날갯짓 기능을 가진 도약 로봇의 종방향 안정성 해석

Abstract

Due to safety concerns, it is difficult for human beings to access a disaster area to rescue survivors. Even a robot may fail to conduct a rescue mission if it can use only one mode of transportation. A robot with multiple modes of transportation may have a greater chance to successfully search for survivors within the golden time. In previous work to develop a dual-mode mobile robot, we introduced a jumping robot assisted by flapping wings called Jump-flapper. The robot was equipped with one driving motor and dual transmissions to operate a winching mechanism for elastic energy storage used for jumping and flapping mechanisms to provide additional thrust in the air immediately after jumping. In this paper, we analyzed the stability of Jump-flapper using a linearized equation of motion. With commercial software ANSYS-Fluent, computational fluid dynamics were used to compute stability derivatives included in the system matrix. The eigenvalue analysis finds that the robot eventually becomes unstable due to two unstable oscillatory modes. For a more accurate estimation of vertical jumping height, the drag of the robot body was included in the equation. Consequently, the equation of motion became non-linear and we used the Euler method to solve the non-linear equation. The estimated vertical jumping height agreed with the prediction by a simple model and with the measured height from our previous work.