Four Wheel Independent Drive Electric Vehicle Lateral Stability Control Strategy

In this paper,a kind of lateral stability control strategy is put forward about the four wheel independent drive electric vehicle.The design of control system adopts hierarchical structure.Unlike the previous control strategy,this paper introduces a method which is the combination of sliding mode control and optimal allocation algorithm.According to the driver’s operation commands(steering angle and speed),the steady state responses of the sideslip angle and yaw rate are obtained.Based on this,the reference model is built.Upper controller adopts the sliding mode control principle to obtain the desired yawing moment demand.Lower controller is designed to satisfy the desired yawing moment demand by optimal allocation of the tire longitudinal forces.Firstly,the optimization goal is built to minimize the actuator cost.Secondly,the weighted least-square method is used to design the tire longitudinal forces optimization distribution strategy under the constraint conditions of actuator and the friction oval.Beyond that,when the optimal allocation algorithm is not applied,a method of axial load ratio distribution is adopted.Finally,Car Sim associated with Simulink simulation experiments are designed under the conditions of different velocities and different pavements.The simulation results show that the control strategy designed in this paper has a good following effect comparing with the reference model and the sideslip angle is controlled within a small rang at the same time.Beyond that,based on the optimal distribution mode,the electromagnetic torque phase of each wheel can follow the trend of the vertical force of the tire,which shows the effectiveness of the optimal distribution algorithm.

Influence of Tire Dynamics on Slip Ratio Estimation of Independent Driving Wheel System

The independent driving wheel system, which is composed of in-wheel permanent magnet synchronous motor（I-PMSM） and tire, is more convenient to estimate the slip ratio because the rotary speed of the rotor can be accurately measured. However, the ring speed of the tire ring doesn’t equal to the rotor speed considering the tire deformation. For this reason, a deformable tire and a detailed I-PMSM are modeled by using Matlab/Simulink. Moreover, the tire/road contact interface（a slippery road） is accurately described by the non-linear relaxation length-based model and the Magic Formula pragmatic model. Based on the relatively accurate model, the error of slip ratio estimated by the rotor rotary speed is analyzed in both time and frequency domains when a quarter car is started by the I-PMSM with a definite target torque input curve. In addition, the natural frequencies（NFs） of the driving wheel system with variable parameters are illustrated to present the relationship between the slip ratio estimation error and the NF. According to this relationship, a low-pass filter, whose cut-off frequency corresponds to the NF, is proposed to eliminate the error in the estimated slip ratio. The analysis, concerning the effect of the driving wheel parameters and road conditions on slip ratio estimation, shows that the peak estimation error can be reduced up to 75% when the LPF is adopted. The robustness and effectiveness of the LPF are therefore validated. This paper builds up the deformable tire model and the detailed I-PMSM models, and analyzes the effect of the driving wheel parameters and road conditions on slip ratio estimation.

“主动面向、科教融合、双轮驱动”——工程管理专业新工科改革与引领的探索实践

面对国家战略需求以及新一轮科技革命和产业变革所带来的严峻挑战,工程管理专业建设正面临转型升级的迫切需要。西安建筑科技大学工程管理专业始终坚持改革探索与自我革新,在新工科背景下,努力探索工程管理专业改造升级路径、人才培养模式、课程体系建设、创新体系建设、平台建设和机制体制设计;坚持“主动面向”,以国家重大战略需求和科技创新的双轮驱动为导向,拓展专业内涵,加速科教融合,积极探索和重构专业课程体系;创新“精课程、微课堂”的课程建设和教学模式;开发“工程管理云专业”平台,大力推动“2+X”创新体系建设,构建“师生成长共同体”。为探索和形成工程管理专业发展的新模式、新路径、新体系提供重要支撑和经验借鉴。

Monitoring Longitudinal Vehicular Velocity by Using Driving Wheels Information

In order to enhance the accuracy and overcome the limitation of representing the vehicular velocity with non driving wheel speed signals, which is commonly used in researching on automotive dynamic control systems at present, the dynamic and kinematics models of running vehicles and wheels are established. The concept that expresses vehicle velocity using only the driving wheel speed information with adjustable weight factors is described and an algorithm is proposed. A Matlab program with the algorithm embedded is made to simulate the vehicle’s accelerating under different road conditions, and it’s simulation results coincide well with the experimental results, which demonstrates the validity of the algorithm.

双马达混合驱动及汇流结构研究

针对应急抢险、军事后勤等用途对轮式工程机械高速机动性能的特殊需求,结合其结构特点,提出一种双马达混合驱动系统方案,并分析其传动原理。以某轮式工程机械底盘为对象,以实现机动性能和动力性能为目标,对传动参数设计、液压泵、马达选型计算等进行系统分析。根据设计计算结果,完成了汇流齿轮箱的结构设计,展示了系统总体结构,并对关键承载件进行了结构和模态分析。结果显示:整机最高车速可达70 km/h,最大爬坡度31°,具备Ⅳ级以上路面高速越野机动能力。

果树剪枝机器人四驱式底盘控制系统设计与实现

能够自主完成果树修剪任务的机器人是目前林果业智能装备的一个主要研究方向。四驱底盘是机器人的基础,其控制系统设计对机器人的性能和稳定性有至关重要的作用。对果树剪枝机器人四驱式底盘控制系统进行设计,包括控制系统硬件选型和搭建、运动路径设计、避障算法、程序设计,并进行了验证。实验结果表明,剪枝机器人底盘控制系统的半自动控制可以实现模糊避障功能,为后续果树剪枝机器人的研究提供参考。

基于轮轨驱动的新型桥梁转体装置力学性能研究

转体施工在跨越既有线路的桥梁建设中得到广泛应用,针对传统桥梁转体装置存在的控制性不强、转速不均、转角超限等工程难题,以合肥市文忠路上跨合肥东站立交桥为载体,从转体施工的转动设备与转动能力入手,提出了基于轮轨系统驱动的新型桥梁转体施工装置,增强了桥梁转体施工的精确性和可操作性;为验证装置的可行性和可靠性,通过精细化有限元模拟,探究装置在不同齿轮摩擦因数、球铰静摩擦系数以及齿轮宽度下的受力性能。通过对上述影响因素的分析结果表明,球铰静摩擦系数对齿轮及球铰受力性能的影响最显著;齿轮宽度对小齿轮系统峰值应力降低的贡献率,随着宽度的增长而逐渐降低;齿轮摩擦因数对轮轨系统的受力影响较小。所提出的新型转体装置能够安全、可靠地用于桥梁转体施工,为实现桥梁结构的精确化转体施工提供了重要的技术支撑。

四驱电动赛车TCS滑模预测控制系统设计与实现

针对四驱电动方程式赛车在不同路面工况下过度打滑的问题,设计了一种结合卡尔曼滤波车速估计和滑模控制的牵引力控制系统,以提高整车直线加速性能、减小车轮打滑以保证稳定性和快速加速中的安全性;控制器以车轮滑转率为控制变量,通过调整各驱动轮输出扭矩,以保证滑转率控制在最优范围内;考虑获取准确车速是得到最优滑转率的前提,设计卡尔曼滤波器,实现车速估计;针对滑模控制自身存在的抖振问题,采用改进的指数趋近律,提高稳定性;利用Matlab/Simulink和CARSIM联合仿真,验证了该控制系统的有效性;最终完成实车测试与应用,在实际应用中实现控制系统满足四驱电动方程式赛车的快速平稳加速的工程要求。

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。

Design of driving wheel speed test device based on magnetoelectric sensor

In order to study the transmission efficiency of engine and optimize the structure of driving wheel,the rotational speed storage test device of driving wheel in tracked vehicle based on magnetoelectric sensor was designed.The device consisted of a mounting bracket,a sensor and a tester.The mounting bracket was installed in vehicle body after fixing the tester and sensor to mounting bracket beside the driving wheel.Using the storage test instrument,the wireless trigger technology was applied to synchronously record and stored the rotational speed data of the driving wheel in tracked vehicle.After the experiment was finished,the data was read out through the upper computer.Both valid data and satisfactory results were obtained through both simulated and actual vehicle tests.

PHENOMENON OF CARVED DRIVING WHEELS

A newly found phenomenon of carved driving wheels of a rear-wheel-drive tractor used in an airport is discussed. The circum of every driving wheel is damaged at three regions, which distribute regularly and uniformly. Everyday, the tractor tows a trailer which are times heavier than the tractor, and moves on the same road in the airport. The phenomenon is explained by the torsional self-excited vibration system of the powertrain. The simplified torsional vibration system is discribed by a 2-order ordinary differential equation, which has a limit circle. Experiments and numerical simulations show the followings： Because of the heavy trailer, the slip ratio of the tractor＇s driving wheels is very large. Therefore, there is severe torsional self-excited vibration in the tractor＇s drivetrain, and the self-excited vibration results in severe and regular fluctuations of the rear wheel＇s velocity. The severe fluctuations in velocity fastens the damage of the driving wheels. At the same time, the time interval in which an arbitrary point in the circum of the driving wheel contacts with the road twice is two times more than the period of the torsional self-excited vibration, and this times explained the existence of three damaged regions. At last, it points out that the phenomenon can be avoided when the torsional damping is large enough.

基于DSP的电动拖拉机开关磁阻电机双轮驱动系统

以TMS320LF2407 DSP控制器为核心,采用三相不对称半桥功率转换模块,以mos管为主开关器件,利用光电传感器检测电机位置和电机相电流,设计了一套电动农用拖拉机开关磁阻电机双轮驱动系统。实验结果表明:所设计的开关磁阻电机双轮驱动系统可以实现电动农用拖拉机运行过程中的差速控制,且系统运行比较稳定,提高了电动农用拖拉机的行驶性能。

提质培优背景下“TWD”内部质量保证体系建设探索与实践——以山西水利职业技术学院为例

提质培优背景下,内部质量保证体系是全面提高和保证人才培养质量的工作体系和运行机制。目前高职院校普遍存在内部质量保证体系不够完善、信息化程度不够高、运行机制不能形成闭环等问题。山西水利职业技术学院以职业教育提质培优行动计划为引领,以培养适应区域经济发展需要的高素质技术技能人才为根本目标,基于PDCA质量管理理论,借鉴“五纵五横”内部质量保证体系的建设理念,贯彻“三全”育人的教育理念,探索形成以教学督导和数据监控为双轮驱动质量管理的“双轮驱动”内部质量保证体系,有效提高了职业教育人才培养质量。

采煤机机电短程截割传动系统设计及整体联合仿真分析

对截割电机、啮合齿轮及行星轮系进行选型,完成机电短程截割传动系统设计,并进行联合仿真分析,对比不同牵引速度、截割速度下的截割能力,结果表明,截割-牵引联合调速控制方式,传动齿轮啮合受力平稳,调节效果更好,截割效率也更高。

基于专创融合的摩擦轮传动教学体系的构建

文章基于专创融合的理念,在总结摩擦轮传动,特别是在交错轴摩擦轮传动100多年发展的基础上,完善了摩擦轮传动的分类体系,结合创新思维方法系统地梳理了交错轴摩擦轮传动在工程上的应用及特点,并提出了可破除领域知识壁垒的交错轴摩擦轮传动规范命名,突破了传统的摩擦轮传动教学体系,为机械设计中摩擦轮传动知识体系系统传播和教学体系的完整设计提供了参考,也为交错轴摩擦轮传动知识的普及传播奠定了基础。

“双元四驱”框架下江苏职业教育与现代学徒制产教融合机制及优化路径

现代学徒制是职业教育中的一种新方式,对提升职业教育人才培养质量具有重要作用。现代学徒制在西方国家职业教育中取得了较大成功,但当前我国江苏现代学徒制职业教育中还存在保障制度不完备、联合培养驱动力不强、未能体现现代学徒特征和优秀师资不足等问题。构建“双元四驱”框架下职业教育现代学徒制产教融合人才培养体系,需要从推动招生制度改革、学徒合法身份确认、建立学历教育与资格教育融通制度、完善四驱导师选拔机制和共建共享教学资源等方面入手,强化现代学徒制在江苏职业教育体系中的育人实效。

圆截面管道轮式机器人驱动系统设计

根据在金属及非金属圆截面管道条件下自动化作业的需求,确定了机器人驱动系统采用双侧6组驱动装置同步运行的设计方案。通过对驱动系统机构设计、驱动装置结构设计、力学分析以及驱动力的计算,设计了一种沿管道横截面120°布置的轮式驱动系统,以满足机器人在内径为108~133 mm圆截面管道中行走的要求,并制作了试验样机。经过行走、爬坡等多项性能试验表明,机器人运行稳定、性能可靠,为轮式管道机器人驱动系统设计提供了一种新方案。

液电混合驱动轮式挖掘机行走系统特性分析

轮式挖掘机行走时,行驶速度变化频繁,负载的剧烈变化导致发动机效率低下;制动时动能由机械制动器消耗,大量机械能转化为热能,能量损失严重。为此,提出液电混合驱动轮式挖掘机行走系统,采用高能效的伺服电机控制行走速度,液压泵/马达与蓄能器组合,回收制动动能,并在加速等大功率工况辅助电机驱动行走系统。对系统的工作原理进行参数设计,制定驱动与制动控制策略,建立原机行走系统与所提系统的多学科联合仿真模型,进行仿真分析。结果表明:相同工况下,与原机行走系统相比,液电混合驱动行走系统能耗降低了56.5%,高效回收了制动动能。

基于电机直驱的玉米勺轮排种器排种质量监测系统

针对非直驱式玉米勺轮排种器存在排种量、播种粒距监测精度低等问题,设计一种基于步进电机直驱的玉米勺轮排种器排种质量监测系统。该系统以STM32为核心,采用光电传感器对排种量进行检测,基于光电脉冲信号的相邻落种时间间隔实现对播种粒距的监测。台架试验结果表明:在3~8 km/h设定车速下,排种量监测准确率平均值为98.55%,标准差为1.4%;与分析相邻落种运动过程得到的播种粒距理论值相比,播种粒距监测误差绝对值的平均值为2.84 cm,标准差为3.66 cm,播种粒距监测合格指数大于97.1%,满足实际排种质量监测需求,可为玉米排种质量监测技术提供参考。

轮式变径管道机器人结构分析及控制系统设计

针对现有导弹发射试验筒管道机器人机械结构受限,不能很好适应狭小管道的问题,对适用于狭小管道的管道机器人结构及其控制系统展开研究。首先,建立管道机器人模型,分析其实现行走和变径的工作原理、主要结构和动力机构的力学特性;其次,分析管道机器人的行走性能,对管道机器人的牵引能力和过弯能力进行了计算,确定了机器人的可应用场景。最后,开发了行走装置控制器,在设计管道机器人控制系统的前提下,详细阐述了管道机器人系统的控制原理,对上位机界面做了简要的功能介绍,并通过实验对机器人结构和控制系统的合理性做了验证。研究结果表明,管道机器人能与狭小管道保持良好接触状态,独立完成行走动作,实验验证了管道机器人在垂直管道内的行走能力与基于视觉的管道内壁损伤情况识别能力。