厚壁管全位置焊接可变增益PID弧长调节器的设计

摘要

在厚壁管窄间隙全位置TIG焊中，弧长是影响焊接质量最敏感的焊接参数之一。由于钨极的烧损、前道焊缝的成形、熔池变化、焊件几何形状及全位置空间变化时重力引起的弧长调节的阻力不断变化等因素的影响，没有弧长调节功能，不可能维持电弧长度的恒定。特别是全位置焊接时，重力对弧长影响非常突出，必须采取特殊的控制方法克服其不良影响，因此作者设计了基于单片机控制的弧压传感可变增益PID控制器，并针对不同的弧压偏差范围采用快速控制、分离积分和附加不敏感区来改善其控制品质，在实际产品焊接中取得了较好的控制效果。%The arc length is one of the most sensitive parameters that influence welding quality at all-position TIG welding.Due to the influence of tungsten electrode burning out,fromer pass appearance of weld,molten pool movement,weldment geometry shape and effect of gravitation on arc length adjustment at different position,if arc length adjustment were not adopted ，the arc length could not be keeped fixed length.It is more extrusive that the force of gravity influences arc length at all-position welding,the some especial controlling measures must be taken in order to overcome its influence.Therefore,a Changeable Gain PID controller is developed based on the single chip microcomputer controlling,in which the techniques of fast control,separated integral and appended non-sensitive scope are used for improving control properties.