Bekir Çakır

Online Monitoring Of Tool Wear In Drilling and Milling By Multi-Sensor Neural Network Fusion

In manufacturing systems the detection of tool wear during cutting process is one of the most important considerations. In order to perform online tool condition monitoring (TCM) for different cutting conditions, a sensor-integration strategy with machining parameters is proposed. TCM systems are most frequently based on the research which attempts to correlate the condition of drilling and milling tools to the signals obtained from multiple sensors (namely, cutting forces, vibration, current and sound connected to a CNC machine). The aim of the proposed study is to create a TCM system that will lead to a more efficient and economical machining tool usage. The used system is capable of accurate tool wear monitoring in around 97% accuracy. Experimental results under different conditions have demonstrated that TCM can be implemented by using neural network.

Speed control of a conveyor system by means of fuzzy control aided PLC

Programmable logic controllers are microprocessor based control systems which manage a machine or an industrial foundation by means of change of situations and a program edited before. Basically, a PLC is composed of a microprocessor, a power supply and input/output units. Beside these units mentioned above, some certain units were developed which respond to requirement of faster and more effective processing in industrial control systems. These special units, such as high speed counters, heat controllers and pH controllers increase the control performance of PLCs. Application of fuzzy logic theory in control systems proved to be superior to the conventional control systems. Fuzzy logic controllers can infer coherent results in uncertain conditions when it is necessary to control a complex system which is impossible to model using mathematical ways. In this paper, fuzzy control applications on PLCs are investigated under two captions, the first of which is the applicability of a special unit to PLCs which is controlled by a software that performs fuzzy logic processes by means of improvement on a real industrial control system, and the other is realization of fuzzy control algorithms by basic PLC instructions.

Switched reluctance motor drive by using fuzzy controller

In this paper, fuzzy control application of linear inductance switched reluctance motor (SRM) drives with the C-Dump power converter is presented. A mathematical model of the SRM, by considering mutual inductances, is obtained. The study aims at reducing the torque ripple and the acoustic noise and is carried out by a simulation model by using an efficient algorithm that is developed using fuzzy logic. Superior results in the drive performance are achieved by the fuzzy logic controller described. The simulated results are experimentally verified on a scaled down laboratory prototype and found to give good torque ripple and reduced acoustic noise.

DC motor control by using computer based fuzzy technique

In this paper, the authors propose a new control method of a separately excited DC traction motor using fuzzy logic. The design of a fuzzy logic controller for a DC motor drive, which produces the traction moment, is illustrated and implemented. The drive system has been simulated and results have been compared with those obtained by a conventional PID controller. The superior results in the drive performance, which are achieved by fuzzy logic controller, are provided. The proposed controller exhibits superior transient and steady state performance compared to the usual PID controllers.

New software implementation of the space vector modulation

A new software implementation of the space vector modulation (SVM) on the vector controlled induction machine is proposed. The conventional SVM requires square root and arctangent computations. New SVM algorithm is develop to determine directly conducting times without square root and arctangent computations.

A fast simulation technique for the power electronic converters

In this study, a fast simulation technique is proposed for the analysis of power electronic circuits. After switching, these circuits behave like a linear circuit. Therefore, linear circuit analysis methods can be used. In the simulation, capacitors and inductors are replaced by voltage and current sources respectively, whose values are determined by their current and voltages in the previous step. The method is based on solving a system of algebraically modified nodal equations at each integration step. The technique requires only DC analysis. The writing or solving of time-differential equations or Laplace transform inverses are not required. Thus, the simulation is fast and the simulation time is essentially the same as for a linear, time-invariant circuit of the same complexity. A simulation algorithm is given and an example is included.

Neuro-PID position controller design for permanent magnet synchronous motor

A new speed control strategy is presented for high performance control of a Permanent Magnet Synchronous Motor (PMSM). A self-tuning Neuro-PID controller is developed for speed control. The PID gains are tuned automatically by the neural network in an on-line way. In recent years, the researches on the control of electrical machines based on ANN are increased. ANNs, developed controller in this work, offer inherent advantages over conventional PID controller for PMSM , namely: Reduction of the effects of motor parameter variations, improvement of controller time response and improvement of drive robustness. The PMSM drive system was simulated by using MATLAB 5.0/Simulink software package. The performance of the proposed method is compared with the conventional PID methods. At the result, the control based on self-tuning Neuro-PID control has better performance than the conventional PID controller.

Fuzzy control application of SR motor drive for transportation systems

We present a simple technique to minimise torque ripple of fuzzy controlled switched reluctance (SR) motor drives in electric vehicle propulsion. Fuzzy control application of linear inductance SRM drives with the C-dump converter using an electric vehicle propulsion system is presented. The control technique is based on the control of the sum of the square of the phase currents by using fuzzy control technique. The combination of low cost, high reliability, and competitive weight and efficiency makes the fuzzy controlled SRM drive a strong candidate for application in future electric vehicle propulsion systems. The mathematical model of SRM by considering mutual inductances is obtained.

A new maximum power point tracking approach for decreasing convergence time

This study presents a new maximum power point tracking (MPPT) approach for solar panels. By using voltage current characteristic of solar panel, some analytical approaches have been developed. With the help of this approach, determination of initial operation point has been improved. In other words, this point has been determined by making some assumptions. Thus, one of the challenging tasks related to MPPT, convergence time is reduced. Benefits of developed approach have been shown by making a comparison with the Perturb and Observe (P&O) and Incremental Conductance (IC) algorithm. In this context, a low power boost converter has been designed with direct duty control in order to verify the proposed approach. Experimental results show that proposed approach performs better than conventional ones. While convergence time is high in case of P&O and IC usage, with proposed approach, it is reduced remarkably. Besides, steady state oscillation is almost eliminated in proposed approach.

A new ZVT–ZCT quasi-resonant DC link for soft switching inverters

In this article, the new ZVT–ZCT Quasi-Resonant DC Link, which ensures zero crossings at any time required for soft switching (SS) and provides zero voltage transition (ZVT) turn-on and zero current transition (ZCT) turn-off together for the main switch of active snubber cell in pulse width modulated or space vector modulated operation of inverter is presented. The new circuit combines the most desirable features of the circuits presented previously and overcomes most drawbacks of these circuits by using only one auxiliary switch with fewer other components. Consequently, new ZVT–ZCT Quasi-Resonant DC Link, which is verified by a prototype of a 1.2 kW and 50 kHz circuit, is analysed in detail. All semiconductor devices operate under SS, the main switch is subjected to no additional voltage and current stresses, and the stress on the auxiliary switch is very low in the proposed new inverter.