Analytical model of a butterfly micro-swimmer

We propose a simple mechanical model consisting of two spheroids (wings) connected by a single hinge. Unlike micro-swimmers proposed so far, this model has just one hinge, but its motion allows two degree of freedom, corresponding to open-close and twisting. Its non-reciprocal operation cycles resembles conformational motions characteristic for real protein machines and similar to the propulsion pattern of a butterfly. The net velocity and the net stall force are calculated analytically and their dependence on the model parameters is discussed.