US Patent 7905463 Multiple axis gimbal employing nested spherical shells

A multi-axis gimbal has each axis defined by a respective spherical shell driven by a flat, compact motor attached to the driven shell and to a next outer shell (or to an external mounting platform, in the case of the outermost shell). The shells rotate about respective axes. In one configuration, the outermost shell is referred to as the “azimuth” shell because in use it rotates about a vertical axis. The next inner shell is an elevation shell that rotates about a first horizontal axis that is orthogonal to the axis of the camera or other sensor payload. An optional third shell can be used to provide “roll” motion, such as rotating a camera about its axis to obtain a particular rotational orientation with respect to a target.