用8098单片机实现电压空间矢量脉宽调制

电压空间矢量脉宽调制是一种先进的调制方法。本文介绍了其基本原理和输出电压，建立了开关模型和最佳开关顺序。分析了滞后开通时死区时间对输出电压的影响，提出了补偿方法，用８０９８单片机系统来实现电压空间矢量脉宽调制，具有简单，可靠的优点，试验结果证明，变频器运行稳定，输出波形正统性较好。     

基于支持向量机的船舶航向广义预测控制

船舶的动态性能具有大惯性、大时滞、非线性等特点,经采用基于结构风险最小化原则的神经网络--支持向量机,能充分发挥其可以任意逼近非线性模型的良好特性来对船舶进行辨识,并以此作为广义预测控制算法中的预测模型,加以相应的预测控制算法达到航向保持的目的.仿真结果表明:支持向量机学习速度快,在小样本情况下具有良好的非线性建模和泛化能力;基于支持向量机的广义预测控制算法具有很好的控制性能.     

磁阻式传感器在EPS中的应用

为解决接触式转角和扭矩传感器在使用寿命及测量精度方面的问题,研制出一种非接触式的传感器,在测量角度的同时,还能测出系统被施加的扭矩。本文介绍了一种基于磁阻式的,集成了转角和方向以及扭矩测量的传感器系统,并对该系统的结构进行相关设计,以实现同时测量转角和扭矩的功能。     

Common underlying steering curves for motorcycles in steady turns

We study the steady turn behaviours of some light motorcycle models on circular paths, using the commercial software package ADAMS-Motorcycle. Steering torque and steering angle are obtained for several path radii and a range of steady forward speeds. For path radii much greater than motorcycle wheelbase, and for all motorcycle parameters including tyre parameters held fixed, dimensional analysis can predict the asymptotic behaviour of steering torque and angle. In particular, steering torque is a function purely of lateral acceleration plus another such function divided by path radius. Of these, the first function is numerically determined, while the second is approximated by an analytically determined constant. Similarly, the steering angle is a function purely of lateral acceleration, plus another such function divided by path radius. Of these, the first is determined numerically while the second is determined analytically. Both predictions are verified through ADAMS simulations for various tyre and geometric parameters. In summary, steady circular motions of a given motorcycle with given tyre parameters can be approximately characterised by just one curve for steering torque and one for steering angle.     

Sideslip angle estimation based on input–output linearisation with tire–road friction adaptation

An adaptive sideslip angle observer considering tire–road friction adaptation is proposed in this paper. The single-track vehicle model with nonlinear tire characteristics is adopted. The tire parameters can be easily obtained through road test data without using special test rigs. Afterwards, this model is reconstructed and a high-gain observer (HGO) based on input–output linearisation is derived. The observer stability is analysed. Experimental results have confirmed that the HGO has a better computational efficiency with the same accuracy when compared with the extended Kalman filter and the Luenberger observer. Finally, a road friction adaptive algorithm based on vehicle lateral dynamics is proposed and validated through driving simulator data. As long as the tires work in the nonlinear region, the maximal friction coefficient could be estimated. This algorithm has excellent portability and is also suitable for other observers.     

基于粒子群算法的粘性土主动土压力计算方法

假定挡土墙后滑动面为库伦平面滑裂面,基于能量法,推导出了适合与砂性土与粘性土的主动土压力计算公式,然后引入粒子群智能优化算法,对最危险滑动面所对应的破裂角在变量范围内进行全局搜索。运用本文方法分别对墙后填土为为砂性土和粘性土的挡土墙土压力进行计算,发现对于砂性土,优化方法得到的破裂角与理论精确解完全一致;对于粘性土,方法计算结果与实测结果相对误差为5.5%。     

应用弦长与弦方位角、切线方位角推算公路曲线坐标

该文阐述了利用公路曲线上某已知点、弦长及其方位角推算公路曲线未知点的基本思路、计算公式;并结合集丰高速公路某处曲线的坐标计算作了说明。     

LX1300型铣刨机最小转弯半径的分析

根据汽车的转向梯形原理,分析后得出LX 1300型铣刨机工作时前轮的最大转向角.为建立铣刨机在工作状态时的数学模型,对其进行几何分析,通过改变模型中的参数,对比确定铣刨机的最小转弯半径,从而有效减小轮胎侧滑,延长轮胎的使用寿命.     

基于视频检测的交通冲突判别方法和模型

为了克服交通冲突传统人工判别方法的缺陷,提出了基于视频检测的交通冲突发生判别的基本流程,将交通冲突发生的判别划分为交通参数的视频检测、坐标变换和交通冲突判别3个阶段。在借助OpenCV和Matlab标定工具箱进行交通实体检测和坐标变换的基础上,建立了以冲突角度、速度和距离等指标为核心的交通冲突综合判别模型,并通过现实场景验证该模型的有效性。     

DVVT对缸内直喷增压发动机性能影响的试验研究

通过对GDI增压发动机进行DVVT扫点试验,研究了DVVT对GDI增压发动机外特性性能、部分负荷燃油经济性和怠速稳定性的影响。试验结果表明:对于试验发动机的凸轮轴型线而言,排气VVT的开启对发动机性能起到负面影响;外特性方面,中等转速工况采用较大的气门重叠角可提高体积效率;高转速采用较小的气门重叠角可提高充量系数;怠速和部分负荷工况下,较小的气门重叠角对改善发动机稳定性有一定帮助。