Development of multi-wheeled snake-like rescue robots with active elastic trunk

Abstract

A practical robot for search and rescue operation is demanded. We believe that one of the most promising robot is a snake-like robot with a slim and active trunk. This paper proposes a new multi-wheeled snake-like robot with active elastic trunk. We choose active wheels for the propulsive device due to mechanical robustness and simplicity, and increase locomotion capability by serially arranging many active wheels along to the trunk. We also propose a new mechanism for the trunk which satisfies both active bending motion and passive compliance. The active elastic trunk consists of deformable elastic segments made of sponge and rigid (or semi-rigid) segments, where active wheel is attached, stacked in layers. The active bending motion is generated by pulling the cables passing through the trunk from the head to tail. We develop three prototypes named "Souryu-VII", "Souryu-VIII" and "Souryu-IX". The mechanical design and features for each prototypes are explained and their performances are evaluated through the experiments with various measures.

Hypermobile Robots – the Survey

“…For the wheeled robots this density is limited by the maximum turning angle of the joints (wheels on the consecutive segments have to keep distance to avoid collision on curve). You can gain some improvement by mounting one wheel on the side every two segments, like in [6,44]. Tracks provide much higher k PR especially when used on each side of the segment, like in [30,34,35] for cuboid shape and [50] for cylindrical shape.…”

“…• avoid slippage by active [2,8,11,17] or passive joints [23,28,44], or additional elements [32,38,45] that provide good trafficability of the robot -maximize tractive power, • detect slippage and estimate true value of the speed [39,48].…”

“…20, [44]. They inherited structure partially from Koryu II -robots consist of many segments, each of them has only one wheel and neighboring segments have wheels on other sides -and partially from previous Souryu robots -joints are coupled.…”

“…on the surface that normally cannot generate effective traction force. To keep the robot light-weight and less complicated the authors removed the wire driven bending mechanism from the rear section and therefore this section is passively following the frontal part of Souryu-IX [44].…”

“…No doubt that the task is very challenging as we have many (usually more than 10) local variables to regulate in the synchronized manner. Most of the hypermobile and Souryu-VIII (right), reproduced from [44] robots presented to date lack the autonomy or this autonomy is limited to very specific environment of operation [15,45]. However, starting from the very first hypermobile robot authors try to make the teleoperation task as intuitive and easy as possible.…”