Design and evaluation of PID electronic control system for seed meters for maize precision planting.

A proportional-integral-derivative (PID) electronic control system for seed meters was developed to improve the planting quality and operation efficiency of conventional planters with ground wheel and chain driven system. A PID algorithm was used for controlling seed plate rotation speed. In addition, the PID controller incorporated integral separation of the integral term to increase the response time and reduce the occurrence of overshoot when the set point was far away from the current rotation rate. The final tuned PID parameter values were Kp=16, Ki=0.05, and Kd=36. The response time, overshoot, and steady error for a seed plate rotation speed step response from 0 to 24 r/min were 0.4 s, 1.56%, and 0.75%, respectively. Experiment results showed that the Singulation index (SI) of seed meter could receive to 98.4%, and the Multiple index (UI) and Miss index (MI) were not more than 1% even at the highest planting speed of 12 km/h, which indicated that the seed meter with the developed control system and tuned PID parameters could obtain better planting quality and higher planting speed. [ABSTRACT FROM AUTHOR]