In order to solve the problem of speed planning in complex road environment（large curvature, low adhesion） meeting the constraints of safety and efficiency, a differential equation programming method based on vehicle dynamics was proposed. Firstly, the structural parameter expression of the limit velocity satisfying the lateral tire force constraint was derived in steady-state steering. Secondly, the spatial combination of the tire forces of the front wheel and the rear wheel is shown in the F-F diagram. And the implicit differential equation considering load transfer and driving mode factors was derived. The limit velocity along the path can be obtained by solving the differential equation. A method for calculating the limit speed based on discrete path information was given. Finally, a model prediction controller was designed and a co-simulation platform of CarSim and Simulink was built. The trajectory tracking simulation experiments were carried out with the planned limit speed on the continuous and discrete information paths. The results show that the proposed limit speed planning method can complete the trajectory tracking task as soon as possible in the complex road environment and control the-tire force within the range of stable friction circle.

针对目前快递终端取件模式,尤其是例如高校等人口密集,包裹流量大的区域,仍存在取件效率低、人工成本较高等问题,提出了一种新型无人快递终端模式.该模式以STM32单片机作为控制系统,通过机械装置进行无人情况下的自动化取件,并设计制作了该终端模型机.经实验验证,该快递终端模式提高了取件效率,同时降低了驿站工作人员的劳动强度,符合预期功能及要求.

为减少日益增长的交通安全问题,车辆碰撞预警及避碰控制系统必不可少.本文提出了一种结合车辆横纵向动力学的复合控制避碰方法,以达到减少交通事故发生的目的.首先,分别建立了车辆逆纵向和横向动力学模型,纵向控制器通过安全距离模型来判断车辆是否处于危险状态并进行碰撞预警,采用分层控制方法设计了上层模型预测控制器和底层单神经元PID控制器.横向上结合不同时速时的参数约束设计模型预测控制器.最后,在不同工况下进行了仿真实验,表明本文控制系统能成功避碰,提高了车辆的安全性、稳定性、舒适性.

考虑了行车过程中的侧风干扰,基于反步法设计了车辆稳定控制器,在保证车辆稳定行驶的同时完成车辆无线通信技术(V2X)目标.V2X模型包括车辆与路面之间(Vehicle-to-road,V2R)模型和车辆与车辆之间(Vehicle-to-vehicle,V2V)模型两部分,其中,V2R为巡航轨迹模型,其作用是对驾驶员期望行驶路径进行跟踪,V2V为队列保持模型,用于与前车维持一定的安全距离.为验证本文所设计的控制器能抵抗行车过程中的侧风干扰,完成期望行驶目标,利用MATLAB平台搭建车辆的V2X模型和三自由度模型对反步法控制器进行验证.仿真结果表明:在侧风干扰存在的情况下,反步法控制器可逐步实现车辆稳定控制,具有较强的适用性和鲁棒性.

汽车电子稳定控制系统在行车安全方面发挥着极其重要的作用,对稳定控制系统的横摆控制研究可以分为2个层次进行.上层为控制器设计,先采用反馈线性化思想将车辆动力学模型进行线性化处理,再采用线性二次型调节器进行优化控制器设计,以产生期望的力(矩);下层采用最优控制算法进行制动力分配,用加权最小二乘法将稳定性控制力(矩)最优的分配到各车轮的执行器上,以满足车辆稳定性行驶的要求.在Matlab中搭建整车模型并进行仿真验证,结果表明,基于以上方法的车辆横摆稳定性控制能很好的跟踪上期望的纵向速度、横向速度以及横摆角速度.

针对节气门开度和负载的随机大幅突变而导致的复杂工况下发动机失火诊断策略精度下降的问题,提出利用爆炸及燃烧学理论和牛顿运动定律对发动机汽缸内部做功时的爆炸形式进行建模,建立关于节气门开度和负载的一步迭代转速模型.利用卡尔曼滤波器对转速迭代模型的输出进行最优估计以消除噪声影响.针对失火故障按失火缸数进行分类,提出转速一步迭代模型和转速实际观测值的序列残差变化率时频变换分析法,即对转速一步迭代模型和转速观测值残差序列变化率的频率特性进行分析,得到报警阈值,进而得出失火诊断策略.AMESim软件仿真结果表明:失火工况和非失火工况以及不同的失火类型对应的残差序列变化率的时频特性在低频、基频和倍频的幅值上存在明显的差异,利用神经网络对不同的失火类型表现出的不同频谱特性进行分类,完成对失火故障类型的确定,证明了本方法的可行性、有效性和精确性.

针对侵入式发动机压力传感器造价高以及运行环境恶劣导致寿命短、可靠性低的问题,利用发动机做功能量转化和牛顿运动定律对发动机做功进行建模,建立转速一步迭代模型,利用扩展卡尔曼滤波器(EKF)对转速迭代模型进行线性化处理并进行最优估计.利用奥拓循环搭建做功循环的标准模型,利用工程热力学知识对缸内压力峰值进行求取,利用压力峰值和转速最优估计分别进行24阶傅里叶级数的频率、幅值的调制,最终完成发动机汽缸压力辨识.采用大众牌EA211发动机进行试验验证,结果表明:当设定发动机空燃比系数为0.85时,转速跟踪误差在10％以内,压力功谱误差低于2％;当设定空燃比系数为0.95时,转速跟踪误差在1.5％以内,压力功谱误差低于1.5％.试验结果证明了本文模型和算法的有效性、可靠性和精确性.

针对传统的植被覆盖度估算方法费时费力、效率低且难以大范围提取等问题,该文基于泉州市2001-2016年TM/OII遥感影像,运用归一化植被指数和像元二分法进行植被覆盖度的反演并通过决策树法划分不同的覆盖度等级,研究泉州市植被覆盖度与景观格局变化趋势.结果表明,泉州市总体植被覆盖度良好,部分区域由于城区扩张和人为破坏,呈下降趋势;2001-2016年非植被,低植被覆盖度和较低植被覆盖度的斑块密度降低,连片性增强,中度植被覆盖度和较高植被覆盖度的斑块密度增加,连片性减弱;多样性指数先增加后保持稳定,说明研究区内植被生态环境正在逐渐变好且趋于稳定.

To explore the spatial distribution of lithium resources in Arizaro salt lake, the Sentinel—2 A satellite data and the measured data of lithium ion content were used for statistical analysis and the band combination method is used to establish the salt index. Combining principal component analysis, separation of lithium ion content in the salt lake is achieved and the remote sensing prediction model for lithium ion content is established. The results show that the inversion accuracy of the lithium ion content prediction model in the salt lake is more than80％, and the distribution of lithium ion content in the inversion is basically the same as the actual situation.

Traditional model reference adaptive theory MRAS( Model Reference Adaptive System) of induction motor speed sensorless drive has a shortcoming that the reference model is not accurate. This paper proposes a adaptive speed sensorless control AFO( Adaptive Full-Order Observer) that uses motor itself for the reference model, luenberger full order observer for the adjustable model. The syetem consists of a full order observer that yields the rotor fluxes of motor needs and also estimates the speed using an adaptive law. Based on the Lyapunov stability theory. The adaptive rotor speed is actually derived by using estimated stator currents error and estimated rotor flux. A fast convergent feedback matrix is designed based on the pole assignment method, to ensure the stable operation of the motor in a wide range. In view of the instability of the rotor speed estimation in low speed regenerative braking, by using the Routh stability criterion, a new feedback matrix is designed to guarantee the global stability of the speed estimation. The simulations results show its validity and effectiveness.

考虑侧风干扰研究了车辆稳定控制系统的执行器故障诊断算法.建立了带有侧风干扰和执行器故障的车辆七自由度整车模型.为实现侧风干扰存在时ESC系统执行器故障诊断,利用微分几何方法对系统进行微分同胚变换,使得不可测干扰转为可测输入以便干扰解耦.针对变换后系统设计执行器故障观测器,根据残差将执行器故障定位到某一车轮上,并得到实际执行器故障估计值.最后,通过仿真实验验证了该方法的有效性.

《计算机控制系统》作为自动化专业一门难度较大的专业主干课程,其教学改革一直受到专家学者们的广泛重视.本文针对该课程知识面宽、综合性强且与工程实践关系紧密的特点,提出了一种以工程实践为前提的教学模式.通过哲学和教育心理学相关理论,对该教学方法的可行性进行了分析论证,并对基于此方法的课程建设方案展开了讨论.以自选实际项目为前提,采用实验拓展法逆序教学,可以有效地激发学生自主学习的积极性,引导学生能在知识结构上精通局部的同时把握全局,从而提高学生的主观能动性,获得良好的教学效果.本教学模式可向本科高年级相关专业综合性较强的其他课程推广.

Vehicle stability control system features obvious nonlinear characteristics.It is difficult for fault diagnosis of its sensor and actuator.The eight degree of freedom model of vehicle is simplified and the virtual input is established.Aiming at the virtual input model,the actuator fault is considered as part of augmented state vector,and an augmented system is constructed.The observer is designed by using Lyapunov theory;the asymptotic estimation of the state of original system and the virtual actuator fault is obtained,and the stability and convergence of the augmented observer is analyzed.Through LMI technology,the solution of inequalities of linear matrix is realized,the design of observer is completed.By adopting simple filter,a new state vector is selected as low-pass 1 st order filter;the sensor fault is transformed into actuator fault;the 2nd augmented system is constructed,then the fault estimation of sensor is implemented by directly using actuator fault estimation.The feasibility of this method is verified by Simulink.Comparing with other methods,this method can obtain the fault signals of virtual actuator and sensor simultaneously for warning the system,and provide reliable data for subsequent design of fault tolerant control.

In order to solve the problem of engine misfire fault, a diagnosis method based on cylinder pressure identified by Fourier Transform (FT) and L-M optimized BP neural network is proposed.The BP neural network is trained by the steady state simulation data from AMESim to obtain the relationship between open value of valve and frequency, and FT is used to identify the cylinder pressure.The misfire failure can be diagnosed by comparison of the FT identified pressure with the pressure mapped from crank speed.By offsetting the phase and frequency of the identified model, the accuracy and generalization of the identified model are improved.When misfire fault occurs, high tracking ability can be obtained by re-offsetting the phase and frequency of the identified model.Two random and independent open values of the valve are used to verify the proposed method, Results show that no matter engine at high speed with light load condition or at low speed with heavy load condition, this method can precisely diagnose the signal-cylinder continuous misfire fault and multi-cylinder random misfire fault.

为估计汽车横摆角速度并提高估计器精度,采用BP(Back Propagation)神经网络的方法对汽车转向过程的横摆角速度进行估计.现实情况通常存在4种路面:干燥路面、沥青路面、积水路面和冰雪路面,若单纯训练一个网络难以涵盖4种不同的路面情况.为解决上述问题,提高网络估计器的精度,分别在4种路面工况下训练4个网络,构成一个网络组,再加入网络选择机制,根据路面情况选择对应的网络的输出值作为横摆角速度的估计值.通过AMESim与Matlab联合仿真,获得网络估计器残差并对估计情况进行分析和评价.该基于数据的方法与基于解析模型的估计方法相比,不依赖精确的模型,就能准确估计汽车横摆角速度.仿真结果表明,基于BP神经网络的方法对横摆角速度估计是可行的且偏差小,成本低,精度高.

Eight degrees of freedom vehicle model contains many control variables,it is difficult to directly analyze and control. Based on the eight degrees of freedom vehicle model,a model decomposition method is proposed,which decomposes the original model into three parts. Every part includes less control variables. It is easy to design a controller for each part. Considering the roll angle and the roll angular speed of the decomposed model,the linear quadratic optimal control method is introduced to design the optimal state controller,which can achieve vehicle’s stability control. It is proved that the designed controller shows more excellent control effect.

针对发动机失火故障信息难以提取的问题,提出了一种基于集合经验模态分解(EEMD:Ensemble Empirical Mode Decomposition)的发动机失火故障检测方法.该方法能自适应地将曲轴转速信号分解为若干个本征模态函数(IMF:Intrinsic Mode Function),确定包含故障信息的IMF,通过该IMF幅值的异常波动,可以较准确地判断发动机发生失火故障的时间.并通过AMESim建立了发动机仿真模型,从中采集了3种情况的曲轴转速信号,分别利用EEMD分解并最终检测失火故障.实验结果表明,该方法能有效提取故障信息,实现失火故障的离线检测,并可以作为在线检测的基础.

Due to the phenomenon of engine misfire in single cylinder and dual cylinders often occured in vehicles,PNN( Probabilistic Neural Network)was used to detect the engine misfire by analyzing the engine rotary velocity and crankshaft angular displacement. Under the circumstance of AMEsim software,we construct a kind of four cylinders in line engine and use the injecting approach to simulate engine misfire. Then,extract the engine velocity and crankshaft angular displacement,put these data in the Matlab software to process and classify them. A PNN for training and testing is established. The experiment results indicate that the engine rotary velocity and crankshaft displacement reflect the real operation condition of the engine,the tested PNN can diagnose and probe single cylinder or double cylinders misfire in the engine. This technique has series of advantages of simplicity,economy,efficiency and high accuracy.

针对传统异步电机直接转矩控制系统在低速运行状态下存在磁链轨迹发生波动、转矩脉动大的问题,提出一种新型异步电机直接转矩控制策略.采用滑模控制和空间矢量脉宽调制技术(SVPWM:Space Voltage Pulse-Width Modulation),引入滑模控制器,以提高系统对参数变化和外界干扰的鲁棒性.利用空间电压矢量脉宽调制技术产生系统所需要的任意期望空间电压矢量,使磁链轨迹更趋近于圆形,即降低了转矩和磁链脉动,又增强了系统的鲁棒性.同时引入无速度传感器技术,以提高系统工程应用性.通过在Matlab/Simulink软件仿真结果表明,新型直接转矩控制系统改善了磁链轨迹波动并有效地降低了转矩脉动,使转速估计具有较高精度.

针对汽车侧倾角速度传感器故障对控制系统的影响问题,提出了一种基于模型的故障诊断和故障重构方法,并给出了系统的理论证明.对于满足Lipchitz条件的多输入多输出非线性系统,可应用带有模型不确定性的一维线性状态方程作为其等效模型,进行传感器的故障诊断.并在此基础上应用经典的观测器理论设计了残差生成器,通过特征结构配置的方法,证明了模型不确定性、执行器故障和干扰可以实现在残差中的完全去耦.采用整车的八自由度模型进行Simulink仿真,结果证明了结论的有效性.与其他方法相比,笔者算法得到的残差具有很强的鲁棒性,重构出的传感器信号具有很高的精度.