A first rotating axis and a second rotating axis are respectively connected to one of a sun gear, a ring gear, and a planetary gear carrier of a first planetary gear train and a second planetary gear train. One of the sun gear, ring gear, and planetary gear carrier of the first planetary gear train is fixed to a frame, and one of the other elements is synchronized in revolution. One corresponding sun gear, ring gear, and planetary gear carrier of the second planetary gear train is rotatably mounted. A rotation degree of the rotatably mounted sun gear, ring gear, and planetary gear carrier of the second planetary gear train is measured. Then, a phase difference with respect to rotations of the first rotating axis and the second rotating axis can be detected.
An electric drive configuration for a skid steered vehicle comprises: a pair of propulsion motors (74a, 74b), each with a motor shaft protruding from both ends of the motor and mounted on the same axis across the vehicle, each being coupled at the outer end to drive one of a pair of tracks or set of wheels of the skid steered vehicle; a control differential steep gear unit (72) positioned between the two propulsion motors and in driveable communication with the inner ends of the two motor shafts: and a steer motor (71) in driveable communication with the controlled differential (72), the steer motor (71) being controllable from zero speed giving straight line running in which both motor shafts are coupled to run at the same speed, to a range of speeds in both directions of rotation giving steering capability in both directions.
