# Experimental Study of the Vibration of the Spot Welding Gun at a Robotic Station
## 1 Introduction  
Due to their high accuracy and repeatability of movements (approximately 0.1 mm), industrial robots are often used in the automotive industry [1], performing processes such as arc welding, painting and spot welding. Among the main advantages of six-axis robotic systems, we can include: working in conditions unfavorable for humans (standard welders on overhead cranes, moved by workers), access to hard-to-reach places (unlike stationary welders), due to the heating of the material spot welding must be performed in different places, too many points next to each other can lead to loss of material properties, do not require downtime [2]. These advantages make the robotization of the car body welding process, for which it is necessary to perform several thousand welds, an effective and profitable investment [3, 4]. To meet the needs of the market, the largest robot manufacturers offer specialized equipment to support the process of robotized welding. Due to the large weight of the tool (around 90 kg), six-axis robots with a lifting capacity of more than 100 kg are most often used, their advantage is a wide range and the ability to approach hard-to-reach parts of the workpiece. In addition, manufacturers provide, among other things:  
* Specialized software to support programming (RobotWare Spot from ABB, KUKA. SpotTech from KUKA, Spot Tool from FANUC);
* DressPacks-channels protecting the wires, tailored in shape to the type of robot;
* Specialized HMIs for programmers and operators;* Advanced controllers that allow direct communication with the welding machine controller;
* Automatic recalculation of the tool's TCP after tip dressing. Due to the comparatively low cost, simplicity of the process and the possibility of joining complex parts, resistance welding is a very attractive process for manufacturers. The possibility of relatively simple robotization of the welding process and its reliability causes the continuous development of dedicated solutions (Figure 1). Given the high demand for robotic welding workstations, global market leaders are also providing libraries and software to support offline programming and simulation. Inertial tests were carried out using triaxial accelerometers and a high speed camera. The work resulted in the acquisition of acceleration values appearing on the robot's flange and mounted tool, and the impact of the robot's trajectory parameters on the occurrence of construction vibrations on the robot was investigated. Despite the fact that the problem of tool vibration is important and often addressed by engineers integrating robots at real production workstations, there is a lack of scientific publications addressing implemented production stations. According to the authors, the best effect is given by experimental determination of tool vibrations on a specific production station [5]. The development of a measuring test bench provides an opportunity to support industrial robot developers in the preparation of robot motion trajectories with optimal motion parameters, allowing for shortening production cycles. Reducing production cycles by even a few percent in high-volume production can lead to significant savings. The premise and novelty of the presented approach is how to use IMU and high-speed camera equipment and developed software to analyze robot vibrations at specific production stations equipped with specific tools. The idea of the authors is to use the proprietary measurement station to optimize the production process and then remove the sensory elements from the test object.