[论文解读] Improving the GMAW process through current control

Alexandre Sanfelice Bazanella, Mateus Gaspary de Freitas|arXiv (Cornell University)|Jan 13, 2026

Welding Techniques and Residual Stresses被引用 0

一句话总结

论文提出了一种用于 GMAW 的闭环开关式 PID 电流控制器，基于数据驱动的开关式电模型设计，在微控制器上实现，并通过手工与机器人焊接进行验证，以改善电流波形控制和焊接质量。

ABSTRACT

A control strategy for the electrical current in GMAW processes is proposed. The control is in closed-loop, designed by formal methods, based on a mathematical model of the electrical behavior of the GMAW process, and implemented in C+ language in a microcontroller. The model consists of a switched equivalent electrical circuit whose parameters are obtained in a data-driven manner. The strategy is tested in numerous experiments with both manual and robot welding, showing improvements in the overall welding process.

研究动机与目标

• Motivate precise control of GMAW current to improve weld quality and repeatability.
• Develop a switched, physically inspired electrical model of the GMAW process for control design.
• Design and implement a closed-loop switched PID controller to enforce desired current waveforms.
• Validate the approach experimentally on manual and robotic welding setups and analyze weld quality.

提出的方法

• Propose a closed-loop switched PID controller whose specifications enforce target current ramp rates in short-circuit and arc phases.
• Model the GMAW electrical behavior with a switched equivalent circuit, and identify phase-specific parameters using data-driven Prediction Error Identification (PEI).
• Use root locus to tune the PID gains for each phase and incorporate a switching logic to update controller gains at phase transitions.
• Implement the controller in the welding power source microcontroller (STM32F407VET6) in C++.
• Validate the model accuracy by comparing simulated and measured currents/arc voltages, using both manual and robot welding experiments.

Figure 1: Schematics of the GMAW process

实验结果

研究问题

• RQ1 Can a switched, data-driven model of GMAW electrical behavior support effective current control design?
• RQ2 Does a closed-loop switched PID controller achieve the desired current ramp rates with acceptable transients in both short-circuit and arc phases?
• RQ3 Does the proposed control improve welding stability and reduce defects (e.g., spattering) in manual and robotic welding?
• RQ4 How do the experimental results compare to open-loop and commercial closed-loop controls in terms of current waveform quality and weld integrity?

主要发现

• The switched PID controller, designed from a data-driven switched circuit model, achieves the target current ramp rates during short-circuit (60 A/ms) and arc (−20 A/ms) phases.
• Experimental results show smoother current behavior and arc voltage adjustments that enforce the desired current trajectories across both manual and robot welding setups.
• Robot welding tests indicate the proposed controller maintains current-rate specifications with smaller discrepancies than open-loop and commercial closed-loop controls (worst-best ranges: dI/dt S 56.3–58.5 A/ms; dI/dt D 20.1–23.0 A/ms).
• Metallographic analyses of welds produced with the proposed controller show clean beads, little spatter, and good penetration, indicating improved weld quality and consistency.

Figure 2: Metal transfer cycle in the GMAW process