基于自适应MPC算法的轨迹跟踪控制研究

为了保证智能车辆在低附着且变速条件下跟踪控制的精确性和稳定性,提出一种基于自适应模型预测控制（MPC）的轨迹跟踪控制算法。针对低附着条件下轨迹跟踪存在行驶稳定性较差的问题,对车辆动力学模型添加侧偏角软约束,分别设计有无添加侧偏角约束的MPC控制器。仿真结果表明,添加侧偏角约束后MPC控制器性能更优,车辆行驶稳定性得到有效提高。在此基础上,又提出了一种自适应的轨迹跟踪控制策略,能够根据车辆速度的变化,实时产生预测时域[(Hp)],分别设计自适应的MPC控制器与4组定值[Hp]的MPC控制器。仿真结果表明,基于自适应模型预测控制的轨迹跟踪控制算法在提高低附着且变速条件下智能车辆轨迹跟踪控制的精度和稳定性方面具有一定的有效性和先进性。     

基于模型预测控制的车道保持控制策略及对比研究

基于模型预测控制（MPC）方法,设计了自适应MPC和非线性MPC的两种车道保持辅助控制策略。在Matlab/Simulink平台下,搭建了车辆驾驶员仿真环境,对两种控制策略下的LKA系统性能进行了对比研究。仿真结果表明,两种控制策略均可以主动帮助驾驶员及时调整前轮转向,并具有良好的稳定性。另外在加速度执行和速度追踪方面,基于非线性MPC的控制策略表现得更为平稳,可提供更佳的乘坐舒适性。     

智能车逆向超车控制算法

针对双向车道因受限于道路条件及交通特性仅能借用对向车道完成超车（逆向超车）的问题,通过采用车联网以及车载传感器获取环境车辆的速度、加速度等全局信息,将多车场景中各个实体所造成的影响纳入超车决策中,从而提出一种基于图搜索和模型预测控制（Model Predictive Control, MPC）的逆向超车控制方法。首先,根据车车通信获取的全局信息,结合非合作博弈,对各车在整个时段内的行为进行预测,并根据预测情况对道路的各个区域进行安全评估,评估依据为该区域在下一时刻出现车辆的概率。对道路完成评估后,得到碰撞概率热区图,之后采用A*算法搜索安全路径,根据安全路径完成目标车辆的轨迹规划,并设计模型预测控制器来对主车进行实时控制,使车辆按照既定轨迹行驶。最后,借助Carsim与MATLAB/Simulink搭建联合仿真平台,对提出的算法进行验证。仿真实验结果表明,该模型的控制误差最大不超过0.15 m,平均误差率约为1.7%,能实现对车辆的精准控制,保证被控车辆安全完成逆向超车。     

基于禁区惩罚函数和MPC倍增预测的车辆避障研究

为了增强无人驾驶汽车对障碍物预测及躲避的可靠性,以模型预测控制（MPC）和车辆动力学模型为基础,提出了一种基于障碍物禁区惩罚函数和MPC预测距离倍增法的避障控制策略。考虑车辆的尺寸,对于障碍物边界的确定引入以阶跃函数为基础的禁区边界惩罚函数。同时在障碍预测环节中对预测距离进行倍数扩增,提高了车辆在较远距离处对障碍物的预测能力。仿真实验以车辆动力学平台CarSim为基础,结合Matlab/Simulink的S函数,对不同仿真工况进行测试。实验结果表明车辆可以避开给定障碍物并能够返回到原始路径,结果达到预期要求,验证了算法的可行性。     

电流型变流器的改进模型预测控制

传统的模型预测控制(MPC)采用脉冲响应的非参数模型作为系统的预测控制模型,计算量大,很难直接应用于实时控制系统.本文提出将传统的MPC进行改进,应用到电流型变流器(CSC)功率因数校正系统中.改进的MPC根据CSC控制量与被控制量的传递函数得出CSC的一阶差分方程作为预测控制模型,同时保留传统MPC反馈校正、动态优化等优点.将此改进的MPC与传统的PID控制进行对比研究,结果表明:改进的MPC用于电流型变流器,比传统的PID控制具有更好的鲁棒性和更快速的动态响应特性.     

适用于路径跟踪控制的自适应MPC算法研究

为提高自动驾驶车辆在不同工况下的路径跟踪精度和行驶稳定性,基于车辆的单轨模型和模型预测控制（MPC）理论,提出一种依据跟踪偏差和道路曲率自适应调整成本函数权重系数的路径跟踪控制算法。该算法主要是通过模糊控制理论动态优化传统MPC路径跟踪控制器中权重系数矩阵,使得当车辆与参考路径偏差比较大时,能够快速减小跟踪偏差,保证车辆行驶的安全性;当路径跟踪偏差比较小,且参考路径曲率比较小时,使得系统更加侧重行驶稳定性的要求。为验证所设计的路径跟踪控制器的性能,搭建CarSim/Simulink联合仿真模型,在联合仿真过程中,基于权重系数自适应的MPC路径跟踪控制器与基于权重系数为常量的MPC路径跟踪控制器相比,路径跟踪精度和车辆的行驶稳定性均得到了提高。     

基于强化学习的大时延过程控制策略研究

具有长时延的过程控制被公认为是较难的系统过程控制.模型预测控制(MPC)是一种适用于大时延过程的新的过程控制方法.相比于PID等传统的控制方法,MPC基于模型对未来状态的预测进行决策,能够兼顾及时反馈与长期规划.但MPC对于过程的预测步数依然是有限的.强化学习作为机器学习的重要部分,原则上能够预测策略在无限长时间内的收...     

约束非线性车辆队列分布式多目标模型预测控制

针对具有状态和控制约束的非线性车辆队列系统多目标控制问题,提出一种分布式多目标模型预测控制(model predictive control, MPC)策略.首先,基于前车-后车单向通信拓扑,建立网联车辆队列非线性纵向巡航模型,应用字典序算法描述分布式多目标MPC问题;然后,通过设计弦稳定与收缩约束,并结合MPC三要素条件,保证车辆队列在经济性能与协同性能最优条件下的稳定性和弦稳定性结果;最后,通过典型工况的仿真结果验证所提出策略的有效性.     

基于模型预测控制的直升机轨迹跟踪控制

针对直升机在实际任务中对轨迹精确控制的实际需求,提出基于模型预测控制(model predictive control,MPC)的直升机轨迹跟踪算法.轨迹控制的整体方案采用分层的架构:底层对直升机的速度以及姿态进行调节,顶层通过实施MPC算法对底层的姿态和速度指令进行调度,以期实现直升机轨迹的精确控制.通过分段MPC方法,有效降低了优化问题求解的复杂度.针对响应动态的不确定性,采用基于min-max原则的MPC参数整定法,保证了算法的鲁棒性.仿真案例对方法的有效性进行了验证,结果表明提出的方法控制精度高,计算代价合理,具有工程推广应用的前景.     

单交叉路口交通灯实时配时算法的研究

研究了城市道路交通信号实时控制系统的问题,重点论述了单交叉路口交通信号灯控制(点控制)模型的实时配时算法.根据城市交通流分布规律,设计出流量序列生成算法来模拟实时交通流;通过建立信号灯动态模型从而获得最佳周期长度和有效绿灯时间,然后采用模糊控制算法对信号灯配时方案进行实时的动态优化调整,并建立基于排队的车辆延误模型来对模糊控制算法进行评价.计算机模拟仿真的结果表明所设计实时配时方案比定时配时方案有显著的改善.     

基于随机模型预测控制的插电式混合动力汽车 多目标能量管理策略

为了改善插电式混合动力汽车的燃油消耗和排放, 开展多目标随机模型预测控制策略的研究. 首先, 建立适用于模型预测的多元线性回归的发动机和电池模型, 建立融合燃油消耗和排放的多目标价值函数的模型预测控制, 随后, 基于随机驾驶员模型未来时刻的车速, 结合交通信息并利用动态规划(DP)算法进行参考电荷状态(SOC)优化, 进而建立多目标随机模型预测控制策略. 最后, 通过与DP, MPC等策略进行对比验证, 及给出两组不同权值进行多目标控制效果分析. 结果表明, 该策略的燃油消耗和排放最接近DP的控制效果, 且设置不同权重值可获得相应的控制目标, 说明该策略对提升燃油消耗和排放的多目标性能的有效性.     

插电式混合动力汽车车速预测及整车控制策略

本文针对插电式混合动力汽车(plug-in hybrid electric vehicle,PHEV)这一典型混杂系统,提出了一种基于车速预测的混合逻辑动态(mixed logical dynamical,MLD)模型预测控制策略.首先,通过对发动机和电动机能量消耗模型进行线性化,建立双轴并联插电式混合动力城市公交车的动力传动系统数学模型;其次,运用模糊推理进行驾驶意图分析,提出基于驾驶意图识别和历史车速数据相结合的非线性自回归(nonlinear auto-regressive models,NAR)神经网络车速预测方法进行未来行驶工况预测.然后,以最小等效燃油消耗为目标建立PHEV的混合逻辑动态模型,运用预测控制思想对车速预测时域内最优电机转矩控制序列进行求解.最后,通过仿真实验验证了本文所提出控制策略在特定的循环工况下与电动助力策略相比,能够提高燃油经济性.     

Distributed Model Predictive Control Method for Optimal Coordination of Signal Splits in Urban Traffic Networks

Coordination and control approaches based on model predictive control (MPC) have been widely investigated for traffic signal control in urban traffic networks. However, due to the complex non‐linear characters of traffic flows and the large scale of traffic networks, a basic challenge faced by these approaches is the high online computational complexity. In this paper, to reduce the computational complexity and improve the applicability of traffic signal control approaches based on MPC in practice, we propose a distributed MPC approach (DCA‐MPC) to coordinate and optimize the signal splits. Instead of describing the dynamics of traffic flow within each link of the traffic network with a simplified linear model, we present an improved nonlinear traffic model. Based on the nonlinear model, an MPC optimization framework for the signal splits control is developed, whereby the interactions between subsystems are accurately modeled by employing two interconnecting constraints. In addition, by designing a novel dual decomposition strategy, a distributed coordination algorithm is proposed. Finally, with a benchmark traffic network, experimental results are given to illustrate the effectiveness of the proposed method.     

Neural control of fast nonlinear systems--application to a turbocharged SI engine with VCT.

Today, (engine) downsizing using turbocharging appears as a major way in reducing fuel consumption and pollutant emissions of spark ignition (SI) engines. In this context, an efficient control of the air actuators [throttle, turbo wastegate, and variable camshaft timing (VCT)] is needed for engine torque control. This paper proposes a nonlinear model-based control scheme which combines separate, but coordinated, control modules. Theses modules are based on different control strategies: internal model control (IMC), model predictive control (MPC), and optimal control. It is shown how neural models can be used at different levels and included in the control modules to replace physical models, which are too complex to be online embedded, or to estimate nonmeasured variables. The results obtained from two different test benches show the real-time applicability and good control performance of the proposed methods.     

Neural Control of Fast Nonlinear Systems— Application to a Turbocharged SI Engine With VCT

Today, (engine) downsizing using turbocharging appears as a major way in reducing fuel consumption and pollutant emissions of spark ignition (SI) engines. In this context, an efficient control of the air actuators [throttle, turbo wastegate, and variable camshaft timing (VCT)] is needed for engine torque control. This paper proposes a nonlinear model-based control scheme which combines separate, but coordinated, control modules. Theses modules are based on different control strategies: internal model control (IMC), model predictive control (MPC), and optimal control. It is shown how neural models can be used at different levels and included in the control modules to replace physical models, which are too complex to be online embedded, or to estimate nonmeasured variables. The results obtained from two different test benches show the real-time applicability and good control performance of the proposed methods.     

Optimization management of hybrid energy source of fuel cell truck based on model predictive control using traffic light information

Energy optimization management can make fuel cell truck (FCT) power system more efficient, so as to improve vehicle fuel economy. When the structure of power source system and the torque distribution strategy are determined, the essence is to find the reasonable distribution of electric power between the fuel cell and other energy sources. The paper simulates the assistance of the intelligent transport system (ITS) and carries out the eco-velocity planning using the traffic signal light. On this basis, in order to further improve the energy efficiency of FCT, a model predictive control (MPC)-based energy source optimization management strategy is innovatively developed, which uses Dijkstra algorithm to achieve the minimization of equivalent hydrogen consumption. Under the scenarios of signalized intersections, based on the planned eco-velocity, the off-line simulation results show that the proposed MPC-based energy source management strategy (ESMS) can reduce hydrogen consumption of fuel cell up to 7\% compared with the existing rule-based ESMS. Finally, the Hardware-in-the-Loop (HiL) simulation test is carried out to verify the effectiveness and real-time performance of the proposed MPC-based energy source optimization management strategy for the FCT based on eco-velocity planning with the assistance of traffic light information.     

Adaptive neural network model based predictive control for air–fuel ratio of SI engines

The dynamics of air manifold and fuel injection of the spark ignition engines are severely nonlinear. This is reflected in nonlinearities of the model parameters in different regions of the operating space. Control of the engines has been investigated using observer-based methods or sliding-mode methods. In this paper, the model predictive control (MPC) based on a neural network model is attempted for air–fuel ratio, in which the model is adapted on-line to cope with nonlinear dynamics and parameter uncertainties. A radial basis function (RBF) network is employed and the recursive least-squares (RLS) algorithm is used for weight updating. Based on the adaptive model, a MPC strategy for controlling air–fuel ratio is realised to a nonlinear simulation of the engines, and its control performance is compared with that of a conventional PI controller. A reduced Hessian method, a new developed sequential quadratic programming (SQP) method for solving nonlinear programming (NLP) problems, is implemented to speed up the nonlinear optimisation in MPC.     

Energy Control of Plug-In Hybrid Electric Vehicles Using Model Predictive Control With Route Preview

The paper proposes an adoption of slope, elevation, speed and route distance preview to achieve optimal energy management of plug-in hybrid electric vehicles (PHEVs). The approach is to identify route features from historical and real-time traffic data, in which information fusion model and traffic prediction model are used to improve the information accuracy. Then, dynamic programming combined with equivalent consumption minimization strategy is used to compute an optimal solution for real-time energy management. The solution is the reference for PHEV energy management control along the route. To improve the system's ability of handling changing situation, the study further explores predictive control model in the real-time control of the energy. A simulation is performed to model PHEV under above energy control strategy with route preview. The results show that the average fuel consumption of PHEV along the previewed route with model predictive control (MPC) strategy can be reduced compared with optimal strategy and base control strategy.      

城市交叉口车辆速度与交通信号协同优化控制

为了降低城市交通中的行车延误与燃油消耗,针对人类驾驶车辆与自动驾驶车辆混合交通环境,提出一种基于交通信息物理系统(TCPS)的车辆速度与交通信号协同优化控制方法.首先,综合考虑路口交通信号、人类驾驶车辆、自动驾驶车辆三者之间的相互影响,设计一种适用于自动驾驶车辆与人类驾驶车辆混合组队特性的过路口速度规划模型;其次,针对车辆速度规划单一应用时的局限性,即无法减少车辆路口通行延误且易出现无解情况,提出一种双目标协同优化模型,能够综合考虑车辆速度规划与路口交通信号控制,同时降低车辆燃油消耗与路口平均延误.由于双目标优化问题求解的复杂性,设计一种遗传算法-粒子群算法混合求解策略.基于SUMO的仿真实验验证了所提出方法的有效性.     

Hybrid modelling of homogeneous charge compression ignition (HCCI) engine dynamics—a survey

The Homogeneous charge compression ignition (HCCI) principle holds promise to increase efficiency and to reduce emissions from internal combustion engines. As HCCI combustion lacks direct ignition timing control and auto-ignition depends on the operating condition, control of auto-ignition is necessary. Since auto-ignition of a homogeneous mixture is very sensitive to operating conditions, a fast combustion phasing control is necessary for reliable operation. To this purpose, HCCI modelling and model-based control with experimental validation were studied. A six-cylinder heavy-duty HCCI engine was controlled on a cycle-to-cycle basis in real time using a variety of sensors, actuators and control structures for control of the HCCI combustion. Combustion phasing control based on ion current was compared to feedback control based on cylinder pressure. With several actuators for controlling HCCI engines suggested, two actuators were compared, dual fuel and variable valve actuation (VVA). Model-based control synthesis requiring dynamic models of low complexity and HCCI combustion models were estimated by system identification and by physical modelling, the physical models aiming at describing the major thermodynamic and chemical interactions in the course of an engine stroke and their influence on combustion phasing. The models identified by system identification were used to design model-predictive control (MPC) with several desirable features and today applicable to relatively fast systems, the MPC control results being compared to PID control results. Both control of the combustion phasing and control of load-torque with simultaneous minimization of the fuel consumption and emissions, while satisfying the constraints on cylinder pressure, were included.