激光切割过程中位置检测系统抗干扰研究

A Study on the Interference of Position Detection Systems During Laser Cutting

针对激光切割过程中位置检测系统的电容传感器检测信号易受切割熔渣影响的问题,提出了一种通过有限元法计算熔渣溅射对电容传感器影响的方法。首先,通过COMSOL软件对传感器建模,并采用有限元法对电容传感器的电容变化及熔渣飞溅过程中各因素改变对电容的影响进行仿真计算;然后,采用金属球模拟熔渣,对仿真结果进行实验验证;最后,通过插补法处理仿真计算结果及实测电容,绘制电容的等值线图并得到熔渣溅射过程中电容的变化规律:在熔渣飞向切割头的过程中,电容变化存在逐渐增大并两次突变的特征,变化大小与熔渣体积呈正比关系,与极板间距呈反比关系,且熔渣处于平面影响区及其下方区域时对传感器影响更大。实测值与仿真结果误差在0.001pF以内,因此仿真结果可准确地反映熔渣溅射对电容传感器的干扰情况,为干扰滤除及切割头设计提供理论依据。

A method for calculating the influence of slag splash on capacitance sensor is proposed by using a finite element method to solve the problem that the capacitance sensor detection signal of the position detection system is susceptible to the influence of cutting slag in the laser cutting process.Firstly,a model for the sensor is built through COMSOL software,and the finite element method is used to simulate the capacitance change of the capacitive sensor and the influence of various factors on the effect of the capacitance during the slag splash process.Secondly,metal balls are used to simulate molten slags and to verify the simulation results.Finally,an interpolation method is used to process the simulation results and the measured capacitance,and an isoline map of capacitance is drawn to obtain the change rule of capacitance in the process of slag sputtering:Capacitance change is characterized by gradual increasing and two mutations in the process of slag moving towards the cutting head,while the size of the change is directly proportional to the volume of the slag and has an inverse relationship with the spacing of the plates.Moreover,the slag has great impact on sensors when it is in the plane affected area and the lower area.Experimental results show that the error between the measured value and the simulation result is less than 0.001 pF,the simulation results accurately reflect the interference of slag splash to capacitance sensor,and provide a theoretical basis for interference filtering and cutting head design.