Modelling and Analysis of Legged Robots with Temporary Flight Capabilities

Abstract

The high obstacle-crossing potential of legged robots has made them a widely studied subject. However, the obstacles that can be overcome are generally proportional to the length of the legs. And any study, that states a legged robot can overcome an obstacle higher than twice the length of the leg has not been encountered in the literature. This situation has made many researchers think about the integration of the capability of flying. Also, this thesis covers the same idea on the RHex robot which is not studied yet. Also, no study has been presented so far in which the orientation of a RHex robot's body is controlled with the help of legs in space. The basis of this thesis is how we humans use our arms and bodies while trying to stay in balance. Similarly, the orientation of the robot's body was controlled by the reactions of the forces applied to the legs in space so that it was possible to control the magnitude and direction of the thrust vector of a thruster fixed to the robot. This means that the movements of the robot could also be controlled. In this study, an existing robot platform RHex was used. The complex geometry and dynamics of the RHex robot were not studied; instead, a 2D simplified model was obtained, and a controller with the desired transient behavior was designed by extracting and linearizing the equations of motion of the simplified model. Then, with the help of a designed flight simulator, the designed controllers' transient behaviors and actuator efforts were examined, and their performances were evaluated.