基于PLC的步进电机驱动排种器控制系统设计

Design of Control System with Stepper Motor Driving Seed-metering Device Based on PLC

播种过程中排种器的驱动方式对播种质量有很大影响。地轮驱动的排种器虽然控制简单,但因地轮滑移常造成排种器漏播;而以步进电机取代地轮来驱动排种器,可以精确控制播种株距,减少漏播现象的发生,提高播种质量。为此,以三菱FX3U系列PLC为控制器,分析控制步进电机的硬件电路和梯形图,通过数字编码器检测拖拉机行进速度,根据拖拉机行进速度和株距计算出步进电机所需脉冲的频率,并输出控制步进电机的速度。为操作方便,系统采用触摸屏进行参数设定和工作状态显示。研究结果对提高排种器的排种质量具有重要的应用价值。

The driving way of seed-metering device has a great influence on the seeding quality during the seeding process.Although the control system of seed-metering device driven by the ground wheel is simple,it often causes the seed-metering device to miss the seeding because of the slide of the ground wheel.It can accurately control the planting distance,reduce the occurrence of missing seeding and improve the seeding quality with stepper motor instead of the ground wheel to drive the seeder.In this paper,Mitsubishi FX3 U series PLC is used as the controller to analyze the hardware circuit and ladder diagram of stepping motor control.The tractor speed is detected by the digital encoder.The frequency of the pulse needed by the stepping motor is calculated to control the speed of the stepping motor according to the tractor speed and spacing between two crops.The system adopted touch screen for parameter setting and working state display to operate easily.The research results have important application value for improving the metering quality of seed metering devices.