This paper describes a hardware and software system for carrying out assembly tasks. The manipulator is a PUMA-761 robot equipped with a gripper having solidary motion and auto-aligned fingers, designed for parts assembly. The gripper, built at the Institute de Automatica Industrial, has two 220 kHz ultrasonic transducers, two 40 kHz ultrasonic transducers, and two tridimensional dynamometric structures. The system is multisensorial and the software design was based on logical sensor concepts. The supervision and control of the proposed system is managed by a personal computer. The computer executes digital processing of ultrasonic and force signals, and supervises and controls the PUMA 761 robot as well as the finger motion of the gripper. This system was employed for executing typical assembly tasks, including objects location and identification, and stages of grasping, transferring and mounting of different parts.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>