| At present,the domestic transplanter is mainly a semi-automatic transplanter,which is limited by the frequency of artificial seedling,the efficiency of transplanting is restricted,and the semi-automatic transplanter has many problems,such as more manual labor,high labor intensity,high cost of transplanting.Therefore,it is imperative to develop an efficient fully automatic tomato transplanter suitable for the current situation of our country.Aiming at the above problems,on the basis of the existing semi-automatic tomato transplanter,the key mechanism of the automatic tomato transplanter is designed,and the automatic transplanter is trial-produced,and the experiment of transplanting and seedling picking is carried out.The main contents are as follows:(1)Statistical and experimental analysis of physical and mechanical properties of tomato seedlings and substrates were carried out to provide basis for mechanical structure and size design of various mechanisms.The growth of tomato seedling substrates at different seedling ages was analyzed.The growth of Seedling Substrates for about 40 days was suitable for mechanical transplantation.Compression resistance and ejection force of seedling substrates were tested.The results showed that when the moisture content of substrates was 21.3%,the maximum pressure resistance was 16.5N,and the compression displacement was 10.5mm.When the moisture content of seedling substrates was 13.4%,the maximum ejection force was 4.14 N.Finally,the physical shape size of seedlings was analyzed.(2)The overall scheme of the transplanter is determined,and the structure and working principle of each mechanism are expounded.The automatic tomato transplanter uses modular design and six seedling fetching devices to work synchronously.Through the cooperation of the seedling fetching mechanism with the automatic tray moving mechanism,the automatic seedling feeding mechanism and the planting mechanism,the transplanting,grasping,throwing,feeding and planting of the tomato seedlings are completed.(3)The design and Simulation of the key components of the automatic tomato transplanter,the tray-moving mechanism and the seedling-taking mechanism,were carried out.Through theoretical analysis and calculation,the design of the transmission system and the selection of key accessories are completed,and the auxiliary device is designed to reduce the rubbing force of the mechanism.Geometric analysis model and force balance equation were established to meet the requirements of seedling trajectory.Constraint equation was established for the process of seedling needle insertion into matrix.Based on theoretical analysis,a set of better data was put forward.Based on ADAMS,the kinematics simulation of seedling harvester was carried out,and the movement parameters curve of seedling harvester was obtained.The movement process of each stage was analyzed to verify whether the mechanism meets the design requirements.(4)The prototype was processed,installed and debugged,and the tray-moving test and seedling-taking test were carried out.The experiment results show that when the transplanting speed is less than 350 mm/s,the average positioning accuracy is 99.62% when a new seedling tray is moved to the seedling location,and 98.53% when the seedling tray moves a row of distances,which can meet the requirements of the positioning accuracy of the tray.The results showed that when the angle between the claw and the vertical direction was 8 degrees,the highest success rate was 97.5%.The design of the claw was reasonable and met the working requirements. |
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