基于热-质解耦控制的多电极电弧增材制造自稳定性机制

Wire arc additive manufacturing (WAAM) has significant advantages in low-cost and short-cycle manufacturing of large-size metal parts. However, WAAM is currently a simple transplant of traditional arc welding, and its heat transfer and mass transfer cannot be freely decoupled so as to adapt to complex trajectory and dynamic thermal dissipation in WAAM, thereby leading to poor stability. This research aims to deal with this problem based on the characteristic of multi-electrode arc that the heat transfer and mass transfer can be decoupled freely, on the basis of which disturbance compensation mechanism is investigated in order to ensure stability of WAAM under complex disturbances. For the two types of predictable disturbances, complex trajectory and dynamic thermal dissipation, a feedforward compensation mechanism is established based on the disturbance mathematical model, and the heat and mass transfer inversion model subjected to consistent physical boundary constraints. For other unpredictable disturbances, an iterative compensation mechanism is established based on iterative learning control and arc length self-feedback mechanism. Arcing-wire VPPA is used as the experimental platform for verification. A universal method for multi-electrode arc based WAAM is finally formed, which allows for strong self-stability without relying on external sensors. This research provides an innovative control strategy for WAAM with much higher stability and accuracy, and lays the foundation for subsequent industrial automation applications.

电弧增材制造技术（WAAM）在大尺寸金属零件的低成本、短周期制造中具有显著优势，但目前WAAM多是传统电弧焊接的简单移植，其传热和传质无法自由地解耦调控以适应WAAM中复杂轨迹、动态热扩散等扰动条件，导致成形稳定性不足。为此，本课题以多电极电弧热源热、质自由解耦的特性为出发点，立足于WAAM在复杂扰动条件下的成形稳定性需求研究扰动补偿机制。针对复杂轨迹和动态热扩散这两类可预知扰动，基于扰动数学模型和一致性物理边界约束下热、质传输反演模型建立热、质解耦控制前馈补偿机制；针对其它不可预知扰动，基于迭代学习控制和弧长自反馈机制建立热、质解耦控制迭代补偿机制；以Arcing-wire VPPA为实验平台进行验证。最终形成一套对多电极电弧热源具有普适性的方法，在无需依赖外部传感器条件下实现WAAM的自稳定性控制，为WAAM稳定化和精细化成形控制提供一条全新思路，并为后续工业自动化应用奠定基础。

电弧增材制造技术（WAAM）在大尺寸金属零件的低成本、短周期制造中具有显著优势，但目前WAAM多是传统电弧焊接的简单移植，其传热和传质无法自由地解耦调控以适应WAAM中复杂轨迹、动态热扩散等扰动条件，导致成形稳定性不足。为此，本课题以多电极电弧热源热、质自由解耦的特性为出发点，立足于WAAM在复杂扰动条件下的成形稳定性需求研究扰动补偿机制。针对复杂轨迹和动态热扩散这两类可预知扰动，基于扰动数学模型和一致性物理边界约束下热、质传输反演模型建立热、质解耦控制前馈补偿机制；针对其它不可预知扰动，基于迭代学习控制和弧长自反馈机制建立热、质解耦控制迭代补偿机制；以Arcing-wire VPPA为实验平台进行验证。实验表明，综合运用本课题提出的扰动补偿方法，可以将电弧增材成型误差控制在5%以内。这种方法是对多电极电弧热源具有普适性的方法，在无需依赖外部传感器条件下实现WAAM的自稳定性控制。其有助于拓展多电极电弧热源在WAAM领域的应用，弥补传统电弧热源应用于增材制造时的固有不足，为WAAM的稳定化和精细化成形控制提供一条全新思路，并为后续的工业自动化应用奠定基础，因此具有重要的基础研究和实用价值。