Robust MIMO disturbance observer analysis and design with application to active car steering

A multi‐input–multi‐output extension of the well‐known two control degrees‐of‐freedom disturbance observer architecture that decouples the problem into single‐input–single‐output disturbance observer loops is presented in this paper. Robust design based on mapping D‐stability and the frequency domain specifications of weighted sensitivity minimization and phase margin bound to a chosen controller parameter space is presented as a part of the proposed design approach. The effect of the choice of disturbance observer Q filter on performance is explained with a numerical example. This is followed by the use of structured singular values in the robustness analysis of disturbance observer controlled systems subject to structured, real parametric and mixed uncertainty in the plant. A design and simulation study based on a four wheel active car steering control example is used to illustrate the methods presented in the paper. Copyright © 2009 John Wiley & Sons, Ltd.     

The impact of false warnings on partial and full lane departure warnings effectiveness and acceptance in car driving

In the past, lane departure warnings (LDWs) were demonstrated to improve driving behaviours during lane departures but little is known about the effects of unreliable warnings. This experiment focused on the influence of false warnings alone or in combination with missed warnings and warning onset on assistance effectiveness and acceptance. Two assistance unreliability levels (33 and 17%) and two warning onsets (partial and full lane departure) were manipulated in order to investigate interaction. Results showed that assistance, regardless unreliability levels and warning onsets, improved driving behaviours during lane departure episodes and outside of these episodes by favouring better lane-keeping performances. Full lane departure and highly unreliable warnings, however, reduced assistance efficiency. Drivers’ assistance acceptance was better for the most reliable warnings and for the subsequent warnings. The data indicate that imperfect LDWs (false warnings or false and missed warnings) further improve driving behaviours compared to no assistance.

Practitioner Summary: This study revealed that imperfect lane departure warnings are able to significantly improve driving performances and that warning onset is a key element for assistance effectiveness and acceptance. The conclusion may be of particular interest for lane departure warning designers.     

基于综合法的火炮方向机齿轮传动误差分析

方向机对火炮射击精度影响很大,齿轮传动误差是方向机传动误差的主要来源。恰当的分析方法能提高方向机齿轮传动设计精度与效率。本文将齿轮传动误差分为静态误差与动态误差。结合理论分析,用概率分析法计算出静态误差;用有限元分析法计算出动态误差,最后得到总的传动误差。基于分析结果采样拟合出不同载荷下的误差曲线。将这种分析方法应用到火炮方向机齿轮传动误差分析中,得到了该火炮方向机齿轮传动在变载荷下的误差曲线。该分析方法为火炮方向机齿轮传动设计提供参考。为火炮其他部件的设计提供一种思路。     

某螺旋簧结构驱动桥有限元分析

用有限元法计算分析螺旋簧结构驱动桥在多工况下的结构应力,找出结构薄弱环节并加以改进.     

DYNAMIC ANALYSES AND ROBUST STEERING CONTROLLER DESIGN FOR AUTOMATED LANE GUIDANCE OF HEAVY‐DUTY VEHICLES

In this paper, we present various linear analyses of the linearized lateral dynamics of heavy‐duty vehicles (HDVs) (tractor‐semitrailer type), which include time domain, frequency domain and pole/zero analyses. These analyses are conducted to examine the vehicle response to the steering input subjected to variations of speed, road adhesion coefficient, cargo load in the trailer, and look‐ahead distance for the lateral deviation sensor. These parameters (uncertainties) have significant influence on vehicle dynamics. It has been shown that redefining the look‐ahead lateral error as the controlled output has a favorable impact on the lateral control problem. Based on these analyses, a robust steering controller using H_∞ loop‐shaping procedure is designed for a tractor semitrailer combination to follow the road center line on both curved and straight highway sections. The proposed controller ensures the robust performance under model uncertainties which include varying vehicle longitudinal speed, road adhesion coefficient, and cargo load in the trailer. The performance of the designed controller is evaluated by simulations and validated by experiments.     

整体式转向梯形的优化和运动仿真分析

通过理论分析和建模推导出转向梯形机构优化目标函数,构建了一种连续性权重函数来代替传统的阶跃型权重函数进行计算,利用MATLAB强大的计算和绘图功能直观地得到优化后的参数,并使用CATIA的数字化运动分析模块对优化后的转向梯形进行运动仿真,仿真分析显示优化结果较为理想。同时创建ActiveX对象来建立VB与MATLAB的接口,拓宽了其使用范围。     

飞机除冰车后桥壳有限元分析

针对中央液压驱动形式飞机除冰车的底盘开发,利用Solidworks和ANSYS软件,建立驱动桥壳三维模型,对驱动桥壳进行满载静力分析、模态分析和瞬态动力分析,找到驱动桥壳应力最大变形量的部位,得到其结构前10阶固有频率和相应的模态振型,发现后桥壳的振动规律,利用分析结果提出了在桥壳的一侧(前或后)或者两侧增加纵向稳定杆的改进建议。     

车辆轴载作用下半刚性基层沥青路面破坏潜力分级

针对不同轴载对半刚性基层沥青路面的潜在破坏能力问题,提出一种根据不同轴载作用下路面力学响应为标准的路面破坏分级方法。该方法应用弹性层状体系理论分析了不同轴载作用下的半刚性基层沥青路面力学特性,通过计算沥青层的抗剪强度、半刚性基层的拉应力和各结构层的压应力,并与标准轴载作用下结构层力学特性进行了比较,辅以各结构层的设计允许应力值,得到不同轴载作用下的路面破坏潜力表。通过对某公路安徽段实测数据的分析表明,该方法可以有效地实现不同轴载对半刚性基层沥青路面的潜在破坏能力分析。