基于RFID和磁导航的AGV小车S7-1200PLC控制系统设计

该项目利用S7-1200PLC作为AGV主控制器,采取驱动轮差速进行转向控制,采用磁导航传感器和RFID标签传感器实现循迹和定位功能,实现AGV小车在立体仓库、VMC850数控加工中心、CK40S数控车床、RB20工业机器人、装配单元之间产品的搬运功能。

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.

Electric Drive for an In-wheel Fractional-slot Axial Flux Machine

This paper describes the electric drive for an in-wheel fractional-slot axial flux machine,designed for achieving a wide flux-weakening operating region.By using a slotted stator with fractional-slot windings and additional cores enclosing end windings,the axial flux machine reaches a wide constant power speed range.The machine is designed for increasing flux-weakening capability while obtaining low harmonic back-electromotive force and low cogging torque.A 10 N.m axial flux machine exhibiting 3 to 1 flux-weakening speed range has been built.A flux-weakening controller,able to maximize the output torque in the flux-weakening region,is designed and implemented.The goodness of both design and control algorithm is proved by experimental tests.However,such a fractional-slot machine has not only advantages.Rotor losses are very high,and they have to be properly considered during the design process.

分类治理:中国社区双重属性及其实现机制研究--基于珠海市社区议事协商的案例分析

“强行政-弱自治”是当前社区治理研究的核心议题之一,既有研究聚焦国家-社会关系视角下的社区属性定位,试图从“去行政化”和激活社区活力两个角度入手解决社区自治不畅问题,但实践探索未达到预期效果。基于事务与运行机制相匹配的组织学理论,构建社区分类治理的分析框架,并以珠海市香洲区社区协商治理实践为例展开的个案研究发现:破解社区自治难题的关键在于区分社区双重事务,在社区建立行政与自治两种工作机制,以实现社区党委领导下双轮驱动的社区治理。其中,以规则为核心的可操作化自治机制是自治有效运转的关键。这一研究不仅对加强社区自治给出了具体路径建议,也是对中国社区双重属性及相关问题之争的某种厘清。

乡村产业发展路径及保障机制研究--以广宁县洲仔镇为例

产业振兴是乡村内生发展的重要渠道。为探索广宁县洲仔镇乡村产业发展路径,通过对本镇四类产业驱动典型案例比较分析,发现各自的优势和不足,在此基础上,提出洲仔镇应采取“外生驱动+内生驱动”双轮驱动,实施“政府+企业+合作社+基地+农民”“村集体+企业+基地+农户”“农民专业合作社+企业+基地+农户”三种形式,走通力合作、彰显特色、共享剩余、持续稳定的产业之路。同时,结合洲仔镇产业发展实际,建议保障机制层面应坚持规划先行、因地制宜,发挥村党支部战斗堡垒作用,构建激励相容的利益联结机制,促进产业融合升级,壮大新型职业农民队伍,规范农民专业组织建设。

Driving Force Model for Non-pneumatic Elastic Wheel

In order to obtain good driving performance,a driving force model is presented for non-pneumatic elastic wheel.Brush model of pneumatic tyres is introduced and the deformations of elastic supports and tread are also taken into account.The longitudinal slip rate is redefined.The grounding pressure distribution of elastic wheels is analyzed and corrected according to speed,temperature and stiffness.Then rolling resistance equation is developed.Finally,simulation is conducted by software CarSim,and the results show that the estimated values are consistent with simulation values,especially at low longitudinal slip rate.The research can help to optimize design of non-pneumatic elastic wheel.

基于磁-热双向耦合的电动拖拉机轮边电机电磁性能分析与结构优化

为预测和评估电动拖拉机轮边驱动电机的电磁性能同时优化电磁转换装置结构,该研究以一种减速式12槽7对极永磁无刷直流轮边驱动电机为对象,建立电机电磁有限元模型并通过试验验证模型的正确性,分析了空载、半载和额定负载工况下电机的动态特性。在此基础上,基于热损耗载荷构建电机的磁-热双向耦合模型,模拟分析额定负载工况下电机的温度场分布规律。结果表明,3种工况下电机最高温度均发生在永磁体部位,温升分别为54.61、77.63和87.1℃。以气隙宽度、定子槽口宽度、永磁体间距和宽度为变量,以齿槽转矩、转矩密度和永磁体损耗为优化目标,提出一种田口法-响应面法双层多目标优化方法,确定电机最佳结构参数为:永磁体间距为0.4 mm、永磁体宽度为3.5 mm、气隙宽度为1.1 mm、定子槽口宽度为4.75 mm。仿真结果表明,优化后的电机转矩密度较优化前增加了8%,永磁体损耗降低了18.6%。样机台架试验结果表明,优化后电机齿槽转矩较优化前降低了20.9%,验证了所提优化方法的有效性,对电机性能研究具有一定的参考价值。

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.

The Roll Stability Analysis of Semi-Trailer Based on the Wheel Force

It is different for the liquid tank semi-trailer to keep roll stability during turning or emergency voidance,and that may cause serious accidents.Although the scholars did lots of research about the roll stability of liquid tank semi-trailer in theory by calculating and simulation,how to make an effective early warning of rollover is still unsolved in practice.The reasons include the complex driving condition and the difficulty of the vehicle parameter obtaining.The feasible method used currently is evaluating the roll stability of a liquid tank semi-trailer by the lateral acceleration or the attitude of the vehicle.Unfortunately,the lateral acceleration is more useful for sideslip rather than rollover,and the attitude is a kind of posterior way,which means it is hard to take measures to cope with the rollover accident when the attitude exceeds the safety threshold.Considering the movement of the vehicle is totally caused by the wheel force,the rollover could also be predicted by the changing of the wheel force.Therefore,in this paper,we developed a method to analyze the roll stability by the vertical wheel force.A thorough experiment environment is established,and the effectiveness of the proposed method is verified in real driving conditions.

Microstructural Characteristics and Wear Performance of Plasma Sprayed Al_2O_3-13 wt. % TiO_2 Coating on the Surface of Extrusion Wheel

The conventional Al2O3-13 wt. % TiO2 composite ceramic coatings are fabricated by plasma spraying on the surface of extrusion wheel. The microstrueture, morphology and phase compositions of the substrate and coat- ing are investigated by using X-ray diffractometry （XRD） , scanning electron microsopy （SEM） and energy dis- persive spectroscopy （EDS）. Moreover, the microhardness of the substrate and the coating are investigated using Vickers mierohardness tester, the friction and wear behaviors of the substrate and the coating are investigated by using a block-on-ring tribometer under dry sliding conditions with the load of 245 N. The results show that both γ-Al2O3 and α-Al2O3 phases are observed in the as-sprayed coatings, the mian phase is γ-Al2O3. There are white particulates Al2O3 on its surface. The Al2O3-13 wt. % TiO2 coating possesses higher mierohardness which is about 1018HV and 1.6 times that of the substrate. The wear performance of coating is better than that of the substrate. In a practical application, the life of the extrusion wheel which is plasma sprayed Al2O3-13 wt. % TiO2 coating on the surface is 1.2 times that of the conventional extrusion wheel, and the life is about 330 h.

“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。

基于CKF的四轮驱动电动汽车质心侧偏角估计

针对传统质心侧偏角观测精度不高、实时性能差的问题,提出了一种基于CKF算法的质心侧偏角观测器。首先基于CKF算法结合Dugoff轮胎模型,实时观测路面附着系数,计算实时的轮胎力。再结合七自由度整车模型,基于CKF算法,实时、精确观测车辆的质心侧偏角。最后,利用Simulink/Carsim联合仿真验证平台和硬件在环平台进行仿真验证。试验结果表明,CKF算法相比与传统无迹卡尔曼滤波估计精度更高、实时性能更好,较好的改善了传统质心侧偏角观测器在非线性条件下的观测精度。

渗层强化的果园运输机驱动轮耐磨性能

为解决牵引式果园运输机绳-轮驱动系统驱动轮绳槽磨损严重而导致牵引滑移失效的问题,该研究对基于渗层强化的果园运输机驱动轮耐磨性能进行了分析。首先通过ANSYS软件探究了驱动轮表面应力应变随其硬度的变化规律;随后采用热扩散沉积(thermal diffusion, TD)技术对45钢驱动轮进行了渗钒与渗硼处理,并对渗层的显微结构、力学性能和摩擦磨损特性进行了对比分析,最后利用运输机模拟台架对渗层强化后驱动轮的应用性能进行了测试。结果表明:驱动轮渗钒层和渗硼层厚度分别为20.9和97.3μm,均与基材结合较好;且由于渗层中碳化钒、硼化铁等硬质相的存在,渗钒层与渗硼层硬度分别达到22.08和13.45 GPa,较未处理前提升3~4倍;往复摩擦试验下渗钒层与渗硼层表面摩擦系数分别为0.47、0.44,较45钢分别下降19%、24%。运输机模拟台架应用性能测试表明,干摩擦下渗钒与渗硼处理后驱动轮的平均磨损量较45钢分别降低了88%和81%,其中渗钒驱动轮表面磨损较小;油润滑下渗钒与渗硼处理后驱动轮的平均磨损量较45钢分别降低了92%和85%。综上,热扩散渗钒与渗硼处理均可大幅提高驱动轮抗磨性,其中渗钒层具有更高的硬度与耐磨性,但在应用时需进行实时油润滑,更适合对满足定时维护条件下的驱动轮进行强化;而渗硼层耐磨性虽有所降低,但可在干摩擦下使用,更适合对野外山地环境下无法满足润滑的驱动轮进行强化。该研究结果可为改善牵引式果园运输机驱动轮耐磨性提供可行技术方案。

产教融合背景下基于“四轮驱动”机制的高职建筑设计类课程教学创新与实践

根据高职人才的创新创业能力培养要求,结合建筑设计专业的特点,针对传统课程项目化教学模式的不足,提出构建高职院校“建筑设计”课程项目“意识引动”“平台助动”“教学推动”“研赛带动”的“四轮驱动”教学机制;深化产教融合,以培养学生创新创业能力为目标,以“双师型”建筑设计大师创新创业工作室为平台,针对学生个性化需求,进行分学期阶段、分阶段项目、分项目任务、分任务内容的分类培养,使“建筑设计”课程项目教学实现“产、教、学、研、赛、创”相互融合,为高职建筑设计类课程项目教学模式的创新与实践提供参考。

考虑道路识别的四驱电动汽车再生制动策略

为了充分利用路面附着条件分配再生制动力,提高制动能量回收率,根据双电动机四驱结构电动汽车复合制动系统的特点,对其制动能量回收控制策略进行了研究.分析了驱动轮与地面附着特性,设计了道路识别器来计算每个轮胎与当前路面之间的峰值附着系数,并使用模糊控制策略确定每个车轮与8种道路的滑移率和附着利用率的相似输入.根据双电动机外部特性的制动力分配关系,提出了使更多制动能量回馈给电池的策略.结果表明:制动强度为0.3时,能量回收率为65.55%,具有较高的回收效率.

考虑制动意图识别的四驱电动汽车制动控制策略

为进一步提高制动能量回收率,考虑不同工况下驾驶员不同制动意图所需的制动效果,提出了一种四驱电动汽车制动控制策略。首先,针对常规制动工况,基于常规制动意图识别,从制动能量回收率、稳定性和安全性角度分别设计控制策略;其次,针对滑行工况下的不同滑行制动意图,判断电机制动力是否介入及何时介入,并根据驾驶员所需的滑行距离计算电机制动力的大小;然后,由台架试验获得前后电机外特性并建立前后电机最优利用效率模型;最后,利用Carsim和Simulink进行了联合仿真分析。仿真结果表明,在新欧洲驾驶循环(New European Driving Cycle,NEDC)工况下,与并联控制策略相比,能量回收率提升了13.64百分点;在滑行工况下可有效识别驾驶员需求滑行距离,提升了整车滑行经济性。

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。

电动轮汽车驱动系统的滑模-PID控制

针对电动轮汽车驱动系统响应时间过长,响应不稳定,鲁棒性差等问题,建立简化了的电动轮汽车整车动力学模型和永磁无刷直流轮毂电动机驱动模型.以滑模变结构理论和PID控制理论为基础,根据电动轮汽车驱动系统运行的动态特性品质及滑模运行的动、静态特性要求,分别设计系统外环滑模-PID决策控制器及内环PID跟踪控制器,通过内、外环控制的有效结合,使系统具有了兼顾滑模变结构控制稳定性好、鲁棒性高和PID控制简单易行、响应迅速的特点,提高了系统的控制品质.仿真结果表明:基于滑模-PID控制的驱动系统能够迅速控制整车驱动系统和轮毂电动机的运行,明显改善了汽车动力学特性和轮毂电动机特性.