الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
The stepper motor is originally used with open loop control, where the motor must respond to each excitation changes. With too fast changes, the stepper motor would lose some steps and therefore, a permanent error can be introduced between the load position and that expected by the controller. Moreover, if the motor is subjected to a sudden load disturbance, it may also lose some steps, whatever its speed. Additionally, the system suffers from a large overshoot and long settling time. Also, in most control systems, the output from the driver is usually noisy, which may cause serious oscillatory response. Due to these limitations, the stepper motor cannot be used alone. Practically, an advanced control algorithm with a feedback sensor is essentially required especially, in high performance applications where exact positioning and/or rotor speed is required. The objective of the present thesis is to study the feasibility of using the PID and the fuzzy control systems to control the hybrid stepper motor speed for a given reference input. Additionally, instead of using pulse train to drive the HSM. For the feedback sensor, the mechanical/electrical sensors such as optical encoders or potentiometers are usually used. The problem with these types of sensors is that their performance is degraded with time at long term use. And also many of them suffer from low resolution and mechanical friction which causes a steady state error to the output. Additionally, these sensors must be mechanically coupled to the motor shaft which may be technically difficult in some cases. In this thesis, a sensorless technique called the discrete extended Kalman filter is used instead of the traditional feedback sensor. The Jacobian matrices obtained from the continuous motor model is employed and then used in the filter after transforming it to state transition matrix to give the best filter performance. A simulation program is constructed to verify the performance of the HSM in open loop, PID and the proposed fuzzy control algorithm using the discrete model of the HSM obtained from the first order Euler approximation. This program is also used to determine the optimal parameters of the PID and the proposed control algorithm. Results show that the classical PID control system gave inconsistent results when used alone to control the HSM. Also, the open loop control system suffers from large overshoot and long settling and recovery time when used with the HSM. However, when the PID controller used in parallel with the open loop control system, it gave a reasonable results compared to that of the open loop control system. Also, the fuzzy control algorithm shows a better performance than that of open loop and the PID control system even when the system is subjected to a sudden load disturbance and working at high motor speed. Moreover, results show that the discrete extended Kalman filter yields a good estimation of the position, rotor speed and the winding currents.