# Pipe Spatter Detection and Grinding Robot
## 2 SGR Design  
The design elements, hardware configuration, and control systems required for the SGR design must be accurately analyzed. The main requirements for the SGR are as follows [10; 11]:  
* It should be able to operate within small pipes with diameters of 15-25 cm;
* It should have the ability to drive, detect spatters, and grind them in a narrow space;
* Driving errors should be minimized when slip occurs inside a steel pipe;
* The spatter position should be accurately recorded to prevent damage to the base material during grinding.  
The design of the pipe robot for driving, inspection, and grinding work inside the pipe comprises a link structure that can maintain the center of the robot in the center of the pipe according to the required diameter via a driving wheel. In the case of a pipe robot with a large diameter, a system that transmits traction force directly by configuring a motor and a reducer on the driving wheel unit can be configured, but a pipe robot with a small diameter causes a space problem in the design of the driving wheel. Therefore, in the concept design of the pipe robot, the work head was configured on the front side and fixed, and a link was applied to the main driving module. A system is proposed that can control the driving speed by configuring a passive wheel on a spring-loaded rod in close contact with the pole and varying the pitch and rotational speed according to the spiral angle through the spiral rotation and steering of the passive wheel.  
As shown in Figure 1, the proposed robot, which satisfies these conditions, comprises a work-head module with roll motion support for spatter detection and grinding, a head-driving module responsible for controlling the elevation drive, and a main driving module for spiral driving in the pipe.  
Because the robot must perform spatter detection, grinding, and driving inside pipes with diameters as low as 18 cm, if the diameter of the robot exceeds 4 in, it would be difficult to secure enough space to work and move inside the pipe. This results in a minimum design requirement that the various components, such as the motor, reducer, controller, sensor, and camera, must be able to be installed inside an SGR with a maximum size of 4 in. Furthermore, it is important to design an optimal expansion link, motor, and reducer for horizontal and vertical driving within a pipe.  
Driving inside a pipe can be largely divided into two types, wheel or caterpillar, depending, respectively, on whether a motor and reducer are applied directly to the driving wheels or the power is transmitted through a belt structure. There are limits to the overall mechanical size of the structure that constrain the design of many mechanical elements, motors, and reducers to transmit power as well as design limits for the optimization of the driving mechanism suitable for small pipes. Therefore, in this paper, a spiral-type driving mechanism was proposed and designed, and a passive-type link structure was selected to enable adjustment to different pipe diameters [12; 13; 14; 15; 16].  
Figure 1 shows the proposed robot platform, which can detect and grind spatters inside pipes. It was designed to run horizontally and vertically inside a pipe. Detailed specifications are listed in Table 1.