Co-Design of Consensus-Based Approach and Reliable Communication Protocol for Vehicular Platoon Control

A mobile agent system is regarded as an attractive technology when developing distributed applications. However, mobility makes it more difficult to trace agents. It is also more complex for agents to communicate with each other in a reliable manner. Therefore, a reliable communication protocol is necessary to control and monitor mobile agents and deliver messages between them. In this paper, a new reliable communication protocol (RCP) is proposed for a multiregion mobile agent computing environment. RCP is implemented on the ODDUGI mobile agent system. Analysis and evaluation show that RCP fulfills the following design goals: reliability, asynchrony, timeliness, location dependency, scalability, and communication cost.

This publication describes a process to develop and calibrate a physics-based model for vehicle stability control. The approach consists of two phases. In the first phase, a baseline vehicle dynamics model was established using the commercially available simulation tool CarSim. The model was calibrated and validated for a variety of steady state, transient state and brake intervention handling manoeuvres using experimental test data. In the second phase, a simplified stability control model was developed in Matlab/Simulink based on representative control strategies. Subsequently, the vehicle dynamics model and stability control model developed were coupled using co-simulation and calibrated such that the closed-loop system behaviour approximated the real world test behaviour as best as possible. Finally, two case studies were developed to showcase the application of the closed-loop mathematical model in simulation-based studies addressing aftermarket vehicle modifications and their implication on vehicle stability control behaviour.

Traffic congestion frequently occurs on slope segments of highways, which are typical bottlenecks. With the development of connected and autonomous vehicle (CAV) technology, CAVs and human-driven vehicles (HDVs) are anticipated to coexist on the same roads in the foreseeable future, thereby transforming the traffic environment from predominantly HDVs to a mixture of CAVs and HDVs. To the best of the authors’ knowledge, no studies address slope bottlenecks on highways in mixed traffic flow. Thus, this paper proposes a traffic flow model for slope bottlenecks incorporating CAV platooning based on cellular automata. A novel traffic flow control strategy for slope bottlenecks is proposed, based on variable speed limits (VSL) and vehicle platooning. Firstly, it divides the upstream section of the slope bottleneck into two zones for implementing VSL and vehicle platooning. Via speed restrictions within the VSL zone, the inflow of vehicles into the vehicle platooning zone is effectively mitigated to create low traffic density. In the vehicle platooning zone, a hybrid vehicle platooning method for mixed scenarios is proposed. Extensive experiments are conducted to validate that the proposed strategy increases the traffic flow of the slope bottleneck, improves the average speed, and alleviates traffic congestion.

무선 센서 네트워크에서 구조대나 군 소대와 같은 이동 싱크 그룹을 위한 통신은 군집 이동 특성에 의해 이동성 지원 측면에서 새로운 도전 과제를 야기한다. 최근에 그룹 영역 기반의 이동성 지원 접근법이 제안되었지만, 접근법에서 제시하는 3 단계(싱크 그룹 영역 발견, 영역 정보 통지, 데이터 전달)의 과정은 과도한 플러딩(flooding)을 요구한다. 따라서 많은 에너지 소모와 혼잡 및 간섭으로 인한 데이터 전달 실패를 야기한다. 더욱이, 이는 개별 싱크 단위의 이동성을 지원하기 때문에 앞의 문제를 심화시킨다. 따라서, 본 논문은 가상 격자 구조를 활용한 에너지 효율적이고 신뢰성있는 이동 싱크 그룹 통신 방안(Energy-efficient and Reliable Mobile Group communication protocol, ERMG)을 제안한다. ERMG는 그룹 영역의 발견과 영역 정보 통지, 데이터 전달을 위해 오직 싱크 그룹을 관리하는 격자 셀의 대표(cell heads)와의 통신만을 요구한다. 또한, ERMG는 효율적인 이동성 지원을 위해 격자 단위의 이동성 지원 방안을 사용한다. 시율레이션 결과는 ERMG가 기존 방안들에 비해 에너지 소모량이 평균 30% 감소하였고, 전달 요구 시간 내 성공률이 평균 6% 증가하였음을 보인다. Communications for mobile sink groups such as rescue teams or platoons bring about a new challenging issue for handling group mobility in wireless sensor networks. Recently, a group region-based approach has been proposed to send data to a mobile sink group. However, it uses excessive flooding for 3 steps (group region discovery, region information notification, and data dissemination) to support mobile sink group. Thus, it causes high energy consumption and data delivery failure. Moreover, its per-sink mobility supporting scheme makes energy consumption and data delivery failure more serious. Thus, this paper proposes an Energy-efficient and Reliable Mobile Group communication protocol (ERMG) to support a mobile sink group, which exploits a virtual grid structure. For the group region discover and notification and the data dissemination, ERMG uses communications with only cell heads of grid cells that manages group sinks. ERMG also uses a per-grid based scheme to support sink mobility. Simulation results show that ERMG has 30% less energy consumption and 6% more desired delivery deadline success ratio than the existing protocols.

In consideration of the uncertain and time-varying driving resistance in vehicle dynamics, a distributed adaptive sliding model control protocol is proposed in vehicle platoon control. Firstly, the vehicle resistance, which is relevant to vehicle mass, weather conditions, deadweight, motorcycle type and etc, is analyzed and the vehicle platoon model is established. Then, a coupled sliding mode surface is designed to link the inter-connected vehicles and an adaptive control method is adopted to identify and estimate the variations of resistance coefficients. After that, a distributed adaptive sliding mode control algorithm for vehicle platoon with uncertain driving resistance is proposed, which realizes the stable vehicle platoon in the presence of uncertain and time-varying driving resistance. The feasibility and effectiveness of the proposed control laws is validated by numerical simulations.

Vehicular platoons in cyclic interconnections

This paper presents a new approach for distributed control of automatic guided vehicle system (AGVS) that uses constraint logic programming formalism to model system operation. The proposed method constructs a feasible schedule by exploiting the constraint propagation mechanism determining the flow of automated guided vehicles. The AGVS is treated as a distributed system composed of autonomous and repetitive processes of automated guided vehicle (AGV) flows. Its periodic behaviour follows from a class of repetitive job shops considered. The approach employs a concept of asynchronous traffic semaphores that provide local mechanism (a dispatching rule) for vehicle flows synchronization. Setting and allocation of particular dispatching rules results in distributed control of vehicle flows possessing self-synchronization features.

Currently, several automotive companies are joining forces through the analysis and development of active safety systems for hazard avoidance and mitigation; from which according to the current regulations in the European Union the Anti-lock Braking System (ABS) and the Electronic Stability Control (ESC) outstand as mandatory for each new vehicle. The above has motivated the study of these two safety systems. Then, this research examines the ABS and ESC systems through a proposed diagnostic methodology, which identifies the main effect of these systems on the vehicle dynamics. To achieve this goal a software was developed, looking for processing the data acquired during the development of some specific vehicle maneuvers. The diagnostic results expose: (1) an indicator about the ABS/ESC systems performance; and (2) the impact of these systems on the vehicle dynamics; also, some of the results here obtained can also be taken as reference for the Brake Assistant System and the Anti-Roll Control analysis.

<div class="htmlview paragraph">The performance of an integrated Vehicle Stability Control (VSC) system depends on not only control logic itself, but also the performance of state estimator and control threshold. In conventional VSCs, a control threshold is designed by vehicle characteristics and is centered on average drivers. A VSC algorithm with variable control threshold has been investigated in this study. The control threshold can be determined by phase plane analysis of side slip angle and angular velocity. Vehicle side slip angle estimator has been evaluated using test data. Estimated side slip angle has been used in the determination of the control threshold. The performance of the proposed VSC algorithm has been investigated by human-in-the-loop simulation using a vehicle simulator. The simulation results show that the control threshold has to be determined with respect to the driver steering characteristics. A VSC with variable control thresholds would provide an improvement compared to a VSC with a constant threshold.</div>

In order to ensure the safety and stability of vehicle platoons, the spacing error between vehicles needs to be maintained within a given range and gradually converge to 0. Due to actuator saturations and time-varying uncertainties in vehicle dynamics, the vehicle platoon control remains a major challenge. This paper presents a robust control method for vehicle platoons, ensuring the spacing error performance within a compact prescribed band region. Firstly, an improved spacing modeling method is presented, embedded with an auxiliary variable to modify the spacing error. It effectively circumvents actuator saturations caused by excessively large initial errors. Then, bilateral constraints are imposed on the modified error to characterize collision avoidance and compact formation (CA&CF) performance, and subsequently the constrained error is transformed into an unconstrained state via potential function transformation. The uniform boundedness (UB) performance of the unconstrained state ensures the compact prescribed band region performance of the spacing error. Then, based on the constraint-following control theory, a robust controller is designed to ensure the system’s UB and uniform ultimate boundedness (UUB) performance. Finally, simulation results demonstrate the effectiveness of the proposed control.

The era of the electrification of vehicle drivelines is rapidly approaching. Motors are capable of providing controls with response and accuracy two orders of magnitude greater than internal combustion engines. It is also relatively simple to design a driveline capable of independently controlling the driving force at each wheel by providing compact motors throughout the vehicle. Although the potential of such driving force distribution control in improving vehicle dynamic performance has been a serious topic of research since even before the current wave of driveline electrification, the complex mechanisms required to realise these controls have prevented mass adoption. However, it seems that these research efforts are finally reaching a stage where practical adoption might be possible. This state-of-the-art review examines the background and most recent research related to vehicle dynamics control, particularly controls that use electrical drive units, and investigates the topics of interest and trends of a wide range of researchers. Subsequently, taking into account ongoing efforts to pair vehicle dynamics controls with electrical actuators, this review also discusses a novel control architecture that depart from control design methods formulated in the past by researchers across the field, and points the way toward the future of vehicle dynamics control research.

This paper discusses a concept for enhanced active safety by introducing a driver warning system based on vehicle dynamics that predicts a potential loss of control condition prior to stability control activation. This real-time warning algorithm builds on available technologies such as the Electronic Stability Control (ESC). The driver warning system computes several indices based on yaw rate, side-slip velocity, and vehicle understeer using ESC sensor suite. An arbitrator block arbitrates between the different indices and determines the status index of the driving vehicle. The status index is compared to predetermined stability levels which correspond to high and low stability levels. If the index exceeds the high stability level, a warning signal (haptic, acoustic, or visual) is issued to alert the driver of a potential loss of control and ESC activation. This alert will remain in effect until the index is less than the low stability level at which time the warning signal will be terminated. A vehicle speed advisory algorithm is integrated with the warning algorithm to provide a desired vehicle speed of a vehicle traveling on a curve. Simulation results and vehicle tests were conducted to illustrate the effectiveness of the warning algorithm.

The growing use of Internet of Things (IoT) devices has increased the need for secure and reliable communication protocols, with MQTT being one of the most widely used. However, MQTT brokers are vulnerable to denial-of-service (DoS) attacks, which can disrupt data flow in IoT systems. This research compares three MQTT brokers, Mosquitto, HiveMQ, and EMQX, to evaluate their resilience against DoS attacks, specifically the MQTT publish flooding attack. Using a testing environment replicating real-world IoT scenarios, the brokers were subjected to simulated attacks, and their performance was measured based on five key metrics: latency, packet loss, throughput, CPU usage, and recovery time. The results show varying levels of resilience among the brokers. Mosquitto demonstrated quick recovery but suffered from high latency and moderate packet loss. HiveMQ maintained low latency but experienced high packet loss and failed to recover without manual intervention. EMQX balanced performance with the lowest packet loss and a reasonable recovery time, making it the most robust among the three. These findings provide insights into selecting suitable MQTT brokers for IoT deployments, emphasizing the importance of considering factors such as latency, message reliability, and recovery capability when dealing with potential DoS attacks.

This paper presents the first, novel, dynamic, resilient, and consistent Blockchain COngestion ContrOL (BCOOL) system for vehicular networks that fills the gap of trustworthy Blockchain congestion prediction systems. BCOOL relies on the heterogeneity of Machine Learning, Software-Defined Networks and Network Function Virtualization that is customized in three hybrid cloud/edge-based On/Offchain smart contract modules and ruled by an efficient and reliable communication protocol. BCOOL’s first novel module aims at managing message and vehicle trustworthiness using a novel, dynamic and hybrid Blockchain Fog-based Distributed Trust Contract Strategy (FDTCS). The second novel module accurately and proactively predicts the occurrence of congestion, ahead of time, using a novel Hybrid On/Off-Chain Multiple Linear Regression Software-defined Contract Strategy (HOMLRCS). This module presents a virtualization facility layer to the third novel K-means/Random Forest-based On/Off-Chain Dynamic Service Function Chaining Contract Strategy (KRF-ODSFCS) that dynamically, securely and proactively predicts VNF placements and their chaining order in the context of SFCs w.r.t users’ dynamic QoS priority demands. BCOOL exhibits a linear complexity and a strong resilience to failures. Simulation results show that BCOOL outperforms the next best comparable strategies by 80% and 100% reliability and efficiency gains in challenging data congestion environments. This yields to fast, reliable and accurate congestion prediction decisions, ahead of time, and optimizes transaction validation processing time. Globally, the Byzantine resilience, complexity and attack mitigation strategies along with simulation results prove that BCOOL securely predicts the congestion and provides real-time monitoring, fast and accurate SFC deployment decisions while lowering both capital and operational expenditures (CAPEX/OPEX) costs.

: An important function of communication networks is to implement reliable data transfer over an unreliable underlying network. Formal specifications are given for reliable and unreliable communication layers, in terms of I/O automata. Based on these specifications, it is proved that no reliable communication protocol can tolerate crashes of the processors on which the protocol runs.