Design and test of automatic cuttage device for arched shed

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.