A variable configuration articulated tracked vehicle comprises a chassis, a pair of right and left drive pulleys, a right and left planetary wheel, a right and left track, a right and left arm mechanism, and a right and left drive motor. The drive pulleys are rotatably attached to the chassis and each pair of drive pulleys is in the same plane. The planetary wheels are movable relative to the chassis such that each planetary wheel is in the same plane as its respective drive pulleys. The tracks extend around the pair of drive pulleys and the planetary wheel on the respective sides. The arm mechanisms connect the respective planetary wheel to the chassis. Each arm mechanism is rotatably attached to the chassis with a cam. The cam defines a motion path of one end of the arm whereby the motion of the planetary wheel provides a path for the planetary wheel such that the track path defined by the respective drive pulleys and the planetary wheel is a constant track length. The motors are each operably connected to the respective pair of drive pulleys for driving the track.