Abstract:To meet the no-till sowing pattern of wide and narrow rows in the drip irrigation area of Xinjiang, the sowing of traditional large maize no-till planter has problems of touching stubble, failing to constrain path accurately and having a low qualified rate of maize kernel spacing. Combining the agronomic requirements of no-tillage seeding, the navigation and positioning technology was utilized to obtain information about the deviation between the current position of the seeder and the target path. The deviation automatic adjustment system was designed based on the no-tillage seeding stubble avoidance device. The system included a stubble avoidance device, a hydraulic actuating system, and a hydraulic steering control system. Through establishing the mechanical model of machine, stubble avoidance device and hydraulic actuating system were analyzed in terms of movement and force. The key structural parameters of stubble avoidance and hydraulic steering were determined. Meanwhile, the optimal hook-up length of stubble avoidance device and the maximum driving force of hydraulic actuating system were obtained. Moreover, the hydraulic steering control system was optimized to realize function of automatic adjustment for stubble avoidance devices and acceptance of feedback information. The results showed that the maximum steady state error of desired adjustment angle was 0.932° for neural network PID, the overshooting amount was less than 1%, and the average response steady state error was less than 0.9°, which met expectations. When the tractor operating speed was no more than 1.0m/s and amount of straw covered between rows was no more than 1.0kg/m2, the field test showed that the stubble avoidance rate was no less than 85%, vertical adjustment distance was no more than 8.6m, and coefficient of variation for qualifying grain spacing in maize was no more than 21.63%. Seeder had the best effect of offsetting and stubble avoidance and met the agronomic index requirements of maize no-tillage planter.
