Research on the Stability Control Strategy of Four-Wheel Independent Driving Electric Vehicle

In order to research stability of four-wheel independent driving (4WID) electric vehicle, a torque allocation method based on the tire longitudinal forces optimization distribution is adopted. There are two layers in the controller, which includes the upper layer and the lower layer. In the upper layer, according to the demand of the longitudinal force, PID controller is set up to calculate the additional yaw moment created by yaw rate and side-slip angle. In the lower layer, the additional yaw moment is distributed properly to each wheel limited by several constraints. Carsim is used to build up the vehicle model and MATLAB/Simulink is used to build up the control model and both of them are used to simulate jointly. The result of simulation shows that a torque allocation method based on the tire longitudinal forces optimization distribution can ensure the stability of the vehicle.

MPC-based Torque Distribution for Planar Motion of Four-wheel Independently Driven Electric Vehicles:Considering Motor Models and Iron Losses

The most critical obstacle for four-wheel independently driven electric vehicles(4WID-EVs)is the driving range.Being the actuators of 4WID-EVs,motors account for its major power consumption.In this sense,by properly distributing torques to minimize the power consumption,the driving range of 4WID-EV can be effectively improved.This paper proposes a model predictive control(MPC)-based torque distribution scheme,which minimizes the power consumption of 4WID-EVs while guaranteeing its tracking performance of planar motions.By incorporating the motor model considering iron losses,the optimal torque distribution can be achieved without an additional torque controller.Also,for this reason,the proposed control scheme is computationally efficient,since the power consumption term to be optimized,which is expressed as the product of the motor voltages and currents,is much simpler than that derived from the efficiency map.With reasonable simplification and linearization,the MPC problem is converted to a quadratic programming problem,which can be solved efficiently.The simulation results in MATLAB and CarSim co-simulation environments demonstrate that the proposed scheme effectively reduces power consumption with guaranteed tracking performance.

Research on Vehicle Control Technology Using Four-Wheel Independent Steering System

The enhancement of vehicle handling stability and maneuverability through active and independent rear wheels control is presented. Firstly, the configuration of four-wheel independent steering prototype vehide is introduced briefly. Then the concrete overall design of the electronic controllers of four wheel independent steering system （4WIS） is formulated in details. Under the control strategy of zero sideslip angle at mass center, the mathematical model of 4WIS is established to deduce the equations of separated rear wheel steering angles. According to these equations, simulation analysis for 4WIS vehicle performances is finished to show that 4WIS vehicle can improve the maneuverability greatly at low speed and increase the handling stability at high speed. Finally, the road test of 4WIS vehide has performed to verify the correctness of simulation and show that compared with the conventional four wheel steering （4WS） vehicle, the 4WIS vehicle not only improves the kinematical harmony but also decreases steering resistance and lighten abrasion of tires.

Autonomous Tracking Control for Four-Wheel Independent Steering Robot Based on Improved Pure Pursuit

Autonomous tracking control is one of the fundamental challenges in the field of robotic autonomous navigation,especially for future intelligent robots.In this paper,an improved pure pursuit control method is proposed for the path tracking control problem of a four-wheel independent steering robot.Based on the analysis of the four-wheel independent steering model,the kinematic model and the steering geometry model of the robot are established.Then the path tracking control is realized by considering the correlation between the look-ahead distance and the velocity,as well as the lateral error between the robot and the reference path.The experimental results demonstrate that the improved pure pursuit control method has the advantages of small steady-state error,fast response and strong robustness,which can effectively improve the accuracy of path tracking.

Study on simulation and scheduling algorithm of CAN control for independently driving electric vehicle

Safety-critical applications such as the independently driving systems of electric vehicle （EV） require a high degree of reliability. The controller area network （CAN） is used extensively in the control sectors. A new real-time and reliable scheduling algorithm based on time-triggered scheduler with a focus on the CAN-based distributed control systems for independently driving EV is exploited. A distributed control network model for a dual-wheel independendy driving EV is established. The timing and reliabili- ty analysis in the worst case with the algorithm is used to evaluate the predictability and dependability and the simulation based on the algorithm with CANoe software is designed. The results indicate the algorithm is more predicable and dependable.

Estimation of Vehicle Speed Based on Wheel Speeds from ASR System in Four-Wheel Drive Vehicles

Three major methods currently in the use of determining vehicle speed based on wheel speeds, the minimum wheel speed, minimum wheel speed corrected by slope method and the Kalman filter method, are analyzed, with merits and defects of each approach stated. Through simulations, the Kalman filter method based on minimum wheel speed shows improved accuracy, in addition to better adaptivity to vehicle reference speed. It also can be used to acceleration ship regulation （ASR） in part-time four-wheel drive vehicles.

Track Tension Analysis of Four-Wheel Drive Tracked Vehicles

The distribution of track tension on track link is complex when the tracked vehicles run at a high speed.A multi-drive track link structure,which changes the traditional induction wheel into the driving wheel was proposed.The mathematical model of the system was established and the distribution of track tension was studied.The combined simulation model of RecurDyn and Simulink of the structure with multi-drive track was established.The simulation results show that our proposed structure has more uniform tension distribution than traditional structures,especially under the high speed condition.The maximum tension can be reduced by 28 kN-36 kN and the transmission efficiency can be improved by10%-16% under high speed condition with this new structure.

Lessons Learned from Practical Independent Verification and Validation Based on IEEE 1012

IEEE 1012 [1] describes the SDLC phase activities for software independent verification and validation (IV & V) for nuclear power plant in truly general and conceptual manner, which requires the upward and/or downward tailoring on its interpretation for practical IV & V. It contains crucial and encompassing check points and guidelines to analyze the design integrity, without addressing the formalized and the specific criteria for IV & V activities confirming the technical integrity. It is necessary to list up the inspection viewpoint via interpretation of the standard that is practical review points checking design consistency. For fruitful IV & V of Control Element Driving Mechanism Control System (CEDMCS) software for Yonggwang Nuclear Power Plant unit 3 & 4, the specific viewpoints and approach are necessary based on the guidelines of IEEE 1012 to enhance the system quality by considering the level of implementation of the theoretical and the practical IV & V. Additionally IV & V guideline of IEEE 1012 does not specifically provide the concrete measure considering the system characteristics of CEDMCS. This paper provides the seven (7) characteristic criteria for CEDMCS IV & V, and by applying these viewpoints, the design analysis such as function, performance, interface and exception, backward and forward requirement traceability analysis has been conducted. The requirement, design, implementation, and test phase were only considered for IV & V in this project. This article also provides the translation of code to map theoretical verification and validation into practical verification and validation. This paper emphasizes the necessity of the intensive design inspection and walkthrough for requirement phase to resolve the design faults because the IV & V of early phase of SDLC obviously contributes to find out most of critical design inconsistency. Especially for test phase IV & V, it is strongly recommended to prepare the test plan document which is going to be the basis for the test coverage selection and test strategy. This test plan document should be based on the critical characteristics of function and performance of CEDMCS. Also to guarantee the independency of V & V organization participating in this project, and to acquire the full package of design details for IV & V, the systematic approach and efforts with an aspect of management is highlighted among the participants.

分布式驱动车辆操纵稳定性控制综述

为研究分布式驱动车辆的驱动控制问题,从转向控制、独立驱动控制及2个系统联合控制等3个角度入手,分析了分布式驱动车辆操纵稳定性控制策略的研究进展。首先,基于转向控制技术对影响操纵稳定性的方面进行分类;其次,分析了分层式与集中式控制结构的特点;然后,分析了基于控制结构的操纵稳定性研究;最后,结合分布式驱动车辆操稳性改善的研究现状和技术进展,展望了未来的发展趋势。

多频率组合波形阵风场模拟与测量研究

基于数值模拟方法选取设定FL-51风洞阵风发生器的装置参数,如发生器叶片的数量、展长、弦长及间距等。发生器采用液压摆动缸独立驱动形式,可模拟正弦波、三角波及随机波等多种波形的多频率组合运动,同时能够减少安装传动件,并提升发生器性能。通过阵风场校测结果表明:叶片能够实现摆动频率为0 Hz~15 Hz,在校测范围内发生器产生的正弦流场较均匀;在来流风速40 m/s、叶片摆动频率为10 Hz、摆角为15°时,最大阵风幅值为8.5 m/s。地面测试与流场校测结果表明:该文所提出的阵风场模拟技术可以实现低速风洞多频率多波形组合运动,为风洞试验提供复杂的阵风流场。

无人船载监控系统的设计与开发

为了满足无人船实时通信和远程操控需要,综合利用计算机、传感器及无线通信等技术,设计一种无人船载监控系统,实现了对无人船的实时监测、控制与实时通信。设计一种双驱动独立控制方案,实现了无人船遥控器控制与计算机控制的相互分离,可提高无人船运行操控的安全性与可靠性。提出采用插件式软件架构,将易变动的功能模块以插件的方式动态加载至系统框架中,加快了开发速度,降低了系统的耦合程度,提高了系统的可扩展性,并利用插件动态加载与卸载方法,实现了插件功能的动态加载与在线升级,提高了系统应对任务多样化的能力。

床椅一体化机器人设计与实现

针对床椅机器人在室内狭小空间灵活行走的问题,研制一款四轮独立驱动转向的床椅一体化机器人。根据室内狭小空间的转向需求,确定了底盘总体布局方案和主要技术参数。对重要部件进行了理论计算、有限元分析,对驱动轮支架进行了应力及形变分析;在ADAMS软件中建立了床椅机器人的动力学仿真模型,进行了稳定性分析。仿真结果表明,驱动轮支架的强度和刚度均满足设计要求,床椅机器人的各项指标符合国家相关标准的规定。样机试验进一步验证了仿真分析的结果,确认了床椅一体化机器人的稳定性、越障性能和在室内狭小空间的转向性能。

CEEMD-FastICA-CWT联合瞬态响应阶次的电驱总成噪声源识别

以某增程式电驱动总成为研究对象,提出基于联合算法的噪声分离识别模型。首先,采用互补集合经验模态分解(complementary ensemble empirical mode decomposition,CEEMD)联合快速独立分量分析(fast independent component analysis,FastICA)方法提取纯电模式稳态工况下单一通道噪声信号特征,利用复Morlet小波变换及FFT对各分量信号时频特性进行识别。其次,采用阶次分析法和声能叠加法对稳态分量信号对应的各瞬态响应阶次能量进行对比分析,并结合皮尔逊积矩相关系数(Pearson product moment correlation coefficient,PPMCC)相似性识别确定不同噪声激励源贡献度。结果表明:减速齿副啮合噪声对该增程式电驱总成纯电模式运行噪声整体贡献度最大。

四轮独立电驱动越野车驱动力优化控制

为了充分利用四轮独立电驱动越野车各轮转矩独立可控的优势,提高越野车的牵引力和越野能力,提出了一种驱动转矩协调控制策略.根据越野车前后轴载荷预分配驱动电动机转矩,利用基于车轮滑转率-路面附着系数的极值寻求算法实现路面最优滑转率估计.采用比例-积分-微分(proportional-integral-differential, PID)控制-滑模控制(sliding mode control, SMC)和基于状态的驱动力再分配方法实现各轮驱动转矩的协调分配,抑制越野车在恶劣路面条件下的车轮打滑.通过CarSim/MATLAB联合仿真以及硬件在环(hardware-in-the-loop, HIL)测试,进行了爬陡坡、单一附着路面、对开路面及连续起伏路面工况的试验验证.结果表明:提出的控制策略能根据实际工况分配驱动轮的转矩,降低驱动轮滑转率,实现整车驱动力的优化.

复杂地形六轮独立驱动与转向机器人轨迹跟踪与避障控制

为研究六轮移动机器人在复杂地形的运动控制方法,针对六轮独立驱动与转向机器人复杂地形轨迹跟踪问题,提出一种预测控制和动态补偿的控制方法。基于非完整约束的线性六轮移动机器人运动学模型,以模型预测控制算法为基础,引入比例-积分-微分补偿控制器,抑制动态滞后引起的跟踪误差,设计速度与转向角动态反馈补偿,以应对地形扰动对轨迹跟踪的影响。分析机器人运动过程中障碍物的避碰问题,设计可求解避障轨迹的避障规划器,通过轨迹跟踪系统对局部避障轨迹进行跟踪控制,实现机器人的轨迹跟踪和自动避碰。对轨迹跟踪算法和避障算法进行仿真实验。实验结果表明:在典型工况下,机器人可完成凹形斜坡、凸形斜坡和凹凸地形正弦型轨迹跟踪控制和静态与动态障碍物避碰,验证了新方法的有效性。

An Integrated Control Framework for Torque Vectoring and Active Suspension System

Four-wheel independently driven electric vehicles(FWID-EV)endow a flexible and scalable control framework to improve vehicle performance.This paper integrates the torque vectoring and active suspension system(ASS)to enhance the vehicle’s longitudinal and vertical motion control performance.While the nonlinear characteristic of the tire model leads to a relatively heavier computational burden.To facilitate the controller design and ease the load,a half-vehicle dynamics system is built and simplified to the linear-time-varying(LTV)model.Then a model predictive controller is developed by formulating the objective function by comprehensively considering the safety,energy-saving and comfort requirements.The in-wheel motor efficiency and the power loss of tire slip are treated as optimization indices in this work to reduce energy consumption.Finally,the effectiveness of the proposed controller is verified through the rapid-control-prototype(RCP)test.The results demonstrate the enhancement of the energy-saving as well as comfort on the basis of vehicle stability.

基于滑模协调控制的四轮独立电驱动车辆稳定性控制研究

针对四轮独立电驱动车辆动力学特性及驱动控制策略复杂等问题,提出了基于力矩分配系数法的驱动协同控制策略,并设计了驱动力矩滑模协调控制器,配合车辆失稳判断模块计算出车辆维持稳定所需的附加横摆力矩,同时利用载荷分配方法设计了驱动力矩最优分配控制器,基于载荷分配方法将驱动力矩分配至4个车轮,以维持车辆稳定行驶。为验证驱动协同控制策略的有效性,基于CarSim软件建立四轮独立电驱动车辆模型,并将提出的驱动协同控制策略和普通滑模控制策略进行仿真对比。结果表明:驱动协同控制策略使横摆角速度偏差降低了25%,质心侧偏角偏差降低了23%,能够满足车辆稳定性控制要求,同时降低了整车驱动力矩分配控制难度。

基于多胞体系统的FWID EV鲁棒加权增益调度轨迹跟踪控制

为了提高四轮独立驱动电动汽车(FWID EV)轨迹跟踪控制性能,针对车辆横向运动系统的不确定性与非线性问题,考虑转向执行机构的动态特性,提出了基于线性变参数(LPV)的鲁棒加权增益调度轨迹跟踪控制策略。首先利用凸分解技术将LPV系统转化为有限多胞顶点凸组合的多胞体系统,然后基于离线设计的每个多胞顶点控制器和线性组合在线计算任意时变参数对应的系统控制器参数,并利用MATLAB和CarSim进行联合仿真。结果表明:在加速变道场景下,所设计的控制器可以保证横向偏移误差不超过2 cm,横向偏移平均绝对误差不超过0.9 cm的较高跟踪精度及行驶稳定性和鲁棒性。

第二课堂活动对大学生学习内驱力培养的影响研究

军校学员面临多重压力,容易形成学习倦怠。第二课堂活动通过学术讲座、学科竞赛、社团活动、志愿服务等多样化学习活动促进学生综合素质养成。第二课堂活动与学习内驱力提升有直接关系,可以培养学习兴趣,养成自主学习习惯,积累实践经验,促进社交互动,提供成长见证。

4WID高地隙自走式电动喷雾机定速巡航控制方法

针对4WID高地隙自走式电动喷雾机在复杂工况下,面对来自外部道路坡度改变及内部药液喷洒带来整备质量下降,从而导致喷雾机行驶速度稳定性差、作业质量恶化等问题,在分析4WID高地隙自走式电动喷雾机结构与纵向动力学特性基础上,设计一种定速巡航分层控制算法。控制算法模型接收用户设定的期望行驶车速,经过算法计算后对纵向动力学系统模型输入加速度控制信号,实现喷雾机对期望车速的跟踪。搭建的纵向动力学系统结构主要包括5个部分:逆纵向动力学模型、加速与制动切换模型、转矩分配模型、电机模型和纵向动力学模型。通过对斜坡行驶状态下喷雾机的车身状态进行受力分析可获得其逆纵向动力学及纵向动力学模型;同时,为建立合理的四轮转矩分配策略,在喷雾机车身同时具有俯仰及侧倾的条件下进行分析,以各驱动轮的附着率作为分配依据,满足不同工况下各车轮的最佳驱动力矩,确保喷雾机动力的均衡性。模型定速巡航控制采用分层控制方法,通过建立上层PID控制及下层的模糊PID控制实现对喷雾机车速的有效跟踪,通过制定模糊控制规则,自动对下层控制器的PID参数进行整定,保证在各种复杂工况下喷雾机定速巡航系统的良好适应性。应用Matlab/Simulink建立控制模型,对控制系统进行仿真分析。试验结果表明,在典型工况下,设计的定速巡航控制系统能够有效地对喷雾机的速度进行控制。具体而言,在系统输入外部干扰及自重变化条件下,该控制系统的表现良好,超调量在2%以内,响应时间小于0.2 s,稳态误差趋于0,验证了所采用控制算法的准确性。