  A spherical robot has many practical advantages as the entire electronics are
protected within a hull and can be carried easily by any Unmanned Aerial
Vehicle (UAV). However, its use is limited due to finding mounts for sensors.
Pendulum actuated spherical robot provides space for mounting sensors at the
yoke. We study the non-linear dynamics of a pendulum-actuated spherical robot
to analyze the dynamics of internal assembly (yoke) for mounting sensors. For
such robots, we provide a coupled dynamic model that takes care of the
relationship between forward and sideways motion. We further demonstrate the
effects of wobbling and precession captured by our model when the bot is
controlled to execute a turning maneuver while moving with a moderate forward
velocity, a practical situation encountered by spherical robots moving in an
indoor setting. A simulation setup based on the developed model provides
visualization of the spherical robot motion.
