Low-cost turn compensation control system for conserving seeds and increasing yields from maize precision planters

Inconsistencies in seed spacing can occur between rows when a traditional maize precision planter drives along a curve because the inner and outer rows travel faster or slower than the center rows. This results in the wastage of expensive seeds and a decrease in the yield. In this study, a low-cost turn compensation control system (TCCS), based on a dual-radar system, for maize precision planters was developed to address these problems. The system automatically modifies the seeding rates for different rows by individually adjusting the rotary speeds of the drive motors. During the research, a mathematical model for calculating the individual travel speed of each plant row was developed according to rigid body kinematics and the Ackerman steering principle. A simulation model was also built in the MATLAB Simulink software to qualitatively evaluate the primary factors (speed accuracy (SA), turning radius (TR), and turning speed (TS)) that affected the performance of the TCCS. Field trial results showed that the average seeding rate error (AEQ) did not exceed 4.52%, 2.12%, and 2.77% for TRs of 7 m, 14 m, and 28 m, respectively. These values were significantly lower than those at the equivalent TR conditions when the turn compensation function was turned off: 19.41%, 9.04%, and 5.47%, respectively. With the newly developed TCCS, a uniform seed spacing for each plant row was obtained, regardless of the changes in TR and TS. Additionally, the maximum average seed spacing variation coefficient (APREC) did not exceed 19.93%, a value lower than the requirements set by Chinese national standards. In summary, the proposed TCCS reduced maize production costs and improved net profits by ensuring the same seed spacing for all the plant rows. The total cost of the TCCS for a six-row precision planter was only $4,496.82, which is significantly less than that for functionally similar control systems produced by some well-known agricultural machinery manufacturers, making it more suitable for cost-sensitive farmers.