全要素雷达目标模型构建方法

雷达目标模型的构建是雷达目标数据仿真领域的热点之一,本文首先就影响目标生成的内外部因素进行分析,包括RCS起伏等目标自身因素、雷达工作参数及性能指标的影响和电磁环境因素的影响,对目标因素、雷达自身因素及电磁环境因素进行详细的数学模型阐述,并仿真了目标原始视频。该模型可以通过参数配置、基础数据替代等方式实现快速扩展。     

T型翼主动控制策略的数值研究

[目的]主动控制T型翼对船舶有着较好的纵向运动减摇效果,但最佳的T型翼主动控制策略仍未有定论,因此需对T型翼主动控制策略进行研究计算与分析。[方法]首先,采用细长体理论对Wigley III船型在不同波长规则波中的纵向运动响应进行数值计算;然后,在相同航速与波浪工况下,对加装了主、被动T型翼的船舶纵向运动进行数值预报,分析不同主动控制策略的减摇效果。[结果]计算结果显示:T型翼被动控制在共振区具有较好的减摇效果,长波区和短波区的减摇效果相对有限;纵摇角速度信号控制对纵摇运动和艏部运动加速度的减摇效果非常显著,但对于长波区的垂荡运动会有减益效果;船艏部运动速度信号对纵摇运动和艏部运动加速度的减摇效果较纵摇角速度信号均有10%~20%的提升,并且对垂荡运动的减摇效果也有一定提升。[结论]对于T型翼的主动控制,艏部运动速度信号控制综合考虑了纵摇与垂荡这2种运动,可以实现更好的减摇效果。     

Integrated control of ground vehicles dynamics via advanced terminal sliding mode control

An integrated vehicle dynamics control (IVDC) algorithm, developed for improving vehicle handling and stability under critical lateral motions, is discussed in this paper. The IVDC system utilises integral and nonsingular fast terminal sliding mode (NFTSM) control strategies and coordinates active front steering (AFS) and direct yaw moment control (DYC) systems. When the vehicle is in the normal driving situation, the AFS system provides handling enhancement. If the vehicle reaches its handling limit, both AFS and DYC are then integrated to ensure the vehicle stability. The major contribution of this paper is in improving the transient response of the vehicle yaw rate and sideslip angle tracking controllers by implementing advanced types of sliding mode strategies, namely integral terminal sliding mode and NFTSM, in the IVDC system. Simulation results demonstrate that the developed control algorithm for the IVDC system not only has strong robustness against uncertainties but also improves the transient response of the control system.     

城区繁忙交通道路下方残留桩基精确探测技术

在某城区顶管隧道始发井和接收井开挖施工过程中均发现基坑中存在未知的建筑残留桩基。因时间久远,施工区域内残留桩基的位置和范围均无法获知。为保证顶管隧道顺利施工,需在施工前调查清楚其影响范围内是否存在残留桩基。由于顶管隧道横穿繁忙交通道路,地表没有大范围钻孔勘查的条件,只能采用地球物理方法进行探测。经比选,采用探地雷达和磁法探测相结合的方法可满足探测要求。根据探测结果,在异常区域进行钻探验证,并采取针对性的处理措施,保证了顶管隧道的安全施工。     

A study on single lane-change manoeuvres for determining rearward amplification of multi-trailer articulated heavy vehicles with active trailer steering systems

The Society of Automotive Engineers issued a test procedure, SAE-J2179, to determine the rearward amplification (RA) of multi-trailer articulated heavy vehicles (MTAHVs). Built upon the procedure, the International Organization for Standardization released the test manoeuvres, ISO-14791, for evaluating directional performance of MTAHVs. For the RA measures, ISO-14791 recommends two single lane-change manoeuvres: (1) an open-loop procedure with a single sine-wave steering input; and (2) a closed-loop manoeuvre with a single sine-wave lateral acceleration input. For an articulated vehicle with active trailer steering (ATS), the RA measure in lateral acceleration under the open-loop manoeuvre was not in good agreement with that under the closed-loop manoeuvre. This observation motivates the research on the applicability of the two manoeuvres for the RA measures of MTAHVs with ATS. It is reported that transient response under the open-loop manoeuvre often leads to asymmetric curve of tractor lateral acceleration [Winkler CB, Fancher PS, Bareket Z, Bogard S, Johnson G, Karamihas S, Mink C. Heavy vehicle size and weight – test procedures for minimum safety performance standards. Final technical report, NHTSA, US DOT, contract DTNH22-87-D-17174, University of Michigan Transportation Research Institute, Report No. UMTRI-92-13; 1992]. To explore the effect of the transient response, a multiple cycle sine-wave steering input (MCSSI) manoeuvre is proposed. Simulation demonstrates that the steady-state RA measures of an MTAHV with and without ATS under the MCSSI manoeuvre are in excellent agreement with those under the closed-loop manoeuvre. It is indicated that between the two manoeuvres by ISO-14791, the closed-loop manoeuvre is more applicable for determining the RA measures of MTAHVs with ATS.     

深水钻井波浪补偿装置总体技术研究

波浪补偿装置是深水钻井平台和钻井船必不可少的核心设备,文章研究了波浪补偿装置的总体关键技术,首先根据高海情海况要求构建目标平台,确定钻井工况,然后完成总体环境载荷分析、平台运动响应分析、原理性设计、总体及分系统技术参数设计等研究工作,最终形成了高海情工况下的完整研究方案,形成了钻井波浪补偿装置总体技术较为全面的研究成果。     

现代有轨电车主动信号优先模型研究

为了提高现代有轨电车运行效率,在道路平交路口处实施信号优先是应用最为普遍的方法。对现代有轨电车通过交叉口时形成的离散交通流,提出了其特定的延误公式,构建了以人总延误的减小量为参考指标的主动优先效益模型,并通过判断效益模型的结果是否为正来决定能否采取主动优先控制策略。以武汉市东湖高新区的现代有轨电车T1线为例,对模型进行仿真分析与验证。结果表明,与常规信号控制策略相比,主动信号优先具备更好的控制效果;与绿灯提前控制策略相比,绿灯延长策略的效果更加显著。     

双站聚束SAR的方位分辨特性和波束压缩比研究

与双站条带SAR相比，双站聚束SAR只要有足够的聚束时问，理论上就可以达到理想的方位分辨率，不受收、发天线波束宽度和天线尺寸大小的影响，文中主要研究双站聚束SAR方位分辨特性、波束压缩比等，并给出了相关数学解和仿真结果。     

低活性粉煤灰的路用性能试验研究

通过室内试验研究分析,确定了低活性粉煤灰用于公路建设中的可行性,以及相应混合料的路用性能指标,为低活性粉煤灰的推广应用做了较为充分的技术准备。     

浅谈有线通信设备防雷击

分析了雷击对通讯设备的危害,以及通讯设备遭受雷击的原因并提出防雷击的措施。