Adnan Derdiyok

Speed-sensorless control of induction motor using a continuous control approach of sliding-mode and flux observer

This paper presents a continuous approach of sliding-mode current and flux observers for an induction machine. The proposed observer structure both decouples machine equations and makes them completely insensitive to rotor resistance variation. An estimation algorithm based on these observers is proposed to calculate speed and rotor resistance independently. In the proposed algorithm, the speed and rotor resistance are considered to be unknown constants, because the speed and rotor resistance change slowly compared to the electrical variables such as currents and fluxes. The simulation and experimental results demonstrate the good performance of the proposed observer and estimation algorithm and of the overall indirect-field-oriented-controlled system.

A novel speed estimation algorithm for induction machines

Abstract In this paper, a novel speed estimation algorithm mathematically derived from current model of an induction motor is presented. The method used here is more advantageous than other techniques due to its simplicity. In this technique, since the speed varies slowly as compared to electrical variables such as currents and fluxes, the speed is assumed to be an unknown constant. Based upon this assumption, a definition of a new speed estimator is reported and its performance is confirmed experimentally.

The application of chattering-free sliding mode controller in coupled tank liquid-level control system

A chattering-free sliding mode controller (CFSMC) is proposed to realize level position control of liquid level system for two coupled water tanks, as is often encountered in practical process control. The controller is used due to its robustness against large parameter variation, disturbances rejection and reduction in chattering. Experimentation of the coupled tank system is realized in two different configurations: configuration 1 and configuration 2. In configuration 1, the water level in the top tank is controlled by a pump. In 2, the water level in the bottom tank is controlled by the water flow coming out of the top tank. The validity of the proposed controller is verified by means of a practical testing on an experimental liquid level control device.

Sliding mode control of a bioreactor

In this paper, sliding mode control (SMC) of a bioreactor is considered and is compared with PID control. The magnitude of the error in SMC is found to be lower than that in PID control. Moreover, the magnitudes of cells and nutrients were very close to the selected reference values in SMC, whereas they were quite different in PID control. Overall, SMC was more robust against disturbances and had better performance than PID control.

An adaptive compensator for a vehicle driven by DC motors

Abstract A vehicle system driven by two independent DC motors is presented here, one of which is used for the right wheel and the other is used for the left wheel. An adaptive compensator using Takagi–Sugeno fuzzy systems is proposed to control the vehicle system. The compensator includes an adaptive model identifier and adaptive controller. An online method is used to adjust the parameters of the identifier model to match the behavior model of the vehicle system. Then, the parameters of the identifier model are employed in a standard parallel-distributed compensator to provide asymptotically stable equilibrium for the closed-loop vehicle drive system, in which the velocity and direction angle of the vehicle are controlled. Results demonstrate that the proposed controller structure is robust to load changes and follows different trajectories very well.

Sensorless control of an automated guided vehicle based on extended Kalman filter observer

In this paper, sensorless velocity and direction angle control of an automated guided vehicle (AGV) is performed by using extended Kalman filter (EKF) observer. The speed information of each motor is estimated by using armature current data measured from dc motor and command voltages applied to motors. The command voltages are used rather than the measured ones therefore only current sensors are needed. The estimated speeds are used to estimate velocity and direction angle of vehicle. The observed velocity and direction angle are used in the closed loop instead of measured ones for sensorless control of AGV. The experimental results show that the EKF observer can perfectly be implemented for sensorless control without using mechanical sensor.