几何参数对转动轴临界转速的影响

应用材料力学的方法,研究转动轴在圆盘为质点和阻尼不计时的临界转速,圆盘为质点和阻尼不能忽略时的临界转速以及圆盘不能视为质点时圆盘几何尺寸对临界转速的影响。得出临界转速随轴的直径、相对阻尼系数的增加而增大,随轴的长度（圆盘在轴上的位置）的增大而减小的结论;作出了临界转速随几何参数变化的曲线,对工程设计、实时控制具有一定的实用价值。     

基于VB的港口内燃机械临界转速的研究

为让内燃机工作转速远离临界转速,合理使用机械设备,实现避振减振,介绍了一个实用的VB计算软件,通过该软件的分析计算,为港口内燃机械曲轴扭振自振频率的计算和临界转速的确定提供了一条途径。     

基于SIMPACK仿真分析的高速列车蛇行失稳识别方法

高速列车的横向运动稳定性不仅会影响列车的运行品质,还影响车辆的运行安全。现有的高速列车失稳在线监测方法大多是对高速列车大幅蛇行失稳状态进行识别,然而高速列车的小幅蛇行失稳状态很难被准确有效地识别出来。为此,提出了一种基于信号分析的蛇行失稳识别方法,不但可以识别出大幅蛇行失稳,而且可以识别出小幅蛇行失稳。首先通过SIMPACK软件建立高速列车动力学仿真模型,再现高速列车运行过程中出现的稳定、小幅蛇行失稳和大幅蛇行失稳状态;再对仿真结果的构架横向加速度进行分析,利用信号的周期性差异,计算其自相关系数并设定阈值,以此来识别小幅蛇行失稳状态和大幅蛇行失稳状态;最后通过实验数据验证了所提出的监测方法的有效性。     

控制参数对刚性磁悬浮转子模态的影响

对刚性磁悬浮转子进行了动力学建模,并在此基础上推导了动力学方程,利用实际转子结构参数在PD和PID控制方式下对转子进行了仿真分析,说明了控制参数对刚性磁悬浮转子模态的影响.     

基于ADAMS模型的履带车辆半主动悬挂自适应控制

建立了某履带车辆ADAMS整车模型。搭建了控制算法MATLAB与实体模型ADAMS之间的联合仿真接口。提出了采用模糊控制器调整PID调节器参数实现基于ADAMS建模的整车半主动悬挂控制策略。用动行程及其变化率作为模糊控制器的输入,通过模糊控制器的输出动态调整PID调节器的参数,形成了车辆半主动悬挂自适应控制系统。仿真研究表明,该自适应控制系统能够有效协调加速度和动行程在不同频段的矛盾,明显改善履带车辆行驶的平顺性。     

空气弹簧支撑控制模式对车辆曲线通过性能的影响

目前,我国的动车组CRH1、CRH2、CRH3和CRH5都采用了空气弹簧,其不仅起到支撑车体并隔振的作用,且可以维持车体在不同静载荷下都与轨面保持一定的高度,但它们采用的空簧存在较大的差别,比如CRH3采用的是2点支撑控制,而其他动车采用的是4点支撑控制,且国内铁路提速车辆一般都采用四点支撑控制,与之相关的汽车较多采用...     

Fuzzy chaos control for vehicle lateral dynamics based on active suspension system

The existing research of the active suspension system（ASS） mainly focuses on the different evaluation indexes and control strategies. Among the different components, the nonlinear characteristics of practical systems and control are usually not considered for vehicle lateral dynamics. But the vehicle model has some shortages on tyre model with side-slip angle, road adhesion coefficient, vertical load and velocity. In this paper, the nonlinear dynamic model of lateral system is considered and also the adaptive neural network of tire is introduced. By nonlinear analysis methods, such as the bifurcation diagram and Lyapunov exponent, it has shown that the lateral dynamics exhibits complicated motions with the forward speed. Then, a fuzzy control method is applied to the lateral system aiming to convert chaos into periodic motion using the linear-state feedback of an available lateral force with changing tire load. Finally, the rapid control prototyping is built to conduct the real vehicle test. By comparison of time response diagram, phase portraits and Lyapunov exponents at different work conditions, the results on step input and S-shaped road indicate that the slip angle and yaw velocity of lateral dynamics enter into stable domain and the results of test are consistent to the simulation and verified the correctness of simulation. And the Lyapunov exponents of the closed-loop system are becoming from positive to negative. This research proposes a fuzzy control method which has sufficient suppress chaotic motions as an effective active suspension system.     

基于并联机构的车辆多维减振座椅的设计

车辆系统的振动是典型的多自由度振动,多自由度减振座椅的减振性能是乘员的乘座舒适性的关键。基于并联机构的多维运动原理,构造出一种新型的具有3自由度的汽车并联减振座椅。对该3自由度的汽车并联减振座椅的主体并联机构建立运动学模型,进行了位置理论分析,最后通过ADAMS软件建立减振座椅振动模型并进行减振性能仿真,验证了该减振座椅系统具有良好的减振效果。     

A novel pre-control method of vehicle dynamics stability based on critical stable velocity during transient steering maneuvering

The current research of direct yaw moment control(DYC) system focus on the design of target yaw moment and the distribution of wheel brake force. The differential braking intervention can effectively improve the lateral stability of the vehicle, however, the effect of DYC can be improved a step further by applying the control of vehicle longitudinal velocity. In this paper, the relationship between the vehicle longitudinal velocity and lateral stability is studied, and the simulation results show that a decrease of 5 km/h of longitudinal velocity at a particular situation can bring 100° increasing of stable steering upper limit. A critical stable velocity considering the effect of steering and yaw rate measurement is defined to evaluate the risk of losing steer-ability or stability. A novel velocity pre-control method is proposed by using a hierarchical pre-control logic and is integrated with the traditional DYC system. The control algorithm is verified through a hardware in-the-loop simulation system. Double lane change(DLC) test results on both high friction coefficient(μ) and low μ roads show that by using the pre-control method, the steering effort in DLC test can be reduced by 38% and 51% and the peak value of brake pressure control can be reduced by 20% and 12% respectively on high μ and low μ roads, the lateral stability is also improved. This research proposes a novel DYC system with lighter control effort and better control effect.     

基于ADAMS和ANSYS的电动汽车悬架仿真研究

针对在电动汽车悬架的动力学特性分析中提高分析的准确性问题,对电动汽车悬架仿真研究中的刚性建模、刚柔耦合建模、柔性替换等进行了研究。对电动汽车悬架仿真研究在模型建立过程中出现的刚性假设与实际工作中刚柔混合情况的不合理性进行了归纳,提出了一种采用虚拟软件ADAMS和ANSYS对电动汽车悬架进行虚拟分析的仿真方法。利用ADAMS软件适合于机械系统的动力学和力学分析,不适合于线性和非线性的应力应变分析,而ANSYS软件的适用范围与之刚好相反的特点,建立了电动汽车的悬架模型,并进行了仿真研究。研究结果表明,优化后的电动汽车悬架模型特性更贴近于实际工作状况下的悬架,提高了悬架模型的准确度,能够较好地解决悬架系统ADAMS建模中的不合理性,为电动汽车实际前悬架的优化设计提供了依据。     

环境参数变化对风速值检定的影响

文章主要研究环境参数温度和湿度在风速值检定中的影响,通过实验给出各湿度点及温度段在实验开始和结束时的环境参数差值对风速值检定结果的影响程度,并提出了减少差值的方法。     

利用ANSYS和坎贝尔图对燃气轮机压气机转子模态及临界转速的分析计算

建立了某型燃气轮机低压压气机转子的几何模型,使用可计算陀螺效应的体单元建立了转子的有限元模型.利用数值仿真软件求解转子的前8阶模态,并基于其高速旋转结构模态分析功能画出了特征频率随转速的变化曲线即坎贝尔图.计算得到了一阶临界转速,并就支承刚度对其影响进行了研究.计算结果表明:转子的设计具有良好的结构刚度;设计中需要对压气机转子第4级轮盘附近转鼓的强度给予一定的重视;转子系统临界转速安全系数合理;支承刚度的改变对临界转速的影响处于非敏感区,有利于转子的稳定运行.     

Integrated control of lateral and vertical vehicle dynamics based on multi-agent system

The existing research of the integrated chassis control mainly focuses on the different evaluation indexes and control strategy. Among the different evaluation indexes, the comprehensive properties are usually not considered based on the non-linear superposition principle. But, the control strategy has some shortages on tyre model with side-slip angle, road adhesion coefficient, vertical load and velocity. In this paper, based on belief, desire and intention（BDI）-agent model framework, the TYRE agent, electric power steering（EPS） agent and active suspension system（ASS） agent are proposed. In the system（SYS） agent, the coordination mechanism is employed to manage interdependences and conflicts among other agents, so as to improve the flexibility, adaptability, and robustness of the global control system. Due to the existence of the simulation demand of dynamic performance, the vehicle multi-body dynamics model is established by SIMPACK. And then the co-simulation analysis is conducted to evaluate the proposed multi-agent system（MAS） controller. The simulation results demonstrate that the MAS has good effect on the performance of EPS and ASS. Meantime, the better road feeling for the driver is provided considering the multiple and complex driving traffic. Finally, the MAS rapid control prototyping is built to conduct the real vehicle test. The test results are consistent to the simulation results, which verifies the correctness of simulation. The proposed research ensures the driving safety, enhances the handling stability, and improves the ride comfort.     

基于VB的阶梯搅拌轴临界转速算法实现

针对阶梯搅拌轴的临界转速计算问题,提出了一种计算方法。该算法先将带叶轮的阶梯搅拌轴去除其叶轮及阶梯部分,运用传统算法计算出了简化后的临界转速;再计算所去除的叶轮及阶梯部分临界转速,该部分通过综合运用经典算法及积分法进行计算并得出了其临界转速;最后,利用邓柯莱累加法得出了原搅拌轴的临界转速。利用VB编程软件对算法进行了编程,以几种常用搅拌轴为例,对其一阶临界转速进行了计算。利用ANSYS软件对算例结果进行了计算对比。研究结果表明,该算法准确可靠,简单方便。     

ADAMS/Matlab环境下车辆悬架联合仿真分析

针对ADAMS/View环境下某车辆1/4整车动力学模型,通过ADAMS/Control模块建立了ADAMS与Matlab软件之间的通信连接,在Matlab/Simulink环境下建立最优联合控制系统,运用ADAMS和Matlab/Simulink软件(即ADAMS/Matlab)进行联合仿真,并与在Matlab单一环境下运行的仿真模型进行对比分析。结果发现:两种分析方法都能使车辆悬架簧上总质量质心加速度均方根值和控制能量降低,而ADAMS/Matlab软件联合仿真控制下的悬架簧上总质量质心加速度和控制能量下降幅度更大。     

数控系统速度曲线研究

加减速控制方法是现代高精度、高性能数控系统中的重要环节,现代加减速控制方法主要分为梯形速度曲线与S形速度曲线。通过对梯形速度曲线与S形速度曲线的比较,可知S形速度曲线在减小冲击和振动方面更具有优势。接着对S形速度曲线进行了深入研究,给出了加速度、速度和位移各个时间段的计算公式。由于在实际插补计算时,会有各种特殊情况出现,所以又对各个特殊情况进行了讨论,得出各个特殊情况的计算公式。最后给出了程序段预处理过程流程图和程序段插补过程流程图。     

轮式行星探测车移动系统研究状况综述及发展态势

行星探测车移动系统是研究行星探测车的关键技术之一,其性能的好坏直接影响行星探测计划能否顺利进行,轮式行星探测车作为行星探测车的主流,其移动系统成为行星探测车研究的热点之一.该文对国内外轮式行星探测车移动系统进行了概括和分类,分析了各移动系统性能的优缺点,最后指出了轮式行星探测车移动系统的特点及其发展态势.     

基于BP神经网络的蓄电池车辆调速控制系统故障诊断研究

以蓄电池车辆调速控制系统为研究对象,提出一种基于故障表征的诊断模型,建立了BP神经网络模型,运用Matlab给出该网络的训练过程及结果,并提供基于所述方法的蓄电池车辆调速控制系统的故障诊断实例。     

基于路面随机激励的8自由度整车动力学仿真

建立包括6个垂直跳动和2个转动的整车8自由度动力学模型,应用拉格朗日原理建立各自由度动力学方程,采用振型叠加法进行求解.针对一整车模型实例,以随机输入模拟路面激励,应用Fortran语言编制程序进行动力学仿真,计算分析了整车的8阶自振特性以及各个自由度的动力特性,通过位移响应曲线评价了汽车运动时的平顺性.     

Design and optimization for the occupant restraint system of vehicle based on a single freedom model

Throughout the vehicle crash event, the interactions between vehicle, occupant, restraint system (VOR) are complicated and highly non-linear. CAE and physical tests are the most widely used in vehicle passive safety development, but they can only be done with the detailed 3D model or physical samples. Often some design errors and imperfections are difficult to correct at that time, and a large amount of time will be needed. A restraint system concept design approach which based on single-degree-of-freedom occupant-vehicle model (SDOF) is proposed in this paper. The interactions between the restraint system parameters and the occupant responses in a crash are studied from the view of mechanics and energy. The discrete input and the iterative algorithm method are applied to the SDOF model to get the occupant responses quickly for arbitrary excitations (impact pulse) by MATLAB. By studying the relationships between the ridedown efficiency, the restraint stiffness, and the occupant response, the design principle of the restraint stiffness aiming to reduce occupant injury level during conceptual design is represented. Higher ridedown efficiency means more occupant energy absorbed by the vehicle, but the research result shows that higher ridedown efficiency does not mean lower occupant injury level. A proper restraint system design principle depends on two aspects. On one hand,the restraint system should lead to as high ridedown efficiency as possible, and at the same time, the restraint system should maximize use of the survival space to reduce the occupant deceleration level. As an example, an optimization of a passenger vehicle restraint system is designed by the concept design method above, and the final results are validated by MADYMO, which is the most widely used software in restraint system design, and the sled test. Consequently, a guideline and method for the occupant restraint system concept design is established in this paper.