基于QN旋转布局的10位500 MS/s分段电流舵DAC

针对分段电流舵数/模转换器（Digital-to-Analog Converter，DAC），通过理论分析和推导，研究电流源阵列系统失配误差和寄生效应对非线性的影响，采用电流源阵列Q^N旋转游走版图布局方案，能够减小电流源系统失配的一次误差，而且版图布线简单，由寄生效应引起的电流源失配较小，利于DAC非线性的优化.基于0.18μm CMOS，采用"6+4"的分段结构，设计了一种10位500MS/s分段电流舵DAC，流片测试结果表明，在输入频率为1.465MHz，采样速率为500MS/s的条件下，无杂散动态范围（Spurious Free Dynamic Range，SFDR）为64.9dB，有效位数（Effective Number of Bits，ENOB）为8.8 bit，微分非线性误差（Differential Non-linearity，DNL）和积分非线性误差（Integral Non-linearity，INL）分别为0.77LSB和1.12LSB.     

基于PLC控制技术和气压传动控制技术的汽车前悬架与转向轮螺纹装配设备研发

在装配汽车前悬架与转向轮时需要拧紧螺纹,一旦操作不当就会出现前倾角过大的缺陷,加快车轮胎的磨损,降低小轴承及轮毂紧固螺母的使用寿命。对此,本文设计了一种基于PLC控制技术和气压传动控制技术的装配设备,能有效避免上述问题。     

四川非常规气田开发主要钻井技术及其应用效果

随着油气勘探开发难度不断加大,尤其是近年来非常规气田的开发,定向钻井成为钻井主流技术,如何有效控制钻井成本和保护环境并防止井下事故的发生成为作业者必须面对的问题。为此,自2010年以来,在荷兰皇家壳牌集团(中国)四川非常规气项目50余井次的钻井工作中,运用了旋转导向技术、新型钻井液配方、钻井液回收技术和固控配套技术,取得了快速、安全、环保的应用效果,其中DXXX井应用旋转导向钻井,实现完钻井深5 729 m,水平段长1 418 m,钻井周期105 d,同比螺杆钻水平井节约时间65 d,钻井工程创下了该区新纪录。尤其是针对不同地层特点,兼顾环保要求,成功研制和应用了新型钻井液配方、固控和钻屑处理技术,取得了较好的环保效果。结论认为,上述配套技术的应用对提高钻遇产层成功率、提高钻井速度、缩短钻井周期、控制钻井成本、获得更好的经济效益和社会效益,具有重要的保障作用。     

Generating a multiplicity of policies for agent steering in crowd simulation

Pedestrian steering algorithms range from completely procedural to entirely data‐driven, but the former grossly generalize across possible human behaviors and suffer computationally, whereas the latter are limited by the burden of ever‐increasing data samples. Our approach seeks the balanced middle ground by deriving a collection of machine‐learned policies based on the behavior of a procedural steering algorithm through the decomposition of the space of possible steering scenarios into steering contexts. The resulting algorithm scales well in the number of contexts, the use of new data sets to create new policies, and in the number of controlled agents as the policies become a simple evaluation of the rules asserted by the machine‐learning process. We also explore the use of synthetic data from an “oracle algorithm” that serves as an as‐needed source of samples, which can be stochastically polled for effective coverage. We observe that our approach produces pedestrian steering similar to that of the oracle steering algorithm, but with a significant performance boost. Runtime was reduced from hours under the oracle algorithm with 10 agents to on the order of 10 frames per second (FPS) with 3000 agents. We also analyze the nature of collisions in such a framework with no explicit collision avoidance. Copyright © 2014 John Wiley & Sons, Ltd.     

Evaluation method on steering for the shape-shifting robot in different configurations

The evaluation method on steering is based on qualitative manner in existence, which causes the result inaccurate and fuzziness. It reduces the efficiency of process execution. So the method by quantitative manner for the shape-shifting robot in different configurations is proposed. Comparing to traditional evaluation method, the most important aspects which can influence the steering abilities of the robot in different configurations are researched in detail, including the energy, angular velocity, time and space. In order to improve the robustness of system, the ideal and slippage conditions are all considered by mathematical model. Comparing to the traditional weighting confirming method, the extent of robot steering method is proposed by the combination of subjective and objective weighting method. The subjective weighting method can show more preferences of the experts and is based on five-grade scale. The objective weighting method is based on information entropy to determine the factors. By the sensors fixed on the robot, the contract force between track grouser and ground, the intrinsic motion characteristics of robot are obtained and the experiment is done to prove the algorithm which is proposed as the robot in different common configurations. Through the method proposed in the article, fuzziness and inaccurate of the evaluation method has been solved, so the operators can choose the most suitable configuration of the robot to fulfil the different tasks more quickly and simply.     

新型加工细长轴类工件的拉压式尾座机构装置

为进一步消除细长轴工件切削轴向力引起的变形,结合多年生产经验,设计了一款新型拉压式多功能尾座机构装置。经力学分析可知,新型装置能有效改良细长轴类车削加工效果,且机构结构简单、操作方便,特别适宜于细长轴类长径比较大工件的车削加工。     

液力联轴器的使用

液力联轴器是一种应用广泛的通用传动装置 ,它利用液体动能来传递功率 ,能改善电动机起动性能 ,实现过载保护。在煤矿井下使用过程中 ,经常发生断轴 ,工作液体渗漏等情况。针对上述问题 ,提出了合理的预防措施     

曲轴的喷涂修复

喷涂技术是以氧—乙炔焰的热量,将具有多种特性的自熔性合金粉末喷涂到金属表面上的新型热加工技术。它是以提高耐磨性为主要目的表面强化方法,并以操作简便,生产成本低等优点被人们所重视。介绍了针对精密、复杂的工件—曲轴,进行喷涂的修复工艺。     

零件固定联接新方法的研究

通过理论分析与计算,提出了一种代替键、销、螺钉等零件固定联接的新方法,简化了制造工艺,降低了成本,保证了联接的可靠性。     

弹性扭矩轴的设计

弹性扭矩轴是截割传动系统的弹性缓冲装置 ,安装在截割电机空心轴内两端。在截割电机空心轴内使用弹性扭矩轴是设置传动系统弹性缓冲的好办法。下面简单阐述弹性扭矩轴的典型结构、适用材料、最大传递扭矩的确定。