热熔系统误差修正及控制算法的研究

Research of Error Correction and Control Algorithm for Thermal Melting System

为保证燃气管接头焊接质量,防止重大事故发生,研制了高性能热熔管件焊接控制系统。该系统采用双向可控硅为主控电路,利用定时器中断技术,通过PWM(Pulse Width Modulation)对可控硅的控制,实现热熔焊接系统的可调电压输出。为提高系统的可靠性,对传感器采集信息产生的误差进行分析,利用传感器采集信息最小二乘法分段动态标定,减少了传感器输出的非线性和零漂的误差;采用自适应滑动滤波法,平抑了噪声干扰和工频干扰的误差;对控制电压,设计了改进的PID(Proportion Integration Differentiation)快速电压调节算法,提高了输出响应速度和输出稳定度。经现场测试,焊接过程快速达到稳态,有效地平抑环境噪声对采集数据的干扰,电压波动小于±0.1 V,低于±0.5 V国家标准,满足焊接工艺的需求。

In order to guarantee the welding quality of gas pipe joints and prevent serious accidents,a high performance welding control system for thermal melt pipe fittings is developed.The system uses bidirectional thyristor as the main control circuit,and uses timer interrupt technology to control the bidirectional thyristor through PWM(Pulse Width Modulation)to realize the adjustable voltage output of the thermal melt welding system.In order to improve the reliability of the system,the errors generated by the information collected by the sensor are analyzed.And the nonlinear and zero drift errors of the sensor output are reduced by the piecewise dynamic calibration of the sensor information using the least square method.The adaptive sliding filtering method is adopted to suppress the errors of noise and power frequency interference.For the control voltage,an improved PID(Proportion Integration Differentiation)fast voltage regulation algorithm is designed to improve the output response speed and output stability.The field test shows that the welding process can reach steady state quickly and effectively suppress the interference of environmental noise to the data acquisition,the voltage fluctuation is less than±0.1 V,lower than±0.5 V national standard,which meets the requirements of welding process.