Hermetically-sealed flexible mobile robot “MOLOOP” for narrow terrain exploration

Abstract

Almost all of conventional exploratory robots adopt crawler or wheel mechanisms. However, such robots are often stuck at narrow spaces. This study proposes an innovative flexible mobile robot named “MOLOOP”. This robot consists of a hermetically-sealed outer cover with double-looped structure. The robot is driven by original flexible crawlers which are composed of multiple flexible bags with loop connection. Since the whole body of the robot is quite flexible, the body can change its shape adaptively according to the terrain. However, the performances of the previous prototype are not enough in terms of the speed and the size. This report describes the performance improvement of MOLOOP aiming speed-up and miniaturization. For the purpose of using high input pressure, this study reinforces the flexible bags of the crawler by fibrous materials. This improvement contributes not only the power of the crawler but also downsizing. The new HS crawler improves the torque and speed from 0.23 Nm to 3.43 Nm and from 3.0 mm/s to 39.0 mm/s respectively. The new prototype of MOLOOP with the new crawler achieves downsizing from 370 mm to 275 mm in the width. The speed is also increased from 3.0 mm/s to 9.0 mm/s. The prototype robot successfully passed through a space with 230 mm height which is narrower than the robot width (275 mm). For the purpose of shock resistance test, we dropped the robot from 1.5 m height to a hard floor. After that, it moved without any problems.