Performance Enhancement Mechanism of Laser Scanner for 3D Surface Reconstruction

Abstract

This research paper presents a performance enhancement mechanism of laser scanner for three-dimensional (3D) surface reconstruction. Design and development of a 3D vertical surface-scanning mechanism along with control systems for roll-motion stabilization and periodic pitch speed is used for measuring/colleting laser-scanner point cloud data, which can be installed on a surface vessel. As a result, accuracy and precision of object’s position and physical characteristics measurement from laser cloud points can be improved. In a designing phase, testing with kinematics and dynamics models helps computing for link’s length of a four-bar linkage mechanism such that a pitch angle of ± 16.5° around y-axis for the laser scanner is obtained. Derived dynamic model of this mechanism assists in calculating proper maximum torque of motors for each axis. In the second phase, two control systems are developed within Arduino microcontroller 1) for laser-scanner roll-motion stabilizing using a PID control system with the top DC motor’s encoder feedback, and 2) for reconstructing a smooth vertical surface from laser cloud points during a pitching motion of the four-bar linkage mechanism, driven by bottom DC motor, using a feed-forward control system with the pitching angle from Inertial Measurement Unit for a gravity compensation. In the third phase, the 3D vertical reconstructed surface from laser cloud points, measured along a radial direction, is processed as a 3D point-cloud surface in a Cartesian coordinate system. A statistically analysis of reconstructed surface precision along the horizontal direction is within ±7 centimeter with a standard deviation less than 2.2 centimeter.