拱棚自动插架装置设计与试验

Design and test of automatic cuttage device for arched shed

目前建造拱棚主要以手工为主,为了提高其机械化、自动化水平以及建造拱棚的效率,该文设计与研制了拱棚智能插架覆膜机的拱棚自动插架装置。基于拱棚搭建的入土深度、棚架宽度、棚架高度等技术要求和曲柄存在的条件,对其关键部件曲柄滑块机构和弯折手臂进行结构设计与优化。当曲柄的长度为230 mm,连杆的长度为220 mm,偏心距为220 mm时,达到最好的传力效果和运动效率;同时对曲柄滑块机构进行运动分析,确定插架作业时曲柄的初始角度和最大位置角度分别为132°和30°;设计弯折手臂使棚杆变弯,确保棚杆垂直入土;然后基于ANSYS分析拱棚抗风性能,当棚度架宽与棚杆长度的比值在0.60~0.66之间时,拱棚抗风性最强;最后通过田间试验测量分析棚架平均宽度、棚杆平均入土深度和棚架平均高度分别为93.85、15.23和56.19 cm,获得棚架高度、棚架宽度的稳定系数均为99%。装置插架效果满足农艺需求,进一步验证了装置设计的正确性和方案的可行性。研究结果可为实现拱棚的自动插架覆膜机研制提供理论基础。

In modern agricultural production,the arched shed is more and more widely used in vegetable cultivation and seedling breeding.The arched shed is mainly built by manual.At present,the agricultural demand of arched shed width is about 0.8-1.5 m,and the height of arched shed is about 0.4-1 m.In order to improve the mechanization and automation level and the efficiency in the process of building arched shed,automatic cuttage device of arched shed was designed in this paper.Automatic cuttage device of arched shed was mainly composed of hydraulic transmission system,arm bending,crank slide mechanism,and tent pole cuttage mechanism.The hydraulic transmission system was the power source of the device.According to the technical requirements of building the arched shed and the conditions for the existence of crank,the structural optimization design of the crank slider mechanism was carried out,which was the critical component of automatic cuttage device of arched shed.When the length of the crank was 230 mm,the length of the connecting rod was 220 mm,and the eccentricity was 220 mm,the best force transmission effect and the movement efficiency were achieved.In addition,,the motion analysis of the crank slider mechanism was carried out.The initial angle and the maximum position angle of the crank were determined as 132°and 30°,respectively.The bending arm was designed to bend the shed rod,and at the same time to ensure that the shed rod vertical into the soil.The stress analysis of the rod in the initial state was simulated with different place of application of force,which is the different distance between the end of the bending platen and both ends of the rod.The closer this distance is,the greater the deformation will be.Therefore,the total bending arm length was set to be 44 cm,of which the length of bending platen was 7 cm.The thin and soft skeleton of the arched shed was covered with a flexible plastic film on the outside of the structure,which is more sensitive to the wind load.It is particularly important to ensure the wind resistance of the arch canopy.The wind resistance of small arch shed was analyzed by ANSYS,and it was found that the wind resistance of arched shed was the best when the ratio of frame width to frame length was between 0.60-0.66.The key parameters such as the height of the roof from the top of the shed,the width of arbor and the depth of shed insert soil were measured.The average buried depth was 15.23 cm,and the stability coefficient was 97.86%.The average height and width of the tunnel were 56.19 cm and 93.85 cm respectively,the stability coefficient of them were 99%.Combined with the agricultural demand,the errors were within the allowable range.The correctness of the optimized design,the feasibility of the solution and the stability of the machine operation are further verified.