A control or robot articulated arm comprising motorised articulations, at least some of which are remote controlled by motors (15, 16) place on a base (3) to lighten the arm. The motors (15 and 16) are side by side and control coaxial pulleys (12 and 13) due to bulges (24, 25) at stages on the motor shafts (17 and 18). This reduces the overall size. FIG. 2.