纯电动汽车动力传动系参数匹配及仿真

为实现纯电动汽车传动系传动比与驱动电机的合理匹配,提出了一种基于MOGA-Ⅱ遗传算法的多目标优化方法。根据配备两挡变速器的某纯电动汽车的整车参数和设计要求,对其动力传动系统主要部件驱动电机及动力电池进行了匹配和选型。基于GT-drive软件搭建整车仿真模型进行仿真分析并验证了匹配的合理性。利用多目标优化软件modeFRONTIER进行了传动系传动比优化。优化结果表明,纯电动汽车的一次充电续驶里程及原地起步加速时间分别提高了5.5%和2.9%。     

Base Station Placement for Dynamic Traffic Load Using Evolutionary Algorithms

In this paper, dynamic traffic load is considered to determine optimal location of base station (BS) using evolutionary optimization algorithms. The various parameters such as site coordinates (x, y), transmitting power, height and tilt are taken as design parameters for BS placement. Coverage maximization and cost minimization are considered as two conflicting objectives with inequality constraints such as handover, traffic demand and overlap. RGA and MNSGA-II algorithms are used to solve single objective and multiobjective BS placement problem respectively. A $2 \times 2\, \text{ km}^{2}$ synthetic test system is discretized as hexagonal cell structure for simulation purposes. Receiving field strength for all service testing points is calculated using simulations and path loss is calculated using Hata model. In dynamic traffic model, both vehicle and pedestrian movements in up and side directions are considered. Dynamic movement is achieved by randomly moving vehicles and pedestrians for a fixed speed in each sample time. The results show that the RGA is able to determine the optimal BS location after considering the dynamic traffic load and satisfying inequality constraints for both coverage maximization and cost objectives. MNSGA-II algorithm gives well distributed pareto-front for the multiobjective BS placement in single simulation run. The simulation results reveal that the proposed dynamic traffic model is suitable for the real world BS placement problem.     

Energy based closed form solution of ZCS multiresonantseries-parallel converters

Under-resonant operation of an ideal multi-resonant series-parallel power converter (MRSPC) with a capacitive output filter is modeled in this paper. This operation allows zero current switching (ZCS), which is convenient for bipolar devices. The capacitive output filtering reduces the recovery effect of the rectifier diodes and is suitable for high output voltage applications. A closed-form solution is found for this power converter, based on state space analysis using energy concepts. This approach simplifies the mathematical operations and gives better physical insight of the system variables. Based on the model, the steady-state characteristics of this power converter are derived by a simulation program, which are discussed and compared with the series resonant half-bridge power converter (SRHC). The optimum power converter parameters are found for given design requirements using computerized optimization routines. Several design examples are presented and compared with SRHC. The validity of the model is verified by SPICE simulations     

Putative dynamics of vasopressin in its V1a receptor binding site

The molecular architecture of the GPCRs, including the dynamic set of interactions between the receptor and the ligand, is one of the key structural questions of biophysical approaches. In the present study, molecular dynamics (MD) simulations were performed on the well-validated molecular model of the vasopressin V1a receptor applying different parameters (i.e., force fields, time variation, use of constraints) in order to sample the conformational space of the endogenous ligand arginine vasopressin (AVP), to explore different putative binding modes, and to analyze the simulation results with respect to experimental data. Noteworthy, it is to mention that for the first time a model of the vasopressin receptor remained stable in a 500 ps MD simulation run under vacuo boundary conditions using the Kollman all-atom FF even though no constraints were imposed. Conclusively, we determined an optimized experimental procedure for studying the dynamics and structure-functionship of this highly important family of GPCRs: the use of MD simulations with the Kollman all-atom force-field parameters on a constrained receptor. Our simplified model may be used as a basis for structure based design of new GPCR ligands and for in silico screening of virtual combinatorial chemistry libraries.     

RBCC动力飞行器上升段轨迹优化设计

针对火箭基组合循环（Rocket Based Combined Cycle,RBCC）动力系统工作模态复杂、与飞行状态耦合程度高的特性,建立了一种适用于RBCC动力高超声速飞行器的动力段轨迹优化模型。同时,针对RBCC动力飞行器,基于凸优化理论建立了上升段轨迹优化设计框架和求解策略。在此基础上,进行了上升段末端机械能最大算例仿真。仿真结果表明,相关模型和轨迹优化方法具备良好的可行性,优化结果符合RBCC动力系统工作特点。论文提出的轨迹优化方法可有效处理复杂工作模态下RBCC助推飞行器上升段轨迹优化问题,为未来关于这一类轨迹设计与优化的工作提供了一些新的思路。     

Insights in wind turbine drive train dynamics gathered by validating advanced models on a newly developed 13.2 MW dynamically controlled test-rig

Guaranteeing reliable and cost-effective wind turbine drive trains requires expert insights in dynamics during operation. A combination of advanced modeling techniques and detailed measurements are suggested to realize this goal. The flexible multibody modeling technique enables the simulation of dynamic loads on all drive train components. Moreover it facilitates estimation of structural component deformation caused by dynamic loading. This paper gives a detailed overview of the assumptions made in this modeling approach. Furthermore the influence of the different structural component flexibilities is investigated in detail. To gain confidence in the models created, model validation by means of a comparison with measurements is necessary. To overcome issues concerning test repeatability experienced in field testing, test-rig testing is suggested as a valid alternative. In order to be representative, dedicated dynamic load cases, which represent specific dynamic behavior of the gearbox in a wind turbine need to be realized on the test-rig. However a highly dynamic test-rig complying with the specifications was not commercially available. Therefore Hansen developed a high dynamic test-rig with a nominal power of 13.2 MW and a peak power capacity of 16.8 MW. A back-to-back gearbox configuration was used. The complexity of controlling dynamics of the test-rig was solved by identifying dedicated load cases which represent specific wind turbine behavior. This paper describes the development process of the project consisting of four phases. During two phases a scaled set-up was used, which enabled iterative optimization of the complex interaction between the mechanical dynamics and the electrical controller of the test-rig. In the final part of the paper the two previously discussed approaches are combined, as it discusses results from the validation of simulation models using measurements performed on the 13.2 MW test-rig.     

Evaluation of motor characteristics for hybrid electric vehicles using the hardware-in-the-loop concept

If the concept of Hardware-in-the-Loop (HIL) is applied to component testing, characteristic of component of hybrid electric vehicle in real vehicle environment can be evaluated without actually installing that component in real vehicle. In this paper, when commercially available test motor is adopted as a drivetrain of hybrid vehicle, we need to figure out which drive train configuration would be best for specific purpose. The characteristic of the motor when it is installed in the vehicle at different drive train and driving mode can be simulated and actual characteristic can be measured. Also both results can be compared. For the hardware characteristic measurement, test facility which consists of vehicle simulator and dynamometer is required. In this case, vehicle controller in the vehicle simulator is used as a vehicle controller and dynamometer is used to simulate vehicle dynamics. Two drive train types, 4-motor series, and 2-motor parallel type are proposed. Vehicle speed tracks driving cycle speed command well in both simulation and HIL implementation.     

Design optimization on the drive train of a light-weight robotic arm

A drive train optimization method for design of light-weight robots is proposed. Optimal selections of motors and gearboxes from a limited catalog of commercially available components are done simultaneously for all joints of a robotic arm. Characteristics of the motor and gearbox, including gear ratio, gear inertia, motor inertia, and gear efficiency, are considered in the drive train modeling. A co-simulation method is developed for dynamic simulation of the arm. A design example is included to demonstrate the proposed design optimization method.     

三层手征网格结构的特性研究

首先基于希腊十字型手征结构,提出一种新型的三层手征网格结构,并对该结构的关键几何参数进行了优化选择;随后对新型手征结构的电磁波响应进行了数值模拟,得到结构对于不同频率入射波的透射和反射响应,依据模拟得到的透射反射系数进行反演计算;最后根据反演计算得到的旋光度、椭偏度、介电常数、磁导率和手征参数等结构特性参数分析结构的旋光性和电磁特性。结果表明,这一结构具有比以往类似结构更好的光学特性,为未来这一类型手征结构的应用提供了更加广阔的思路。     

Real-Time Automatic Obstacle Detection method for Traffic Surveillance in Urban Traffic

Network-on-Chip (NoC) is a flexible and scalable solution to interconnect multi-cores, with a strong influence on the performance of the whole chip. On-chip network affects also the overall power consumption, thus requiring accurate early-stage estimation and optimization methodologies. In this scenario, the Dynamic Voltage Frequency Scaling (DVFS) technique have been proposed both for CPUs and NoCs. The promise is to be a flexible and scalable way to jointly optimize power-performance, addressing both static and dynamic power sources. Being simulation a de-facto prime solution to explore novel multi-core architectures, a reliable full system analysis requires to integrate in the toolchain accurate timing and power models for the DVFS block and for the resynchronization logic between different Voltage and Frequency Islands (VFIs). In such a way, a more accurate validation of novel optimization methodologies which exploit such actuator is possible, since both architectural and actuator overheads are considered at the same time. This work proposes a complete cycle accurate framework for multi-core design supporting Global Asynchronous Local Synchronous (GALS) NoC design and DVFS actuators for the NoC. Furthermore, static and dynamic frequency assignment is possible with or without the use of the voltage regulator. The proposed framework sits on accurate analytical timing model and SPICE-based power measures, providing accurate estimates of both timing and power overheads of the power control mechanisms.     

A Vehicle Roll-Stability Indicator Incorporating Roll-Center Movements

In the development of active-passive roll control systems, a vehicle model that can represent realistic roll behavior is essential for predicting the impending rollover and for accurately applying the control force to avoid vehicle rollover. The vehicle roll center is a key parameter that influences the vehicle roll dynamics. Since the roll center movement becomes important as the vehicle roll angle increases, it is desirable to include this effect in the roll control system. This paper proposes a dynamic roll stability indicator (RSI) incorporating roll center movement that generates rollover threshold in terms of lateral acceleration. A robust parameter identification algorithm using a disturbance observer is designed to estimate the lateral and vertical roll center movements. These estimates are later used in the RSI to update the rollover threshold. The effectiveness of the proposed method is demonstrated through simulations, and its performance is compared with other rollover warning algorithms.     

纯电动中型客车动力系统参数匹配及性能研究

针对现有车辆改装技术缺乏相应的参数匹配研究及动力学仿真分析,提出利用参数匹配和动力学分析研究汽车改制的方法,该方法以“LS6600C1”型普通中型客车改装的纯电动试验车为研究对象,对动力系统进行参数匹配设计,并利用电动汽车仿真软件ADVISOR建立相应的纯电动汽车动力系统及整车仿真模型,对整车模型的最高车速、加速能力、爬坡性能和续驶里程等指标进行了仿真研究。结果表明,典型工况下改装后的纯电动试验车续驶里程、最高车速、加速性能和爬坡性能等均满足普通中型客车的运行要求和使用条件,该改装技术具有广泛的应用前景。     

Design of multiple-input power converter for hybrid vehicles

This paper deals with designing and sizing of a multiple-input power electronic converter (MIPEC) to be used in an electric vehicle propulsion system that includes a fuel cell (FC) generator and a combined storage unit. The combined storage unit is composed by an ultracapacitors tank (UC) and a battery unit (BU). MIPEC is responsible for power-flow management on-board the vehicle for each mode of operation. Specifications for MIPEC designing come out from many considerations concerning traction drive and reference driving cycle, on-board power source and storage unit characteristics. However, to date sizing and configuration of both storage units and on-board generators are directly related to traction drive and driving profile (i.e., vehicle performances and characteristics) and no relation with power electronic interface is considered during preliminary design. Then, power electronic interface is selected in order to fit traction drive requirements with power source and storage unit characteristics; as a consequence converter mode of operation lacks of optimization, as well dynamic behavior and efficiency cannot be maximized. In this paper, MIPEC design and power source and storage unit selection are achieved at the same project stage according to traction drive requirements. Experimental results on 60-kW power electronic interface are presented.     

Propulsion system design of electric and hybrid vehicles

There is a growing interest in electric and hybrid-electric vehicles due to environmental concerns. Efforts are directed toward developing an improved propulsion system for electric and hybrid-electric vehicles applications. This paper is aimed at developing the system design philosophies of electric and hybrid vehicle propulsion systems. The vehicles' dynamics are studied in an attempt to find an optimal torque-speed profile for the electric propulsion system. This study reveals that the vehicles' operational constraints, such as initial acceleration and grade, can be met with minimum power rating if the power train can be operated mostly in the constant power region. Several examples are presented to demonstrate the importance of the constant power operation. Operation of several candidate motors in the constant power region are also examined. Their behaviors are compared and conclusions are made     

Estimating net joint torques from kinesiological data using optimallinear system theory

Net joint torques (NJT) are frequently computed to provide insights into the motor control of dynamic biomechanical systems. An inverse dynamics approach is almost always used, whereby the NJT are computed from 1) kinematic measurements (e.g., position of the segments), 2) kinetic measurements (e.g., ground reaction forces) that are, in effect, constraints defining unmeasured kinematic quantities based on a dynamic segmental model, and 3) numerical differentiation of the measured kinematics to estimate velocities and accelerations that are, in effect, additional constraints. Due to errors in the measurements, the segmental model, and the differentiation process, estimated NJT rarely produce the observed movement in a forward simulation when the dynamics of the segmental system are inherently unstable (e.g., human walking). Forward dynamic simulations are, however, essential to studies of muscle coordination. The authors have developed an alternative approach, using the linear quadratic follower (LQF) algorithm, which computes the NJT such that a stable simulation of the observed movement is produced and the measurements are replicated as well as possible. The LQF algorithm does not employ constraints depending on explicit differentiation of the kinematic data, but rather employs those depending on specification of a cost function, based on quantitative assumptions about data confidence. The authors illustrate the usefulness of the LQF approach by using it to estimate NJT exerted by standing humans perturbed by support-surface movements. They show that unless the number of kinematic and force variables recorded is sufficiently high, the confidence that can be placed in the estimates of the NJT, obtained by any method (e.g., LQF, or the inverse dynamics approach), may be unsatisfactorily low     

Propulsion system design optimization using the Taguchi method

The authors discuss the Taguchi method as an approach to design optimization for quality. The method is briefly explained, and its application is illustrated for a propulsion system design optimization study for an advanced space transportation vehicle. The results suggest that the Taguchi method is a systematic and efficient approach that can aid in designing for performance, quality, and cost. Principal benefits include significant time and resource savings and the determination of parametric sensitivities and interactions     

Recent Advances in Control-Oriented Modeling of Automotive Power Train Dynamics

This paper presents a survey of the recent research results of the authors in the field of modeling of automotive power train systems and components. The goal of the research is to propose simple and accurate power train models for controller design and to propose computationally efficient simulations. The modeling includes typical power train components such as electronic throttle, SI engine, torque converter, planetary gear set, wet clutch, differential, half shaft, and tire. Experimental model validation results are presented.     

Vehicle Stability Enhancement of Four-Wheel-Drive Hybrid Electric Vehicle Using Rear Motor Control

A vehicle stability enhancement control algorithm for a four-wheel-drive hybrid electric vehicle (HEV) is proposed using rear motor driving, regenerative braking control, and electrohydraulic brake (EHB) control. A fuzzy-rule-based control algorithm is proposed, which generates the direct yaw moment to compensate for the errors of the sideslip angle and yaw rate. Performance of the vehicle stability control algorithm is evaluated using ADAMS and MATLAB Simulink cosimulations. HEV chassis elements such as the tires, suspension system, and steering system are modeled to describe the vehicle's dynamic behavior in more detail using ADAMS, whereas HEV power train elements such as the engine, motor, battery, and transmission are modeled using MATLAB Simulink with the control algorithm. It is found from the simulation results that the driving and regenerative braking at the rear motor is able to provide improved stability. In addition, better performance can be achieved by applying the driving and regenerative braking control, as well as EHB control.     

弹载合成孔径雷达动态海面成像模拟研究

海面成像模拟是对海作战导弹弹载合成孔径雷达(SAR)成像制导全过程动态仿真的重要组成部分,对于系统的性能分析和优化设计具有重要意义。研究了弹载情况下SAR对海成像模拟问题,提出了基于三维海面波动模型及弹载SAR工作过程的成像模拟方案。出于逼真性及运算速度的考虑,仿真时动态海面选用基于海浪谱的双尺度模型,海面散射模型选用双尺度散射模型。结合一组典型弹载SAR系统参数,分别在正侧视和斜视模式下对三种典型海况的动态海面进行了成像模拟,并利用实际海面SAR图像的统计特性验证了模拟结果的有效性。     

PSIM-based modeling of automotive power systems: conventional, electric, and hybrid electric vehicles

Automotive manufacturers have been taking advantage of simulation tools for modeling and analyzing various types of vehicles, such as conventional, electric, and hybrid electric vehicles. These simulation tools are of great assistance to engineers and researchers to reduce product-development cycle time, improve the quality of the design, and simplify the analysis without costly and time-consuming experiments. In this paper, a modeling tool that has been developed to study automotive systems using the power electronics simulator (PSIM) software is presented. PSIM was originally made for simulating power electronic converters and motor drives. This user-friendly simulation package is able to simulate electric/electronic circuits; however, it has no capability for simulating the entire system of an automobile. This paper discusses the PSIM validity as an automotive simulation tool by creating module boxes for not only the electrical systems, but also the mechanical, energy-storage, and thermal systems of the vehicles. These modules include internal combustion engines, fuel converters, transmissions, torque couplers, and batteries. Once these modules are made and stored in the library, the user can make the car model either a conventional, an electric, or a hybrid vehicle at will, just by dragging and dropping onto a schematic blank page.