Access Type

Open Access Dissertation

Date of Award

January 2014

Degree Type


Degree Name



Electrical and Computer Engineering

First Advisor

Abhilash Pandya


The objective of this research is to compare barycenter offset based designs of spherical robots to control moment gyroscope (CMG) based designs in order to determine which approach is most effective. The first objective was to develop a list of current state of the art designs in order to gain an overall understanding of what the obstacles in this area of research were. The investigation showed that barycenter offset designs can produce a low, continuous output torque, whereas CMG based designs can usually only produce a high, momentary output torque. The second objective was to develop a CMG based design that has the potential to outperform current state barycenter offset based designs. A design consisting of a dual, scissored-pair CMG (DSP-VSCMG) configuration was proposed and the dynamics derived from first principles. The third objective was to develop a set of equations that can describe performance characteristics of spherical robots . The equations that were modeled were power consumption, translational velocity, maximum incline plane, step size from rest, as well as CMG inertias and geometries. The fourth objective was to perform a series of parametric analysis using the developed equation set to compare barycenter and DSP-VSCMG based designs in a controlled environment. The analysis showed that DSP-VSCMG based designs can be more agile than barycenter designs, but require more power to do so.