Design of an Automated Regolith Preparation Process for Rover Locomotion Experiments

Abstract

The rover locomotion on different planetary surfaces is an important topic in the current research. In order to test the rover wheel designs and verify wheel-soil contact models, test stands are build. These test stands use one rover wheel, which can be driven in planetary soil simulants. To create consistent initial test condition, the soil has to be prepared for each experiment. The state of the art preparation is manual work. It is elaborate and due to the individual worker inconsistent. In a new robotic singel-wheel testbed (SWT), a automated preparation process is desired to achieve reliable and reproducible soil conditions. In this thesis, an automated soil preparation process is developed. Therefore, the current manual procedure is analyzed and categorized in three major steps: loosening, leveling and compaction. The loosening procedure removes the load history of the soil. The leveling creates an even surface and the compaction restores desired soil conditions. This information is used to define the requirements for an automated process. In the next step possible concepts are created and rated. This results in two final preparation concepts for three different kind of planetary soil simulants. The first one is for more fine sands and consists of an air system, which blows air through the soil to loosen it. The achieved surface is already even and the leveling can be skipped. The compaction is done with a board that is pressed on top of the soil surface, performed by the industrial robot of the test stand. The second concept is for a soil with bigger particles. It consists of tillage tines, which are moved through the soil by the robot. Subsequently, the soil is leveled with a perpendicular to the surface orientated plate that is moved over the soil. All developed concepts are tested and validated with prototypes in order to prove the fulfillment of the requirements.