC scenarios
✅ Full support for parametric uncertainty and non-ideal communication
✅ Certified safety via Control Barrier Functions (CBFs)
✅ Emergency and cruise control strategies for robust train platooning
✅ Real-time Delay Estimator Module
✅ Extendable for future research in multi-train convoys and hybrid control
This tool implements a composable, safety-centric architecture with the following key blocks:
🧩 Leader RLP Predictor
Estimates the Robust Lower Proxy (RLP) of the leader’s trajectory under worst-case (emergency braking) assumptions. Ensures the follower can predict a minimum safe trajectory in the absence of fresh data.
🛡️ Safety Control Block
Implements a Control Barrier Function-based safety supervisor.
Triggers emergency braking of the follower if predicted trajectories violate safety guarantees.
🚦 Cruise Virtual Coupling Block
Predictive controller that regulates the follower’s position during normal operations, optimizing speed tracking and spacing with real-time adaptation based on communication health.
⏱️ Delay Estimator Block (Optional)
Estimates packet delay distributions and updates a safety horizon dynamically.
Mitigates unnecessary braking due to transient communication issues.
virtual-coupling-tool/ ├── src/ │ ├── controller/ # Control logic (cruise, emergency, switching) │ ├── dynamics/ # Train longitudinal models + uncertainties │ ├── safety/ # CBF computation and safe set definitions │ ├── communication/ # Delay modeling and estimator │ └── simulation/ # Scenario definitions and run scripts ├── data/ # Train and line parameter sets ├── results/ # Output logs and plots ├── docs/ # Methodology documentation and architecture diagrams ├── tests/ # Unit tests
This simulation tool is intended for advanced experimentation and scientific validation in the following domains:
- 📊 Academic research in train control and railway safety
- 🚄 Benchmarking of virtual coupling (VC) control algorithms
- 🛠️ Prototyping of ETCS Level 4 control architectures
- 📡 Validation of delay-tolerant controllers under communication uncertainty
- 🧮 Safety enforcement via Control Barrier Functions (CBFs)
This project is licensed under the terms of the GNU General Public License v3.0.
You are free to use, modify, and distribute this software, provided that:
- Source code remains open and freely available.
- Any derivative work is also distributed under the GPL-3.0 license.
- Proper attribution to the original authors is maintained.
📄 See the LICENSE file for full details, or visit
🔗 https://www.gnu.org/licenses/gpl-3.0.en.html
© 2025 Mario Terlizzi, Luigi Glielmo, and Davide Liuzza
Developed in collaboration with Rete Ferroviaria Italiana (RFI S.p.A.)