Distributed MPC of vehicle platoons with guaranteed consensus and string stability

Area of Science:

• Automotive Engineering
• Control Systems
• Traffic Management

Background:

• Vehicle platooning offers significant benefits, including reduced traffic accidents, improved fuel efficiency, and lower emissions by minimizing inter-vehicle gaps.
• Current control strategies often struggle to balance safety, consistency, and passenger comfort in dynamic platooning scenarios.

Purpose of the Study:

• To propose a hierarchical control scheme for vehicle platoons that ensures safety, consistency, and passenger comfort.
• To guarantee string stability and asymptotic consensus within vehicle platoons.
• To develop a robust lower-level controller for precise vehicle dynamics adjustment.

Main Methods:

• A synchronous distributed model predictive controller (MPC) was designed as the upper-level controller, incorporating a string stability constraint.
• A terminal equality constraint was implemented in the MPC to ensure asymptotic consensus.
• A lower-level control scheme, utilizing a PID feedback controller and a feedforward component based on the inverse longitudinal dynamics model, was developed to manage throttle and brake pressure.

Main Results:

• The proposed hierarchical control scheme effectively guarantees string stability, ensuring inter-vehicle gap errors attenuate downstream.
• Asymptotic consensus of vehicle platoons was achieved through the implemented terminal equality constraint.
• Joint simulations using PreScan, CarSim, and Simulink validated the performance of the longitudinal tracking control.

Conclusions:

• The developed hierarchical control scheme provides a robust solution for safe and efficient vehicle platooning.
• The integration of MPC with string stability constraints and a PID-based lower-level controller enhances platoon performance.
• The simulation results confirm the effectiveness of the proposed control strategy in real-world platooning applications.