This paper introduces an autonomous robot designed for in-pipe structural health monitoring of oil/gas pipelines. This system employs a 3D Optical Laser Scanning Technical Vision System (TVS) to continuously scan the internal surface of the pipeline. This paper elaborates on the mathematical methodology of 3D laser surface scanning based on dynamic triangulation. This paper presents the mathematical framework governing the combined kinematics of the Mobile Robot (MR) and TVS. It discusses the custom design of the MR, adjusting it to use of robustized mathematics, and incorporating a laser scanner produced using a 3D printer. Both experimental and theoretical approaches are utilized to illustrate the formation of point clouds during surface scanning. This paper details the application of the simple and robust mathematical algorithm RANSAC for the preliminary processing of the measured point clouds. Furthermore, it contributes two distinct and simplified criteria for detecting defects in pipelines, specifically tailored for computer processing. In conclusion, this paper assesses the effectiveness of the proposed mathematical and physical method through experimental tests conducted under varying light conditions.

This paper presents a novel approach to modeling and analyzing chaotic mechanical vibrations in laser scanning systems. The model explicitly incorporates nonlinear friction using the LuGre friction model. Experimental validation demonstrates chaotic behavior manifested in irregular velocity fluctuations. Dominant frequencies and maximum vibration amplitudes were identified under various operational conditions. A maximum disturbance amplitude of 1.65~rad/s\textsuperscript{2} was observed under the most demanding conditions (25~RPS, $\pm$15° inclination). The proposed model was validated experimentally, providing insights into the interplay of chaotic vibrations and nonlinear friction. A robust control strategy was introduced to mitigate these effects. This strategy is supported by Lyapunov stability analysis and computational implementation. The results demonstrate the effectiveness of the control strategy in reducing the negative effects of friction and chaotic vibrations. The findings could benefit precision engineering, nonlinear dynamics research, and machine vision.

Some laser scanners utilize stepper motor-driven optomechanical assemblies to position the laser beam precisely during triangulation. In laser scanners such as the presented Technical Vision System (TVS), to enhance motion resolution, gear transmissions are implemented between the motor and the optical assembly. However, due to the customized nature of the mechanical design, errors in manufacturing or insufficient mechanical characterization can introduce deviations in the computed 3D coordinates. In this work, we present a novel method for estimating the degrees-per-step ratio at the output of the laser positioner’s transmission mechanism using a stereovision system. Experimental results demonstrate the effectiveness of the proposed method, which reduces the need for manual metrological instruments and simplifies the calibration procedure through vision-assisted measurements. The method yielded estimated angular resolutions of approximately 0.06° and 0.07° per motor step in the horizontal and vertical axes, respectively, key parameters that define the minimal resolvable displacement of the projected beam in dynamic triangulation.