Topological design of a new family of legged mobile landers based on Truss-Mechanism Transformation method

Abstract To meet the needs of the “Returning” and “Base construction” missions of the extraterrestrial body's exploration task, it is necessary to enable the legged stationary lander (LSL) to walk, i.e., it is important and imperative to design novel legged mobile landers (LMLs). This paper aims to address a novel synthesis method based on Truss-Mechanism Transformation (called as TMT method) for LMLs with the capabilities of trusses and mechanisms during different phases. The overall topological design concept and procedure of TMT method are proposed. Based on the extract rules and intersection operations of the motions, the motion requirements for TMT method are obtained. The number condition, the relationship among motions and the methods for allocating the motions in the truss for TMT method are proposed. Some qualitative evaluations are also proposed. By means of this method, numerous structures of LMLs based on the structure of Chang'e lander are synthesized. Finally, after type evaluation, two typical LMLs’ legs with transmission limbs or electronic bolts are taken as examples to analyze the properties and abilities of LMLs during different phases. The TMT method is universal and effective for topological design of robots which can transform between truss and mechanism.