Double differential steering

It is for steering vehicles of continuous tracks.
Input:
1. Orange bevel gear of receiving rotation from the vehicle engine.
2. Pink bevel gear of nc velocity from a steering motor that makes two white gear boxes (carriers of two planetary mechanisms) rotate in opposite directions with the same velocity.
Output: green shafts of large gears and wheels of n2 and n3 velocities.
Violet satellite gears connect the two green shafts with blue shaft.
When the pink bevel gear is immobile (nc = 0), the vehicle moves straight (n2 = n3).
When the pink bevel gear rotates, the vehicle turns. The turning direction depends on the motor rotary direction. The turning radius depends on the motor velocity.
In first three scenes of the video: the vehicle first moves straight, turns right when the motor rotates clockwise and moves straight again when the motor stops.
This mechanism can perform neutral turn (when two green shafts rotate in opposite directions with the same velocity) as shown in last scene of the video.
Here the differential with spur gears is used:
   • Car differential with spur gears 1  
It can be replaced with any kind of car differentials, for example:
   • Double Differential Steering  

Inventor files of this video:
http://www.mediafire.com/file/9iu95ig...