Automated induction brazing control system based on optimal trajectory planning
摘要
This study proposes an optimized induction brazing approach for waveguides aimed at improving joint quality and thermal stability, which are critical requirements in high-reliability aerospace assemblies. A multi-objective optimization framework is formulated to minimize deviation from a target temperature profile (within ± 5 °C), reduce temperature differences between brazed parts to below 2 °C, and limit heating-rate mismatch to less than 0.2 °C/s. Optimal trade-offs among these competing objectives are obtained using the Non-dominated Sorting Genetic Algorithm II (NSGA-II), with simplified single- and bi-objective formulations adopted for practical implementation. The thermal behavior of the waveguide is modeled using a heat conduction equation accounting for reflected electromagnetic energy. The optimized trajectories are implemented using a PID-controlled induction heating system with infrared pyrometric feedback. Experimental validation on aluminum alloy AD31 waveguides demonstrates that the proposed method reduces thermal nonuniformity to below 2 °C and decreases the joint defect rate to 1%, confirming its effectiveness for stable and high-quality induction brazing.