Short-range guidance of autonomous vehicles—a comparative study

In this paper, two generic line-of-sight (LOS) sensing-based short-range guidance methodologies are presented for the docking of autonomous vehicles. The first method utilizes a passive LOS sensing scheme to provide vehicle corrective motions, while the latter method utilizes active sensing. The novelty of the proposed guidance methodologies is their applicability to situations that do not allow for direct proximity measurements of the vehicle. In such instances, one must employ a guidance-based technique to move the vehicle to its desired pose using corrective actions at the final stages of its motion. The objective of both proposed guidance methods is, thus, to successfully minimize the systematic errors of the vehicle, while allowing it to converge to its desired pose within random noise limits. Both techniques were successfully tested via simulations and are discussed herein in terms of convergence rate and accuracy, in addition to the types of localization problems that each method should be used in.     

高速、高精度数控伺服工作台摩擦误差的研究

建立了一种考虑摩擦影响的PID控制下的高速、高精度进给伺服工作台的数学模型。伺服机构中的摩擦力是采用一种“两维混合摩擦模型”来描述的。该模型可以根据滑动速度、表面接触物体的油膜厚度等计算摩擦力。通过数值仿真与实际测量 ,在大范围的工况下 ,研究了圆运动过象限时出现凸起的误差现象。通过计算与试验结果的比较 ,证明了提出的考虑摩擦影响的数学模型能够精确地模拟PID控制下的高速、高精度进给伺服工作台的动力学过程 ,能够正确地预测进给运动过程中摩擦误差大小及特征。     

高精密定位平台驱动波纹管迟滞的建模与验证

为了提高精密定位平台的精度和行程,设计了一种新型的气动伺服定位平台。以金属波纹管为独立执行机构,采用有限元法设计了气浮导轨。以气浮导轨支撑,研究无摩擦条件下的较大行程的精密控制。对波纹管的机械特性进行分析,结合实验数据形成的迟滞初载曲线,进行参数辨识,确定基本迟滞算子的阈值和权值,建立了基于PI模型的系统迟滞模型,并对模型进行了验证。结合建立的系统迟滞模型,采用变化速率为0.5 V/s和5 V/s的锯齿波进行实验,结果表明:系统的迟滞模型输出很好地逼近了系统输出;开环情况下,实际逼近误差慢速信号输入逼近小于10%m,快速信号输入逼近小于20%m,其性能上能够满足高精密定位平台的精度要求。     

利用高精度导爆管雷管实现露天矿中深孔"逐孔起爆"技术

降低爆破震动和岩石破碎块度是露天矿中深孔爆破技术改进的主题。近些年来，新型爆破器材的出现，促进了中深孔爆破技术的发展。文中介绍了利用国产高强度、高精度导爆管实现“逐孔起爆”技术及其在露天矿中试验与应用情况，并对国产器材的质量进行了测试和检验。对逐孔起爆技术的机理、爆破网络设计以及爆破震动和质量等结果进行了分析。     

综合物探法开展深部隐伏岩（矿）体勘查的探索研究——以河南西部多金属成矿带为例

运用可控源音频大地电磁法、频谱激电法和高精度磁法等多种物探方法,在河南省西部多金属成矿带上进行深部隐伏金属矿体勘查。研究表明,利用CSAMT方法进行隐伏岩体的确定,再利用SIP法对目标体埋深进行具体定位,确定其含矿性,对于指导该区隐伏矿找矿具有重要作用。利用CSAMT方法在该区共圈定隐伏岩体2个,其走向NW,并向NE倾伏;运用SIP法在2号剖面进行实测,发现了双峰异常特征,认为该处可能有金属硫化物富集,与CSAMT测深推断的断层破碎带相吻合,由分析可知,该金属硫化物呈浸染状。由于开采埋藏较深的隐伏矿体风险较大,采用多种物探方法进行综合调查可以降低风险,减少物探勘查的多解性,提高地质解释的可信度和准确度。     

一种新的高分辨率宽波束机载SAR成像算法

目前的频域成像算法在应用于高分辨率宽波束机载合成孔径雷达(SAR)时不能精确补偿运动误差,而可以精确成像的时域算法存在计算效率低下的问题。针对上述问题,该文提出一种新的成像算法。该算法通过对信号2维频谱进行扰动操作,将频域与时域算法结合互补,在提高运补精度的同时,也提高了后向投影的计算效率,从而在应用于高分辨率宽波束机载SAR时得到成像精度与效率的平衡。通过仿真和实际数据分析,验证了该算法应用于高分辨率宽波束系统的有效性。     

高精密库仑滴定法测定三氧化二砷的纯度

高精密库仑滴定法是国际上公认的基准测量方法,该方法根据法拉第电解定律,通过质量、电阻、电动势、时间等基本物理量及法拉第常数来进行三氧化二砷纯度的测定,直接溯源到国际SI单位,不需要用标准物质进行比对。样品以氢氧化钾溶液溶解,通过电解产生碘与亚砷酸盐定量反应,以死停终点法确定终点。该方法具有很高的测量精度和准确性。     

New research trends on high-precision time transfer technology

High-precision time transfer plays an important role in the areas of fundamental research and applications. Accompanying with the remarkable improvements in the ability of generating and measuring high-accuracy time-frequency signal, seeking for new time-transfer techniques between distant clocks with much further improved accuracy attracts attentions world-widely. The time-transfer technique based on optical pulses has the highest precision presently, and the further improvement in the accuracy is heavily dependent on the time-domain properties of the pulse as well as the sensitivity of the applied measurement on the exchanged pulse. The application of optical frequency comb in time transfer for a precision up to femtosecond level are currently the focus of much interest, and has recently achieved many breakthroughs. Further investigations show that, utilizing quantum techniques, i.e. quantum measurement technique and quantum optical pulse source, can lead to a new limit on the measured timing information. Furthermore, it can be immune from atmospheric parameters, such as pressure, temperature, humidity and so on. Such quantum improvements on time-transfer have a bright prospect in the future applications requiring extremely high-accuracy timing and ranging. The potential achievements will form a technical basis for the future realization of sub-femtosecond time transfer system.     

利用普通钻床或铣床加工高精度坐标孔

提供了一种用普通钻床加工高精度坐标孔的方法。提出了联合使用量块和一套导向镗孔装置的解决方案。     

作为开环系统的高精度定位装置

作者分析了闭环及开环控制系统各自的优缺点,提出了利用计算机高速大容量的特点进行离线检测、在线补偿的可能性,以及在实施过程中必须解决的关键问题。最后附有实测数据。该系统在25mm行程中示值误差≤1μm、回程误差≤0.3μm、分辨率为0.1μm,结构简单、可靠、价格低廉。已获得专利。