An orbital motor, also known as an orbital hydraulic motor, is a special type of internal gear hydraulic motor. The stator of this motor is an internal gear, while the rotor is an external gear, and its tooth profile is cycloidal. The gear center of this motor has an eccentricity. Due to the small number of teeth, the volume of the working space is large, and there are no isolation components for high-pressure and low-pressure oil, making the structure simple, compact, small in size, and light in weight. ATO will introduce the orbital motor, mainly including the following aspects: structural principle, power output, automatic variable, and friction cycloid.