Platoon Of Automated Vehicles Research Articles

Research of obstacle vehicles avoidance for automated heavy vehicle platoon by switching the formation

AbstractWith the development of automated vehicles, researches related to automated vehicle platoon (AVP) have received more and more attention. AVP is considered one of the effective means to alleviate traffic congestion and reduce vehicle energy consumption. This paper studies a three‐layer method of avoiding obstacle vehicles in traffic by switching the formation for the automated heavy vehicle platoon. In the decision‐making layer, a decision‐making system based on the finite‐state machine is established for formation switching. In the second layer, the lane‐changing trajectory is optimized based on the quantic polynomial curve fitting for vehicles that need to change lanes. In terms of vehicle control layer, each vehicle has a longitudinal controller based on sliding mode control and a lateral controller based on model predictive control to track the planned trajectory to complete the target formation. Finally, the proposed method is simulated in MATLAB/TruckSim. The simulation results show that the proposed method could effectively avoid the obstacle vehicles by switching the formation and has a small average value of errors in speed tracking and trajectory tracking.

Communication Resource-Efficient Vehicle Platooning Control With Various Spacing Policies

Platooning represents one of the key features that connected automated vehicles may possess as it allows multiple automated vehicles to be maneuvered cooperatively with small headways on roads. However, a critical challenge in accomplishing automated vehicle platoons is to deal with the effects of intermittent and sporadic vehicle-to-vehicle data transmissions caused by limited wireless communication resources. This paper addresses the co-design problem of dynamic event-triggered communication scheduling and cooperative adaptive cruise control for a convoy of automated vehicles with diverse spacing policies. The central aim is to achieve automated vehicle platooning under various gap references with desired platoon stability and spacing performance requirements, while simultaneously improving communication efficiency. Toward this aim, a dynamic event-triggered scheduling mechanism is developed such that the inter-vehicle data transmissions are scheduled dynamically and efficiently over time. Then, a tractable co-design criterion on the existence of both the admissible event-driven cooperative adaptive cruise control law and the desired scheduling mechanism is derived. Finally, comparative simulation results are presented to substantiate the effectiveness and merits of the obtained results.

Collision Avoidance Motion Planning for Connected and Automated Vehicle Platoon Merging and Splitting With a Hybrid Automaton Architecture

Collision Avoidance Motion Planning for Connected and Automated Vehicle Platoon Merging and Splitting With a Hybrid Automaton Architecture

Stability and Safety Analysis of Connected and Automated Vehicle Platoon Considering Dynamic Communication Topology

Stability and Safety Analysis of Connected and Automated Vehicle Platoon Considering Dynamic Communication Topology

Lane-Changing Tracking Control of Automated Vehicle Platoon Based on MA-DDPG and Adaptive MPC

Lane-Changing Tracking Control of Automated Vehicle Platoon Based on MA-DDPG and Adaptive MPC

Distributed MPC for Automated Vehicle Platoon: A Path-Coupled Extended Look-Ahead Approach

Distributed MPC for Automated Vehicle Platoon: A Path-Coupled Extended Look-Ahead Approach

Reference Generator for a Platoon of Position-Controlled Vehicles on a Curved Path

<div>Vehicular automation in the form of a connected and automated vehicle platoon is demanding as it aims to increase traffic flow and driver safety. Controlling a vehicle platoon on a curved path is challenging, and most solutions in the existing literature demonstrate platooning on a straight path or curved paths at constant speeds. This article proposes an algorithmic solution with leader-following (LF) communication topology and constant distance (CD) spacing for platooning homogeneous position-controlled vehicles (PCVs) on a curved path, with each vehicle capable of cornering at variable speeds. The lead vehicle communicates its reference position and orientation to all the follower vehicles. A follower vehicle stores this information as a virtual trail of the lead vehicle for a specific period. An algorithm uses this trail to find the follower vehicle’s reference path by solving an optimization problem. This algorithm is feasible and maintains a constant inter-vehicle distance. The PCVs can be holonomic or nonholonomic. For simulations, this article considers a holonomic four-wheel independent steering four-wheel independent drive (4WIS4WID) PCV for platooning. This vehicle has superior maneuverability and traction and can extend the applications of vehicle platoons from highways to paths with smaller radii of curvature. Simulation of a five-vehicle platoon suggests a satisfactory performance of the proposed approach. This article also presents an alternate curved platooning approach where the lead vehicle communicates its reference longitudinal and lateral velocities and yaw rate to a follower vehicle. The follower vehicle directly follows these communicated signals for platooning. This approach does not store the communicated signals and also cuts the cost of the position controller for the follower vehicles. Simulation results show that this alternative approach is applicable to constant-speed motion.</div>

Cooperative Lane-Change Motion Planning for Connected and Automated Vehicle Platoons in Multi-Lane Scenarios

Multi-vehicle motion planning (MVMP) has become an emerging paradigm in connected and automated vehicles (CAVs). The cooperative lane-change movements with the coexistence of platoons and CAVs are typical scenarios on the muti-lane roads. This paper proposes an optimal control framework with the advantages of completeness and universality for platoons and CAVs’ cooperative lane-change motion planning in different task scenarios. Two typical cooperative scenarios are designed for the subsequent study of optimal modeling. The platoons’ reconfiguration and original shape maintenance are considered to reflect the universality of moving objects and the diversity of cooperative tasks. Approximately geometric contour models, dynamic externally tangent rectangle and inflated rectangle, are utilized to describe the platoon’s profile. Analytical complete collision avoidance constraints among different motion objects are constructed effectively. Other necessary constraints and the weighted cost function that minimizes lane-change time and motion energy are comprehensively considered. The optimal control models are established for the desired scenarios. Moreover, a numerical solution method combined with the simultaneous direct collocation method based on the trapezoidal rule and the barrier function method is proposed to obtain the optimal schemes. Simulation and contrast experiments are conducted for two scenarios. The results indicate that the cost function’s weight coefficients and specific lane-change tasks influence the cooperative motion planning effects and verify that the proposed optimal control framework is of reasonability, effectiveness, and unification.

Centralized model‐predictive cooperative and adaptive cruise control of automated vehicle platoons in urban traffic environments

AbstractRecent research has demonstrated that cooperative and automated driving functions can improve traffic efficiency and safety. Traffic efficiency can be increased and the overall vehicle energy consumption can be reduced through cooperative driving functions not only on the highway, but also in urban areas. To this end, this paper presents a linear model predictive control (MPC) algorithm for the optimization of velocity trajectories of vehicles in a platoon in an urban traffic environment. A novel centralized approach is implemented to optimize the total energy consumption of all vehicles while improving traffic efficiency. To solve the optimal control problem, for the first time, an additional data‐driven velocity prediction model of the vehicle in front of the platoon is used to consider the influence of realistic prediction errors when evaluating the developed control strategy in a vehicle simulation environment. The simulated total energy consumption is compared with a rule‐based cooperative adaptive cruise control (CACC) algorithm. Furthermore, the traffic density and the platoon string stability, the robustness and computer time of the centralized approach are also included in the evaluation. Simulation results indicate that, considering all evaluation criteria, the centralized cooperative control strategy can improve energy efficiency by up to 15% in the investigated urban scenario.

A Collaborative Merging Method for Connected and Automated Vehicle Platoons in a Freeway Merging Area with Considerations for Safety and Efficiency.

To solve the problems of congestion and accident risk when multiple vehicles merge into the merging area of a freeway, a platoon split collaborative merging (PSCM) method was proposed for an on-ramp connected and automated vehicle (CAV) platoon under a mixed traffic environment composed of human-driving vehicles (HDV) and CAVs. The PSCM method mainly includes two parts: merging vehicle motion control and merging effect evaluation. Firstly, the collision avoidance constraints of merging vehicles were analyzed, and on this basis, a following-merging motion rule was proposed. Then, considering the feasibility of and constraints on the stability of traffic flow during merging, a performance measurement function with safety and merging efficiency as optimization objectives was established to screen for the optimal splitting strategy. Simulation experiments under traffic demand of 1500 pcu/h/lane and CAV ratios of 30%, 50%, and 70% were conducted respectively. It was shown that under the 50% CAV ratio, the average travel time of the on-ramp CAV platoon was reduced by 50.7% under the optimal platoon split strategy compared with the no-split control strategy. In addition, the average travel time of main road vehicles was reduced by 27.9%. Thus, the proposed PSCM method is suitable for the merging control of on-ramp CAV platoons under the condition of heavy main road traffic demand.

Impact of Communications Delay on Safety and Stability of Connected and Automated Vehicle Platoons: Empirical Evidence From Experimental Data

Impact of Communications Delay on Safety and Stability of Connected and Automated Vehicle Platoons: Empirical Evidence From Experimental Data

Development of Connected and Automated Vehicle Platoons With Combined Spacing Policy

Vehicle platoon has the potential to significantly improve traffic throughput and reduce fuel consumption and emissions and thus has attracted extensive attention recently. In this study, we propose a vehicle platoon of connected and automated vehicles (CAVs) with a combined spacing policy to enhance traffic performance. First, a combined spacing policy composed of the constant time gap (CTG) and constant spacing (CS) is formulated for the proposed vehicle platoon, where the leader adopts the CTG and the followers use the CS policy. Based on the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$h_{2}$ </tex-math></inline-formula> -norm string stability criteria, the notion of exogenous-head-to-tail string stability is newly introduced, and the sufficient conditions of the local stability and string stability in the frequency domain are derived using the Routh-Hurwitz criterion and Laplace transform respectively. Numerical experiments are conducted to validate the string stability. The effectiveness of the proposed vehicle platoons is verified by theoretical analysis and numerical experiments using two typical scenarios and several measurements of effectiveness (MOE) in various performance aspects, including efficiency, safety, energy, and emission. The results show that the proposed vehicle platoon performs better than the CS-based vehicle platoon in all aspects except for efficiency. It also indicates that the proposed vehicle platoon has obvious advantages over the CTG-based vehicle platoon in efficiency and safety aspects. The findings have demonstrated the merits of the combined application of CTG and CS policies for the vehicle platoon in enhancing stability and traffic performance.

A Review of Connected and Automated Vehicle Platoon Merging and Splitting Operations

Connected and automated vehicle (CAV) platoons have drawn much attention in the past decades, given their potential to reduce fuel consumption, elevate roadway capacity, and enhance traffic safety. As two basic platoon operations, platoon merging and splitting have been widely investigated. This study provides an overview of theoretical models and field experiments of CAV platoon merging and splitting operations. A three-step framework, including protocol design, trajectory planning, and vehicle control, is proposed to unify existing representative studies. Methodological techniques in each step are summarized and discussed. Finally, future research directions are discussed. This study contributes to the literature by providing a framework that categorizes relevant literature and guides the successful development of platoon merging and splitting operations. More importantly, it offers researchers and practitioners a rich reference for further investigations.

Effects of assignments of dedicated automated vehicle lanes and inter-vehicle distances of automated vehicle platoons on car-following performance of nearby manual vehicle drivers

Deploying dedicated lanes for automated vehicles (AVs) can effectively alleviate the coordination issues between AVs and manual vehicles (MVs). However, AV platoons running on dedicated AV lanes (DAVLs) have a prominent collective behavior characteristic of small inter-vehicle distance. The nearby MV drivers’ imitation of this characteristic may reduce their car-following time headway (THW). The researchers conducted a simulation experiment to investigate the influence of DAVL assignments, inter-vehicle distances of AV platoons and AV platoon speed on the car-following performance of nearby MV drivers. The data of mean THW, standard deviation of THW, standard deviation of lateral position, standard deviation of velocity, standard deviation of horizontal gaze position and mean saccadic peak velocity were collected from 36 participants. Statistical analysis results show that the three factors considerably affected the MV drivers’ car-following performance. In particular, the MV drivers showed a worse car-following safety but a better driving stability when the left lane was dedicated to AVs than when the right lane was dedicated to AVs (Note the experiments were done in a drive-on-the-left environment.). With respect to the inter-vehicle distances of AV platoons, the MV drivers’ car-following safety was poorer under the 4 m condition than that under the 10 and 18 m conditions. In addition, the MV drivers showed a poorer car-following safety and bore a larger mental workload when driving next to the AV platoons running at 110 km/h. This study may provide some suggestions for DAVLs. Assigning the right lane of a three-lane motorway as the DAVL may have a slighter negative impact on the nearby MV drivers in China. In terms of traffic management in DAVLs, the inter-vehicle distance of AV platoons can be reduced to 10 m, and the speed of AVs should not be higher than the design speed of adjacent MV lanes.

Connected and automated vehicle platoon formation control via differential games

In this study, the connected and automated vehicles (CAVs) platooning problem is resolved under a differential game framework. Three information topologies are considered here. Firstly, Predecessor-following (PF) topology is utilized where the vehicles control the distance with respect to the merely nearest predecessor via a sensor link-based information flow. Secondly, Two-predecessor-following topology (TPF) is exploited where each vehicle controls the distance with respect to the two nearest predecessors. In this topology, the second predecessor is communicated via a Vehicle-to-vehicle (V2V) link. The individual trajectories of CAVs under the Nash equilibrium are derived in closed-form for these two information topologies. Finally, general information topology is examined and the differential game is formulated in this context. In all these options, Pontryagin's principle is employed to investigate the existence and uniqueness of the Nash equilibrium and obtain its corresponding trajectories. In the general topology, we suppose numerical computation of eigenvalues and eigenvectors. All these approaches represent promising and powerful analytical representations of the CAV platoons under the differential games. Simulation experiments have verified the efficiency of the proposed models and their solutions.

Energy-oriented car-following control for a front- and rear-independent-drive electric vehicle platoon

In this paper, a cooperative multi-objective platoon control (CMOPC) strategy is proposed for a front- and rear-independent-drive electric vehicle (FRIDEV) platoon. Two major measures are taken in this approach to enhance platoon economy. Firstly, a novel multi-objective nonlinear model predictive control (NMPC) system is devised by combining car-following control for connected and automated vehicle platoons and torque distribution control for FRIDEVs to exploit the energy-saving potential of an FRIDEV platoon. Secondly, the total power of all vehicles in the platoon is considered in the cost function to better reflect the overall energy consumption of the platoon. The proposed CMOPC strategy is evaluated under three typical driving cycles, i.e. UDDS, WLTC and HWFET; the ecological cooperative adaptive cruise control strategy is employed as the benchmark of evaluation. The comparative simulation results demonstrate that the proposed CMOPC not only ensures equivalent car-following performance, but also improves the platoon economy by 3.0%, 1.6% and 4.7% respectively under UDDS, WLTC and HWFET driving cycles.

Fundamental diagram and stability of mixed traffic flow considering platoon size and intensity of connected automated vehicles

The connected automated vehicle platoon is a critical organizational form of the intelligent transportation system in the future. Considering the platoon size and intensity of connected automated vehicles (CAVs), this paper studies the fundamental diagram and stability of mixed traffic flow. Firstly, the spatial distribution of vehicles in the mixed traffic flow is analyzed. Based on the platoon intensity and Markov chain, the proportion of different types of vehicles in the mixed traffic flow is deduced. Then, the general model framework of the fundamental diagram of the mixed traffic flow is established. The influence factors of the fundamental diagram under the critical scenarios are discussed. Finally, the general condition of mixed traffic flow stability considering the platoon size and intensity of CAVs is developed. Numerical experiments are adopted to analyze the influence of the characteristics of the CAVs platoon on stability. The results show that: (1) a greater platoon size leads to the increase of traffic capacity while it is harmful to the maintenance of traffic flow stability; (2) the platoon size is recommended to be set at 4 to 6 to balance the relationship between traffic capacity and stability; (3) a more significant platoon intensity can help improve the traffic capacity and stability; (4) the penetration rate of CAVs has a positive effect on the traffic flow stability until it increases to a certain degree.

Scalable and Resilient Platooning Control of Cooperative Automated Vehicles

This paper addresses the problem of distributed cooperative longitudinal control of automated vehicle platoons subject to a variety of uncertainties, including unknown engine time lags, external disturbances, measurement noises, and actuator anomaly in follower vehicles as well as unknown leader control. First, a unified framework is proposed for accomplishing resilient vehicle platooning, which empowers longitudinal vehicle state estimation, anomaly signal estimation and compensation, and adaptive platoon controller design to be addressed in a comprehensive way. Second, a novel scalable platooning control design approach is developed to guarantee desired platoon stability and resilience over generic communication topologies and various spacing policies. A salient feature of the approach is that the design procedure does not depend on any global information of the associated topology, and thus preserves essential scalability for large and/or size-varying platoons. Third, it is shown that the proposed longitudinal platooning control approach is promising for performing flexible cooperative maneuvers such as platoon splitting and merging that are beyond the capacity of most existing longitudinal platooning strategies. Finally, simulation results for different platoon maneuvers are elaborated to substantiate the efficacy of the proposed approach.

Connected and automated vehicle platoon maintenance under communication failures

Connected and automated vehicles (CAVs) use vehicle-to-vehicle (V2V) wireless communication to drive in platoons, which can improve traffic efficiency and reduce energy consumption. However, some vehicles in a platoon may experience communication failures for various reasons, such as packet loss, signal blocking, or damage to vehicle communication module hardware. This will result in two phenomena: the platoon communication topology will be changed, and the behavior of vehicles without communication capabilities will degenerate to that of automated vehicles (AVs). The platoon will be unstable under the influence of these two phenomena. To mitigate the impact of these two phenomena on platoons, we propose a dynamic communication topology-based CAV-following model. This model takes into account changes in communication topology in a platoon due to communication failures or perceptual errors resulting from vehicle degradation. Two core features ensure that this model is able to perform platoon maintenance under communication failure. First, the CAVs in a platoon dynamically adjust the weight values of the acquired driving information based on the communication topology. Second, an adaptive Kalman filter (AKF) method is applied to reduce perceptual error. The effectiveness of the platoon maintenance scheme proposed in this study is verified by a series of simulation experiments. The results show that the proposed model can effectively maintain CAV platoons regardless of communication failures under steady-state or non-steady-state traffic flows. This finding indicates that CAV designers should design control schemes that take into account possible changes in the communication topology. Furthermore, our method has potential advantages for improving the platoon stability of CAVs driving on roads where communication is poor.

Correction: Yang et al. A Learning Control Method of Automated Vehicle Platoon at Straight Path with DDPG-Based PID. Electronics 2021, 10, 2580

The authors wish to make the following corrections to this paper [...]