Fuzzy logic based control strategies for an electromagnetic actuated sewing machine presser foot

Industrial sewing machines have been significantly improved in recent years and especially electronic sewing control is now being introduced. This study concerns the development of a controller for an electromagnetically actuated presser foot. The controller is responsible for controlling the vertical movement of the presser foot. This is an important point since the presser foot tends to bounce at high sewing speeds, resulting in irregular seams. In this study a fuzzy logic controller was used. The reference displacement value is set up by an adaptive method in order to respect changes on the number of plies. The tested fuzzy logic controller allows a better performance of the control especially in relation with different fabrics. During this study another control strategy was considered. This control strategy combines a PI-algorithm with a fuzzy logic controller. Yet, the controller restricts the use of new fabrics, which have not been defined in advance. This aspect will be a major point in the future development in order to recognize the fabrics during sewing and to adapt the controller adequately.