智能交通系统车道保持纵横向耦合控制

考虑车辆纵横向运动之间的相互影响,采用位置预瞄和固定车辆间距跟随策略,对基于一列车队的自动化公路系统车道保持纵横向耦合控制进行了研究.利用车载前后双位置传感器检测车辆位置偏差,基于车辆纵横向动力学耦合模型,推导了基于预瞄的车道保持控制系统数学模型;采用非奇异的终端滑模控制技术,设计了车道保持纵横向耦合控制规律.通过构造李雅普诺夫函数,结合相平面方法,分析了控制系统的有限时间收敛性.采用6车辆编队,通过计算机仿真,对文中设计的控制规律进行了验证.仿真结果显示,车队中每个被控车辆在纵向上跟随期望状态的同时能够实现对期望车道轨迹的理想跟踪,跟踪误差精度不超过0.05 m.     

DYNAMIC ANALYSES AND ROBUST STEERING CONTROLLER DESIGN FOR AUTOMATED LANE GUIDANCE OF HEAVY‐DUTY VEHICLES

In this paper, we present various linear analyses of the linearized lateral dynamics of heavy‐duty vehicles (HDVs) (tractor‐semitrailer type), which include time domain, frequency domain and pole/zero analyses. These analyses are conducted to examine the vehicle response to the steering input subjected to variations of speed, road adhesion coefficient, cargo load in the trailer, and look‐ahead distance for the lateral deviation sensor. These parameters (uncertainties) have significant influence on vehicle dynamics. It has been shown that redefining the look‐ahead lateral error as the controlled output has a favorable impact on the lateral control problem. Based on these analyses, a robust steering controller using H_∞ loop‐shaping procedure is designed for a tractor semitrailer combination to follow the road center line on both curved and straight highway sections. The proposed controller ensures the robust performance under model uncertainties which include varying vehicle longitudinal speed, road adhesion coefficient, and cargo load in the trailer. The performance of the designed controller is evaluated by simulations and validated by experiments.     

Fuzzy motion control strategy for cooperation of multiple automated vehicles with passengers comfort

This paper considers motion control for a cooperative system of automated passenger vehicles. It develops a cooperative scheme based on a decentralized planning algorithm which considers the vehicles in an initial open chain configuration. In this scheme the trajectories are intersections-free, and each trajectory is planned independently of the others. To ensure the stabilization of each vehicle in the planned trajectory, a fuzzy closed loop motion control is presented, where, based on the properties of the Fuzzy maps, the Lyapunov’s stability of the motion errors is demonstrated for all the vehicles. Based on the ISO 2631-1 standard, the saturation property of the Fuzzy maps guarantees low values of longitudinal and lateral accelerations, to ensure comfort of the human body during the motion. The validity of this control algorithm is supported by simulation experiments.     

Advances in the development of a virtual car driver

Fundamental approaches to modeling the control of a car by a driver are reviewed briefly. The context of the work presented is explained. Then previous research on the application of optimal linear preview control to aspects of driving road vehicles is extended. This prior research treated the tracking of a roadway by a vehicle and driver at constant forward speed and the tracking of a speed demand while running straight. The two previously separate problems are now combined, so that longitudinal and lateral path demands are considered in parallel. A new feature is that low-pass filters are included in the driver modeling to represent driver bandwidth limitations. This feature enables the finding of the influence of the driver’s control bandwidth on the optimal strategies and on the closed-loop system performance, by way of frequency-response calculations. A new optimal preview control toolbox is employed. Simulations of the virtual driver-controlled car are shown to demonstrate the closed-loop system following longitudinal and lateral position demands.     

Non-linear velocity observer for vehicles with tyre–road friction estimation

A non-linear observer is proposed for the estimation of the longitudinal and lateral velocities of automotive vehicles due to highly non-linear friction. To take the unknown time-varying road conditions into account, a real-time tyre–road friction estimation algorithm is provided for adaptation to changes of different road adhesion characteristics. Besides, the coupling effects of the longitudinal and lateral forces are fully exploited to design the non-linear observer based on the longitudinal and lateral acceleration measurements. The observer is computationally efficient and is based on a standard sensor configuration commonly available in modern cars. The uniform global asymptotical stability of the adaptive observer is guaranteed under a certain persistency-of-excitation condition. Moreover, a stronger local stability result can also be obtained, i.e. uniform local exponential stability. The performance of the observer is compared with that of existing approaches under different manoeuvres and road conditions.     

Robustness analysis of a reusable launch vehicle flight control law

This paper describes a novel optimisation-based framework for analysing the robustness of advanced flight control laws for reusable launch vehicles. The proposed analysis methods are applied and tested on an industrial-standard simulation model of a reusable launch vehicle equipped with a full authority nonlinear dynamic inversion-based flight control law. The reliability, computational complexity and efficiency of the framework are evaluated against standard industrial approaches based on Monte Carlo simulation. The results of the study show that the proposed approach has the potential to significantly improve both the reliability and efficiency of the flight clearance process for future reusable launch vehicles.     

Integrated Dynamics Control and Energy Efficiency Optimization for Overactuated Electric Vehicles

A large number of studies have been conducted on the dynamics control of electric vehicles or on the optimization of their energy efficiency but few studies have looked at both of these together. In this study, an integrated dynamics control and energy efficiency optimization strategy is proposed for overactuated electric vehicles, where the control of both longitudinal and lateral dynamics is dealt with while the energy efficiency is optimized. First, considering the trade‐off between control performance and energy efficiency, criteria are defined to categorize the vehicle motion status as linear pure longitudinal motion and non‐linear motion or turning motion. Then different optimization targets are developed for different motion status. For the pure linear longitudinal motion and cornering motion, the energy efficiency and vehicle dynamics performance are equally important and a trade‐off control performance between them needs to be achieved. For the non‐linear turning motion, vehicle handling and stability performance are the primary concerns, and energy efficiency is a secondary target. Based on the defined targets, the desired longitudinal and lateral tyre forces and yaw moment are then optimally distributed to the wheel driving and steering torques. Finally numerical simulations are used to verify the effectiveness of the proposed strategies. The simulation results show that the proposed strategies can provide good dynamics control performance with less energy consumption.     

智能电动车辆横纵向协调与重构控制

针对具有高度非线性、强耦合和冗余特性的智能电动车辆运动控制问题,提出了一种由协调控制律和控制分配律组成的横纵向综合控制新方法.首先,建立准确表征智能电动车辆行为机理的动力学模型;其次,采用非奇异滑模控制技术,引入非线性滑动模态切换面,设计有效克服非线性及不确定特性的协调控制律,保证系统状态在有限时间内收敛至平衡点;在此基础上,考虑到轮胎存在冗余和耦合特性,提出基于内点法的控制分配算法来完成期望广义力/力矩的优化分配,实现轮胎横纵向力的协调与重构.仿真结果表明了该方法的有效性.     

Vehicle velocity estimation using nonlinear observers

Nonlinear observers for estimation of lateral and longitudinal velocity of automotive vehicles are proposed. The observers are based on a sensor suite that is standard in many new cars, consisting of acceleration and yaw rate measurements in addition to wheel speed and steering angle measurements. Two approaches are considered: first, a modular approach where the estimated longitudinal velocity is used as input to the observer for lateral velocity, and second, a combined approach where all states are estimated in the same observer. Both approaches use a tire-road friction model, which is assumed to be known. It is also assumed that the road is flat. Stability of the observers is proven in the form of input-to-state stability of the observer error dynamics, under a structural assumption on the friction model. The assumption on the friction model is discussed in detail, and the observers are validated on experimental data from cars.     

Nonlinear observer-based active control of ground vehicles with non negligible roll dynamics

In this paper we present an observer–based nonlinear controller for lateral and yaw velocity, for a vehicle in which the roll dynamics can not be neglected. The observer estimates the lateral velocity, and the roll position and velocity. This technique is based on measurements of the longitudinal and lateral accelerations, longitudinal velocity, yaw rate and steer angle, usually available in modern vehicles. The nonlinear observer ensures exponential convergence of the estimations. The test maneuvers, obtained with the full–vehicle CarSim model under different road adhesion conditions, have been used to check the controller performance, as well as its robustness with respect to parameter variations.     

Lateral control for autonomous wheeled vehicles: A technical review

Autonomous driving has the ability to reshape mobility and transportation by reducing road accidents, traffic jams, and air pollution. This can yield energy efficiency, convenience, and more productivity as significant driving time will be gained and used in other activities instead. Autonomous vehicles are complex systems consisting of several modules that perform perception, decision-making, planning, and control. Control is essential for achieving automatic driving; it is basically divided into longitudinal control that handles speed tracking and lateral control which ensures accurate steering. The latter is primordial in path tracking applications and recent research has witnessed a huge leap in this field. The aim of this paper is to provide a technical survey of the latest research on the lateral control of autonomous vehicles as well as to highlight technical challenges and limits for further developments.     

基于侧喷流控制的运载器弹道建模与仿真

直接侧向力技术已在大气层外动能拦截器和大气层内防空导弹中得到成功应用。运载火箭的飞行弹道跨越大气层,可以尝试采用直接侧向力对其进行控制。在介绍直接侧向力控制技术原理的基础上,建立了采用直接侧向力进行姿态控制的运载火箭弹道的简化模型（不考虑风干扰和弹体滚转）,运用Matlab／Simulink软件进行了计算机数字仿真,并与传统的摆动喷管控制方式进行了对比,给出了第一级弹道的仿真结果。得出了直接侧向力控制作用下的弹道能够满足运载器总体设计要求的结论。     

Robust control of connected vehicles via V2V communication

This paper introduces a robust controller for connected vehicles which are communicating through dedicated short‐range communication (DSRC) protocol to avoid collision and improve safety. By a comprehensive analysis on both longitudinal and lateral dynamics of the vehicles, the controller covers a wide range of collision avoidance scenarios, such as: Intersection Movement Assistant (IMA), Automatic Emergency Brake (AEB) and Lane Change Warning (LCW). By implementing an advanced Sliding Mode Controller (SMC), the effect of uncertainties will be mitigated for a variety of path plans. It turns out that the proposed control scheme can robustly improve the safety. Finally, we optimize the performance of vehicles in tracking the paths by an MPC controller.     

Smooth path and speed planning for an automated public transport vehicle

This paper presents a path and speed planner for automated public transport vehicles in unstructured environments. Since efficiency and comfort are two of the key issues in promoting this kind of transportation system, they are dealt with explicitly in the proposed planning algorithm. To that end, a global path planner has been designed with bounded continuous curvature and bounded curvature derivative to ensure smooth driving. This will allow the public transport system to know a priori which is the shortest path within a selected area that guarantees lateral accelerations and steering wheel speeds below given pre-set thresholds. A closed-form speed profiler uses semantic information provided by the path planner to set a continuous velocity reference that takes into account not only bounds on lateral and longitudinal accelerations consistent with comfort, but also a bound on longitudinal jerk. The suitability of the above two features was compared to manual driving in a real instrumented public transport vehicle on a test track.     

基于模型预测控制的电动车辆队列控制研究

针对车辆队列建模时参数不确定导致控制存在误差的问题,以及队列中跟随车辆稳定性问题,分析车辆纵向动力学,设计一个鲁棒MPC控制器和滑移率控制器来提高队列车辆的控制精度和稳定性.首先对纵向MPC控制器进行改进,提高车辆队列控制精度；同时为防止跟随车辆的轮胎打滑,设计一个MPC滑移率控制器对跟随车辆的轮胎滑移率进行控制约束,保证了跟随车辆的纵向稳定性.最后,进行仿真实验验证其有效性.仿真实验结果表明,与传统的LQR、MPC控制器相比,改进的鲁棒MPC纵向控制器控制精度更高,同时MPC滑移率控制器可防止跟随车辆的轮胎打滑,保证了跟随车辆的纵向稳定性.     

Fault‐tolerant path‐following control for in‐wheel‐motor‐driven autonomous ground vehicles with differential steering

Over the past several decades, the automobile industry has denoted significant research efforts to developing in‐wheel‐motor‐driven autonomous ground vehicles (IWM‐AGVs) with active front‐wheel steering. One of the most fundamental issues for IWM‐AGVs is path following, which is important for automated driving to ensure that the vehicle can track a target‐planned path during local navigation. However, the path‐following task may fail if the system experiences a stuck fault in the active front‐wheel steering. In this paper, a fault‐tolerant control (FTC) strategy is presented for the path following of IWM‐AGVs in the presence of a stuck fault in the active front‐wheel steering. For this purpose, differential steering is used to generate differential torque between the left and right wheels in IWM‐AGVs, and an adaptive triple‐step control approach is applied to realize coordinated lateral and longitudinal path‐following maneuvering. The parameter uncertainties for the cornering stiffness and external disturbances are considered to make the vehicles robust to different driving environments. The effectiveness of the proposed scheme is evaluated with a high‐fidelity and full‐car model based on the veDYNA‐Simulink joint platform.     

Aeronautical and space vehicle control in dynamic sliding manifolds

Multiple loop multiple time scale sliding mode control technique based on dynamic sliding manifold is developed and applied to aeronautical and space vehicle control. Minimum and non-minimum phase output tracking problems for aeronautical and space vehicles are addressed in dynamic sliding manifold. Numerical examples of the flight controller design for controlling minimum and non-minimum phase manoeuvres of an F-16 jet fighter are presented. An example of an attitude controller design for the X-33 technology demonstration reusable launch vehicle using sliding mode control based on dynamic sliding manifold is also considered. Numerical simulations illustrate the effectiveness of the dynamic sliding manifold technique.     

运载火箭地面一体化测发控系统设计

现役运载火箭各分系统的测发控系统各自独立,存在资源浪费,兼容性差、信息传递低效等问题;随着测控技术发展和火箭电气系统需求牵引,新一代运载火箭地面测试、发射与控制在通用化、集成化、智能化等方面提出了更高的要求;通过梳理一体化设计的功能,提出一种运载火箭地面测发控系统的体系架构,整合传统运载火箭控制、测量、总控网等分系统的测发控共性需求,在统一供配电、有线测控、无线调制解调、数据处理与分析4个功能层面进行设计,包括系统组成、交互关系、重要单机(软件)的设计及其关键技术应用;该设计在某型号完成了原理性试验和关键技术验证,结果表明系统通用性强、集成度高、信息架构合理高效,能够在确保可靠性安全性的情况下,简化操作、提高效率、降低成本。     

Sitting and sizing of aggregator controlled park for plug-in hybrid electric vehicle based on particle swarm optimization

Environmental constraints, high and unstable fuel prices, limitation on fuel resources have led to emergence of Plug-in Hybrid Electric Vehicles (PHEVs). In order to launch the regulation service for grid-use of electric-drive vehicles, a smart control interface called an aggregator between the grid and the vehicles has been developed. In this paper, a particle swarm optimization (PSO), as well as its modified version (MPSO) based approach is presented for optimal sitting and sizing of aggregator controlled public car park for vehicle fleets in modern power system, which is convenient to the optimal charger control of PHEVs. The optimal location and sizing is calculated by minimizing the power loss and voltage deviations. The proposed approach is tested on IEEE 14 bus system.     

Motion Control of a 6WD/6WS wheeled platform with in-wheel motors to improve its maneuverability

Multi-axle driving mobile platform that are favored in special environments require high driving performance, steering performance, and stability. Among these, six wheel drive and six wheel steering vehicles hereinafter called 6WD/6WS, gain structural safety by distributing the load and reducing the pitching motion during rapid acceleration and braking. 6WD/6WS mobile platforms are favorable for military use, particularly in off-road operations because of their high maneuverability and mobility on extreme terrains and obstacles. 6WD vehicles that use in-wheel motors can generate independent wheel torque without a need for additional hardware. Conventional vehicles, however, cannot generate an opposite driving force on wheels on both sides. In an independent steering and driving system six-wheel vehicles show better performance than conventional vehicles. This paper discusses the improvement of the cornering performance and maneuverability of 6WD/6WS mobile platform using independent wheel torque and independent steering on each wheel. 6WD/6WS vehicles fundamentally have satisfactory maneuverability under low speed, and sufficient stability at high speed. Consequently, there should be a control strategy for improving their cornering performance using the optimum tire forces that satisfy the driver’s command and minimize energy consumption. From the driver’s commands (i.e., the steering angle and accelerator/brake pedal stroke), the desired yaw moment with virtual steering, desired lateral force, and desired longitudinal force are obtained. These three values are distributed to each wheel as torque and steering angle, based on the optimum tire force distribution method. The optimum tire force distribution method finds the longitudinal/lateral tire forces of each wheel that minimize cost function, which is the sum of the normalized tire forces. This paper describes a 6WS/6WD vehicle with improved cornering performance and the results are validated through TruckSim simulations.