Planetary exploration autonomous science target touchability evaluation using a fuzzy rule-based approach

With regards to Mars rover exploration, the ExoMars 2018 is the next ESA/Roscosmos mission. This is part of the Aurora programme with the future goal of returning rock samples to Earth as part of the Mars Sample Return (MSR) mission. Currently, science target selection, and whether or not it is possible for a robot arm to touch the target, is accomplished using human operators and scientists on Earth. The use of the onboard autonomy would greatly reduce the human intervention, and it would be advantageous if the in-situ rover could evaluate autonomously if its robot arm could place an instrument against an identified science target. In this paper we propose a new approach to the problem of autonomous science target touchability evaluation. We assess the touchability of a potential science target in terms of its size (the number of pixels of the science target in the image), SV (SV is referred to as the science value of the science target), distance (the reachable distance of the arm between some minimum and maximum values; currently defined as near, medium, and far), and orientation (the angular regions of the arm's shoulder azimuth). We have identified that these science target attributes can be represented by fuzzy linguistic variables. We have divided the plane in front of the arm into the several partitions, which are ranked with the different touchability levels as a fuzzy-rough set. Currently the resultant fuzzy-rule base incorporates some 74 fuzzy rules. We have employed the MAT-LAB software architecture to implement our algorithm, and we have simulated various rock distributions to verify the validity and accuracy of our autonomous science target touchability evaluation approach.