# Pipe Spatter Detection and Grinding Robot
## 1 Introduction  
Various automation and robotic systems have been implemented to improve the efficiency of pipe production. This study focuses on the manufacturing of small electric-resistance-welded (ERW) pipes with thicknesses of 10-20 mm and outer diameters of 10-60 cm. Owing to the nature of the process, spatters occur during ERW due to changes in the current and material composition. Thus, residual beads and weld seams generated by ERW exist inside pipes and must be removed by inserting a tool [1, 2]. During the removal process, the roller of the tool presses the spatters against the inner surface of the pipe, causing them to adhere. After a subsequent tube expansion process, such as the one performed in a stretch-reducing mill, eye-shaped tears or eye-ball defects may occur.  
[PERSON] et al. [3] utilized a KUKA robot to perform weld seam tracking and polishing on the outside of pipes using a polishing machine and laser vision equipment. [PERSON] et al. [4] performed grinding through a robotic abrasive belt to remove weld seams. These can remove weld seams on the outer surface of a pipe using a manipulator and have relatively no restriction on space. However, in the case of the insides of pipes, the space is narrow, and a small robot must be fused with its own driving force, grinding equipment, and vision systems. [PERSON] et al. [5] developed a wheel-drive-based polishing robot to polish weld beads inside medium-sized pipes (550-714 mm).  
To remove spatters at the production site, workers attach a camera to a long rod and use it to inspect the inside of the pipe on a monitor. After visually checking the spatters and marking the corresponding distance on the rod, they move a manual grinder up to the marked distance and operate it to remove the spatters. Because the maximum length of thepipe is 12 m, the operator must inspect up to 6 m from either the front or rear ends before finishing production.  
A method that is adaptable to multiple pipe diameters has been suggested for robotic systems that inspect and clean the insides of pipes [5; 6; 7; 8], especially in the case of actual industrial sites, where various obstacles, such as horizontal, vertical, and branching obstacles, appear in the piping configuration, urging a solution to interconnect multiple modules and overcome the obstacles [9].  
In this paper, a spiral mechanism for the configuration of the driving wheel and a slider crank with a spring link that can adjust to the internal diameters of small pipes with diameters of 18-25 cm were proposed. The mechanisms were designed as part of a structure that can control speed and torque. Image recognition technology was applied to detect spatters inside a pipe. The proposed robot automatically grinds spatters after checking their distance and circumferential position inside the pipe.  
Spatters are granules are generated when the combination of current and voltage is not appropriate during welding or when the molten metal in the welding rod or wire is not fused to the base material of the welding part. This is typically due to poor contact with the earth or to the melting and adherence of the granules around the weld. Spatters must be removed because they can cause defects.  
This study presents a spatter-grinding robot (SGR) that automatically detects spatters in a small pipe while moving inside it, records the detected position in a database, moves to the end of the pipe, and then moves back to automatically grind the detected spatters.