Structure Design And Performance Research On Suspension And Wheel For Manned Lunar Vehicle

Research on manned lunar vehic le is one of hot issues in the field of lunar exploration in recent years. Whether resident in the short-term or permanent on lunar surface, manned lunar vehicle is the ind ispensable research media and probing tool for carrying astronauts to places which are far away from the lunar module and effectively performing of exploration tasks. Because of different science miss ion and objects, the locomot ion configuration and mobile performance of manned lunar vehic le are completely different from unmanned lunar rovers. Higher requirements to the harsh lunar environment and condit ions etc. are put forward. Design theories and key technologies for deployable locomot ion of manned lunar vehicle should be further researched.By topology structure systhesis for deployable locomotion, ride comfort and trafficability analysis related to performanc e parameters and structural parameters, structure design method of suspension and wheel, locomotion building, simulation and experiments for mobility performance, structural design and performance analysis of suspension and wheel for manned lunar vehicle to meet the design locomotion constraints can be achieved.Based on mechanis m and mult i-body dyna mics, deployable chassis can be treated as seria l mechanism and suspension as paralle l mechanism and the whole locomotion as hybrid mechanis m. According to ma in related theories for parallel mechanis m, topology structure synthesis for locomotion parallel mechanism of manned lunar vehic le was done by using loop rank distribut ion. Six themes were obtained which meet requirements of the loop rank distribution for deployable manned lunar vehicle with four branches.For the locomotion of biaxial four- wheel configuration for manned lunar vehic le, body and wheel are linked by elastic ele ments, shock absorbers and suspension guid ing mechanism. Two-degree of freedom vibration model excited by a single point is established by simp lifying the locomotion. The influence of main performance parameters of suspension and wheels on ride comfort by simulation. Based on structural parameters of locomotion, geometry condit ions for jacking failure and contact fa ilure, configuration relations hip analys is for gradeabilit y, obstacle negotiat ion and crossing the moat were analyzed to ensure trafficability ability of the locomotion of manned lunar vehic le.Deployable double wishbone independent suspension wit h torsion bar of manned lunar vehic le is spatial mult i- link mechanis m. Its design is complex because of mult i constraints. At the same time, the design difficult y is enhanced by the coupling effect between steering system and suspension and the ensurance that wheel alignment parameters change within a reasonable range during wheels travel in normal and folded process. By using the four- step design method based on equivalent mechanis m theory, the spatia l multi- link mechanism is transformed into planar mult i- link mechanism in tranverse and horizontal projection. Key points of guiding mechanism and tie rod of the steering can be obtained. Longitudinal torsion bar, as the spring elastic element of suspension, can be designed for mechanical and elastic properties by considering the effect of fo lded process within a larger scope and the stiffness match relationship for the upper and lower torsion bar.As a physical interface between the locomotion and lunar environment, the wheel subsystem takes a decis ive role for mobility performance. Its structure is specia l because of in- wheel motors and driving- transmiss ing structure in one set etc.. Driving torque and power for single wheel are analyzed and improved by applying wheel- soil interaction terramec hanics. Based on mechanical analys is and finite element s imulation by us ing multi- point constraints method, comb ined alloy hub and its key components are designed and improved according to the affection of related factors. Heat treatment of metal forming for flexible wire mesh and assemb ly process for the wheel subsystem were solved by technology tests to ensure the dimension consistency of wheels.Finally princ iple sample for manned lunar vehicle used on earth was built from mechanical and control system, simulation and experiments for mobility performance were done. Fold ing and deployable feasibility on earth was done. Mobilit y performance on lunar surface or on earth were compared. At the base of simulation results, related trafficability experiments such as gradeability, obstacle negotiation etc. were done on analog soil on earth for manned lunar vehicle.