Study on connection between kind of vibration and influence of ground for leg typed rovers

Surveys of the moon and Mars are important missions in space exploration. The rovers which are exploration robots moving on the ground work in these exploration missions. They achieved significant results in these missions. In recent years, the leg typed rovers are focused on as an exploring rover with high running performance. However, it is difficult to walk on the loose ground for the leg typed rovers. The surface of the loose ground is easy to destroy at motion of its legs. Destroying behavior at motion of the leg which is contacting on the surface means that the rovers are easy to occur slip. We previously proposed the walking method which reduces slip distance on the loose ground for leg typed rover. Our study group considered that traction of the leg typed rovers is passive earth pressure given to the leg. Proposed walking method is used changes of the ground when giving vibration. Passive earth pressure given to the leg is increased by changes of the ground when giving vibration. Furthermore, some experiments using a testbed to walk on the loose ground were carried out. In experimental results, the displacement of proposed walking with vibration became long compared with the one without vibration. From previous experimental results, we could get knowledge that the method using vibration was very effective for the leg typed rovers. However, the relationship between the parameters of vibration and the influence of the ground is not still understood. Vibration has the parameters of frequency, amplitude and acceleration. It is considered that influence of the ground when giving vibration is changed by changing the parameters of vibration. If this relationship is understood, suitable vibration can be selected for the proposed walking method. In this study, the effects which are given by vibration to the ground are confirmed from experiment using a few kinds of vibration. Measurement contents are density of ground and passive earth pressure. Vibration parameter to change are frequency, amplitude and acceleration. In experimental results, as these parameters of vibration were large, density of ground and passive earth pressure were increased.