【作者】 卢亚静；

【导师】 胡绳荪；

【作者基本信息】 天津大学 ， 材料加工工程， 2005， 硕士

【摘要】 脉冲熔化极氩弧焊与直流熔化极氩弧焊相比,具有电流调节范围广、热输入量可控性好以及有利于实现全位置焊接等一系列优点,因此被广泛应用。而熔滴过渡的动态控制一直是这种焊接方法的研究前沿。数字化控制因具有更好的稳定性和更高的控制精度以及控制灵活、易于实现柔性化控制等优点,近年来得到了学术界的高度关注。为此,本文以数字信号处理器(DSP)为控制核心,在理论分析的基础上进行了脉冲MIG焊的数字控制系统的研究。本文首先分析了脉冲MIG焊的熔滴过渡行为,提出了相应的控制方案,为一脉一滴控制提出了用电参数进行控制的方法及步骤,即给定电流参数,然后根据一定的控制规则确定脉冲峰值时间和送丝速度,再实时调节脉冲基值时间;以DSP为核心,构建了脉冲MIG焊数字控制系统的模型,并进行了数字化逆变焊接电源的控制系统设计和送丝系统设计;建立了弧焊电源及其控制系统的数学模型以及仿真模型,借助MATLAB对控制系统进行仿真研究,得到了数字控制器的最佳参数范围;采用汇编语言和MATLAB结合的方法编写了实现控制方案的系统软件。仿真实验表明,本文设计的数字控制系统具有很好的实用性,能够实现脉冲MIG焊双阶梯形外特性和熔滴过渡的控制。更多还原

【Abstract】 Pulsed MIG Welding is widely used in the industry. Compared with DirectCurrent MIG Welding, Pulsed MIG Welding has many advantages, such as widerange of current, controllable heat input and full position availability. The researchfocus is the dynamic droplet transfer. Digital control is flexible and has better stabilityand higher precision, as becomes the focus of academia. Therefore, this paper isaiming at the DSP-based Digital Control System research.On the basis of droplet transfer analysis in Pulsed MIG Welding, theelectrical-parameter-control method is brought forward to meet the goal ofone-pulse-and-one-droplet transfer mode. Pulse Peak Time and Wire-feed Speed areobtained when current parameters are given. Pulse Base Time is adjusted on-line toensure the droplet transfer mode. DSP-based digital control system model of PulsedMIG Welding is set up and the hardware of inverter power source control system andwire feed system are successfully designed. Besides, the numerical system model andthe model for simulation are built. Optimal parameters range is obtained bysimulation with MATLAB. Software design is fulfilled with assembler andMATLAB.Simulation experiments indicate that the digital control system designed has finepracticability. The whole system is able to achieve the double-L power sourcecharacteristic curve and the particular droplet transfer mode.更多还原