Masamitsu Watari

An asymmetric robotic catapult based on the closed elastica for jumping robot

In this paper, we propose a new asymmetric robotic catapult based on the closed elastica. The conventional robotic catapults based on the closed elastica which the authors developed are the robotic elements for generating impulsive motions by utilizing a snap-through buckling. In a typical closed elastica, the two ends of an elastic strip are fixed to a passive rotational joint and an active rotational joint, respectively. Here we found that by adding only a range limitation to the passive rotational joint, compared to the conventional type, the deforming shape of the elastic strip becomes more complicated and 40% more elastic energy can be stored. Using this modification, we can develop a compact jumping robot which is able to leap over 700[mm] away and 200[mm] high.

A robotic catapult based on the closed elastica with a high stiffness endpoint and its application to swimming tasks

In this paper, we propose a new robotic catapult with a high stiffness endpoint. The conventional robotic catapults based on the closed elastica are robotic elements for generating impulsive motions by utilizing the snap-through buckling. In a typical robotic catapult, the two ends of an elastic strip are fixed to a free joint and an active joint, respectively. Here we found that by adding only the high stiffness at the free joint, compared to the conventional type, more elastic energy can be stored and release surely without loss of a characteristic of generating impulsive motion repeatedly. By utilizing the high stiffness endpoint, we develop a faster impulsive swimming robot than the conventional one.

A Jumping Robot based on the Closed Elastica

In this paper, we propose jumping robots catapulted by the closed elastica which the authors developed as a robotic element for generating impulsive motions by utilizing the snap-through buckling. We show that one of our robots, which is about the size of 170 x 90 x 50 [mm], leaps 700[mm] away and 200[mm] high. We also show a legged jumping robot which pushes the ground impulsively by its leg attached to the closed elastica.