Design of fuzzy logic controller of industrial robot for roughing the uppers of fashion shoes

The fashion footwear industry is strongly characterized by hand-crafted fabrication. Companies operating in this field are usually reluctant to employ industrial robots in their facilities, where the integration of automated solutions is often an element of disruption. It is also still difficult to perform many of the operations involved with industrial robots. The roughing of the uppers of fashion shoes is a typical example: the great inaccuracy in shoe dimensions and shape makes definition of an automated path a critical aspect, and this is reflected in the complexity of robot programming. In addition, standard industrial position-based control solutions are unsuitable in force-tracking application as roughing by the variable stiffness of the environment and by arm flexibilities. In this scenario, the paper describes an innovative robotic cell for roughing operations with a layout conceived for installation in artisan-based production. The robot controller is an admittance control loop with a fuzzy regulator designed to be integrated with standard robot controller by exploiting the so-called sensor-tracking option. The design of the robot controller is grounded on an in-depth analysis of the manual strategies used by workers skilled in roughing operations. The results of a series of experiments on different kinds of shoes demonstrate the feasibility of this approach.