US Patent 9395725 Self-propelled device implementing three-dimensional control

A self-propelled device can include a spherical housing, an internal drive system, and an inertial measurement unit. The self-propelled device can determine an initial frame of reference for the self-propelled device in a three-dimensional coordinate system. The self-propelled device can further receive control inputs from a controller device, translate the control inputs into commands to maneuver the self-propelled device, and implement the commands on the internal drive system to cause the spherical housing to rotate about each axis of the three-dimensional coordinate system. Utilizing the IMU, the self-propelled device can maintain an awareness of an orientation of the spherical housing relative to the initial frame of reference as the spherical housing rotates about each axis of the three-dimensional coordinate system.