摘要
为了解决现有林果收集装置体积庞大,结构复杂,对果树行间距要求高等问题,该文以国内外现有林果收集设备为基础,以折展性能较好的空间折展机构为切入点,提出了一种小型侧翼折展式林果收集装置。对收集装置的主要结构—侧翼折展机构,进行了运动学分析,采用遗传算法对此机构的主要杆件进行尺寸优化,并建立侧翼折展机构的三维模型,导入ADAMS动力学分析软件中进行仿真和计算。根据理论分析与仿真结果,加工试验样机,进行野外采收试验和末端轨迹验证,比较虚拟仿真轨迹与由高速摄像捕捉到的样机实际运动轨迹,验证了侧翼折展机构设计方案的正确与可靠性,并得出此收集装置对于大枣树和银杏树的平均承接率分别为84.68%和66.71%,可为后续机构的改进提供参考依据。
Most orchard gardens are distributed in the subtropical and tropic zone, and especially in mountainous and hilly region in China. With the development of science and technology and the increasing cost in labor, the mechanized operation for fruit collection is needed. Existing small fruit collecting devices have bulky and complex structure and need to be equipped with high-power drive, and strict requirement in the tree spacing. In order to adapt to the mechanization collection of small fruit and improve the mechanical collecting device, based on the existing fruit collection equipment at home and abroad, and considering deployable and foldable mechanisms of the equipment, a collecting device with flank deployable and foldable mechanism was introduced in this paper. This collection device mechanism can reduce the bulk in process of moving, adapt in line spacing of the fruit trees, have larger coverage area in unfolding state, and can adjust quickly and effectively in operation to improve collecting efficiency. The collecting device consisted of three parts: flank deployable and foldable mechanism (the core mechanism), lifting mechanism, and mobile clamping mechanism. The displacement and coordinate point G at the end of the flank deployable and foldable mechanism were calculated by transformation matrix. Then kinematics of the flank deployable and foldable mechanism was analyzed, and the main components of the mechanism were optimized using genetic algorithm (GA) operated in MATLAB. Rod AB, AD, PE were taken as the main optimization variables by comparing the influence of variable rod length on the displacement of point G and ZEFG. Given the radius in folding and unfolding, the maximum displacement of point G during the unfolding process and the minimum dimension sum of the rods were taken as the optimization objectives. In order to obtain the more preferable rod dimension, the optimization range of the rods was expanded about ~50 mm. And the final optimization range and optimal solution of the main rods dimension were obtained based on the restrictions by iterative calculation at last. The optimal dimensions of the main components were las=277.88 mm, l~=661.64 mm, lp^-=306.58 mm. The obtained results were used to modify the 3D model of the flank deployable and foldable mechanism, and the 3D model of this mechanism was imported into the dynamic analysis software ADAMS. From such model, then the motion trajectory of the mechanism was simulated and the dynamic simulation results showed that the driving torque was 2.4 N.m. The motor type was determined based on the results achieved by simulation. Finally, a prototype of the flank deployable and foldable mechanism was manufactured and tested based on the optimal theoretical model, and the trajectory of point G was recorded by the Phantom v5.1 high-speed camera. Due to precision and errors of the prototype caused by machining and assembling and errors from camera shooting angle and image processing, there was a slight deviation between trajectory of experiment and virtual simulation, but they were basically consistent, which verified accuracy and reliability on the theoretical design of this collecting device. Experiment results of mechanical harvest using a small fruit collecting device with flank deployable and foldable mechanism demonstrated that this collection device had practical value and this research provides a reference for the improvement of the other collection mechanism.
作者
杜小强
李党伟
王丹
武传宇
林乐鹏
Du Xiaoqiang Li Dangwei Wang Dan Wu Chuanyu Lin Lepeng(School of Mechanical Engineering and Automation, Zhejiang Sci-Tech University, Hangzhou 310018, China Zhejiang Provincial Key Laboratory of Transplanting Equipment and Technology, Hangzhou 310018, China)
出处
《农业工程学报》
EI
CAS
CSCD
北大核心
2017年第14期11-17,共7页
Transactions of the Chinese Society of Agricultural Engineering
基金
国家自然科学基金项目(51475433
51505431)
浙江省高校中青年学科带头人培养项目
浙江理工大学科研创新团队专项(13020049-Y)
浙江理工大学521中青年拔尖人才项目
浙江理工大学研究生创新研究项目(No.YCX15029)
关键词
收获机
机构
优化
林果收集
折展机构
遗传算法
仿真
harvesters
mechanisms
optimization
fruit collection
deployable and foldable mechanism
genetic algorithm
simulation