Transient-Safe Platooning via Dynamic Headway
For autonomous vehicle platooning, this work addresses the lack of formal safety guarantees in existing CTH-based methods during velocity transients.
The paper proposes a control framework for autonomous vehicle platooning that ensures formal transient safety and string stability during aggressive maneuvers like highway merging, using a spacing policy that converges to Constant Time Headway at steady state.
Managing autonomous vehicle platoons requires a delicate balance between string stability and rigorous safety. This challenge is intensified by aggressive transients, such as highway merging. Although Constant Time Headway (CTH) spacing is the industry standard for Cooperative Adaptive Cruise Control, it lacks formal safety guarantees during significant velocity deviations. This letter proposes a computationally efficient control framework that considers a linear time-invariant model for the dynamics of each vehicle, while ensuring formal transient safety and stability. By introducing a spacing policy that naturally converges to CTH at steady state, we establish platoon safety as an inductive property. We derive a non-linear and saturated control law for the lead follower and provide sufficient initial conditions to guarantee velocity non-negativity and safety throughout the platoon for any CTH-based followers' control law. Numerical examples indicate the proposed methodology may be applicable even under non-nominal setups.