Novel Design of Legged Mobile Landers With Decoupled Landing and Walking Functions Containing a Rhombus Joint

During extraterrestrial planetary exploration programs, autonomous robots are deployed using a separate immovable lander and rover. This mode has some limitations. In this paper, a concept of a novel legged robot with decoupled functions was introduced that has inbuilt features of a lander and rover. Currently, studies have focused mainly on performance analysis of the lander without a walking function. However, a systematic type synthesis of the legged mobile fancier has not been studied. In this paper, a new approach to the type synthesis used for the robot was proposed based on the Lie group theory. The overall concept and design procedure were proposed and described. The motion requirements of the robot and its legs were extracted and described intuitively. The layouts of the subgroups or submanifolds of the limbs were determined. A family of particular joints with one rotation and one translation was proposed for the first time. The structures of the limbs were synthesized. Numerous structures of the legs were produced and listed corresponding to the desired displacement manifolds. Numerous novel structures of the legs for legged mobile lander were evaluated and listed. Then, four qualitative criteria were introduced. Based on the proposed criteria, a particular case of legs' configuration with a rhombus joint was selected as the best one among them. A typical structure of the legged mobile lander was obtained by assembling the structures of the proposed legs with a rhombus joint. Finally, the typical robot was used as an example to verify the capabilities of the novel robot using a software simulation (ADAMS).