Abstract
The continued interest in extra-terrestrial exploration has led to several robotic missions to Mars. These rovers have provided great insight into the planet, but each has faced difficulty with traversing the Martian surface. Most notably was the MER Spirit rover which has become lodged within the terrain. To address this issue, the Forward Acquisition of Soil and Terrain for Exploration Rover (FASTER) project (an EU-funded multi-partner collaboration) is developing a two-rover team formed by a small scout rover that can survey and assess the trafficability of the surface, thereby eliminating the risk of becoming immobile for the larger, mission-performing rover. The scout rover is designed with five-spoked, rim-less wheel-legs that allow it to traverse hazardous terrain, such as soft soils and obstructing rocks. In order to assay the soil for the main rover, the scout is equipped with an array of sensor systems. The first of these systems observes the interactions between the wheel-leg and the terrain. This system consists of special wheel-leg feet that mimic the soil loading of the main rover wheels in an effort to analyse potential sinkage into soft soils, to locate duricrusts that may give way beneath the main rover’s load, and also to measure the risk of slip. These analyses are accomplished through a combination of robust image processing techniques, inertial measurements, wheel-leg odometry, and motor load profiling. This paper presents the design of the wheel-leg-terrain interaction sensor systems and its performance during laboratory testing under several scenarios, including various Martian soil simulants.