| In recent years, because of the backwardness of pesticide spraying technology and spraying machinery and spraying machinery equipment in China, only a small part of the pesticides are rationally and effectively used by the crops. In addition most of the pesticide is wasted, resulting in insufficient of application rates of the pesticide, unable to play an effective role in pest control. While pesticide residues will go into the soil with the rain, causing serious pollution to the ecological surroundings.Among the plant protection machinery, because of its reliability, stably controlling, easily operating and be able to adapt to the requirements of large-scale mechanized operations, boom sprayer has become the first choice for many farmers in plant protection operations. Because of widespread use of boom sprayer, its shortcoming has become a research object for experts and academics of plant protection. For example, because of the external force, the liquid sprayed by the sprayer will drift during operation. A large amount of liquid can not reach the exact site, causing pesticides waste and residues. Experts and scholars of plant protection sector domestic and foreign drew the conclusion that the motion state of boom has a significant influence on the accuracy of pesticide spraying. Therefore, the posture control system of boom need to be designed to achieve automatic and real-time adjustment of the boom. In order to solve the influence of boom motion on the pesticide spraying, the automatic control system of the boom posture was designed. The liquid spraying test was also conducted to verify the accuracy of system. The main contents are as follows:(1) The components of boom sprayer were designed. And the boom sprayer was assembled with the use of 3D modeling software Solid Works developed by the Dassault in France. The motion simulation of the boom sprayer was also conducted with the use of the simulation function of the Solid Works. The size of some components were optimized according to the results of the simulation. Finally we get the whole assembly 3D models of boom sprayer fit for the posture control system of boom.(2) In order to achieve automatic control of the boom posture, posture induction unit was added at the end of the boom to achieve real time monitoring of boom posture.(3) The boom must be able to fold in order to facilitate the transport. The boom must be also able to expand during the field work. Therefore the hydraulic circuit was designed to achieve automatic folding and expanding of boom. The automatic control system of boom posture was designed. It is controlled by the microcontroller Arduino development board, achieving the automatic control of the boom posture and making boom remains parallel to the ground. Tests showed that, the height of boom sprayer maintains from 1000 cm to 1012 cm away to the ground. And the boom posture will be well controlled when the driving speed is no more than 10 km/h, making the boom substantially parallel to the ground.(4) The finite element modeling and numerical modal analysis for the boom was also conducted, verifying the stability of the boom structure.(5) The field tests for boom sprayer with automatic control system of boom posture was conducted. We drive the tractor through a projection with certain height to simulate uneven pavement in the field. The results showed that the boom could maintain parallel to the ground. The liquid was evenly sprayed. The boom sprayer could satisfiy the requirements of pesticide spraying operation. |
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