基于北斗定位的小麦播种机控制系统优化

Research on Control System of Wheat Planter Based on Beidou Positioning

以西门子S7-200 smart PLC为控制器,通过对基于步进电机的分种器的控制,实现了小麦小区播种机控制系统的设计。采用北斗定位辅助取代了以往误差较大的编码器测距,实现了对作业小区的精准控制,控制精度达到厘米级。目前,PLC内部浮点数存储格式为8位单精度浮点数,而接收到的北斗GPGGA数据有效数值为16位双精度浮点数,直接转化误差非常大。为确保计算精度,提出了一种基于三角恒等式的数值分段法来解决双精度浮点数转单精度浮点数的问题。经测试,精度到达微米级。

In this paper,the Siemens S7-200smart PLC is used as the controller to control the control system of the wheat plotter by using the control of the stepper based on the stepping motor.The Beidou positioning aid replaces the encoder distance measurement with large error in the past,and realizes precise control of the working area,and the control precision reaches centimeter level.Considering that the PLC internal floating point number storage format is 8-bit single-precision floating-point number,the received Beidou GPGGA data valid value is 16-bit double-precision floating-point number,if the direct conversion error is very large.In order to ensure the accuracy of calculation,this paper proposes a numerical segmentation method based on trigonometric identity to solve the problem of double-precision floating-point number to single-precision floating-point number.After testing,the precision reaches the micron level.