基于模板技术的汽车多体动力学建模研究

针对当前汽车动力学仿真软件建模复杂度高、模型结构不易理解、模板开放性不高等缺点,提出开放的模板化建模技术.将汽车动力学模型分解为相对独立的子系统并抽象为基本模板,采用“基本模板—结构模板—模板实例化”的架构,用XML描述模板,从而实现模板的开放性,构建汽车动力学模型的树状层级模板库和实例库,结合基于实例推理的方法生成模型.在此基础上开发了汽车整车建模软件,并以某重型汽车起重机为例说明了该技术的应用.     

Combined state of charge estimator for electric vehicle battery pack

Ah counting is not a satisfactory method for the estimation of the state of charge (SOC) of a battery, as the initial SOC and coulomb efficiency are difficult to measure. To address this issue, an equivalent coulomb efficiency is defined and a new SOC estimation method, denoted as “KalmanAh”, is proposed. This method uses the Kalman filtering method to correct for the initial value used in the Ah counting method. A Ni/MH battery test, consisting of 8.08 continuous federal urban driving schedule (FUDS) cycles, is carried out to verify the method. The SOC estimation error is 2.5% when compared with the real SOC obtained from a discharge test. This compares favorably with an estimation error of 11.4% when using Ah counting.     

A flexible distributed framework for realising electric and plug-in hybrid vehicle charging policies

Motivated by the problems of charging a number of electric vehicles via limited capacity infrastructure, this article considers the problem of individual load adjustment under a total capacity constraint. For reasons of scalability and simplified communications, distributed solutions to this problem are sought. Borrowing from communication networks (AIMD algorithms) and distributed convex optimisation, we describe a number of distributed algorithms for achieving relative average fairness whilst maximising utilisation. We present analysis and simulation results to show the performance of these algorithms. In the scenarios examined, the algorithm's performance is typically within 5% of that achievable in the ideal centralised case, but with greatly enhanced scalability and reduced communication requirements.     

基于Modelica的电动汽车电池建模与仿真

为了实时仿真电动汽车电池组的动态性能,应用Modelica多领域建模语言建立描述电池组的PNGV等效电路模型.通过电池的动态充放电性能实验标定电池组模型的电阻、电容等参数,并利用Dymola多领域仿真软件进行性能参数求解.将该电池模型应用在电动汽车整车的仿真分析中,实验结果表明,该模型准确度高,能实时地仿真电动汽车的动力性能.该电池组建模方法实现简单且便于扩展,可以为电动汽车的产品设计、系统性能分析提供有效的解决办法.     

电力电子技术在电动车驱动系统中的应用

现今世界上节能和环境保护正日益受到重视,因此电动汽车技术的发展步伐正在加速。本文论述了电动汽车技术的现状以及电动机、电力电子技术的快速发展所产生的影响,介绍了电力电子技术在电动车驱动系统中的具体应用,最后就电力电子技术在电力驱动方面将来的发展趋势进行了展望。     

Fault-tolerant traction control of electric vehicles

This paper investigates a new traction control approach that requires neither chassis velocity nor information about tire-road conditions. Plant fault subject to the uncertainties of the mathematical model and slightly sensor fault are concerned. For general traction control of vehicles, the variation of model behavior may break down the steering stability if the chassis velocity is not monitored. This paper presents a fault-tolerant approach based on the maximum transmissible torque estimation (MTTE) scheme which has the ability to prevent electric vehicles from skidding. A PI-type disturbance observer is employed to enhance the steering stability of the MTTE approach. This proposed approach does not require both the differentiator and the inversion of the controlled plant. Finally, illustrated examples are given for evaluating the fault-tolerant performance and feasibility of the presented anti-slip strategy.     

Agent-oriented modeling of the dynamics of biological organisms

In this paper, the agent-oriented modeling perspective to cope with biological complexity is discussed. Three levels of dynamics can distinguished and related to each other: dynamics of externally observable agent behavior, dynamics of internal agent processes, and dynamics of multi-agent organisations. This paper addresses the first two. Basic agent concepts to describe externally observable agent behavior are introduced. In the context of two case studies on animal behavior and cell functioning, it is shown how these concepts can be used to specify dynamic properties. In addition, a number of basic agent concepts to describe an agent’s internal processes are introduced. Also, these concepts are illustrated for specification of dynamic properties in the two case studies. Furthermore, the relationships between dynamic properties of externally observable behavior and dynamic properties of internal agent processes are addressed and illustrated for the animal and cell case studies.     

电动汽车用感应电动机矢量控制技术仿真实现

当今世界节能和环保备受关注,使得电动汽车技术正在加速发展。电机技术是发展电动汽车的关键技术之一,该文在分析矢量控制原理的基础上将其应用于电动汽车的驱动电动机控制。仿真表明电动机的控制性能得到了明显改善,能够满足电动汽车运行工况复杂多变的需求。     

Multibody modeling of human body for the inverse dynamics analysis of sagittal plane movements

A multibody methodology for systematic construction of a two-dimensional biomechanical model of a human body is presented, aimed at effective determination of the muscle forces and joint reaction forces in the lower extremities during sagittal plane movements such as vertical jump, standing long jump or jumping down from a height. While the hip, knee and ankle joints are modeled as enforced directly by the muscle forces applied to the foot, shank, thigh and pelvis at the muscle attachment points, the actuation of the other joints is simplified to the torques representing the respective muscle action. The developed formulation is applicable to both the flying and support phases, enhanced by an effective scheme for the determination of reaction forces exclusively in the lower extremity joints. The determination of reactions from the ground is also provided. The problem of muscle force redundancy in the lower extremities is solved by applying the pseudoinverse method, with post-processing procedures used to assure the muscle being tensile. Results of the inverse dynamics analysis of vertical jump are reported.     

Low-speed vehicle dynamics and ride quality using controlled D.C. electromagnets

The aim of this paper is to establish that attraction type systems, i.e. with controlled d.c. electromagnets, can be successfully employed for the suspension of urban transit vehicles, having speeds around 70 km/hr, without the aid of secondary suspension. The feasibility of the d.c. suspension systems is illustrated through the ride and track-clearance characteristics for a single-degree of freedom suspension system travelling along a ferromagnetic guideway with random roughness. Performance of the suspension system with active feedback of track-clearance, vertical velocity and vertical acceleration are discussed, and the analytical results are compared with experimental data obtained from a vibrating guideway test rig.     

电传动车辆用高功率锂离子电池性能分析研究

为研究功率型锂离子电池性能,对某35 Ah功率型锂离子电池单体进行了充放电特性试验和分析,由此获得功率型电池在不同温度和不同倍率下的充放电特性、内阻特性和温升特性。研究结果表明,低温下电池的充放电内阻较大,充放电性能衰减显著;常温下电池的内阻较小,充放电温升较小,大电流充放电的容量稳定性好,质量比能量高,作为电传动车辆主要或辅助动力源具有良好的应用前景。     

Integrated modeling for ion cyclotron resonant heating in toroidal systems

An integrated model capable of self-consistent Ion Cyclotron Resonant Heating (ICRH) simulations has been developed. This model includes both full shaping and pressure effects, warm contributions to the dielectric tensor, pressure anisotropy and finite orbit width. It evolves the equilibrium, wave field and full hot particle distribution function until a self-consistent solution is found. This article describes the workings of the three codes VMEC, LEMan and VENUS and how they are linked for iterated computations in a code package we have named SCENIC. The package is thoroughly tested and it is demonstrated that a number of iterations have to be performed in order to find a consistent solution. Since the formulation of the problem can treat general 3D systems, we show a quasi-axisymmetric stellarator low power test case, and then concentrate on experimentally relevant Joint European Torus (JET) 2D configurations.     

Specification,analysis and simulation of the dynamics within an organisation

In this paper a modelling approach to the dynamics within a multi-agent organisation is presented. A declarative, executable specification language for dynamics within an organisation is proposed as a basis for simulation. Moreover, to be able to specify and analyse dynamic properties within an organisation, another declarative specification language is put forward, which is much more expressive than the executable language for simulations. Supporting tools have been implemented that consist of a software environment for simulation of organisation models and a software environment for analysis of dynamic properties against traces of dynamics within an organisation.     

基于空间问题建模概念过程的空间分析建模与实现

提出一种基于空间问题建模概念过程的空间分析建模方法,结合城镇土地定级模型和流程,构建基于空间问题建模概念过程的空间分析模型.运用该模型,采用ArcGIS Engine技术,开发独立于GIS平台的城镇土地定级信息系统.实践表明,将空间问题建模概念过程和城镇土地定级模型相结合进行空间分析建模的方法,可优化空间分析流程,有效保证空间分析模型的合理性和分析结果的准确性.     

Low rate error modeling of articulated heavy vehicle dynamics and experimental validation

International Journal of Control, Automation and Systems - In the automotive domain, adequate control and diagnosis rely on the use of state observers and parametric identification systems to...     

Parametric ego-motion estimation for vehicle surround analysis using an omnidirectional camera

Omnidirectional cameras that give a 360° panoramic view of the surroundings have recently been used in many applications such as robotics, navigation, and surveillance. This paper describes the application of parametric ego-motion estimation for vehicle detection to perform surround analysis using an automobile-mounted camera. For this purpose, the parametric planar motion model is integrated with the transformations to compensate distortion in omnidirectional images. The framework is used to detect objects with independent motion or height above the road. Camera calibration as well as the approximate vehicle speed obtained from a CAN bus are integrated with the motion information from spatial and temporal gradients using a Bayesian approach. The approach is tested for various configurations of an automobile-mounted omni camera as well as a rectilinear camera. Successful detection and tracking of moving vehicles and generation of a surround map are demonstrated for application to intelligent driver support.Received: 1 August 2003, Accepted: 8 July 2004, Published online: 3 February 2005     

Three-dimensional stochastic modeling using sonar sensing for undersea robotics

This paper describes an approach to the construction of three-dimensional stochastic models for intelligent systems exploring an underwater environment. Important characteristics shared by such applications are: (1) real-time constraints; (2) unstructured, three-dimensional terrain; (3) high-bandwidth sensors providing redundant, overlapping coverage; (4) lack of prior knowledge about the environment; and (5) inherent inaccuracy or ambiguity in sensing and interpretation. The paper develops an underlying theory of stochastic backprojection and demonstrates how such an approach satisfies these five needs for undersea robotics.Models are cast as three-dimensional spatial decompositions of stochastic feature vectors. A numerical approach to incorporating new sensor information is derived from an incremental adaptation of the summation method for image reconstruction. Error and ambiguity are accounted for by blurring a spatial projection of remote-sensor data before combining them stochastically with the model. By exploiting the redundancy in high-bandwidth sensing, model certainty and resolution are enhanced as more data accumulate. In the case of a three-dimensional profiling sonar, the model converges to a fuzzy surface distribution from which a deterministic surface map is extracted.To verify the fundamental properties of stochastic backprojection and the resulting models, computer simulations are used to demonstrate: impulse and ramp responses; mitigation of artifacts caused by deterministic processing; incremental increase in accuracy and reduction of uncertainty; and convergence. Two examples illustrate how this approach has been successfully applied in the field for three-dimensional modeling of a sunken shipwreck by a remote undersea vehicle and for backscatter modeling of undersea terrain.     

Neural network sliding mode control based on on-line identification for electric vehicle with ultracapacitor-battery hybrid power

In order to deal with three major problems of electric vehicle (EV): the short driving range, the short life of batteries, and the poor ability of start-up, a hybrid power system was designed and applied to the EV. It was composed of an ultracapacitor with high-specific power and long life, four lead-acid batteries, and a bi-directional DC/DC converter. To improve the stability and reliability of the hybrid-power EV, based on establishing the mathematical models of driving and regenerative-braking processes, a novel neural network sliding mode controller (NNSMC) was researched and designed for the EV. The controller comprises a back propagation neural network (BPNN), a radial basis function neural network (RBFNN), and a sliding mode controller (SMC). The BPNN is used to adaptively adjust the switching gain of the SMC on-line so as to avoid the whippings. The RBFNN is used to perform system identification and parameter prediction. The experimental results show that the NNSMC is superior to PID controller at response speed, steady-state tracking error and resisting perturbation whenever driving or braking. Additionally, the hybrid-power EV with NNSMC can improve the ability of start-up, recover more energy, lengthen the life of batteries, and increase the driving range than the EV using batteries as its single power source by about 40%, and than the hybrid-power EV with PID controller by about 4%. Recommended by Editorial Board member Naira Hovakimyan under the direction of Editor Hyun Seok Yang. This work was supported by the National Innovation Funding of China (06C26216100555). Jian-Bo Cao received the B.S. degree in Mechanical Engineering from Dalian Jiaotong University in 2003 and the Ph.D. degree in Mechanical Engineering from Xi’an Jiaotong University in 2008. He is currently working at Transportation College, Zhejiang Normal University. His research interests include electric vehicle, hybrid power, and intelligent control. Bing-Gang Cao received the B.S., M.S., and Ph.D. degrees in Mechanical Engineering from Xi’an Jiaotong University in 1976, 1982, and 1992 respectively. He is currently a Professor at School of Mechanical Engineering, Xi’an Jiaotong University, where he is also the Director of Research & Development Center of Electric Vehicle. His research interests include robust control, intelligent control of electric vehicle, noise and vibration control of liquid system, control technology of renewable energy.     

Integrated modeling methodology for microtubule dynamics and Taxol kinetics with experimentally identifiable parameters

Microtubule dynamics play a critical role in cell function and stress response, modulating mitosis, morphology, signaling, and transport. Drugs such as paclitaxel (Taxol) can impact tubulin polymerization and affect microtubule dynamics. While theoretical methods have been previously proposed to simulate microtubule dynamics, we develop a methodology here that can be used to compare model predictions with experimental data. Our model is a hybrid of (1) a simple two-state stochastic formulation of tubulin polymerization kinetics and (2) an equilibrium approximation for the chemical kinetics of Taxol drug binding to microtubule ends. Model parameters are biologically realistic, with values taken directly from experimental measurements. Model validation is conducted against published experimental data comparing optical measurements of microtubule dynamics in cultured cells under normal and Taxol-treated conditions. To compare model predictions with experimental data requires applying a "windowing" strategy on the spatiotemporal resolution of the simulation. From a biological perspective, this is consistent with interpreting the microtubule "pause" phenomenon as at least partially an artifact of spatiotemporal resolution limits on experimental measurement.     

电动执行机构常见故障及快速排除方法

简要介绍了电动执行机构的定义、分类及其工作原理,着重分析了执行机构的常见故障及其排除方法。