Design and Experiment of a Fertilization Rotation Speed Control System Based on Radar Speed Feedback

Rapeseed planter application in simultaneous fertilization faces extensive mode and poor precision challenges. In this study, we attempt to mitigate these problems by combining high-precision radar speed sensors and fertilization parameters with the relation between the rotation speed and the fertilizer amount of the fertilizer discharge apparatus. We designed a fertilization control system based on a high-precision radar sensor. The mathematical model of the permanent magnetic direct-current motor was constructed, and the transfer function of the control link was determined. Using the regulation toolbox in MATLAB 2020-PD, the proportional-derivative (PD) control parameters were determined. Finally, the tests were performed to validate the performance of the designed fertilization control system. The relation between the actual fertilizer discharge amount and the target value was used for evaluation. The relative errors of 2.82, 2.67, and 3.43% were obtained between the target fertilizer application rates and the actual rates in constant-speed fertilization, pave variable-speed, and field tests, respectively. They fall within the acceptable range, proving that the developed system satisfied the fertilization quality requirements and showed high control precision. The present research results can provide a theoretical reference for simultaneous rapeseed seeding and variable fertilization.