Design and Simulation of a Robot Balancing on a Sphere with Reduced Height

Most of the present robot balancing over a sphere is equipped with three omnidirectional wheels connected directly to stepping motors that drives the sphere. In this paper, special attention was given to reduce the height of the robot chassis for given sphere size, by proposing a chassis which holds most of the electronics and gear mechanism in which stepping motor shaft is connected to axis of the omnidirectional wheel in perpendicular to each other, without sacrificing the omnidirectional traverse and pivot around its vertical axis capabilities. A bevel gear mechanism is used to drive the wheels from the stepper motors. Due to reduced chassis height, the overall height of robot is reduced to 320mm for sphere size of 240mm diameter, and has increased stability of robot due to lower center of mass. The designed robot has been simulated using SimMechanics, physical modeling method and tested in sphere over robot experimental setup which has been fabricated. The feasibility of developing the mechanism, kinematics and highlights of fabricated robot are described in this paper.