\input zb-basic \input zb-ioport \iteman{io-port 06071139} \itemau{Tomik, Filip; Nudehi, Shahin; Flynn, Louis L.; Mukherjee, Ranjan} \itemti{Design, fabrication and control of spherobot: a spherical mobile robot.} \itemso{J. Intell. Robot. Syst. 67, No. 2, 117-131 (2012).} \itemab Summary: In the literature, Spherobot refers to a mobile robot with a spherical exo-skeleton and a propulsion mechanism that uses unbalance masses in a tetrahedral arrangement. A modified design of Spherobot, that is better suited to fabrication, is presented in this paper. The modified propulsion mechanism and other components of the design are discussed in detail to highlight the challenges of fabrication. An adaptive estimation and control algorithm used for position control of the unbalance masses and a steering algorithm used for motion control of Spherobot are also discussed. Experimental results of the Spherobot navigating a hallway with bends is presented. \itemrv{~} \itemcc{} \itemut{mobile robot; spherobot; mechanical design; mass unbalance; adaptive estimation} \itemli{doi:10.1007/s10846-012-9652-2} \end