Salman Kurtulan

Implementation of local modular supervisory control for a pneumatic system using PLC

Abstract In this study, we implement a controller, based on Supervisory Control Theory on a pneumatic assembly system. We use local modular approach, which exploits modular structure of the plant and the specifications. An implementation methodology using a hierarchical control structure where PLCs are utilized is introduced. Local modular approach, together with the implementation methodology presented in this study provides an effective way for synthesizing and realizing supervisors for DES control problems. The resulting PLC program is also modular in structure, making it easy to modify and detect errors.

A new PI tuning rule for first order plus dead-time systems

This paper presents a new PI tuning method for first order systems with a long dead time. The PI tuning rule is aimed to be simple so that it would be easy to design and apply the controller to industrial processes. The proposed tuning rule is found by z-domain design techniques, in order to get the fastest response without overshoot. The results obtained by the proposed method have been compared with other tuning rules like Ziegler-Nichols and Cohen-Coon, which are frequently used in actual practice. In addition to this, experimental results obtained by using the proposed PI tuning rule are also given.

Interlocking and Automatic Operating System Design with Automaton Method

Abstract Interlocking systems are one of the most important elements of railway signalization systems in order to ensure safe transportation. Software design of the interlocking systems can be performed by different methods such as automaton method, petri nets. These systems can be implemented by mechanical components or electronic devices such as Programmable Logic Controllers (PLCs). In this study, an interlocking system is designed by using automaton method for a sample railway simulator so that trains can move in a safe manner. In addition, in order to provide complete automatic operation, another system is also designed. Then both designed interlocking and automatic operation systems are implemented in Beckhoff CX1010 PLC and tested on simulator with the help of human interface that is created for this purpose.

Use of non-identical multiple delayed resonators in active suspension systems of railway vehicles

In this study, an active suspension system with multiple non-identical delayed resonators (DR) is proposed in order to, suppress vibrations that are caused by railway track irregularities. Mathematical models for a railway vehicle and track irregularities are given. In addition to this, methods on choosing the physical parameters and the design steps of multiple DR are mentioned. Simulations using the approximate mechanical parameters of a Shinkansen SKS300 train are made. Results and comparison with other methods are also given to evaluate the success of the proposed method.

AUTOMATIC PLC CODE GENERATION USING MATLAB

Abstract Automata formalism has been used extensively in control design of Discrete Event Systems (DES) and, realization methodologies to implement automata that are synthesized using formal methods are needed. In this study, we present a methodology that can be used to express a given automaton in logical domain. Using this methodology, a Matlab program which automatically generates Programmable Logic Controller (PLC) codes that realize the given automaton has been developed.

IMPROVING THE BEHAVIOUR OF SUPERVISOR UNDER BLOCKING

Abstract Sometimes, under control of a supervisor a discrete event system could constitute a conservative solution in this case relaxing the blocking becomes an inevitable fact to improve the performance. Meanwhile the balance between blocking and achievement has to be preserved. So the strings that drive the system to blocking and also the strings causing achievement have to be investigated in a numerical manner. For this purpose in this study a new performance measure is introduced. The elements of the performance measure depend on numeric values obtained from strings that correspond to blocking and success so the proposed formulation captures the fundamental trade-off motivated by the classical optimization approach. Then a new algorithm that explores the best result according to this performance measure is introduced.

N-version Programming for Railway Interlocking Systems: Synchronization and Voting Strategy

Abstract The main issue in controlling safety-critical systems such as nuclear power reactors or railway signalization systems where risk ratio is at the highest level because small errors might result in hazardous accidents (e.g. death or injury of several people) is to satisfy safety-related standards and provide high-safety with high-reliability. In order to improve reliability and safety of such systems to the required level by decreasing common-cause failures at the same time, diverse programming (or N-version programming) technique where N-different independently designed modules run in parallel on the same input output specifications can be used. In this study, a new bitwise voting strategy based on safe-states of variables is proposed and possible critical races between modules those run in a parallel manner are determined. Solutions for critical races are also explained.

Self-Tuning PID Controller Using Ziegler-Nichols Method for Programmable Logic Controllers

Abstract In this paper a modified PID controller is presented as a dynamic system controller. Here Ziegler-Nichols process reaction method is clarified to designate self-tuning, and advantages of self-tuning are also explained in detail. Moreover, simulation results of self-tuning PID controller using Ziegler-Nichols are acquired from programmable logic controller (PLC), and then are given in related topics. Finally, the complete algorithm is tested in an industrial thermal system, and results of this test are offered and explained.

A performance evaluation algorithm for discrete event systems under blocking

When the supervised language includes too many possible blockings, selecting the minimal restrictive nonblocking solution(MRNBS), which takes away all possible blockings, sometimes corresponds a conservative behavior. Then relaxing the nonblocking condition becomes an inevitable fact to improve the overall performance. At the other hand, selecting the complete satisfying solution (CSS) as supervisor may let serious system failures due to some possible blockings. Then a blocking supervisor between these two solutions has to be selected. So an equilibrium point has to be searched between blocking and achievement in a numerical manner. For this purpose in this work a new formulation, which includes a new performance measure and search algorithm, is proposed. The offered new algorithm explores the best result according to introduced performance measure.

A new approach on angular position control of fan and plate system

In this paper, a linear control technique based on a PID controller, which is the most used controller type in the industrial applications, is proposed for the angular position control of fan and plate system that has a nonlinear characteristic. Although the system is nonlinear, in the experimental studies, it is observed that for any small region in which the system can be considered as linear, the system (the linear model obtained around an operating point) has the same characteristic in the all operating regions. A new control approach is proposed by using this property of the system to guarantee the stability and operation without any overshoot.