40 A. Rababah et al. human tasks in manufacturing and industrial sectors. In the United States, and most other countries, the majority of structures, including bridges, high-rise buildings, and power and petrochemical plants, are typically constructed using structural steel. Recently, the steel shear wall system has been introduced as an effective alternative to conventional lateral loadresisting systems in the construction field. This system offers advantages such as a lighter structure, quicker construction, and superior quality compared to traditional reinforced concrete structures [1]. In addition, the implementation of continuous columns and interconnected column-beam systems is essential for maintaining structural integrity and ensuring optimal performance under various loading conditions and environmental circumstances. Components within a structure are often joined using bolts or welding techniques, including column splice welding and the welding of shear wall systems with steel frames. These methods effectively transfer vertical and horizontal loads between the connected elements. Welding, in particular, is a fundamental component in structural steel construction, enabling the creation of strong and durable structures. The automation of such an important component with mobile robots aligns with the American Institute of Steel Construction’s (AISC) ”Need for Speed” initiative, which emphasizes the importance of efficient and rapid construction methods. In general, welding is a process of joining metals together using pressure or heat on the filler metal, in some methods, and workpiece to form the weld that can substitute the mechanical fastener connections. More than eighty different methods are used to achieve the welding [2]. Welding, brazing, and soldering are joining metal methods with different procedures. Brazing and soldering are characterized by melting the filler metals, but not the base metals as in the welding case. Neither brazing nor soldering is used for structural steel connections; as an alternative, welding is an appropriate option that offers the strongest joint to support the load. Typically, the welded section of a joint shows a greater strength than the base or original metal. However, imperfections that arise during or after the welding process, whether internal or external, can compromise the weld’s performance and weaken the joints between metal components. Identifying and assessing these defects is crucial for ensuring quality control, thereby enhancing the weld’s ability to perform its expected function effectively. Welding fieldrelated workers need to comprehend the prevalent problems associated with welding in structures like causes, effects, and outcomes. Regulations and standards set by the American Welding Society (AWS) [3], are essential to guarantee the integrity and quality of weldment. Furthermore, the detection and inspection of defects are essential for addressing unacceptable defects that could affect the structural reliability of a welded structure. External defects, such as cracks, undercuts, overlaps, porosity, and spatters, are visible on the surface of the weld and can be detected by the human eye. Conversely, internal defects, which include incomplete penetration, inclusion, and lack of fusion, occur within the welding joint and are not visible to the naked eye. Detecting these internal defects requires specific methods including Non-destructive testing (NDT) [4], and destructive testing (DT). NDT can recognize the defects in welding by examining the workpiece without harming it or affecting its strength and reliability. Some of these tools and methods used in NDT are ultrasonic test (UT), radiography test (RT), electromagnetic test, eddy current test (ET), magnetic particle test (MT), acoustic emission (AE), dye penetrant (PT) and leak testing (LT). On the other hand, DT studies and tests the material or welded workpiece with some damages or destructions left on it, typically, such tests are conducted on small workpieces at the initial stages of the process, before welding and fabricating larger components. This approach enables an understanding of how the material will perform under various stress conditions. Gas Metal Arc Welding (GMAW) and Gas Tungsten Arc Welding (GTWA) have traditionally been the most employed in robotic welding applications due to their compatibility with robotic systems [5]. However, developments in welding technology have expanded the range of methods engaged in robotic welding such as laser welding, plasma welding, metal inert gas welding, and spot resistance welding. A robotic welding system typically contains several critical components, including a mobile platform, manipulator, controller, welding torch, and an array of sensors. The mobile platform, or robotic base, serves as the primary structural frame of the system, supporting all other components and providing the capability to move, climb walls, and maneuver around obstacles. The manipulator is tasked with the precise movement and positioning of the welding torch, ensuring high-accuracy welding operations. Acting as the system’s central intelligence, the controller processes input from the sensors and executes pre-programmed welding routines. This sophisticated organization of components not only enhances the precision and efficiency of welding tasks but also allows for real-time adjustments and optimization of welding parameters. In addition, the sensors play a crucial role in monitoring various parameters such as temperature, alignment, and weld quality, providing real-time feedback to the controller to ensure optimal performance and adjust parameters as needed [6]. Performing the welding tasks by using an automated system or robotic manipulator (arm), first developed by a Japanese company, Kawasaki in 1974 and used in the manufacturing of motorcycles has revolutionized the industry [7]. These automated systems offer numerous advantages, including enhanced productivity, improved quality, increased safety, and significant time and cost savings. Additionally, robotic welding systems can operate under extreme conditions, such as high temperatures and high pressures, which pose substantial risks to human workers, especially those working at high elevations in structural steel construction.
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