Design And Dynamic Analysis Of A New Concept Lunar Lander

The Moon is the nearest celestial body to the Earth and the starting point of the space exploration for the human being.The impact energy absorption and landing stability of Lunar landers are extremely critical for Lunar exploration.However,traditional landers cannot adapt to complex landing conditions and response to any unforeseen accidents during the landing process.Although some researchers have proposed the idea for the lander with magnetorheological fluid(MRF)dampers,there are relatively few detailed structural designs and practical landing research studies.In this paper,we propose a detailed new type of lander with MRF dampers implemented as the primary struts,which can absorb the impact energy from landing.Its damping force is controlled by semi-active controlled currents based on the derived hydrodynamics of MRF dampers and can adjust to practical landing conditions.The simulation models of landers with the aluminum honeycomb and semi-active control are constructed in MSC.Adams separately to compare their landing performances.Their simulation results show that this new type of lander can effectively reduce the largest acceleration under the largest acceleration response condition and the largest compression under the largest compression of primary struts condition.It can also increase the distance between cabin centroid and dumping walls under the critical dumping condition and the distance between the docking ring and Lunar land under the shortest distance between the docking ring and Lunar land condition.Its performance for more inclined and both smoother and rougher landing surfaces is better than that of traditional passive landers.It is believed that the proposed new type of lander is capable of landing on more complex and unexplored terrains for future lunar explorations.The MRF hydrodynamics of new landing gear is analyzed under both steady and transient states by both theoretical analysis and simulations.To investigate the landing gear,its coupled Eulerian-Lagrangian(CEL)simulation model was constructed and analyzed in Abaqus.The study compares the simulated damping forces with those of theories.Under low uniform velocities,the simulated damping forces are in good agreements with those of theories.Under high-velocity impacts,the simulated damping forces are more complex.To get lighter landing gear with better landing performance,an optimized lander was designed using the response surface methodology(RSM).In the optimized model,the mass of optimized primary strut reduced by 16.07% with a reduction in the fluctuations of the damping forces.It will be easier to control the landing under smoother damping forces,which is necessary for a successful landing.The electromagnetic coupling simulations of the primary struts are built in Comsol based on the proposed semi-active control approach.In the control schemes required small controllable damping forces,the benefit of the control current is high,which is basically linear with the increment of the yield stress of MRF.In the control schemes required larger controllable damping forces,the increment of the control current is no longer linear with the increment of the yield stress of MRF.The MRF reaches magnetic saturation and requires a quite large control current.Finally,drop experiments systems under different mass blocks,different heights and different control currents are built via the RD-8041-1 MRF damper.Both the simulations and experiments show that the MRF damper is useful to the impact absorption.The controlled current has an obvious influence on the damping force during the landing process.