Integration optimization of novel electric power steering system based on quality engineering theory

The dynamic model of a novel electric power steering (EPS) system integrated with active front steering function (the novel EPS system) is built.The concepts and quantitative expressions of the steering road feel,steering sensibility,and steering operation stability are introduced.Based on quality engineering theory,the optimization algorithm is proposed by integrating the Monte Carlo descriptive sampling,elitist non-dominated sorting genetic algorithm (NSGA-Ⅱ) and 6-sigma design method.With the steering road feel and the steering portability as optimization targets,the system parameters are optimized by the proposed optimization algorithm.The simulation results show that the system optimized based on quality engineering theory can improve the steering road feel,guarantee steering stability and steering portability and thus provide a theoretical basis for the design and optimization of the novel electric power steering system.

H∞ control of novel active steering integrated with electric power steering function

Based on the traditional active steering system, a novel active steering system integrated with electric power steering function was introduced, which can achieve the functions of both active steering and electric power steering. In view of the interference from road random signal and sensor noise in the novel active steering system, the H∞ control model of the novel active steering system was built. With satisfying steering feel, good robust performance and steering stability being the control objectives, the H∞ controller for the novel active front steering (AFS) system was designed. The simulation results show that the novel AFS system with H∞ control strategy can attenuate the road interference quickly, and there is no resonance peak in the bode diagram. It can make the driver obtain more useful information in the low frequency range, and attenuate the road interference better in the high frequency range, thus the driver can get more satisfying road feeling. Therefore, the designed H∞ controller can synthesize the advantages of both robust performance and robust stability, and has certain contribution to the design of novel AFS system.

Multi-objective optimization of active steering system with force and displacement coupled control

A novel active steering system with force and displacement coupled control(the novel AFS system) was introduced,which has functions of both the active steering and electric power steering.Based on the model of the novel AFS system and the vehicle three-degree of freedom system,the concept and quantitative formulas of the novel AFS system steering performance were proposed.The steering road feel and steering portability were set as the optimizing targets with the steering stability and steering portability as the constraint conditions.According to the features of constrained optimization of multi-variable function,a multi-variable genetic algorithm for the system parameter optimization was designed.The simulation results show that based on parametric optimization of the multi-objective genetic algorithm,the novel AFS system can improve the steering road feel,steering portability and steering stability,thus the optimization method can provide a theoretical basis for the design and optimization of the novel AFS system.

Performance optimization of electric power steering based on multi-objective genetic algorithm

The vehicle model of the recirculating ball-type electric power steering (EPS) system for the pure electric bus was built. According to the features of constrained optimization for multi-variable function, a multi-objective genetic algorithm (GA) was designed. Based on the model of system, the quantitative formula of the road feel, sensitivity, and operation stability of the steering were induced. Considering the road feel and sensitivity of steering as optimization objectives, and the operation stability of steering as constraint, the multi-objective GA was proposed and the system parameters were optimized. The simulation results show that the system optimized by multi-objective genetic algorithm has better road feel, steering sensibility and steering stability. The energy of steering road feel after optimization is 1.44 times larger than the one before optimization, and the energy of portability after optimization is 0.4 times larger than the one before optimization. The ground test was conducted in order to verify the feasibility of simulation results, and it is shown that the pure electric bus equipped with the recirculating ball-type EPS system can provide better road feel and better steering portability for the drivers, thus the optimization methods can provide a theoretical basis for the design and optimization of the recirculating ball-type EPS system.

四川盆地深层页岩气钻井关键技术新进展及发展展望

四川盆地页岩气资源丰富,目前深层页岩气已成为该盆地天然气增储上产的重点领域,但随着埋深增加和构造背景变化,地质工程条件将更加复杂,钻井过程中将面临井漏风险高、井下工具高温易失效、水平井轨迹控制难度大等技术难题。为此,在系统分析已完钻井实钻数据的基础上,依据深层页岩气区块地质工程特征,系统梳理了影响安全优快钻井的关键技术难点,形成了以地质工程一体化导向技术、钻井提速技术、防漏治漏与复杂防治技术为主体的深层页岩气安全优快钻井关键技术系列。研究结果表明:(1)以精细地质建模优选地质工程“双甜点”、实时靶体追踪为主的地质工程一体化导向技术,实现了地质目标的精准优选和精确追踪;(2)以“高效PDC钻头选型+个性化优化+大扭矩螺杆”高效破岩技术、“MSE+CCS”参数实时优化技术、油基钻井液地面降温+高温旋转导向技术为主的钻井提速技术,实现了页岩气钻井提速提效;(3)以井壁稳定性评价、裂缝性漏层识别、井漏与复杂防治为主的复杂防治技术,从源头降低了井下漏失和卡钻风险。结论认为:(1)形成的深层页岩气安全优快钻井技术,显著提高了机械钻速和铂金靶体钻遇率,在现场规模化推广应用200余口井,单井平均钻井周期降低42.7%,钻井提速效果显著,有力支撑了深层页岩气效益规模开发;(2)深层页岩气钻井将聚焦“地质工程一体化、水平段一趟钻、防漏治漏及智能钻井决策”等方面的技术攻关。

四轮转向干预下电动助力转向控制策略研究

四轮转向(4WS)车辆相较于前轮转向(FWS)车辆具有更高的灵活性,其后轮转向在提高车辆操稳性的同时转向阻力矩也发生变化,使得原电动助力转向系统助力策略与四轮转向车辆不匹配,对行车安全产生影响.本文以线性二自由度车辆模型为基础,对比分析了前轮转向车辆与四轮转向车辆的转向特性,提出电动助力转向修正控制策略.仿真结果表明,角阶跃工况下,有助力修正的四轮转向车辆,驾驶员操纵方向盘力矩与驾驶前轮转向车辆基本一致,既保证了四轮转向车辆低速时的操纵轻便性,也兼顾了高速时的操纵稳定性.

夏子街油田X50区块随钻地层边界探测工具应用

夏子街油田X50井区受构造复杂影响,水平井钻井过程中出现钻入储层上部或者下部低钻速泥岩中造成井壁不稳定、卡钻、水平段井斜调整困难、追不到目的层而导致侧钻等问题。针对存在问题,斯伦贝谢公司结合本区块地质及储层的电阻率特征,进行旋转导向配合边界探测工具的可行性研究。边界探测工具探测深度较深,是具有方向性测量的随钻电磁感应测井工具,应用实时导向软件对测量参数进行反演,估算出工具到地层边界的距离以及地层边界的延伸方向。现场实践表明,在第一口水平井SP-2井侧钻过程中,使用边界探测工具能够提前预判储层顶和底部泥岩的位置,并根据轨迹与边界的距离进行实时调整,避免钻遇泥岩,机械钻速提升近两倍,储层钻遇率达100%,减少了循环和决策时间,提高了钻井效率。SP-2井侧钻成功为后期新区开发提供了技术保障,也为实现工程地质一体化奠定了基础。

基于磁弹效应的电动舵机压力传感器设计

为了实现对电动舵机的电动缸输出轴压力的动态测量,该文设计并实现了一种基于磁弹效应的非接触式压力传感器,它包括传感器探头和信号处理电路两部分。该文首先从磁致伸缩的理论模型中分析并建立了传感器的测量原理,设计了传感器探头的结构。为优化激励源,通过实验研究分析了不同的激励源对传感器信号的影响,结果表明采用105 kHz、幅值为5 V的方波作为激励源时传感器输出信号最优,并以此设计了传感器信号电路。通过对传感器整体的压力标定实验得到传感器灵敏度为0.294 mV/N,重复性误差为3.53%,在运用三阶多项式拟合对传感器输入输出曲线进行校正后得到传感器的非线性误差为1.76%,适用于承压较大的电动缸输出轴及其他大重量设备的动态压力测量。

差动转向无人车轨迹跟踪和车身姿态控制研究

针对分布式驱动无人车转向时车身在离心力作用下外倾,引起内侧车轮载荷减小,严重时会导致差动转向失效乃至车辆侧翻等问题,提出了一种差动转向无人车的轨迹跟踪和车身姿态控制方法;该控制方法可通过差动转向实现无人车轨迹跟踪,同时通过主动悬架实现转向时车身主动内倾来保证差动转向有效性,提高了无人车的操纵稳定性。建立考虑侧倾因素的车辆模型及参考模型,通过分数阶单点预瞄驾驶员模型得到了参考模型跟踪期望路径所需的参考前轮转角;基于此,设计了H_(∞)鲁棒控制器,通过控制差动转向无人车的横摆角速度和车身内倾角,分别跟踪参考模型提供的参考值,得到了所需的差动力矩及左右侧主动悬架控制力。研究结果表明:所设计的分数阶单点预瞄驾驶员模型和H_(∞)鲁棒控制器能有效保证差动转向无人车实现轨迹跟踪,同时实现了车身姿态控制。

泊车过程中车辆转向状态的分段位姿估计方法

针对泊车过程中转向系统非线性因素影响车辆位姿估计准确度的问题,提出了一种基于车辆转向状态的分段位姿估计方法,提高自动泊车过程中的车辆位姿估计精度。首先,通过试验对车辆运动学航迹推算法定位的误差来源进行分析,确定了转向过程的非线性因素对泊车过程中车辆位姿计算准确度的影响;其次,设计了基于车辆转向状态的分段位姿估计模型,使用LSTM对转向状态进行实时分类,分别训练混合模型进行位姿估计,并对分类结果与位姿估计结果进行后验修正;再次,构建泊车工况车辆横纵向位移数据集,基于数据集对所建模型进行训练和离线测试;最后,利用Python搭建在线测试平台,对模型进行位姿估计测试,并开展对比试验。试验结果表明:该方法能够将泊车过程中的车辆欧式距离误差控制在10 cm以内,航向角误差控制在1°以内。基于车辆转向状态的分段位姿估计方法研究,可以有效提高泊车过程中的车辆位姿估计精度,并具有较高的实时性和较好的鲁棒性。

融合模式决策的4WIS车辆路径规划方法

针对四轮独立转向(four-wheel independent steering,4WIS)车辆的路径规划问题,提出了一种融合模式决策的图搜索算法.首先,对4WIS车辆三种运动模式进行建模,并分析其运动模式的运动特性,据此设计多模式节点拓展策略,实现了4WIS车辆多运动模式与路径规划的融合.然后,针对最优节点选取和运动模式决策问题,设计了多目标代价函数,引导4WIS车辆合理切换运动模式,并生成平滑路径.最后,在MATLAB软件上进行仿真实验,在多种场景中测试所提出算法,验证其可行性与有效性.结果表明:提出的算法在路径规划中考虑了三种运动模式的优化组合与模式切换问题,能实现最优运动模式序列和最短路径规划.且该算法求解效率高,所规划路径优异,能充分发挥4WIS车辆的高灵活性与高通过性,有效解决其路径规划问题.

线控转向系统理想传动比控制策略及优化研究

为设计满足操纵稳定性需求的线控转向系统,提出了可适应不同车速工况的理想传动比控制策略。以稳态横摆角速度增益不变下的传动比为基础,设置低速段、中速段、高速段等3个车速区间;基于参数拟合和定转向增益不变控制法中的稳态横摆角速度增益不变,设计了低速段和中速段的理想传动比,高速段考虑到摩擦特性等非线性因素影响,使用模糊控制设计线控转向系统理想传动比;通过Carsim和Simulink仿真分析了在不同车速下设计理想传动比控制策略的有效性。研究结果表明:在低速段时,车辆转向运动特性明显提高,增强了车辆的转向灵敏性;在中速段时,车辆转向响应跟随性好,且响应速度更快;在高速段时,车辆行驶时的转向稳定性明显提高。

基于ARM的婴幼儿催眠成长智能机器人设计

装置介绍了一种基于ARM的多种智能控制机械臂达到促进婴幼儿睡眠、心理健康成长和缓解母亲压力的效果,其结构由报警单元、烘干装置、机械臂仿真装置、摄像单元、温湿度及压力采集单元、光电传感器、婴儿床等组成。该装置由手机APP手动或自动的对六个舵机全方位的精准控制,使机械臂可以多姿态的运转并呈现仿真人手臂摇摆姿势的循环,机械臂外壳采用热感的慢回弹材料,高度仿真人手臂,为婴儿提供柔和真实的支撑。设计新颖、安全且性能强。

一种多用途仿生六足机器人的设计与实现

由于技术难度大、硬件成本高以及控制算法复杂等因素,六足机器人在小型服务机器人领域的应用受到限制。针对这一问题,采用平行多层结构设计、高扭矩舵机驱动和模块化硬件设计等方法,给出一种紧凑、易扩展和低成本的仿生六足机器人实例,满足巡检、公众服务和实验教具等多用途需求。机械系统采用单足串联3自由度结构,椭圆布置的机体结构以及稳定的三角步态。通过单足简化模型,进行足端点受力分析,计算出需要的关节驱动扭矩,确定舵机选型。利用D-H参数法建立单足的运动学方程,计算出足端点坐标变换与关节转角的对应式。控制系统硬件单元采用7大模块,给出硬件的选型和电路设计。控制系统软件单元包括上位机和下位机程序,通过微控制器程序流程图详细阐述了六足机器人运动解算过程的实现。最后,根据软、硬件调试完成舵机补偿与功能测试,完成多用途仿生六足机器人的运动优化与开发。

轮式工程车辆线控转向系统设计浅析

轮式工程车辆在工程机械领域具有广泛的应用,文章以轮式工程车辆转向系统为研究对象,论述了传统轮式工程车辆机械液压助力转向和全液压转向两种主要形式转向系统的组成及适用工程作业场景。结合当前轮式工程车辆线控转向系统的技术规划和愿景,论述了线控铰接复合转向技术、多轮独立线控转向技术两种典型技术应用方向,并基于技术背景下的发展难点,聚焦论述实现具有良好性能的转向系统所需攻关的路感模拟技术、故障诊断及容错控制技术、变传动比控制技术三大关键技术。

某型舵机异响故障分析与预防

某型号舵机在进行修理调试过程中,发出尖锐异响。通过对舵机的构造及工作原理的分析,建立故障树模型,对信号输入、信号转换、信号输出3个模块进行分析检查。最终确定故障部位,确定故障产生原因为胶液凝固尖角划伤活塞杆。为某型号舵机的修理制定了相应措施,避免故障再次发生。

转向器部件预留间隙问题研究

为解决某乘用车转向器各运动部件的装配预留间隙问题,分析转向器的结构和工作原理,对其关键部件建立计算机辅助工程(Computer Aided Engineering,CAE)模型进行受力模拟,研究传动机构游隙、配合件径向偏差、浮动功能及浮动量需求,进一步建立公差尺寸链,计算并分析封闭环目标极值公差。此外,提出一种产线上100%在线检测方法,以保证在产品实际生产装配过程中,将封闭环目标极值公差控制在0.1mm。

Primary studies on integration optimization of differential steering of electric vehicle with motorized wheels based on quality engineering

The model of the differential steering system(DSS) of electric vehicle with motorized wheels and the three-degree-of-freedom dynamic model of vehicle are built.Based on these models,the concepts and quantitative expressions of steering road feel,steering portability and steering stability are proposed.Through integrating the Monte Carlo descriptive sampling,elitist non-dominated sorting genetic algorithm(NSGA-II) and Taguchi robust design method,the system parameters are optimized with steering road feel and steering portability as optimization targets,and steering stability and steering portability as constraints.The simulation results show that the system optimized based on quality engineering can improve the steering road feel,guarantee steering stability and steering portability and thus provide a theoretical basis for the design and optimization of the electric vehicle with motorized wheels system.

无人驾驶新能源汽车转向制动避障控制策略设计及试验

针对无人驾驶新能源汽车(UNEV)在超车过程中存在转向系统与制动系统配合容易出现干涉及控制策略与控制系统硬件不易匹配等问题,从系统工程学角度给出了UNEV整车结构以及全车传感器安装方法,设计了UNEV机械本体及由控制器模块、信号模块及执行器等组成的控制系统,提出了单一制动避撞、单一转向避撞以及基于PID调节的转向及制动同时避撞等三种方式的控制策略。结合《智能网联汽车道路测试管理规范》,进行了道路试验。试验结果表明,与前车距离超过安全距离时,UNEV匀速行驶,当距离小于安全距离时,UNEV将逐步通过加大制动幅度,进而采用转向避撞等方式绕开前车,所设计的UNEV具有较高的稳定性和可靠性,且降低了因复杂程序导致的车体控制过程出现抖动及转向卡死等现象。

基于模拟退火算法优化增益的车辆传动比算法设计

针对线控转向(SBW)系统车辆进行研究,基于定横摆角速度增益法设计变传动比算法,并依照系统结构与设计目的对算法改进修正。采用模拟退火算法,以郭孔辉院士提出的操纵稳定性综合评价指标函数作为优化算法目标函数,对经验选取的定增益值进行优化,得到全局最优定增益值。以全局最优增益值作为最终传动比算法设计依据。对所设计传动比算法进行仿真分析,结果表明,采用优化后增益值传动比算法的SBW车辆具有更好的转向性能,并有效减轻驾驶员的操作负担。