Muhammet Koksal

Position Control of a Permanent Magnet DC Motor by Model Reference Adaptive Control

Model reference adaptive control (MRAC) is one of the various techniques of solving the control problem when the parameters of the controlled process are poorly known or vary during normal operation. To understand the dynamic behavior of a dc motor it is required to know its parameters; armature inductance and resistance (La, Ra), inertia of the rotor (Jm), motor constant (Km), friction coefficient (Bm), etc. To identify these parameters, some experiments should be performed. However, motor parameters change under operation according to several conditions. Therefore, the performance of controller, which has been designed considering constant motor parameters becomes poorer. For this reason, a model reference adaptive control method is proposed to control the position of a dc motor without requiring fixed motor parameters. Experimental results show how well this method controls the position of a permanent magnet dc motor.

Commutativity of Linear Time-Varying Differential Systems with Nonzero Initial Conditions: A Review and Some New Extensions

Necessary and sufficient conditions for the commutativity of linear time-varying systems are derived in the case of nonzero initial conditions. It is shown that some commutative class of linear time-varying systems may not commute with arbitrary initial conditions. In this respect, commutativity of Euler differential systems is investigated. Explicit commutativity conditions for the fifth-order systems are solved. New results about the effects of commutativity on system sensitivity and disturbance properties are presented, which is very important for network design and industrial applications where many of the systems are composed of subsystems cooperating one after another in a chain. The results are supported by examples treated either analytically or numerically.

Commutativity of cascade connected discrete-time linear time-varying systems

After summarizing the commutativity results for analogue linear time-varying systems, the commutativity of cascade connected discrete-time linear time-varying systems is introduced. Some general open questions on the subject are stated and new results are presented, intended to answer some of them. Two examples are given to reinforce the concept and to show up its possible benefits in engineering to reduce noise effects and design robust systems.

AN ELECTRONICALLY TUNABLE OSCILLATOR USING A SINGLE ACTIVE DEVICE AND TWO CAPACITORS

A novel resistorless oscillator is presented. The proposed structure enjoys electronic tunability property with minimum number of active and passive components. This oscillator uses a current-mode (CM) active device and has properties of current mode circuits. The validity of the proposed circuit is verified by experimental results.

A Program for the Design of Linear Time Invariant Control Systems: CDMCAD

Coefficient Diagram Method (CDM) is a new method proposed for the analysis and design of linear time‐invariant control systems. The control system design by this method results with satisfactory stability, time response and robustness properties compatible with, and in most cases better than, the ones obtained by the other present design methods. In this study, the design procedure described in the literature for CDM is improved so that a systematic and easy tool with understandable sufficient detail is presented. A visual toolbox, which can be used efficiently both for education and research, is obtained based on the procedure presented by using MATLAB.

A new second-order multi-mode multi-funtion filter using a single CDBA

A new second-order multi-mode multifunction filter configuration is introduced. This configuration uses a single current differencing buffered amplifier (CDBA) and, depending on topology, a total of four/five passive elements (two/three capacitors and two/three resistors). Current-mode (CM), voltage-mode (VM), transimpedance-mode (TIM) and transadmittance-mode (TAM) topologies are presented for realizing BP, LP and HP filter responses. The validity of the proposed filters is verified through PSpice simulations and experiments.

Taylor's decomposition on four points for solving third-order linear time-varying systems

In the present paper, the use of three-step difference schemes generated by Taylors decomposition on four points for the numerical solutions of third-order time-varying linear dynamical systems is presented. The method is illustrated for the numerical analysis of an up-converter used in communication systems.

Design of dominantly proportional PID controller using a single commercially available active component

A proportional integral derivative (PID) controller employing only a single commercially available active component, two resistors and two capacitors is presented. The PID controller circuit has low impedance voltage output which can be easily cascaded with other voltage-mode (VM) structures. The effects caused by the non-ideality of the current feedback operational amplifier (CFOA) are analyzed. The performance of the proposed circuit is demonstrated by using PSPICE simulations.

Electronically controllable biquads using single CDBA

Three new electronically tunable filter configurations which employ only one current controlled differencing buffered amplifier (CDBA) are proposed. The proposed filters operate in voltage-mode (VM) and use three passive elements. Each proposed filter can realize one of the band-pass, low-pass or high-pass responses. The parameters omega 0 and omega0/Q enjoy independent electronic tunability. Effect of the non-idealities and the sensitivity analysis of the proposed filter are also examined. The validities of the proposed filters are verified through PSPICE simulations

Electronically tunable universal biquad using a single active component

In this work, a novel voltage-mode (VM) single-input four-output universal filter topology is presented. The proposed structure uses two resistors, two capacitors and only one voltage differencing current conveyor (VDCC) and generates all biquadratic filtering functions namely: low-pass (LP), band-pass (BP), high-pass (HP) and band-reject (BR). The quality factor and natural frequency of the filter can be adjusted electronically without changing the values of the passive components. Moreover, the circuit does not require any condition of component matching and has a good sensitivity performance with respect to tracking errors of passive components and the active parameter. PSpice simulation results confirm the results of the theoretical analysis.