Entwicklung eines vielseitigen und robusten Laserscanners für 3D-Modellierung und Exploration mit einem Roboterarm

Abstract

This work presents the development of the VR-SCAN, a versatile and robust triangulation scanner for robotics. Through optical perception the robot is able to comply with numerous tasks. Therefore perception has to be versatile. However, one single sensor cannot allow for all requirements. This work follows the strategy to design an inherently versatile sensor for a well-defined scenario: The VR-SCAN is dedicated to autonomous 3D modelling and exploration with a robot arm. Growing autonomy in robotics requires robust perception working reliably in unforeseen and changing environmental conditions. The robot has to perform tasks without compromising itself or the environment. The sensors requirements for autonomous modelling and exploration are analyzed. Two hypotheses regarding versatility and robustness are derived. The resulting requirements affect the design of the VR-SCAN: Versatility is ensured by large measuring depth and variable focusing. Confidence rating of each measurement provides robustness against false measurements. Therefore detection of safe-for-motion areas is possible. High integration density is achieved by the use and development of very small components: The compact sensor system merges a MEMS micro mirror, a fiber coupled laser diode, a micro motor for focus control, a compact triplet lens and a central FPGA. A patented calibration procedure is described and applied. Thus the functionality of the laser scanner is successfully demonstrated. The VR-SCAN combines outstanding features such as large measuring depth, robustness by confidence rating and high accuracy at close range in a small, lightweight package. Hence this robust and versatile sensor for robot perception complies with the stated hypotheses.