Simulation of Autonomous Grading of Lunar Surface

Lunar missions of space agencies aim to set up permanent facilities on the surface of the Moon. Vast majority of the construction activities should be executed as unmanned because of the unsuitable habitat conditions of the Moon. In this study autonomous grading of Moon surface by an electric powered small scale dozer is examined. An autonomous grading algorithm is implemented for the grading task of a small region which is large enough to be an artifact base on the Moon. The autonomous grading algorithm takes rolling, tire penetration, grade, hauling of the earth pile, and cutting resistances into account. Gravity of the Moon is lower than the gravity of the Earth which causes skidding of the tires. The grading algorithm also takes the maximum applicable force and adjusts the earth pile in front of the dozer blade. Lead-acid battery powered and lithium-ion battery powered dozers are simulated in order to detect the efficiency of the construction machine. The simulation divides the excavation area into equal sized grids and computes the consumed time to work on each grid. The required force and the consumed energy are computed for each grid. The simulation iteratively updates the elevations of the grids and the iteration continues until the elevations of the grids become equal to the required elevation. Simulation revealed that lead-acid battery powered dozer is more suitable for the earthwork tasks on the Moon.