A low-level sensor fusion scheme is presented for the positioning of a multi-sensor robot. This non-hierarchical framework can be used for robot arms or other velocity- controlled robots, and is part of the task function approach. A stability analysis is presented for the general case, then several control laws illustrate the versatility of the framework. This approach is applied to the multi-camera eye-in-hand/eye- to-hand configuration in visual servoing. Experimental results point out the feasibility and the effectiveness of the proposed control laws. Mono-camera and multi-camera schemes are compared, showing that the proposed sensor fusion scheme improves the behavior of a robot arm.