Abstract:
At present, the tillage and seeding in the production of greenhouse fruits and vegetables have been mechanized. however, current mechanical devices are not suitable for mid-term management and transportation of viaduct cranberry fruits and vegetables. It means low efficiency and the need for more farmers, which restricts the development speed of the hole course mechanization of fruit and vegetable to produce seriously. Aiming at the problems of high labor intensity and low working efficiency in fruit and vegetable management, picking and transportation, pollution problems and so on, an electric lifting platform for greenhouse was designed based on studying and analyzing the collected data, which had the functions of walking, turning, lifting and hanging transportation. The electric lifting platform for greenhouse was mainly composed of the workbench, lifting device, chassis, battery pack and control system with dual operation mode and so on. The working principle was described, and the structure and parameters of key components were studied by theoretical calculation and simulation analysis. In particular, the control system with dual operation mode was designed to remote and online operation of the job platform, which was programmed by C language based on STC 15W4KS4 series single chip computer. In the end, the research about turning performance, slope driving and climbing performance and endurance time of the platform by the bench and field tests were carried out in the lab respectively. The test results showed that the minimum turning radius was 0.94 m, the maximum speed was 2 km/h, and the endurance time could reach to 4 h under 200 kg load. Driving on a slope, the forces analysis of platform from the slope in 3 conditions were carried out, it showed that the climbing angle was unchanged, the stability of the platform under different conditions was related to the platform weight, the loaded weight, the contact length, the lifting height, the center distance between the left and right caterpillar, and the width of caterpillar, etc. The maximum tipping angle was 30.5°, 25.6°, and 20.6° when the platform was lengthwise, crosswise and oblique to the slope respectively. The maximum tipping angle was closely related to the center of gravity of the platform. And it was gradually decreases when the height increase of workbench and loads increase. It was also closely related to the position of state platform and slope. The safety factor was the highest when the platform was lengthwise to the slope, which was better than that crosswise and oblique to the slope. When the power was above 60%, the maximum speed would always be maintained; when the remaining power was below 60%, the maximum speed would gradually decrease with the decrease of the power; when the remaining power was 40%, the endurance time was already 3.5 h; when the power was less than 40%, the power of the battery would decline rapidly; when the remaining power was 10%, the driving speed was only 0.5 km/h and the total endurance time was 3.9 h. So we could deduce that when the power was exhausted, the total duration was enough to reach 4 h. In order to evaluate the driving stability of the field slope, the cornering performance, the ground transportation performance and the lifting performance of the work table, the field experiments were carried out in Changshu, Shandong province. The results showed that all the parameters met the design expectation and the agronomic requirements of greenhouse structure. It provides a reference for fruit and vegetable management, picking and transportation in greenhouse.