Adaptive subsequence adjustment with evolutionary asymmetric path-relinking for TDRSS scheduling

Due to the limited transmission resources for data relay in the tracking and data relay satellite system （TDRSS）, there are many job requirements in busy days which will be discarded in the conventional job scheduling model. Therefore, the improvement of scheduling efficiency in the TDRSS can not only help to increase the resource utilities, but also to reduce the scheduling failure ratio. A model of nonhomogeneous parallel machines scheduling problems with time window （NPM-TW） is firstly built up for the TDRSS, considering the distinct features of the variable preparation time and the nonhomogeneous transmission rates for different types of antennas on each tracking and data relay satellite （TDRS）. Then, an adaptive subsequence adjustment （ASA） framework with evolutionary asymmetric path-relinking （EvAPR） is proposed to solve this problem, in which an asymmetric progressive crossover operation is involved to overcome the local optima by the conventional job inserting methods. The numerical results show that, compared with the classical greedy randomized adaptive search procedure （GRASP） algorithm, the scheduling failure ratio of jobs can be reduced over 11% on average by the proposed ASA with EvAPR.

主被动闭环融合调姿隔振平台运动学及刚度特性分析

针对载体仪器设备调姿隔振的双重需求,提出了一种多维调姿隔振平台新构型。在分支中,主动调姿和被动隔振单元以闭环子链的形式融合。被动隔振时,假定电动缸瞬时锁定,采用等效运动旋量描述闭环子链的运动特性,将包含闭环子链的分支等效为串联分支,并以此为基础,推导了机构的1阶、2阶影响系数,形式简洁紧凑,为后续的运动微分方程建立、振动特性分析奠定了基础。基于虚功原理,推导了考虑重力、外力及位姿变化趋势的完整柔度矩阵和方向刚度模型,并结合数值算例分析了方向刚度在不同坐标系中的表现形式,为机构的性能分析提供参考。

DC LOOP-CURRENT DETECTING AND RESTRAINING METHODS FOR PARALLEL INVERTER SYSTEM

DC component is contained in inverter output voltage due to many reasons such as the zero-point deviation of operational amplifiers and the differences between power switching transistors′ characteristics. For the parallel inverter system without output isolation transformers, the difference of DC components of the output voltage can cause large DC loop-current among modular inverters. Aiming at this problem, this paper studies several DC loop-current detecting and restraining methods. By digital adjustment with high precision on the DC components of reference sine wave, the DC components of inverter′s output voltage can be adjusted to restrain DC loop-current. Experimental results prove that the DC loop-current detecting and restraining methods have a good performance.

全向姿态调整农机履带底盘设计与试验

为满足丘陵山地复杂地形农机行走与作业要求,设计全向位姿调整农机履带底盘。采用理论分析与三维参数化建模方法对该底盘的行走系统、横向调整机构和纵向调整机构等关键部件进行设计分析,电液调姿控制系统实时采集车身横向倾翻角和纵向翻滚角及各调姿液压缸位移等信息,实现在倾角连续变化的坡地上,底盘车身横向姿态与纵向姿态不断调整至水平。为验证该底盘的各项性能,以不同路况和地块为试验场地,反复多次试验整车通过性和稳定性,得到姿态调整机构坡度调平角度误差≤±1.5°、横向姿态调整角≤15°、纵向姿态调整角≥30°。为丘陵山地宜机化作业进一步改造提供参考和技术支持。

基于反向漏风的地铁区间隧道并联通风机运行调节优化

为明确隧道运营期间并联通风机的调节依据,依托青岛地铁八号线大洋站至青岛北站区间隧道,搭建隧道通风系统模型。通过并联试验,测定了通风机变频频率、电功消耗值及相应风量,并以功率差值占比、通风效率为依据,探究并联通风机的反向漏风规律和最佳频率匹配范围。结果表明:由于管网结构的影响,并联通风机反向漏风存在抑制临界点;为避免反向漏风,并联通风机变频调速处于额定转速的30%~50%、>50%~70%、>70%~90%时,其功率差值占比不宜大于1.6%、6.1%、17.6%;并联通风机同型号同频率运行时,通风效率不一定最优,要使并联通风机增效减耗运行,风机变频调速宜处于额定转速的70%~90%且功率差值占比≤6%。频率匹配范围的确定可为隧道运营期间并联通风机的变频调节提供参考。

基于实时监控的动态调节线程池方法研究

在数字社会对强算力的要求下,为使CPU性能最大化,需要使用线程池来提高CPU并行计算能力,然而在开发中线程池的使用往往伴随着线程池状态混乱以及难以监控的问题。针对该问题,本文提出了一种基于实时监控的动态调节线程池方法。该方法通过实时监控线程池参数,动态调整核心线程数与最大线程数的数量来规避由于线程资源的配置不足导致业务故障的问题;引入监控中心与报警中心模块,以便直观监测线程池的执行状态、线程数量、队列容量等来实现实时监控。引入配置中心模块实时同步修改线程池的参数,快速的调整线程池参数并同步到线程池中。实验结果表明,本文所提出的方法能有效的动态调节线程池,缓解线程池状态与任务混乱的问题。

Inhibition characteristics of circulating current in parallel inverter driving system of mine hoist

This research investigated the outputting circulation current inhibition characteristic which are controlled by the instantaneous feedback voltage in inverter parallel driving of the mine hoist. We established a transfer function of the parallel inverters controlled by the close-loop adjustment of instantaneous voltage feedback. The influence of the parameters of the close-loop feedback circuit to the inhibition effects to the outputting circulation current is observed. After analyzing the circulating current inhibition characteristics, the proportion integration （PI） controller is introduced into the close-loop adjustment by instantaneous voltage feedback. The characteristics equation is gained to determine the PI parameters by drawing the Bode plots. The inhibition effects of the proposed controller are examined by the established simulation model of parallel inverter system. The harmonic distortion rate at the outputting voltage frequency value of 4, 10, 20, 41 and 50 Hz, are all lower than 2.32 % by the instantaneous outputting voltage feedback.

Generalized multiple time windows model based parallel machine scheduling for TDRSS

The scheduling efficiency of the tracking and data relay satellite system（TDRSS）is strictly limited by the scheduling degrees of freedom（DoF）,including time DoF defined by jobs＇ flexible time windows and spatial DoF brought by multiple servable tracking and data relay satellites（TDRSs）.In this paper,ageneralized multiple time windows（GMTW）model is proposed to fully exploit the time and spatial DoF.Then,the improvements of service capability and job-completion probability based on the GMTW are theoretically proved.Further,an asymmetric path-relinking（APR）based heuristic job scheduling framework is presented to maximize the usage of DoF provided by the GMTW.Simulation results show that by using our proposal 11%improvement of average jobcompletion probability can be obtained.Meanwhile,the computing time of the time-to-target can be shorten to 1/9 of the GRASP.

Kinematic Calibration of Asymmetricly Actuated 6-DOF 3-PPPS Parallel Mechanism

An asymmetric actuated 3-PPPS parallel mechanism was analyzed in its application to an aircraft wing adjustment process.The posture alignment precision at the wing ends was enhanced with a kinematic calibration method.A constraint equation was built based on a constraint condition that distances among spherical joints of the mechanism were constant,and further eight groups of analytic forward solutions of all poses of the mechanism were solved.An inverse equation of the posture alignment displacements of aircraft wing parts was built based on space vector chains,and a mapping equation of the pose and geometric errors of the posture alignment mechanism containing 39 error sources was derived by differentiating the kinematic equation of the mechanism.After kinematic calibration experiments,the maximum position error of the posture alignment platform dropped from 2.67 mm to 0.82 mm,the maximum angle error decreased from 0.481° to 0.167°,and the posture alignment precision of the aircraft wing end was improved.

Sensorless Vector Control of Parallel-Connected Multiple Induction Motors Fed by a Single Inverter

A method of improving the stability of multiple-motor drive system fed by a 3-leg single inverter has been devised that employs the averages and differences of estimated parameters for field-oriented control. The parameters of each motor (stator current, rotor flux, and speed) are estimated using adaptive rotor flux observers to achieve sensorless control. The validity and effective of the proposed method have been demonstrated through simulations and experiments.

高精度倒装焊机光学对位系统研制及算法研究

针对国内红外焦平面倒装焊机对高精度光学对位系统的迫切需求,对光学对位系统进行了设计及验证,并对该系统用到的平行调整、光学对位及坐标系误差补偿算法进行研究。文章首先对倒装焊接光学对位工艺进行分析;然后对平行性调整及光学对位算法进行介绍,并根据光学对位系统测试流程,提出更加合理的误差补偿算法;最后,以上述算法为理论依据,设计光学对位系统,其包括准直系统、显微成像系统和激光测距三部分。所设计的光学系统可实现平行性粗调,特征点识别及平行性精调功能。试验结果表明,准直系统准直效果较好,显微成像系统分辨率高,成像质量较好,激光测距系统的测距精度为0.084μm。设计的高精度光学对位系统解决了国内红外焦平面倒装焊机对高精度光学对位系统的迫切需求,已经在国内某型号的倒装焊机中得到应用,对于提高国产高端集成电路的自主研发和生产能力具有非常重要的意义。

面向轨道维护的可变轨距轨道模型与钢轨点云的配准方法

基于车载Lidar技术相关的硬件和算法的快速发展,具备发展成快速车载轨道测量技术手段的潜力,从而替代传统的地面人工轨道测量手段。针对其中根据钢轨点云获取轨道轨距、钢轨位置等参数的问题,定义了可变轨距轨道模型,并在此实现可变轨距轨道模型与钢轨点云的配准方法。新算法在配准迭代过程根据钢轨点云到轨道工作边的距离来动态调整模型轨距,从而在轨道配准精度和轨距测量精度两项关键指标获得了同步提高。通过模拟数分析存在不同轨距偏差、超高等情况下算法性能,并和单钢轨轨道模型和固定轨距轨道模型的配准结果进行比较。最后通过一段干线铁路的实测点云进行测试,试验结果表明单钢轨轨道模型配准后左右钢轨的平行性得不到保证;在直线段与固定轨距轨道模型配准精度和轨距测量精度基本相当,配准精度为0.16 mm;在曲线段可变轨距轨道模型配准精度和轨距测量精度不受轨距变化的影响,显著优于固定轨距轨道模型的结果,精度高88.7%。

可适径调整管道清淤机器人结构设计与运动分析

为了实现布局复杂的城市地下管道的清淤,提出了一种基于并联机构的履带式管道清淤机器人。采用折展调姿行走装置以减小机器人体积,采用基于3-US并联机构的工作装置以增大机器人的工作空间;编写了机器人工作空间算法,通过MATLAB软件仿真得到了行走装置和工作装置的工作范围及运动轨迹;采用ADAMS软件模拟了机器人运动状态,并对其驱动特性参数进行分析,得到了行走装置在不同运动状态下驱动力和驱动力矩的变化规律,以及工作装置在不同方向极限位置转换时的驱动力矩。仿真研究表明了行走装置折展调姿的稳定性及工作装置在各个清淤极限位置间转换的灵活性。研究结果对可适径调整管道清淤机器人的研制与应用具有指导意义。

高速并行Gardner算法设计与实现

随着空间探测任务逐步增加、空间信道频谱资源日趋紧张,传统Gardner定时同步算法已经无法满足高速数传系统高通量、高可靠性的需求。为了提高Gardner定时同步算法的吞吐率并增大可纠正误差范围,提出一种高速并行Gardner算法。为了保证插值精度同时减少乘法器消耗,设计了一种并行分段抛物线插值滤波器;为了便于并行流水线设计和最佳采样点选取,构建了计数模块和定时缓存调整模块;为了提高等价吞吐率,重构了流水线并行环路滤波器结构和并行数控振荡器结构。结果表明,该算法等价吞吐率可达1739.13 Msps,数字信号处理器资源消耗可减少44%,可纠正2×10^(-3)的定时误差。

智能旋流器的设计与现场应用

介绍了智能旋流器的结构及在南芬选矿厂的平行试验情况。系统根据沉砂排料夹角装置和相关检测仪表实时检测旋流器的工作状态,通过智能控制系统进行信息采集与处理,分析智能旋流器是否处于最佳工作状态,在检测到智能旋流器工作状态异常时,通过可调节底流口结构和可调冲洗水机构以调整旋流器的底流口大小和底流浓度,实现对溢流和底流的稳定控制。系统通过大数据算法调整智能旋流器的运行参数,可以设定预期的工艺指标,使智能旋流器运行在合理区间,并对异常状态及时报警。智能旋流器不仅具有耐磨、维护便利等特点,与传统旋流器相比,高效智能旋流器沉沙浓度更高、细粒含量更低,溢流则正好相反,分级效率得以显著提高。

基于并联机器人的蒜瓣种芽朝向调整系统的设计与优化

蒜瓣种芽朝上播种的大蒜具有出苗早,蒜苗强壮的特点,是符合中国农艺要求的播种方法。为了提高大蒜机械化播种水平,针对目前大蒜机械化播种种芽朝上率低的问题,研究设计了一种基于并联机器人的蒜瓣种芽朝向调整系统,该系统主要包括四个模块:图像采集、图像预处理、种芽特征提取和指令驱动。首先,蒜瓣运至指定位置后,并联机器人发出的光触发信号,视觉系统接收该信号并立即采集图像。其次,通过对图像进行中值滤波、二值化和形态学处理,填充孔洞,滤除背景颗粒,得到理想的二值图像,并根据蒜瓣的大小范围对二值图像的连通域面积进行筛选,得到大小合适的蒜瓣二值图像。第三,提取并计算图像的中心轮廓和轮廓的曲率,将曲率最大的部分视为蒜瓣的种芽,从而确定蒜瓣的中心位置及朝向,该朝向信息也会被量化为角度值。最后,并联机器人根据蒜瓣的位置信息、速度矢量信息和朝向信息控制机械臂进行蒜瓣抓取和定向摆放的操作,实现蒜瓣种芽朝向的调整。最后本文对调整系统的关键参数进行了试验测试,建立了调整成功率的多元回归模型,结果表明:(1)蒜瓣重量、输送速度和抓取时间对调整成功率有重要影响。(2)影响因素的主次顺序依次为抓取时间、蒜瓣重量、输送速度。(3)当蒜瓣质量为4.54 g,输送速度为0.1 m/s,并且抓取时间为2.445 s时,模型预测的调整成功率最高,达到97.41%。本研究为蒜瓣种芽调整系统的应用提供了技术指导,有助于解决利用嵌入式工控机调整蒜瓣朝向的问题,有利于促进国内大蒜机械化播种。

基于6-UPS并联机器人的副面调整机构设计

针对奇台110 m口径全可动射电望远镜(QiTai radio Telescope,QTT)天线副面调整机构的技术指标,文中提出了一种基于6-UPS并联机器人的副面调整机构。分别利用多刚体动力学分析和控制仿真软件对副面调整机构进行了虚拟样机建模和动力学仿真,得出副面调整机构运动关节在天线指天和仰平两种工况下从零位运动至指定位姿所需要的最大驱动力。进一步建立了大射电望远镜副面调整机构的有限元模型,对其零位时的结构进行了模态分析,得到了前6阶固有频率,为工程设计提供了理论参考。

保证六面体加工平行度的检测及调整装置

在机加工生产过程中,经常会遇到上下两平面有一定平行度要求的六面体零件。对此,设计了一种保证六面体加工平行度的检测及调整装置,以六面体下表面直接找正,保证加工精度。介绍了装置的结构、原理和操作步骤。这一装置结构简单,制作维护方便,可靠性高,具有推广价值。

An Adaptive Modal Discontinuous Galerkin Finite Element Parallel Method Using Unsplit Multi-Axial Perfectly Matched Layer for Seismic Wave Modeling

The discontinuous Galerkin finite element method(DG-FEM)is a highprecision numerical simulation method widely used in various disciplines.In this paper,we derive the auxiliary ordinary differential equation complex frequency-shifted multi-axial perfectlymatched layer(AODE CFS-MPML)in an unsplit format and combine it with any high-order adaptive DG-FEMbased on an unstructuredmesh to simulate seismicwave propagation.To improve the computational efficiency,we implement Message Passing Interface(MPI)parallelization for the simulation.Comparisons of the numerical simulation results with the analytical solutions verify the accuracy and effectiveness of our method.The results of numerical experiments also confirm the stability and effectiveness of the AODE CFS-MPML.

可调阻尼减振器外特性仿真与性能分析

研制了一种用于车辆半主动悬架的可调阻尼减振器,阐述了该减振器的结构形式和工作原理。基于流体力学和弹性力学理论,提出并应用并联管路节流压差和串并混联管路各分支流量计算方法,利用环形薄板阀片受均布载荷作用时的挠曲变形解析式,建立了可调阻尼减振器的详细数学模型。在MATLAB环境下对模型进行仿真研究,仿真结果与试验结果符合较好。同时用该模型分析了"回油管路"结构参数对减振器阻尼力的影响规律,得出的结论为可调阻尼减振器的设计和性能预测提供一定的技术支持。