Variable rate fertilization control system based on reckoning track distance and its application

Developed a control system based on reckon up track distance for a variable rate fertilizer applicator without GPS. The control system is able to read the velocity sensor's pulse signal, calculate the ground speed and track distance of the fertilizer applicator, and recognize the working grid by means of the algorithm of automatic grid recognition after error correction. And then, the control system controls fertilizer output by change the step motor's rotational speed according to the prescription data saved in the control system in advance. The field experiment results showed that maximum error of fertilizer output is 4.11% in a grid field of 40m×40m and satisfy the requirements of variable rate fertilization.