Variable and differential output drive system

A drive system with the capability for providing continuously variable and differential outputs is provided. The drive system may include a power source system and first, second, and third variable drive units coupled to the power source system. The drive system may also include first and second planetary gear assemblies, each planetary gear assembly including a sun gear, a ring gear, a carrier, and a plurality of planetary elements. The first variable drive unit may be mechanically coupled to the first planetary gear assembly. The second variable drive unit may be mechanically coupled to the second planetary gear assembly. The third variable drive unit may be mechanically coupled to the first planetary gear assembly and to the second planetary gear assembly. The drive system may also include first and second output shafts coupled, respectively, to the first and second planetary gear assemblies.