This paper addresses motion analysis of a double spiral propulsion mechanism. Now there are many wetlands in Japan, but area of wetlands has been decreasing. Therefore, some groups of conservation of nature have preserved environment of wetlands, and they have surveyed it as a part of preserving activity. But there is a demand of development of robots which support the surveys, because human beings are difficult to move in wetlands due to mud and dense weeds. Single spiral propulsion mechanism have been proposed for movement in wetlands. Double spiral propulsion mechanism is another type of mechanism for movement in wetlands. This research studied about motion of double spiral propulsion mechanism when it is driving.
