Influence of load and speed on wear characteristics of grey cast iron in dry sliding — selection for minimum wear

The wear of grey cast iron in dry sliding conditions has been studied with the aims of (1) finding the influence of working conditions on the wear rate, and (2) determining the region of speed and load where low wear is accomplished. Grey cast iron with flake and nodular graphite was submitted to investigation using a pin-on-disc machine. The results indicate that the flake graphite cast iron is more suitable for applications at speeds greater than 4 m s⁻¹ and lower loads, while nodular cast iron has greater wear resistance at lower speeds in the range of loads investigated - from 50 N cm⁻² to 200 N cm⁻²     

攀钢“501”滑动水口液压驱动系统的研制

介绍了为攀钢“５０１”滑动水口研制的专用液压驱动系统，对该系统的工作原理，性能特点，主要元件（设备）的选择原则等作了较为详细的说明介绍。     

典型哈夫滑块的加工工艺

通过实例详细介绍了一种典型哈夫滑块的加工工艺，可为编制同类模具滑块的加工工艺提供参考。     

High accuracy path tracking for vehicles in presence of sliding: Application to farm vehicle automatic guidance for agricultural tasks

When designing an accurate automated guidance system for vehicles, a major problem is sliding and pseudo-sliding effects. This is especially the case in agricultural applications, where five-centimetre accuracy with respect to the desired trajectory is required, although the vehicles are moving on slippery ground. It has been established that RTK GPS was a very suitable sensor to achieve automated guidance with such high precision: several control laws have been designed for vehicles equipped with this sensor, and provide the expected guidance accuracy as long as the vehicles do not slide. In previous work, further control developments have been proposed to take sliding into account: guidance accuracy in slippery environments has been shown to be preserved, except transiently at the beginning/end of curves. In this paper, the design of this control law is first recalled and discussed. A Model Predictive Control method is then applied in order to preserve accuracy of guidance even during these curvature transitions. Finally, the overall control scheme is implemented, and improvements with respect to previous guidance laws are demonstrated through full-scale experiments.     

一类分布参数系统的有限维变结构控制

本文研究了一类非线性分布参数系统的有限维变结构控制问题，首先采用Ｇａｌｅｒｋｉｎ近拟法给出了系统的有限维近似模型；进而给出了使近似系统具有良好动态品质的有限维变结构控制器的设计方法；最后分析了闭环系统的渐近性态，给出了近似阶次一定的情况下，原系统具有良好渐近性态的充分条件。     

时滞系统变结构控制设计的新方法

本文研究了两类时滞控制系统，用不同方法分别对它们进行了变结构控制设计。所设计的控制器简单，易于实现且精确度高。     

非线性不确定大系统的分散滑动模控制

本文研究一类非线性不确定大系统的分散滑动模控制问题．首先给出了使滑动模具有良好动态品质的分散切换流形的设计方法；然后给出了一种基于不确定因素已知变化范围的分散滑动模控制器设计方法，该方法只需对各孤立子系统进行降阶滑动模的极点配置及求解降阶Ｌｙａｐｕｎｏｖ矩阵方程即可；最后以一具体例子说明其设计过程。     

船舶操纵非线性系统的鲁棒变结构控制

本文采用伪线性化变换将船舶操纵非线性系统近似地化为线性可控正则型，并对线性化系统设计了一种连续的变结构以提高整个闭环系统的鲁棒性。该方案用于限制水域中船舶的航向航迹纠编控制中，取得了预期的结果。     

基于神经网络非线性系统辨识和控制的研究

本文提出了由静态的前馈网络和稳定的滤波器构成的非线性系统的辨识模型，在神经网络固有的逼近误差存在的情况下，从理论上讨论了神经网络应用于辨识控制过程中系统的稳定性问题，最后研究了在非线性系统的轨迹跟踪过程中增加滑动控制来偿神经网络的逼近误差，从而提高系统跟踪性能。     

折线滑面滑体的稳定分析方法的改进

本文根据刚体极限平衡分析原理，考虑各块体的力矩平衡和块间的嵌合作用，假定作用于块体的已知外力所产生的应力呈线性分布，推导出确定其作用力数值、方向和作用点，以及整体抗滑稳定安全系数的方法和公式。并通过实用研究了嵌合作用、分界面倾角等对反力分布和安全系数的影响，与常用方法的计算结果作了比较，说明本方法有较大的适用性，可应用于工程设计。