Development of Off-road Vehicle with 4 Rotating Crawlers Driven Independently

1.为克服崎岖地形或障碍物，设计并研制了液压动力车样车。该车有四套小型履带作为行走装置，其壳体在履带运动运行的同时自行旋转，每个壳体轴连接两套前、后差速器。样机表现出许多优点，如：1)整个四套履带始终保持与地形保持接触，无论其颠簸的形状，2)两套差速器可以正常工作，而不需要车辆的滚动运动，只要地形水平相同的左右(例如。超越沟渠或树篱)，3)保持车辆底盘水平的控制系统可以简化。然而，车辆往往会在一定的地形形状上诱发其滚动运动，因为左右履带之间的地面接触载荷一般不同。为避免滚动，至少四个壳轴中的一个应根据地形图进行控制。讨论和设计了几种特殊的履带形状，以避免车辆的摇摆运动。与传统形状的履带相比，左右履带间的地面接触力差可减小到2/3~1/2左右。我们设计并研制了一辆装有四套轮胎行走装置的模型车，其壳体轴由两个直线轴承组成，以使左右壳体轴所受的力矩保持一致。该装置的两个壳体轴连接到一组差动齿轮上，轮胎的接地接触力变得相等，即壳体轴处的力矩相同。不同地形形状的台架测试显示了所需的性能，尽管至少其中一个外壳应该如上所述进行控制。

1. We designed and developed a hydrawlic powered prototype vehicle to overcome rough terrains or obstacles. The vehicle has four sets of small type crawler as running device, whose housing rotates by itself at the same time the crawler moves for running, and each housing shafts are connected to two sets of front and rear differential gear. The prototype showed many benefits such as : 1)the whole four sets of crawler can always stay in touch with terrain regardless of its bumpy figure, 2) the two sets of differential gear can work normally without having rolling motion of the vehicle as long as the level of the terrain is the same between right and left side (eg. overriding on the ditch or hedge), 3) the control system to keep maintaining the vehicle chassis horizontal can be simplified. However, the vehicle tend to induce its rolling motion on certain figure of the terrain because the ground contact loads between the right and left crawlers, in general, are different. To avoid rolling, at least one housing shaft out of four should be controlled in accordance with figure of the terrain.2. Some particular crawler's shapes were discussed and designed to avoid the rolling motion of vehicle. By using these crawlers, the difference of the ground contact forces between the right and left crawlers can be decreased to about 2/3-1/2 compared with the traditional shape of crawler.3. We designed and developed a model vehicle equipped with four sets of running device with a tire, whose housing shaft was constituted with two linear bearings so that the moment exerted to the right and left housing shafts stayd the same. Two housing shafts of the device were connected to a set of differential gears, and the ground contact forces of the tires became equal, being the fact that the moments at the housing shafts were the same. A bench test with various terrain shape showed desired performance, although at least one of the housing should be controlled as above.