Study on Effect of Grousers Mounted Flexible Wheel for Mobile Rovers

Abstract

This paper presents the effectiveness of the flexible wheels for lunar exploration rovers. The flexible wheels give high performance while traversing loose soil. The flexible wheel is an effective scheme to traverse loose soil without poor performance. The flexible wheel has a surface which can be changed flexibly for rough terrain. When the surface of wheel performs matching the shape of ground it is crossing, the normal stress between the wheel and loose soil becomes small. It is prevented from sinking because this normal stress is small. However, the flexible wheel doesn’t have high performance without grousers. The grouser is very important to get thrust for rovers. From running experiments using a single wheel tester, we found that the flexible wheel with grousers gave a high performance. The mounted positions of grousers on the surface of the wheel are defined by the same angle (ex) 36 deg). This means that there are two patterns to mount grousers. One is under the rib while the other is between the ribs. The spring force under the rib is different from between the ribs, it is greater. Moreover, each distortion is different. From these considerations, we need to find the optimal position for grousers. We carried out running experiments using wheels with both patterns. From our experiments, we understood the wheel with the position mounted between ribs gave a better performance than when it was set under the rib. When the area giving normal stress is wide, soil under the wheel becomes hard. Therefore, the wheel with grousers mounted between ribs gives a higher performance compared with the one mounted under the ribs.