https://scidar.kg.ac.rs/handle/123456789/8211 Thu, 12 Mar 2026 08:01:54 GMT 2026-03-12T08:01:54Z https://scidar.kg.ac.rs/handle/123456789/23077 Title: Acoustic analysis in gas metal arc welding: Physical mechanisms, signal processing, and applications Authors: Rasinac, Mladen; Bjelić, Mišo; Radičević, Branko; Miodragović, Tanja; Pajović, Stefan Editors: Markovic, Goran Abstract: Acoustic analysis has emerged as a promising, non-intrusive approach for process monitoring and quality assessment in gas metal arc welding (GMAW). The sound generated during the GMAW process originates from complex physical phenomena, including arc plasma dynamics, metal transfer mechanisms, weld pool oscillations, and shielding gas flow. Therefore, acoustic signal contains significant information related to process stability and weld formation. During the previous decades, numerous researches have been focused on the application of audible sound and acoustic emission for real-time monitoring of the GMAW process. This paper provides an overview of the application of acoustic analysis in the GMAW process. The basic mechanisms of acoustic signal generation, as well as signal acquisition and processing techniques in the time, frequency, and time-frequency domains, are considered. Key application areas are reviewed, including process stability monitoring, weld quality assessment, metal transfer mode classification, and welding defects detection. Special attention is paid to contemporary trends, challenges and the integration of acoustic analysis with intelligent welding systems, highlighting its potential as a supplementary tool for advanced GMAW process monitoring. Description: ET 2025 - Vol. 4, No. 4 Wed, 01 Jan 2025 00:00:00 GMT https://scidar.kg.ac.rs/handle/123456789/23077 2025-01-01T00:00:00Z https://scidar.kg.ac.rs/handle/123456789/23076 Title: Iterative Decoupler Design Method for TITO Processes Authors: Prodanović, Saša; Dubonjic, Ljubisa; Rajaraman, Janani Abstract: In this paper, possibilities for iterative tuning of the decoupler for TITO (two inputs and two outputs) process are investigated. The developed algorithm is based on getting decouplers terms iteratively, taking into account previously defined limits of response quality indicators. The effectiveness of the designed new method has been presented in four examples using simulations. It enables similar performances as computational methods for decoupler design from the literature, but without knowing of process mathematical model. So, that is a less complicated and less time-consuming method, which can be used for adding a decoupler to an already controlled process during its functioning and also for improving terms of an existing decoupler. Thu, 01 Jan 2026 00:00:00 GMT https://scidar.kg.ac.rs/handle/123456789/23076 2026-01-01T00:00:00Z https://scidar.kg.ac.rs/handle/123456789/23075 Title: Hybrid PID-feedforward control for trajectory tracking in 2-DOF robotic systems Authors: Stojanović, Vladimir; Dubonjic, Ljubisa; Đorđević, Vladimir Editors: Markovic, Goran Abstract: This paper presents a hybrid control strategy combining proportional-integral-derivative (PID) feedback with model-based feedforward compensation for precise trajectory tracking in two-degree-of-freedom (2-DOF) robotic manipulators. The approach addresses nonlinear dynamics, including inertial coupling, Coriolis effects, and gravity, by deriving the Euler-Lagrange equations for a planar arm and implementing a computed torque feedforward term augmented by PID correction. Theoretical stability is analyzed using Lyapunov methods, ensuring asymptotic convergence of tracking errors. Simulations demonstrate superior performance compared to standalone PID, with root-mean-square errors reduced to 0.5751° for the first joint and 1.4416° for the second under sinusoidal references. Results include phase portraits, torque decompositions, and sensitivity analysis to parameter variations, validating the method's robustness for industrial applications. Thu, 01 Jan 2026 00:00:00 GMT https://scidar.kg.ac.rs/handle/123456789/23075 2026-01-01T00:00:00Z https://scidar.kg.ac.rs/handle/123456789/23074 Title: Collaborative Completion and Alignment for Class-incomplete Multi-source Domain Adaptation in Rotating Machinery Fault Diagnosis Authors: Wang, Boyu; Sun, Yawei; Tao, Hongfeng; Stojanović, Vladimir Abstract: In rotating machinery fault diagnosis, domain adaptation performance is frequently hindered by class-incomplete training data and distribution shifts between operating conditions–scenarios under which conventional methods tend to breakdown. To address this, we introduce a synergistic two-stage framework for multi-source domain adaptation. First, to resolve the critical absence of fault classes and enhance data diversity, the Incomplete Class Sample Completion (ICSC) framework synthesizes high-fidelity pseudo-samples for the missing classes. Subsequently, the Prototype-aware Class Conditional Adversarial Network (PCCAN) performs multi-granularity feature alignment, using global, class-conditional, and prototype-based constraints to enforce intra-class compactness and inter-class separability. The synergy between these class-completion and feature-alignment mechanisms enhances cross-domain recognition accuracy. The method’s efficacy is validated across the JNU, BJTU, and SDUST datasets. The experimental results confirm the framework’s effectiveness in handling cross-domain fault diagnosis tasks under class-incomplete conditions. Thu, 01 Jan 2026 00:00:00 GMT https://scidar.kg.ac.rs/handle/123456789/23074 2026-01-01T00:00:00Z