Study On Variable Spraying Technology And Relative Parameters Optimization Of Spray Seeding Machine Based On Multi-source Information

Pneumatic spraying technology is an effective method to recover degraded grassland vegetation under natural climatic conditions.In order to improve the efficiency of spraying and the quality of spraying in the grassland environment,the precision and intelligence of the spraying were increased,vegetation restoration in the degraded grassland was accelerated,and automatic variable Spraying of Spray Seeder and optimization of related parameters was carried out based on the multi source information.A relationship model was established between key parameters such as spray volume and forward speed,nozzle oscillation frequency,seeder rotation speed,nozzle inlet air flow velocity,and work inclination angle.A compensation mechanism was designed to improve the falling seed trajectory so that the replay rate and leakage rate of the area are minimized.The kinematic model and steering mechanism model of the sprayer’s walking system were constructed,the path tracking controller and steering controller were designed and the effect of the special surface of the grassland on the automatic control and spray broadcasting quality of the sprayer was revealed.The information collected by the visual sensor is processed to realize the automatic,real-time and accurate variable spray control of the sprayer with the change of the vegetation coverage on the ground surface.The main conclusions were as follows:1.The main factors affecting the seeding performance are the airflow velocity at the inlet of the spray cylinder,the particle size of seeds and the speed of seed metering device.2.A walking test platform system was set up.Meanwhile,the kinematics model and the steering mechanism model of spray walking system are constructed.A path tracking controller was designed based on fuzzy control theory.It was optimized according to the idea of variable domain thinking.The two controllers can all carry out path tracking control,and compared with the original controller,the position deviation of the optimized controller was decreased from 0.34 m to 0.18 m,and the angle deviation was decreased from 1.09 degrees to 0.98 degrees.The steering controller is designed by using the auto disturbance rejection technique.The steering adjustment time was within 2s,and the steering accuracy was within 1 degrees.3.Based on the trajectory equation of seed falling during the operation of the seeding machine,aimed at minimizing the rebroadcast area plus the missed broadcast area.The swing frequency of the spray cylinder was optimized and the optimum swing frequency of spray cylinder corresponding to different advancing speed was obtained.After optimizing the swing frequency,the seed trajectory is exactly the same.In the drop area,the area of rebroadcast and missed broadcast is equal.4.The seed dropping trajectory are adjusted by setting seed uniformity compensation mechanism.When the swing frequency of the cylinder is less than 7.3min^-1,the missing broadcast area was reduced by 37.5%and the rebroadcast area was20%in the falling area,by adjusting compensation mechanism.When the pitch angle and roll angle of the spray seeder vary in the range of-11.5 degrees-15 degrees,the height of the compensation mechanism can be adjusted to compensate the change of the falling area caused by topographical changes.5.The automatic variable spraying control system of the spray seeder is built on the basis of the visual sensor recognition,image processing,and mathematical relationship between the speed of the seed metering device,the forward speed of the seeding machine and the coverage of the vegetation.The method of determining the vegetation coverage adjustment coefficient k1 and the uniformity factor k2 of the seeding area is also determined.When the speed of the spraying machine is 0.3 m/s and 0.5 m/s respectively,the swing frequency of the cylinder is less than 15 min^-1,the sprayed amount is adjusted by the automatic variable spray control system to reduce the rebroadcasting,missing broadcast area,and falling seed.The normal sprayed area can reach 92.2%of the total sprayed area.