Eccentric Crank Rover: A novel crank wheel mechanism with eccentric wheels

The crank wheel mechanism, consisting of a wheel mechanism and parallel links connected to each wheel, achieved high mobility and efficiency because it has both wheels and legs in a simple structure. However, each prior model of crank wheel mechanism has had shortcomings such as mass oscillation or fragile structure. In this paper, we propose a novel crank wheel mechanism, the “Eccentric Crank Rover”(ECR), which is an enhanced crank wheel mechanism with eccentric wheels. The eccentric wheels increase the under-body clearance, and change the body trajectory from straight to trochoid curve, which has the same shape as the crank legs but opposite phase trajectory. Thus, the body itself acts as a “second” crank leg. We experimentally confirmed higher step climbability, larger clearance, and lower cost of transport than other models such as normal wheel model, eccentric wheel model, and crank wheel model without eccentric wheel.