Fuzzy logic based control of multiple manipulators in a flexible work cell

Control of multiple robots presents numerous challenges, some of which include synchronization in terms of position, motion, force, load sharing and internal force minimization. This paper presents formulation and application of a fuzzy logic based strategy for control of two six degree-of-freedom robots carrying an object in a cooperative mode. The paper focuses on control of internal forces which get generated when two or more robots carry an object in coordination. Force/torque sensors mounted on wrist of each robot provide the force and torque data in six dimensions. A fuzzy logic controller has been designed to use these Force/Torque (F/T) data to achieve a cooperating movement in which one robot acts as leader and the other robot follows. Matlab's Fuzzy logic, Simulink, and State Flow toolboxes are used for achieving real-time, autonomous and intelligent behavior of the two robots. Simulation results from three experiments show that the above strategy was able to constrain the internal forces and provide a smooth movement of the manipulators.