林木联合采育机的时间-能量综合最优轨迹规划与控制方法研究

Logging harvester is a set of high-performance modern forestry machinery, which can finish a series of continuous operations such as felling, delimbing, peeling, bucking and so forth with manual intervention. The research group which the applicant is in has successfully developed the first domestic multifunctional forestry felling & cultivation machine. It is found in the experiment that: the process of delimbing, peeling, and bucking can be completed fast by the logging harvester, but for the process of the alignment of logging head and capturing trees, the operator needs a lot of observation, judgment and repeating operation, which results in the no-effect time inceasing in one operation cycle; simultaneously, the re-alignment process and unreasonable action of hydraulic cylinderjoints during the working process cause the losses of the fuel in the system, increase operating costs and hinder the promotion of logging harvester. This research is based on previous study on the laser measurement for harvesting trees and trajectory planning of harvesting manipulator based on laser-guided, and in order to realize the efficient autonomous and low-consumption economical harvesting. Dynamics model of multi-DOF harvesting manipulator will be given, time-fuel optimal trajectory planning and control strategies for hydraulic harvesting manipulator will be proposed, and hardware in loop simulation and prototype expriment will be carried out in order to achieve low energy consumption, quick and accurate alignment and capture of the trees, thereafter the problem of long no-effect time and high fuel loss will be solved, the operation efficiency will be improved and the operating costs will be reduced for the logging harvester.

林木联合采育机是一种高性能先进林业装备，可在人工干预下完成采伐、打枝、去皮、造材等连续作业，申请人所在项目组研制成功了国内首台多功能林木联合采育机，在其实验中发现：联合采育机的打枝、去皮、造材环节可快速完成，但将伐木头对准和捕获立木的环节需要操作员做出大量观测判断和反复对准，造成单位采伐周期内无功时间加长；同时液压采伐臂的往复对准运动和液压缸不合理动作轨迹，造成了系统的燃料损耗，增加了作业成本，制约了联合采育机推广应用。本项目以前期开展的立木激光测量和基于激光导引的采伐臂作业轨迹规划为基础，以高效自主和低耗节能的人工林采伐为目标，建立多自由度液压采伐臂的动力学数学模型，运用时间-能量最优化方法开展液压采伐臂的作业轨迹规划与控制策略理论研究，并进行半实物仿真和样机实验，实现伐木头对目标立木的低耗快速对准和捕获，解决目前林木采育机无功时间长和燃料损耗大问题，进一步提升其作业效率并降低使用成本。

林木联合采育机是一种高性能现代林业装备，可在人工干预下完成采伐、打枝、去皮、造材等连续作业，项目组在对研制的林木联合采育机测试中发现：联合采育机的打枝、去皮、造材环节可快速完成，但将伐木头对准和捕获立木的环节需要操作员做出大量的观测判断和反复对准，造成单位采伐周期内的无功时间加长；同时液压采伐臂的往复对准运动和液压缸不合理动作轨迹，造成了系统的燃料损耗，增加了作业成本。针对上述问题，本项目主要开展了如下研究工作：.（一）本研究首先将激光测量技术以及多传感器信息融合处理方法引入到林木联合采伐装备中，激光测量技术具有精度高、受环境影响小、速度快、测量范围大等优势。通过在林木采伐联合机上安装二维激光扫描装置，以非接触测量的方式，获取多株立木的点云数据。通过对点云数据的投影、聚类、滤波、线性化变换和拟合，自动准确提取了采伐目标的胸径、伐木头相对目标立木的三维坐标和方位角、多棵立木间距等参数，为辅助操作员操控伐木头快速地识别、对准和捕获目标立木提供了测量数据。.（二）研制了六维并联式惯性测量单位，可用于本项目中获取伐木头和车体的三维加速度、角速度等惯性信息，以用于液压机械臂的轨迹规划与控制。.（三）本研究在采伐目标立木激光测量的基础上，以高效自主和低耗经济的人工林采伐作业为目的，建立了多自由度的液压驱动采伐臂的正运动学和逆运动学模型，获得伐木头位姿变量、各关节变量与各液压缸之间的变换关系，开展了多自由度液压驱动采伐臂的作业轨迹规划的研究，使伐木头沿给定的直线路径、圆弧路径以及基于激光测量数据自主完成立木的采伐作业。.（四）基于Visual C++平台和OpenSceneGraph三维图形引擎开发了林木联合采育机作业虚拟仿真系统，该虚拟仿真系统包含林木联合采育机多自由度液压采伐臂的数学模型，可输入控制参数和指令，并实时显示和保存运动信息。使用该虚拟仿真系统验证了液压采伐臂的作业轨迹规划与控制策略。.（五）设计和加工了林木联合采育机的液压驱动采伐臂实验样机，进行了该机械臂样机的运动测试实验。.本项目研究是进一步提升林木联合采育机自动化程度和降低作业成本的有效途径，是人工林采育装备研究的新技术与新方法，可为正在实施的国产林木联合采育机的批量制造和推向市场奠定理论和技术基础。