Flexible Hermetically-Sealed Mobile Robot for Narrow Spaces Using Hydrostatic Skeleton Driving Mechanism

Almost all of conventional mobile robots for narrow spaces exploration, e.g. rescue robots, adopt crawler or wheel mechanisms. However, in narrow spaces, such robot is often stuck because the robot body is sandwiched between both sides of a terrain. Especially, with normal crawler or wheel mechanisms, it is impossible to penetrate into narrow spaces lower than the height of the robot. In addition, sealing bushes of drive shaft cause unignorable energy loss because of rotational resistances. In order to solve these problems, this study proposes an innovative flexible robot with new hydrostatic skeleton driving mechanism. The main components of the robot are a hermetically-sealed outer cover with looped structure and flexible crawlers with hydrostatic skeleton named HS crawlers. This new robot provides remarkable advantages in narrow spaces as listed below: i) The robot can change its shape adapting to terrain; ii) All ground contact areas of the robot are driven toward the same direction. Thus, the robot is able to penetrate into narrow spaces changing its shape even if the terrain is rather narrower than the size of the robot. This paper describes the mechanisms of the robot and the detail of the HS crawler. Driving force of the HS crawler is discussed with comparison of simulation and experiment. Performance of first prototype robot is verified by experiments of wireless driving and passing narrow space. The prototype robot could pass through a space of 300 mm height, whereas the ordinary height of the robot is 420 mm