Development of a Butterfly-Style Flapping Robot with Slider-Crank Mechanism Using Flexdible Links(Mechanical Systems)

In this paper, we propose a small and simple slider-crank mechanism using flexible links that can flap wings over a wide angle, i.e., over 150deg, toward the development of a small flying robot modeled on insects. We then demonstrate the validity of this mechanism by analyzing the motion of the constructed butterfly-style flapping robot. Although many researchers have developed hardware inspired by flies and dragonflies, butterfly-style flight is more attractive because of its low flapping frequency and the fewer degrees of freedom (DOFs). Since a butterfly, however, has a wide flapping range of almost 150deg and claps both its left and right wings during flapping, in a conventional slider-crank mechanism, the driver and follower are parallel at the top dead point and insufficient torque can be generated for flapping. To overcome this problem, we have developed a slider-crank mechanism using the stored elastic energy of flexible links that can generate sufficient torque even at the top dead point. The constructed butterfly-style flapping robot with this mechanism realized a wide flapping range and, furthermore, the characteristics of butterfly-style flight, i.e., upward flight during the down stroke and forward flight during the upstroke.