Applied Engineering Letters Vol. 1, No 3, 67-71 (2016) e-ISSN: 2466-4847 CONTACT: Djordje Dihovicni, ddihovicni@gmail.com POLE ASSIGNMENT FOR GLASS CAPILLARY TUBE DRAWING PROCESS BY USING MATLAB AND MAPLE LANGUAGE Djordje Dihovicni 1 1 Technical College, Bulevar Zorana Djindjica 152a, Belgrade, Republic of Serbia, Tel.:+381-11-2600-131, e-mail: ddihovicni@.gmail.com Abstract: The question of pole placement for glass capillary tube drawing process is considered. It is used a frequency domain approach to an arbitrary finite spectrum assignment for multivariable time delay systems in order to control glass capillary tube drawing process. The Padé approximation is used for the system of third order and time delay is eliminated from the transfer function of the process. The responses are shown as well the transfer function of the closed loop after applying finite spectrum method. By choosing state variables it is obtained non degenerative transfer function of process model. The time delays in open loop remained the same as in the closed loop. The all poles are located in the left half plane and system is stable. Appropriate program support for this type of problems is developed in Maple language. ARTICLE HISTORY Received 15 August 2016 Accepted 18 September 2016 Available online 30 September 2016 KEYWORDS Glass capillary, pole placement, time delay, stability, finite spectrum, mathematical model, frequency domain, Pade approximation. 1. INTRODUCTION Hower despite the fact that the drawing of glass capillary tubes is well known technological process, and that the process of drawing of optical fibers is good described in the literature, there is yet not many references relating to this specific field, and as well detailed analyze and synthesis in the frequency domain of this phenomena [3-5]. In brief, the glass capillary tube is produced by heating an end of the hollow cylindrical glass preform and then by drawing out melted part thereof which contracts first quickly and then slowly during cooling process [6-7]. The glass capillary tube takes part at the relatively low temperatures in contrast with drawing process of optical fibre [11]. At low temperatures the viscous stresses are dominant, and thickness of a wall of the capillary tybe should be controlled [12]. The studies of Geyling (1976), Clermont (1984), Mayers (1989) and Papamichael and Miaulis (1990) were extremely important and by them was given the significant contribution to explaining and describing whole process [15]. Taking into account that a very rapid change of the viscosity is very complex problem, the best way is to describe the drawing process qualitatively. There are various processes of drawning glass tubes from a source of molten glass such as Vello, Danner and Down, and the shape of the glass tube is characterized by the diameter of cross sectional area of the tube and the thickness of the wall. The geometry of the tube may be circular, rectangular or square, and there are different geometry techniques for obtaining required results. Sometimes it is used inversion problem such as in manufacturing of non-axisymmetric capillary tubing where the necessity for determination the diametar of the shape is required to achieve the final shape. Mathematical models of the process are usually complex and described by nonlinear partial different equations of higher order [1]. In order to present valid mathematical method time delay which is presented in the system should not be neglected [2]. In time delay systems, delay might occur in state, control and as well in state and in control, when arises the principal difficulty in the control loop, such as increased phase lag