A Fuzzy Logic-in-Loop Control for a Novel Reduced Height Ballbot Prototype

Abstract

Ballbot is a configuration of a mobile robot where a spherical wheel is driven by a chassis over it. Such a configuration has very good maneuverability due to lack of any kinematic constraints applied on the chassis. A ballbot is typical example for a dynamically stable system. Often ballbot configurations have tall height which shift the center of gravity to larger values leading to additional efforts in planning a suitable controller. The proposed design has a very small height owing a novel design idea. This keeps the center of gravity very close to the centroid of the sphere. In addition to this a novel idea of substituting the inverse kinematics model by a rule based fuzzy logic is also presented. Often in the kinematic control of mobile robots the inverse differential kinematic model is used. This paper presents an alternate approach which avoids inverse kinematics computations in the control loop. A fuzzy rule based method is utilized which overcomes the inherent demerits of inverse kinematic problem in any mobile robot system. The paper describes the novelty in the design and the implementation details of the fuzzy logic in a electronic controller for a kinematic control without details of the dynamics involved balancing problem.