贮木场机械系统的优化模型

本文应用线性规划理论研究了贮木场机械系统的优化问题，建立了相应的数学模型，并结合实例对模型进行了解算验证。     

THE APPLICATION OF SPLINE FUNCTION IN THE GEOMETRIC REPRODUCTION OF LOG SHAPE

FORWARDInwood-processingproduction,theeffectivewaytoraiselogutilizationandobtainthebesteconomicalbenefitistohaveaoptimumandreasonablesawcut-tingscheme.Thedeterminationoftheoptimumsawcuttingschemeshou1dbemadein1ightoflognaturalconditions,suchasitsgeometricsize,theoutlinesofthecrosssectionsatitsoppositeends,itsgeometricshape,andalsobasedonsawingwoodspecificationsacquiredandontheprincip1eofoptimumloguti1izationandthebesteconomicalbenefit.Inrecentyears,theresearchpapersconcerningthemethodsofgeom…     

The effect of taper on the MOE of log stringers

Load sharing between the stringers in gravel-decked log bridges is an important design factor when small- diameter stringers are used with thin gravel decks. In order to estimate the load sharing between the stringers, it is necessary to consider the deflection of the stringers; therefore, accurate estimates of the apparent modulus of elasticity (MOE) for full-size log stringers are required. In this paper, load and displacement data from the full- size bending tests are used to demonstrate that taper near midspan has the greatest effect on the MOE used in common log bridge design methods, where the logs are assumed to have constant cross sections. This paper proposes a method to estimate a MOE that can be used in a constant cross-section model given the geometry of the particular log of interest, and the MOE from full-size bending tests calculated when considering actual log geometry.     

原木形状识别技术的探讨

在总结了国内外原木形状识别技术理论发展状况的同时,对我国原木识别技术的发展趋势做了分析,指出利用先进的原木识别技术实现制材优化,提高原料利用率,降低成本,是制材行业发展的必然。     

谈贮木场技术改造中的几个问题

贮木场技术改造要从我国目前林业企业的现状出发,充分考虑资金少,设备不足、技术装备落后、原木产品苯重等特点。论述了当前我国林业贮木场技术改造中存在问题,改造方向艰及搞好贮木场改造规划和设计,设备挖潜和更替等问题,并且对卸车,造林、选材、归楞和装车等工序提出了切实可行的改造措施。     

Log decomposition rates in Tasmanian Eucalyptus obliqua determined using an indirect chronosequence approach

Coarse woody debris (CWD) is a fundamental component of forest ecosystems, but one whose management presents challenges for land managers because its inputs and outputs are linked to, but not often in equilibrium with, disturbance events, including wildfire and logging. Understanding its rate of decomposition is one key element in being able to model its dynamics under different disturbance and management scenarios. We employed an indirect chronosequence approach to determine a decomposition rate for CWD of Eucalyptus obliqua, one of the dominant trees of Tasmania's commercially important lowland wet eucalypt forests. In sequence, we developed an understanding of the relationships of (1) decay-class and wood density; (2) decay-class and years-since-disturbance; and (3) wood density and years-since-disturbance, from which we derived decomposition functions, including single negative exponential functions. We found no clear relationship between decomposition rate and either log diameter or the nature of the disturbance event (logging or wildfire). We showed that models developed without a consideration of the effects of log fragmentation imply unrealistically slow decomposition rates. Our derived first-order decomposition rate constant (k) is 0.0085. This suggests that E. obliqua CWD in Tasmania's southern forests decomposes very slowly in comparison with CWD decomposition rates reported from most other parts of the world. We intend to apply our findings to the task of modelling CWD dynamics for informing forest management.     

基于自动导引小车系统盆栽水稻高通量输送系统的设计

针对栽培区中盆栽水稻需频繁搬运的问题,该文以自动导引小车AGV(automated guided vehicle)系统为核心设计了一套盆栽水稻高通量输送系统。盆栽水稻高通量输送系统包括AGV、无动力种植槽、输送线、上下线机、通讯与控制系统等。水稻主要通过AGV和输送线实现移动。无动力种植槽成行放置于栽培区中,且每个无动力种植槽中栽培24株水稻。AGV按照指令从栽培区中提取种植槽,并将其移动至上下线机,24株盆栽水稻通过上下线机整体进入输送线,并依次移动至指定地点进行作业,作业完成后24株盆栽水稻从上下线机又整体离开输送线,由AGV将盆栽水稻放回原址。AGV移动时通过激光条码定位,定位准确,误差为±5 mm。AGV移动速度快,最高速度达60 m/min。AGV移动平稳,取放、移动种植槽时,盆栽水稻不易倾翻。随机选取的240株盆栽水稻进行输送试验,试验表明,盆栽水稻高通量输送系统联机自动运行可以满足盆栽水稻表型检测速度要求,AGV提取和存放盆栽水稻时位置准确,无歪斜无碰撞,盆栽水稻在移动过程,状态平稳,无倾翻,无折断现象,而且实现了温室中设备的分区管理。该研究成果为其他温室盆栽植物输送提供了参考。     

王草收获机旋转刀盘式平茬切割装置设计与试验

针对目前王草缺少专用机械收获装备,传统通用型切割装置对王草平茬刈割效果不稳定等问题,设计了一种王草收获机旋转刀盘式平茬切割装置。根据王草簇状分蘖生长的生物特性和平茬刈割的收获要求,完成切割装置的总体结构设计,通过理论分析,确定了切割器和塔轮式输送器的关键结构和工作参数。利用ANSYS/LS-DYNA仿真对比单动刀切割和动定刀组合切割的切割效果,结果表明动定刀组合切割断面平整度优于单动刀切割,在刀盘低速切割时,动定刀组合的切割功耗小于单动刀切割;切割输送仿真试验表明塔轮式输送器的输送效果较好,能够实现割后王草茎秆的顺茬输送。搭建切割器试验台,采用Box-Behnken设计方法,选择动定刀间隙、刀盘转速和刀盘倾角为试验因素,留茬破头率和切割功耗为试验指标,建立了因素与指标间的回归模型,通过NSGA-Ⅱ算法,确定切割器最优参数组合为动定刀间隙2.98 mm、刀盘转速为84.7 r/min、刀盘倾角为28.65°,在此参数组合下测得留茬破头率为8.66%,单位切割功耗为7.78 mJ/mm²。在此基础上进行田间试验,试验结果与优化结果基本一致,结果表明旋转刀盘式王草平茬切...     

基于激光扫描的螺旋输送器焊接质量在线检测

联合收获机螺旋输送器因缺乏快速有效的在线检测手段导致其加工质量差,易出现物料堵塞、叶片开焊、叶片与外壳过度磨损等故障。为此,研究基于激光测距传感器的螺旋输送器焊接质量在线快速检测方法,设计联合收获机螺旋输送器焊接质量在线检测系统,通过结构关系和传感器布局,将主轴径向跳动量、螺旋叶片的径向跳动量以及螺距等关键参数的检测转换为对与之相应的距离信息检测,实现了多参数的连续、同步测量。试验表明,与传统人工测量方法需要根据经验选取多个测量位置、进行多次测量、单次测量耗时15~20min相比,系统可实现关键参数连续、同步测量,单次测量时间缩短至1min。主轴径向跳动量检测的最大相对偏差为3.661%,螺旋叶片径向跳动量检测的最大相对偏差为2.030%,螺距的测量标准差为2.07mm,满足检测需求。系统通过对检测数据的分析处理,实现加工误差的精准定位和3D可视化展示,并根据公差要求对螺旋输送器进行合格性检查评价,对超限变形进行报警。     

山地果园轨道运输机研究应用进展

我国是水果种植大国,水果品种资源丰富,分布地域广阔.随着农村产业结构的调整和林果产业的不断发展,林果种植面积不断扩大,但由于我国果园地形以丘陵为主,地势陡峭,作业环境复杂,这些均制约了果园经济的发展.因此,研究适合山地果园的轨道运输机至关重要.本文研究了国内轨道运输机的现状,指出轨道运输机对果园的重要性;在此基础上,归...