To smoothly and continuously change turning radius by setting the rotational speed ration of each driving wheel based on a distance from a crossing point between the rotation axis of a steering wheel and the rotation axis of the driving wheel to each driving wheel.
For a motor-driven carriage 1, a pair of left and right steering wheels 5a and 5b are attached to the front side of a base frame 2 in the lower surface of a loading base 3 and a pair of driving wheels 6a and 6b are attached to the rear side thereof. The two driving wheels 6a and 6b are driven by different drive motors, but these are attached in fixed directions (perpendicular directions) with respect to the base frame 2 while rotations axes C thereof are always coincident with each other. On the other hand, the steering wheels 5a and 5b are attached to the base frame so as to be changed for directions and the rotation axes (a) and (b) of the steering wheels 5a and 5b are linked together so as to intersect in one point P on the rotation axes C of the driving wheels 6a and 6b. The driving wheels 6a and 6b are rotated in the same direction and a speed ratio between the wheels 6a and 6b is controlled in proportion to a distance from the turning center point P to each of the driving wheels 6a and 6b.
UCHIYAMA HIDEHIKO
ARAI KATSUHIRO
