Design and experiments of the single driver for maize precision seeders based on fuzzy PID control

Abstract: A corn precision seeder can determine crop performance during the whole process in Xinjiang of western China. In this study, a single driver of corn precision seeder was proposed to stabilize the planting quality under high-speed working conditions using fuzzy PID control. A functional circuit was built with the STM32F103C8T6 microcontroller as the core, according to the hardware composition and working principles of the motor-driven planting row control system. The operating speed of the planter was collected by a Hall-effect sensor, and the motor speed was fed back in real time by the high-precision photoelectric rotary encoder. A fuzzy PID with the gain adjustment was selected to make the speed control system modify the PID control parameters in real time, according to the speed deviation and deviation change rate. Therefore, the motor speed was quickly and precisely followed the operating speed. The speed control test showed that the motor presented excellent start-up characteristics with the pulse width modulation (PWM) frequency of 60 kHz. Specifically, the actual speed coefficient of variation for the motor was less than 6.29% at the motor speed of 307 to 10441 r/min, indicating higher stability and linearity. The motor speed test showed that the overshoot of the fuzzy PID speed regulation system was 0.4%, which was much lower than before, particularly when the target speed of the motor was set at 1500 r/min. The rising time and regulation time were shortened by 0.12 and 0.49 s, respectively, and the steady-state error was reduced by 0.3 percentage points. Furthermore, the accuracy and robustness of dynamic speed regulation were much higher in the fuzzy PID system than before, when the speed feedback period of the planting bed was T=1.0 s. The motor-driven planting bench test showed that there was a small difference in planting performance indexes between the two control system when the operating speed was 8 and 10 km/h. The planting qualification index of the fuzzy PID control was more than 93.04%, whereas, the reply- and miss-planting indexes were less than 5.13%, and 1.83%, respectively when the operating speed was 12 km/h. Furthermore, the average qualification index increased by 2.50 percentage points, whereas, the average replay- and miss-planting indexes decreased by 0.85 and 0.88 percentage points, respectively, compared with the traditional one. All planting performance indexes were better than before suitable for high-speed planting operations. The finding can provide a strong reference for the design of the corn high-speed precision planter.