Cycloidal gearboxes
Cycloidal gearboxes or reducers contain four simple components: a high-speed input shaft, a single or compound cycloidal cam, cam followers or rollers, and a slow-speed output shaft. The insight shaft attaches to an eccentric drive member that 
induces eccentric rotation of the cycloidal cam. In compound reducers, the first tabs on the cycloidal cam lobes engages cam followers in the casing. Cylindrical cam followers act as teeth on the inner gear, and the number of cam followers exceeds the number of cam lobes. The next track of compound cam lobes engages with cam fans on the output shaft and transforms the cam’s eccentric rotation into concentric rotation of the result shaft, thus raising torque and reducing acceleration.
Compound cycloidal gearboxes offer ratios ranging from as low as 10:1 to 300:1 without stacking stages, as in regular Cycloidal gearbox Planetary gearboxes. The gearbox’s compound reduction and can be calculated using:
where nhsg = the number of followers or rollers in the fixed housing and nops = the number for followers or rollers in the slow rate output shaft (flange).
There are several commercial variations of cycloidal reducers. And unlike planetary gearboxes where variations are based on gear geometry, heat treatment, and finishing procedures, cycloidal variations share fundamental design concepts but generate cycloidal movement in different ways.
Planetary gearboxes
Planetary gearboxes are made of three basic force-transmitting elements: a sun gear, three or even more satellite or world gears, and an interior ring gear. In a typical gearbox, the sun gear attaches to the insight shaft, which is linked to the servomotor. The sun gear transmits motor rotation to the satellites which, in turn, rotate within the stationary ring equipment. The ring gear is section of the gearbox housing. Satellite gears rotate on rigid shafts connected to the earth carrier and trigger the planet carrier to rotate and, thus, turn the output shaft. The gearbox gives the output shaft higher torque and lower rpm.