Design and Implementation of a Stereo Vision Based Navigation System for the Micro-RoSA-2 Mars Rover

摘要

In search of conditions and substances that support life on Mars, the utilization of robotic rovers becomes more and more important. However, the task of robot teleoperation over huge distances involves challenging problems. One of the biggest challenges is the task of autonomous navigation, in particular localization and hazard detection. New approaches and navigation systems of recent Mars rover missions are presented. Based on the particular solutions, a general navigation system for the European Micro-RoSA-2 rover is proposed. In accordance with the rovers mission objectives and following the navigation system design of the Sojourner and the European Nanokhod rover, the proposed system consists of three parts: ground control, lender, and rover. The Earth based control software enables goal designation, leaving the responsibility of local hazard detection to the rover. The rover localization function is implemented on the lander, which continously tracks the vehicle's motion in order to avoid errors imposed by dead reckoning estimations. The implementation of the system does mainly focus on the localization function. By using image processing techniques, active markers mounted on the rover are detected in a pair of stereo images acquired by the lender. An estimation of the instantaneous rover position is calculated by matching the back projected marker positions to their actual geometry. The systems performance was investigated in terms of positioning accuracy and precision. At a distance of 7.5 m the system shows an accuracy of 4 cm (RMS) whereas the precision was determined at 2 cm (RMS).