Handling stability improvement through robust active front steering and active differential control

The design of the integrated active front steering and active differential control for handling improvement of road vehicles is undertaken. The controller design algorithm is based on the solution of a set of linear matrix inequalities that guarantee robustness against a number of vehicle parameters such as speed, cornering and braking stiffnesses. Vehicle plane dynamics are first expressed in the generic linear parameter-varying form, where the above-stated parameters are treated as interval uncertainties. Then, static-state feedback controllers ensuring robust performance against changing road conditions are designed. In a first series of simulations, the performance of the integrated controller is evaluated for a fishhook manoeuvre for different values of road adhesion coefficient. Then, the controller is tested for an emergency braking manoeuvre executed on a split-μ road. In all cases, it is shown that static-state feedback controllers designed by the proposed method can achieve remarkable road handling performance compared with uncontrolled vehicles.     

Rear-heavy car control by adaptive linear optimal preview

Adaptive linear optimal preview control theory is applied to a simple but non-linear car model, with parameters chosen to make the rear axle saturate first in any quasi-steady manoeuvre. The tendency of such a car to spin above a critical speed, which is a function of its running state, causes control to be especially difficult when operating near to the limit of the rear-axle force system. As in previous work, trim states and optimal gains are computed off-line for a given speed and a full range of lateral accelerations. Gain-scheduling with interpolation over trims and gain sets is used to keep the control appropriate to the running conditions, as they change. Simulations of manoeuvres are used to test and demonstrate the system capability. It is shown that utilising the rear-axle lateral-slip ratio as the scheduling variable, in the case of this rear-heavy car, gives excellent tracking, even when the tyres are run close to full saturation. It is implied by this and previous work that the general case can be treated effectively by monitoring both front- and rear-axle slips and scheduling on a worst-case basis.     

工程机械过盈圆锥配合体快速测定与加工

针对在工程机械维修中圆锥配合体零件重新配制设计方法繁琐、维修困难及维修方法难以掌握等问题，本文通过理论和实践，提出一种快速测定过盈圆锥配合体方法和快速调整车床的工艺。通过对误差理论分析及长期应用证明，该测定方法和加工工艺具有精度高、快捷、易掌握等显著特点。     

空间环境因素对VLF通信系统性能的影响

VLF通信是远距离、稳定的对潜通信方式。找出了两种影响通信质量的空间因素——大气波导和大气噪声，分析了大气波导对信号场强的影响，以及大气噪声对接收机误码性能的影响，指出了提高VLF通信质量的方法。     

铁路车轮外形曲线数字测量仪的研究

通过对采用二连杆串联机构的便携式车轮外形数字测量仪的研究,发现该测量仪的2个零位角度安装误差将分别导致测量结果的方位和形状误差。为此,笔者提出了一种借助2种姿态测量同一段曲线,使2个结果重合,以辨识2个活动杆夹角零位误差的标定方法,试验结果证明了其有效性。以二连杆机构外形测量仪研究为基础,笔者进一步提出了基于平面五连杆并联机构的测量仪新方案,并建立了测量模型;对角度分辨率导致的测量误差的对比仿真表明,新方案有较高的精度,同时讨论了用偏置角度和增加采样率提高测量准确度的方法。     

摆式列车过曲线时的圆锥运动效应及其补偿算法研究

分析了摆式列车过曲线时的圆锥运动效应及其对角速率陀螺仪测量结果的影响,提出了圆锥误差补偿的"多子样"算法。仿真计算表明,采用该补偿算法能有效地提高摆式列车姿态解算精度,对于保证摆式列车正确倾摆具有重要意义。     

基于误比特率计算的Ad Hoc传感器网络连接性分析

目前对于AdHoc网的研究主要集中在仿真与分析上,而缺乏理论上的计算与分析。本文在基于网络节点均匀分布的情况下,对AdHoc传感器网络的连接性进行了理论计算,在无干扰和有干扰环境下分别得出了通信路由中端到端平均误比特率(BER)和平均连接跳数(Hop)的精确表达式。结果表明:网络中节点分布密度存在门限值;如果低于此门限值,则网络中节点之间不能进行通信。     

陀螺壳体旋转监控技术

陀螺壳体旋转法监控技术有助于提高平台罗经系统精度、减少陀螺漂移与加速度计误差。本文首先介绍了该项技术的应用背景；详细阐述了系统结构特性、基本工作原理、机械编排与稳定回路，以及实现方法；本文深入研究了旋转平台转速的选取方法并分析了系统误差；最后计算了典型情况下旋转壳体的转速。结果表明：采用陀螺壳体旋转法监控技术可以有效地调制陀螺漂移、从理论上可提高陀螺仪精度二至三个数量级，从而使平台罗经系统精度得到很大的提高。     

基于源代码插桩的C程序内存使用错误动态检测

针对C程序内存使用错误的预防和处理方法分基于静态分析和动态分析两类。静态分析工具研制复杂，目前还没有得到广泛使用的高效工具。动态分析又分为基于目标代码和源代码插桩分析两类。由于缺少完整的语法、语义信息，基于目标代码的分析有时对错误的捕捉、定性不够精确。基于源代码的分析由于其信息的完整可以达到对错误的最精确报告。本文对C程序中的内存使用错误进行了分析，并讨论了一个C程序内存错误动态检测工具的设计思想，给出了系统流程、关键数据结构、错误捕捉方法的设计。     

曲面的保凸插值细分算法Ⅱ

给出了曲面的保凸插值细分算法和分析。此算法是对以前提出的曲面保凸插值细分算法的改进。对于给定的凸多面体，算法构造一个凸的插值多面体顶点的曲面，其极限曲面是C^1的。此算法对控制点是非线性的。该算法不仅适用于封闭曲面，也适用于开曲面。