Research Of A Compound Walking Wheel Having Retractile Laminas With Application To Lunar Rover

Luna is the only secondary planet of earth , and it is the celestial body which is closest to earth . The lunar exploration is significant in many domains such as science,economy,military affairs and polity .Going with the third climax of lunar exploration , the lunar vehicle is becoming the focus of all world's research .The lunar rover is one of the most pivotal parts of the lunar exploration project. The lunar rover is a robot combined with remote control and autonomous navigation, it is a pioneer landing on the Moon and it can do long-time practical exploration in place of astronauts, moreover it can bring back experimental samples that can be analyzed by researchers. The wheel is one of the most important parts of the lunar vehicle,it has a direct influence in the lunar rover's dynamic capability, traffic ability and ride comfort. The successful design of the wheel will determine the success of the lunar rover's missions execution .Recently, the sink of America Mars rover tells us that the research of the wheel's traffic ability is such important when the rover is in the soft soil terra.Now majority of the rover's wheels existed are traditional circular. There are many kinds of advantages but they have many problems such as bad traffic ability and low driving efficiency when confront planet terra circumstance like the soft sandy soil. Recently, more and more researchers start developing the walking wheel and hope it could provide good traffic ability for the rover. At present, while the walking wheel can advance traffic ability, it brings on some problems .For example, when a walking wheel rolls, its centre will fluctuate and the velocity won't be even .When the count of legs is four, the maximum of velocity will be twice of the minimum and when the vehicle turns there will be a difference between the left wheel's velocity and the right one. It will leads big questions such as the rover's body incline, swing and vibrate. In addition, most of the present walking wheel have a complex structure and high price, and need a huge control system.The Intelligent Vehicle Group of Jilin University has developed a new kind of wheel'a compound walking wheel having retractile laminas'on the occasion of the Chinese exploration of Luna. This kind of wheel is based on the productions of other researchers and the advantages of other kind of wheels are taken into account. The point of this wheel's structure is that it has eight laminas which can extend and draw back. The flex of the lamina doesn't need and control from people, it just make it by itself depends on its structure characteristic and exterior circumstance. When the vehicle works on the soft sandy soil, the laminas will extend and interact with soil and by this, provide a traction for rover; when it's on good roads, the laminas draw back, then the wheel will have a good ride comfort.This paper mainly analysed the model of the interaction between the wheel and lunar soil and its influence factor of drawbar pull based on Vehicle-Terramechanics combining the lunar soil physics parameter. Its contents and conclusions can be described as follow:(1) Use the Bekker theory to build the wheel-soil interaction model combining the lunar soil physics parameter.(2) Predict the drawbar pull of the wheel on the lunar surface's circumstance, protract the transformation curve of DP-slip, do the traffic ability research and analyze its influence factor.(3) Use the theory of soil passive pression to do some more research about the wheel-soil interaction, to predict the utmost traction that the lamina can provide. Then make a comparison to the traction curve based on Bekker theory.(4) Analyse the mechanics model at the time of many laminas working together.