ROSPHERE: RObotic SPHERE
ROSPHERE is a spherical shape robot, which was initially thought as an alternative mobile system to move over non-compacted surfaces (e.g. sand). Nowadays, the concept has been extended to perform exploration and monitoring tasks. The robot has as a basic principle of locomotion, the relocation of its center of gravity, which is necessary in order to induce instability to make the robot roll over itself.
After analyzing and assessing different mechanical alternatives, and considering the requirements given in exploration and monitoring tasks, an internal pendulum was selected as instability generator mechanism. The first prototype includes a 2-degree-of-freedom mechanism, which permits to induce forward/backward and turning movements, which given its kinematics restrictions of the 2-DOF results in a non-holonomic system. The robot is provided within an embedded computer (Robovero+Overo-Fire) that processes all sensors information (a 9-DOF Inertial Measurement Unit and GPS) in order to define control actions (positions and velocities) in both DOFs to reach predefined trajectories.
After validating and evaluating the basic principle of motion and its capabilities, a second prototype was designed and built to improve mechanical aspects. The new vehicle has been proved in different scenarios including in-situ measurement of environmental variables on crops, and supervision of large exterior critical infrastructures. Detailed information about the design, construction and tests performed are part of a Master Thesis (Spanish)developed in our group under European and national projects support. For details, review the references mentioned above.
 J. D. Hernández, J. Barrientos, J. del Cerro, A. Barrientos, and D. Sanz, “Moisture measurement in crops using spherical robots,” Industrial Robot: An International Journal, vol. 40, no. 1, pp. 59–66, 2013. http://www.emeraldinsight.com/journals.htm?articleid=17072872
 J. D. Hernández, D. Sanz, G. R. Rodriguez Canosa, J. Barrientos, J. del Cerro, and A. Barrientos, “Sensorized robotic sphere for large exterior critical infrastructures supervision,” Journal of Applied Remote Sensing, vol. 7, no. 1, p. 073522, Jan. 2013. http://remotesensing.spiedigitallibrary.org/article.aspx?doi=10.1117/1.JRS.7.073522
 J. D. Hernández, “ROSPHERE: Diseño, Construcción y Aplicación de una Esfera Robótica,” Universidad Politécnica de Madrid, 2012. http://oa.upm.es/19172/