| dc.description.abstract | In the world of spherical robots groundbreaking innovations with regards to the sensory system and driving mechanism have taken place in last few decades. The motivation in this thesis is to integrate these innovations and develop a spherical robot, “RoboBall”, with a novel elastic spherical shell. This thesis reports on the design of the elastic shell, the modeling of robot’s dynamics and comparison of the analytics with experimental results. In addition to the electric motor-powered motion of the ball, the robot is also able to adjust its air pressure with an embedded pneumatic control system, and this thesis shows how that causes changes in the ball’s dynamics. The design of the internal driving mechanism, prior history, and a taxonomy of the spherical robots is also outlined. A non-trivial feature of the robot is its soft and pressure controlled elastic shell, which presented numerous design challenges. The rigid endplates and elastic exterior together form the skin of the robot, and different elastic-rigid interfaces for an air-tight robot are explored. The development of the internal pressure control system and its components are discussed. The “RoboBall” has an internal pendulum driven mechanism. The pendulum has two degrees of freedom; rolling and steering. A motion in the third direction i.e., oscillation in the vertical direction, is not actively controlled by the pendulum or any other mechanism but is governed by the system’s dynamics. This study focuses on the third degree of freedom, the bouncing of the “RoboBall”, which can be affected by varying the pressure inside the ball. The bouncing of the ball is modeled as a simplified spring-mass damper system and the effect of variation of pressure on different parameters. The thesis concludes with an experimental evaluation of a mass equivalent system, and comparison of these results to the formulated dynamic model. | |
