Development of legged, wheeled, and hybrid rover mobility models to facilitate planetary surface exploration mission analysis

Abstract

This work discusses the Mars Surface Exploration (MSE) tool and its adaptation to model rovers featuring legged, wheeled, and hybrid mobility. MSE is a MATLAB based systems engineering tool that is capable of rapidly designing a large trade space of rovers to fulfill a user defined science mission. This allows mission planners to make well informed design decisions in the earliest stages of a rover mission. The original version of MSE models exclusively six-wheeled rovers. This wheeled mobility model is refined, validated, and applied to an analysis of a Mars Sample Return fetch rover. The trade off between using a larger, more capable rover or a highly accurate landing system to retrieve a sample is examined. The results indicate that highly accurate landing systems are only needed if the fetch rover has a short period of time to retrieve the sample. After the wheeled mobility model and its application are presented, the motivation to model legged and hybrid mobility is explained. Many scientifically interesting locations cannot be reached by traditional wheeled mobility systems, thus new forms of mobility should be considered for future Mars rovers.

(cont.) A survey of different forms of mobility is presented, with particular emphasis on the Modular Rover for Extreme Terrain Access (MoRETA) developed at MIT. The detailed implementation of fourwheeled, eight-wheeled, legged, and hybrid mobility models and their integration into MSE is discussed. The enhanced MSE tool is benchmarked against other simulations and existing robots. Finally, initially application of the tool reveals that wheeled mobility is best suited for flat and level terrain, and legged mobility is best suited for rocky or steep terrain.