# Experimental Study of the Vibration of the Spot Welding Gun at a Robotic Station
## 2 Related Work  
The welding process is associated with the simultaneous interaction of two types of energy-thermal and mechanical-on the materials being welded together. For welding, i.e., inseparable joining with the application of pressure, various physical phenomena are used, which are most often the source of heat. The following types of welding can be distinguished: resistance (resistive), frictional, explosive, ultrasonic, impact and crush welding. Spot welding is one of the most popular methods of resistance welding, and it involves joining parts at separate locations called spots. The high efficiency of the process, the low manufacturing costs, the possibility of robotizing the work, and the ongoing correction of welding parameters make spot welding a competitive welding and mechanical joining. However, it is not without drawbacks; the need to press the parts to be joined, high current densities, and ensuring high surface cleanliness limit the efficiency of spot welding [7; 8; 9; 10]. The design and commissioning of robotic production workstations is a complex issue and requires a great deal of effort on the part of engineers. In the past, this was carried out without the use of high-tech software environments (e.g., RobotStudio, RoboGuide, KUKA Sim), which usually caused delays in the deployment schedule of the workstations. The development of programming environments and hardware has meant that some tasks are implemented in virtual environments using digital twins. This allows the project to be implemented in a hybrid manner, where some activities are carried out online and some offline (also in virtual reality) [11; 12]. The biggest advantage of such an approach is that it reduces the start-up time of the workstations, as a lot of work can be carried out in parallel (e.g., robot programming, workstation construction) [13]. Manufactures of offline robot programming environments assure that simulations conducted in the environments are able to almost 100% replicate the real conditions of a robotic workstation. One of the most important advantages of the environments is the ability to easily generate motion trajectories, which allows the determination of production cycle times. However, it is worth noting here that it remains a problem to conduct analyses related to real accelerations, torques and forces acting on cooperating devices. A comprehensive picture of these quantities can only be obtained by conducting experimental studies. The use of triaxial IMUs makes it possible to measure the vibrations of the robot, these data allow analysis and optimization of the manipulator [14]. With the use of IMUs [15], it is possible to acquire data across the entire production. A significant area of the robotic application research literature is the studies of the dynamic parameters and motion control of robotic manipulators [16]. When it comes to controlling the movement of mechanisms and its parameterization, one of the most important issues is to examine the moment of acceleration, deceleration and the accuracy of achieving set positions. The nature of the dynamics of the robot's movements can significantly influence the forces that affect kinematic joints [17]. As presented in [18], the optimal time trajectory is extremely important for palletizing robots.During the operation of the workstation, the robot can execute complex motion, featuring sudden deceleration and acceleration episodes. These episodes (particularly during the change of direction) affect the longevity of the robot and the accuracy of the execution of the movement path, and their parameterization can accelerate the process of movement direction change and lower the vibrations of the robotic unit [19]. The dynamic studies of the robot workstation must take into account sensitive systems, especially those that are stressed during the robot's operation. These may involve, for instance, the robot wrist, the tool mounting and the tool itself [20].