Design and Control of a Miniature Rolling Robot for Entertainment

Robots for entertainment are currently very popular, and a variety of systems have been developed. Inspired by the image of snowman and Chinese traditional toy tumbler, we have developed a rolling robot, Loobot, for entertainment. In the shape of a snowman that consists of a spherical head and a spherical body, the robot can dance and move by rolling. Moreover, Loobot supports multiple interactive features such as speech recognition, face tracking and remote communication. Combining these features with the ingenious rolling locomotion makes Loobot more interactive and differentiates the robot from other entertainment robots that are actually screens on wheels. In this paper, we introduce the functions of the rolling robot, focusing on the design and control of its rolling locomotion. The act of rolling is driven by a 2-Dof pendulum with counter-weight (ballast mass) to produce a gravitational torque. Due to its incomplete spherical structure, control of Loobot is different to some extent from that of a spherical robot. Stable dancing and running is a key issue. In existing literature of spherical robots, the dynamic models do not fit in with Loobot. Dynamics of the robot is derived and a simple decoupled stabilization controller is proposed, which is independent on its system parameters.