基于FPGA的数控系统直线插补模块化设计

Modular Design of Linear Interpolation Control on CNC System Based on FPGA

文章针对软插补器速度慢、计算复杂、精度不高等缺陷提出了采用可配置电子齿轮箱的硬件插补方案,建立了直线插补的算法模型。采用VHDL硬件描述语言设计了直线插补电子齿轮箱模块,搭建了运动控制多轴联动插补实验平台,伺服电机编码器反馈的实测数据为:在终点坐标为(5000,5000)的直线插补路径上,伺服电机实际运行最大偏差为1.4个脉冲当量,约为总行程的0.02%;在终点坐标为(3000,4000)的直线插补路径上,伺服电机实际运行最大偏差为4.2个脉冲当量,约为总行程的0.035%,实际偏差由伺服电机机械特性及传动刚性产生。由此表明:采用本插补方案的数控系统响应时间短、运行速度快、可靠性高,且不存在偏差累积误差,插补精确度高。

Regarding the software interpolation has the disadvantages of slowspeed,complex calculation and lowprecision,studied for linear interpolation operation.Thereby,interpolation schemes employing reconfigurable electronic gear boxes are developed and the corresponding application algorithms are carried out.Similarly,by using the VHDL language,interpolation modules for linear interpolation is designed and realized.Hence experiment platform for multi-axis linage control is set up.The experimental data shows that within a terminal point coordinate（5000,5000）,the maximum deviation of linear interpolation is below2 pulses for the executed result of physical mechanism,which is approximately 0.02% of the full track.And within a terminal point coordinate（3000,4000）,the maximum deviation is below5 pulses,which is about 0.035%of the radius.The actual deviation is caused by the mechanical characteristics and the transmission rigidity of the servo motor.Therefore,The numerical control system with the interpolation scheme has the advantages of short response time,fast running speed,high reliability,no error accumulation error and high interpolation precision.