Mehmet Topalbekiroğlu

Modeling and simulation of a hybrid actuator

Modeling and kinematic analysis of a hybrid actuator is presented in this study. The dynamic behavior of hybrid actuator is studied by applying numerical simulation on the whole system. Lagrangian mechanics is applied to derive equations of motion. Simulation results are presented to demonstrate the ability of model developed with PID controller action. Similar following characteristics are obtained from numerical simulation, and the performance of the control system with PID controller is quite effective. In hybrid actuator configuration, a seven link mechanism having an adjustable crank is used. One input of the mechanism is given by a gearbox coupled to brushless DC servo motor, and the second input having an adjustable crank is provided by a permanent magnet DC servo motor coupled to a lead screw mechanism.

Development of a machine vision system: real-time fabric defect detection and classification with neural networks

In this study, a machine vision system is developed to achieve fabric inspection and defect classification processes automatically. The system consists of an image acquisition hardware and an image processing software. A simple and portable system was designed so that it can be adapted easily to all types of the fabric inspection machines. The software of the system consists of defect detection and classification algorithms. The defect detection algorithm is based on wavelet transform, double thresholding binarization, and morphological operations. It was applied real time via a user interface prepared by using MATLAB® program. The defect classification approach is based on gray level co-occurrence matrix and feed forward neural network. Five commonly occurring defect types, warp lacking, weft lacking, soiled yarn hole, and yarn flow, were detected and classified. The defective and defect-free regions of the fabric were detected with an accuracy of 93.4% and the defects are classified with 96.3% accuracy rate.

Experimental evaluation of a model reference adaptive control for a hydraulic robot: a case study

This paper presents the implementation of an explicit model reference adaptive control (MRAC) for position tracking of a dynamically unknown robot. An auto regressive exogenous (ARX) model is chosen to define the plant model and the control input is optimised in a H2 norm to reduce computational time and to simplify the algorithm. The theory of MRAC falls into a description of the various forms of controllers and parameter estimation techniques, therefore, applications may require very complicated solution methods depending on the selected laws. However, in this study, the proposed MRAC shows that applications may be as easy as classical control methods, such as PID, by guaranteeing the stability and achieving the convergency of the plant parameters. Despite the selected simple control model, simple optimisation method and drawbacks of the robot the experimental results show that MRAC provides an excellent position tracking compared with conventional control (PID). Many experimental implementations have been done on the robot and one of them is included in the paper.

The effect of weave type on dimensional stability of woven fabrics

Purpose – Testing the effect of machine washing and drying on dimensional stability produces information about the fabric types that satisfy consumers during end use. At present, it is a known fact that the weave patterns affect the dimensional stability property of woven fabrics. But the essential requirement is to determine the magnitude of this effect for weave types and establish the proper weave types for end use in definite tolerances. The purpose of this paper is to investigate the dimensional stability properties of 100 percent cotton woven fabrics as a function of weave type.Design/methodology/approach – In total, 12 woven fabrics with different weave derivatives are woven with 100 percent cotton and Ne 30/1 combed ring spun yarn for this investigation. These samples are then washed and dried according to domestic washing and drying standard test procedures. The shrinkage values are measured and then expressed as a percentage of the initial dimensions.Findings – It was observed that weave pattern...

Design of a pile-yarn-manipulating mechanism

Abstract A pile-yarn-manipulating mechanism for carpet weaving was designed and implemented. The pile-yarn-manipulating mechanism served to prepare the coloured pile yarn for a knotting mechanism according to a carpet pattern used as input. Such a mechanism required two auxiliary mechanisms (a holding mechanism and a cutting mechanism) to perform its function. A model for the pile yarn manipulating mechanism is presented herein. Important developments of weaving technology have been recorded. There are many carpet looms working at high speeds, but production methods of handmade carpets have not changed for several hundred years. The main difference between handmade and machine carpets is their texture type. The pile surface of machine carpets is produced by Jacquards mechanism, but it is produced independently in handmade carpets by the weaver. There are basically two kinds of knot, namely the Turkish knot and the Persian knot.

A Study of Weaving ‘Turkish Knots’ in Handmade Carpets with an Electromechanical System

Abstract To form a Turkish knot in a handmade carpet, a study for a computer-controlled prototype loom and its drive system has been presented. The mechanisms involved in the prototype are described separately and the design considerations for each mechanism are given with the function requirements needed. The control of the knotting system is achieved with the actuators applied. The research on the subject is still continuing at the Department of Textile Engineering, University of Gaziantep.

The improved breathability of polyurethane coated cotton fabric via micro-cracking

Abstract Polyurethane (PU) coating became popular in the last decades to achieve water resistance garment fabrics with enhanced visual properties. But reduced breathability of coated fabric is a setback for clothing industry. This paper represents a facile method of enhancing breathability (air and water vapor permeability) of PU coated fabrics which may be so-called micro-cracking in relevant solvent bath differed in solvent bath, concentration, and duration time. The samples were subjected to air permeability, water vapor permeability, water resistance, and tensile strength measurements and the results were also statistically analyzed. The study showed that the proposed process increased water vapor and air permeability of coated but the permeability values were still significantly lower than that of uncoated sample. This result is also verified through water resistance measurements and; tensile strength of the samples were affected at minimum after micro-cracking.

Kinematic analysis and synthesis of the beat‐up mechanism for handmade carpet looms

The beat‐up process has a great influence on the structure and appearance of the handmade carpet. Since all weaving processes of the handmade carpet are performed by the weaver, the production speed may be increased and the performance of the weaver may be improved by designing a suitable beat‐up mechanism. In this article, a crank‐rocker type of four‐bar mechanism has been studied for the handmade carpet loom beat‐up mechanism. First, the functional requirements of the beat‐up mechanism were established according to the problem statement. Later, a four‐bar crank‐rocker‐type mechanism was generated and developed from a slider‐crank‐type mechanism. Here, the dimensional synthesis of the mechanism was made as a solution to the slider‐crank‐type mechanism. Many alternative mechanisms were generated as a result of the dimensional synthesis. The slider‐crank‐type mechanisms were then translated into the crank‐rocker‐type mechanisms. These mechanisms were evaluated in terms of some mechanical criteria and the most suitable one was selected. Finally, a kinematic analysis of the beat‐up mechanism was performed.

The effect of knit structures with tuck stitches on fabric properties and pilling resistance

Abstract The patterns of knit fabrics are designed by loops, tuck stitches, and float stitches and their combinations. The tuck stitch has important influences on fabric properties. It increases the fabric’s weight, thickness, and width and makes the fabric more porous than other fabrics. In this study, to determine the effects of knit structures which are made from the same cotton yarn with tuck stitches on fabric properties and pilling resistance, circular knit fabrics with different locations and number of tuck stitches were produced and dyed under the same conditions. In the evaluation process of the results, graphs were drawn and variance analyses were performed. At the end of the study, important findings were determined. The number and location of the tuck stitches and stitch length are effective factors on the structural, physical properties and the pilling resistance of knit fabrics. The fabrics with tuck stitches have much higher porosity, weight, and thickness compared to single jersey fabric. The dyeing process increases fabric weight. Single jersey has the lowest pilling resistance in comparison to fabrics having tuck stitches. The fabrics having more pores and larger pores show higher resistance to pilling. Dyeing and finishing processes decreased the pilling resistance of fabrics.

Robotics and servo press control applications: Experimental implementations

Three case studies are performed in robotics and industrial servo press mechanism by using systems nonlinear dynamics. Robotic systems and servo crank press are currently available in Mechanical Engineering Departments laboratory (Gaziantep University/Turkey). Identification and simulation studies are carried out to get dynamic behavior of the systems of interest. Different motion trajectories are applied according to the requirements for all. Soft computing techniques are studied on these systems. Traditional PID is also applied. Control techniques are implemented as PSO-NN (Particle Swarm Optimization-Neural Network), BP (Back Propagation), PSO-PID; PID and also CasFF (Cascade Feed-Forward) control in laboratory testing in this study. All of the studies are given as experimental base herein.