基于路面影响因子的轮毂电机驱动车辆自适应转矩控制

为实现轮毂电机驱动越野车辆在附着条件多变、路面起伏不定的复杂环境中动力性和稳定性的多目标优化,提出一种基于路面影响因子的自适应转矩控制策略。以滚动阻力差异、空气阻力归一化比例、坡度阻力归一化比例、路面附着差异方差以及最小路面附着系数5个特征参数作为输入,并基于模糊理论方法搭建路面影响因子五参数辨识模型。基于辨识出的路面影响因子,开发整车动力性和稳定性多目标优化自适应转矩控制策略,构建了三层式控制架构：顶层引入路面影响因子对加速度紧迫程度进行判定,采用模型预测控制算法得到期望总驱动力;中层为目标决策层,以最优滑转率为目标决策驱动防滑力矩,并基于路面行驶阻力,决策期望前馈补偿力矩;下层为转矩分配层,以需求总驱动力及轮胎利用率作为控制目标,引入路面影响因子优化两者权重系数,以多约束条件的混合优化算法对转矩进行自适应控制。利用Matlab/Simulink-CarSim联合仿真平台进行仿真,基于实车进行验证。结果表明,在低附着路面,在0.2 s内快速完成滑转率抑制;在对开路面,侧向位移接近0;在大扭曲路面,避免腾空车轮出现大滑转率,滑转率最高0.2。     

大直径灌注桩的应力应变测试研究

桩身应力应变测试是从微观上了解桩基工作性状的基本方法.某工程大直径灌注桩采用静压试桩,通过考察应力应变测试结果,即试桩的Q-S曲线、桩身轴力曲线、单位摩阻应力曲线、单位摩阻应力随加载量变化的曲线,从微观上了解桩基工作性状,给出一些结论,供同类型工程设计和施工参考.     

Glacial ice impacts: Part I: Wave-driven motion and small glacial ice feature impacts

Glacial ice features in the northern and central Barents Sea may threaten ships and offshore structures. Particularly, small glacial ice features, which are difficult to detect and manage by concurrent technologies, are of concern. Additionally, small glacial ice features are more susceptible to wave-driven oscillatory motions, which increases their pre-impact kinetic energy and may damage ships and offshore structures. This paper is part of three related papers. An initial paper (Monteban et al., 2020) studied glacial ice features’ drift, size distribution and encounter frequencies with an offshore structure in the Barents Sea. The following two papers (Paper I and Paper II) further performed glacial ice impact studies, including impact motion analysis (Paper I) and structural damage assessment (Paper II). This paper (Paper I) studies the wave-driven motion of small glacial ice features and their subsequent impact with a given offshore structure. The aim here is to develop a numerical model that is capable of efficiently calculating the relative motion between the ice feature and structure and to sample a sufficient amount of impact events from which statistical information can be obtained. The statistical information entails the distributions of the impact location and associated impact velocities. Given the distributions of the impact velocities at different locations, we can quantify the kinetic energy for related impact scenarios for a further structural damage assessment in Paper II (Yu et al., 2020).In Paper I, a numerical model that separately calculates the wave-driven oscillatory motion and the mean drift motion of small glacial ice features is proposed, implemented and validated. Practical and fit-for-purpose hydrodynamic simplifications are made to simulate and sample sufficient impact events. The numerical model has been favourably validated against existing numerical results and experimental data. A case study is presented where a 10 m wide glacial ice feature is drifting under the influence of surface waves towards an offshore structure. The case study shows that if an impact happens, the overall impact location and impact velocity can be best fitted by the Normal and Weibull distributions, respectively. Additionally, the impact velocity increases with impact height. Moreover, the impact velocity increases and the impact range is more dispersed in a higher sea state. It is also important to notice that the approaches and methods proposed in this paper adhere to and reflect the general requirements stated in ISO19906 (2019) and NORSOK N-003 (2017) for estimating the design kinetic energy for glacial ice impacts.     

“输出驱动-输入促成假设”在高职大学英语课堂教学中的应用研究

本文介绍了“输出驱动-输入促成假设”的背景、主要内容及其与传统教学的区别,并对实施该假设的要求进行了研究,希望籍以改进大学英语课堂教学,提高课堂教学质量.     

广清高速三角岭大桥基础设计

广清高速公路银盏至北江二桥段地质情况十分复杂,岩溶尤为发育,桩基设计须考虑的要素较多。文中以三角岭大桥为例,较为详细地介绍了设计中为施工进度及安全考虑而采用的各种基础设计方案。     

基于数据驱动的舰船核动力安全支持技术分析

与核电站相比,舰船核动力系统工况多变,运行环境恶劣,辅助系统及工程安全设施相对简易,因此针对舰船核安全技术的研究一直是行业内的热点问题之一.近年来,随着计算机技术的飞速发展,舰船核动力系统大量历史运行数据被完整真实的保存下来,如能利用数理统计、智能学习等大数据分析手段,归纳提炼其隐含的有价值的信息,可形成有效客观的经验积累,指导舰船核动力系统安全运行,为舰船核动力系统运行安全技术的发展提供新途径.     

三轴客车随动转向轿随动转向原理分析

针对目前市场所用13．7米客车随动转向桥,重点分析随动转向原理,转向半径的减小,锁止控制装置的工作原理。     

自动同步离合器阻尼-时间特性研究

在动力装置自动同步离合器阻尼腔中保持一定的油压,阻尼孔维持不变的情况下,通过改变主机的调节特性达到改变离合器动作时间的目的,简化了传动系统设置.通过对原动机及控制器工作原理的深入研究,建立了相应的数学模型,利用动力学仿真软件ADMAs的平台对离合器特性时间参数进行了深入的分析,得出其时间参数的控制方法,为传动系统的设计运行提供参考.     

储能式多编组虚拟轨道电车全轮转向控制

为了解决虚拟轨道电车转弯半径过大,以及转弯过程中由于后续车辆不跟随而导致的甩尾等安全问题,文章提出了一种双向驱动运行的储能式多编组虚拟轨道电车全轮转向控制方法,分析了其系统结构和控制原理,并进行了全轮转向测试.     

PHC管桩在码头工程中的应用

PHC管桩在沿江、沿海等诸多大型港口码头建设中的应用越来越广泛,但在实际沉桩过程中仍存在诸多质量问题。本研究总结PHC管桩施工过程中常见质量问题,分析各种PHC管桩施工质量检测方法的适应性,提出码头PHC管桩应用中仍需解决的问题。