【作者】 王建利；

【导师】 刘晋浩；

【作者基本信息】 北京林业大学 ， 森林工程， 2015， 博士

【摘要】 目前我国林业增长迅速,人工林种植面积不断增加,随着林业工人收入的不断提高,林业工作亟需采用机械化作业方式。本研究依托公益项目：人工林抚育关键技术装备的研发(201104007-3),该设备的研发主要包括三部分：机械主体、液压驱动以及目标特征提取。本研究紧紧围绕清林抚育割灌机这一主体展开,主要研究内容及方法如下：1、清林抚育割灌工作装置的结构设计、试验。在认真分析、调查国内外现有同类产品技术的发展情况的基础之上,分析国内人工林使用需求,提出了使用盘式割灌的方法,采用传统机械设计理论对关键部件进行分析设计,最终完成样机设计。2、对液压系统进行改进设计。在项目进行中,发现管路中在马达启停的瞬间存在液压冲击现象,通过理论与仿真相结合的方法,确定了液压冲击的成因,并提出改进方案。在此基础上,结合绿色环保、节能减排的需求,提出了一种利用蓄能器进行制动能量回收再利用系统,通过仿真分析给出了优化后的蓄能器参数：充气量1.2L充气压力7MPa,此时的能量回收再利用效果较好,可以在一次启动和停止过程中实现节能1775J。3、对清林抚育保留幼木的特征提取方法研究。在对样机进行实际实验过程中发现,操作员一方面需要驾驶底盘在林木行间向前行进,另一方面要操作工作装置左右摆动式清林作业,同时为了防止误割幼木,在操作时需认真观察周边环境。这样的工作流程极大的增大了驾驶员的工作压力,造成疲劳,降低工作效率。针对此问题,提出采用二维激光扫描测量的方式对工作场景进行扫描,通过对扫描数据进行滤波、分割、特征提取、分类的方法实现对作业场景中幼木的识别,为建立智能操控系统提供了理论依据。通过对以上内容的研究,最终形成了以下成果：1、设计、制造新型清林抚育割灌工作装置样机。2、提出了一种针对二维激光扫描数据处理改进的高斯滤波算法。3、提出了一种用于二维激光扫描数据处理的动态阈值差分提取算法。4、提出了一种基于正切变换的二维激光扫描幼木特征提取方法。通过实际试验证明,所设计的清林抚育工作装置具有良好的清林割灌效果,所提出的滤波、提取算法能够很好的提取出小尺度幼木的二维激光扫描数据,所提出的二维激光扫描数据下的幼木特征具备良好的识别效果。更多还原

【Abstract】 At present, China forestry acreage and plantation acreage increase rapidly. With the continuous improvement of forestry workers’ income, the need for mechanized forestry practice become urgent. This research relies on public welfare project:research on key technology of tending and clearing equipment for plantation (201104007-3), the equipment mainly contains three parts:Mechanical body, hydraulic drive and feature extraction of working target. In the present paper, contents are orgnised focusing on this tending & clearing machine and the main reaserch contents and methods are as follows:1. Structure design and experiment of tending & clearing machine. Based on careful study of development of existing similar products at home and abroad, analysis the demand for platation usage, select disc working device structure as domestic mechine. Design the working device with the guide of traditional machine design theory and complete the prototype finally.2. Design and improvement of hydraulic system. During experiments of the project, hydraulic shock problems are founded, to solve these problems, a combination of theory and simulation methods are used to determine the hydraulic impact. On this basis, combining the needs of environmental protection, and energy conservation, an accumulator brake energy regeneration system is presented, and its optimized accumulator parameters are being obtained by using simulation method. The charge capacity is 1.2L, and its relevant charging pressure is 7MPa, a better energy regeneration effect can be obtained in this situation, in which can save 1775J in each stoping process.3. Study on the feature extaction method of reserved saplings. In actual prototype experiment, we found that operators need to on the one hand drive chassis between the trees lines and rows, on the other hand to operate the working device swing around the forest doing clearing operations, and in order to prevent accidental cut young trees, the driver need to carefully observe the surrounding environment. Such workflow increases the driver’s psychological pressure greatly, resulting in fatigue, thus reduces working efficiency. To solve this problem, a two-dimension laser scanner is used to scan and measure the work scene, by using scan data filtering, segmentation, feature extraction and classification methods to achieve recognition of saplings in the work scene, thus offer a theoretical basis to the establishment of intelligent control system.Through the above study, culminating in the following results:1. Design, manufacture new work equipment prototype for clearing & Tending.2. An improved Gaussian filtering algorithm is proposed particularly used for the two-dimension laser scan data processing.3. A differential algorithm using dynamic threshold is proposed to extract arc like data from 2D laser scan data.4. A set of saplings characteristics extraction method is proposed for 2D laser scanning based on tangent transform.Actual test proved clearing & tending device designed to work with good brush clearing effects, and the proposed filtering, extraction algorithm can extract saplings of small-scale from 2D laser scan data, and the proposed two features of saplings with 2D laser scan data have good recognition results.更多还原