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 vertid 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. https://vssewingmachine.in/ Yet, the controller restrids 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.
Industrial sewing machines have been improved a lot in’the recent years. Most manufactures can support a large field of applications, with machines that can perform operations with high quality and at very high speeds. Yet, some problems arise, mainly due to the constant change in materials being sewn. One important system of a sewing machine is the material feeding system. The objective of this study is the feeding system of an industrial overlock sewing machine, which is depicted in Fig. 1. The system consists of three components: a presser foot, a throat plate and a feed dog. The throat plate is a smooth surface that supports the fabric being sewn with openings for the needle and the feed dog to pass. During this movement the feed dog rises above the throat plate to engage the fabric against the underside of the presser foot before starting the advancing motion. Some of the problems in the sewing process rely in the interaction between the presser foot and the feed dog. The presser foot is responsible for guaranteeing the required pressure to control the fabric feeding and to constrain their movement during needle penetration and withdrawal. In order to study the feeding process and to control the presser foot, the sewing machine was instrumented with a LVDT (linear variable differential transformer) for measuring the vertical displacement of the presser foot, and a miniature piezoelectric force transducer to measure the (compression) farces exerted on the presser foot bar. A proportional force solenoid is used to interact with the presser foot, according to the arrangement presented in Fig. 1. Up to now, the available actuators have a quite large response time (about 50 ms step response), allowing only a stitch-by-stitch control of the maximum displacement point. Future actuators with better response times may permit the control of the whole presser-foot trajectory.