Safety‐guaranteed constraint‐oriented modelling and control for bidirectional vehicular platoons

Abstract

The safety of a vehicular platoon is seriously threatened in the presence of actuator saturations, (possibly fast) timevarying non-linear uncertainties. Meanwhile, the string stability and the strong string stability cannot eliminate the potential safety hazard caused by large initial error conditions. This study focuses on safety-guaranteed distributed control of the vehicular platoon with a bidirectional communication topology and the constant time headway policy. The authors formulate bilateral inequality constraints on the spacing error between adjacent vehicles to represent the collision-avoidance and compact formation performance. A novel state transformation technique is proposed to convert the bounded spacing error space to an unconstrained state space. On the basis, Comprehensive equality constraints for the transformed states are established by integrating the information of proximal (preceding and following) vehicles. In addition, an anti-windup compensation method is utilised to handle actuator saturations. Then an adaptive constraint-following controller is designed to render the uniform boundedness and uniform ultimate boundedness performance of the transformed state. As a result, the string stability, the strong string stability, the collision-avoidance and compact formation are guaranteed despite the presence of actuator saturations and complex uncertainties. Numerical simulations are performed to validate the effectiveness of the proposed control scheme.

Motion control of connected and automated vehicles in a lane‐changing scenario with guaranteed tracking performance

“…Remark Several existing approaches 15,37 consider the longitudinal safety of multi‐vehicle cooperative platoon control, and constrain the spacing error within bilateral inequalities, the upper and lower bounds of which are scalar constants. This requires that all initial, transient and steady states of the spacing error satisfy these constraints.…”

“…Remark It is worth noting that modeling uncertainties are not considered in our paper, that is, the constraint‐following controllers are designed for nominal dynamical systems. However, in the actual driving process, the model uncertainties caused by parameter variations and external disturbances (e.g., the aerodynamic and road resistances) is inevitable 37,42 . In order to deal with this issue, further work will decouple the vehicle dynamics into the nominal portion and the uncertain portion.…”

“…However, in the actual driving process, the model uncertainties caused by parameter variations and external disturbances (e.g., the aerodynamic and road resistances) is inevitable. 37,42 In order to deal with this issue, further work will decouple the vehicle dynamics into the nominal portion and the uncertain portion. The control force designed in this paper is used for nominal dynamics.…”

Collision-free control strategy for on-ramp merging: A spatial-dependent constraint following approach

“…Considering the initial condition offset, we design a feedback control part to modify the system to approach the expected equation constraint (18), that is, 𝑝 𝑖,2 = −𝜅 𝑖 𝑀 𝑖 𝐺 𝑖 𝜑 𝑖,1 𝛽 𝑖 (23) where 𝜅 𝑖 is a scalar constant. Therefore, the overall control force is designed as…”

“…There have been many studies focusing on designing controllers to achieve merging safety and high efficiency, but most of them do not focus on binding the controller performance with static spatial locations in the environment. Our team's previous work [16][17][18][19][20][21][22][23] mainly concentrates on the robust controller design and doesn't deal with this spatial-dependence, neither. Spatial-dependence means that the controller can assure that each vehicle satisfies the safety requirements to avoid collision at specific spatial locations, especially at the most dangerous merging point.…”