الفهرس 
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Abstract
Numerical control (NC) is the automation of machine tools that are operated by programmed commands encoded on a storage medium. Most NC today is computer numerical control (CNC), in which computers play an integral part of the control.
Computer numerical control (CNC) machines have almost replaced the conventional machines mainly because of its competitive advantages on quality and mass production. Manufacturing industries can no longer survive world competition unless they go in for automation with CNC machines and robots doing most of the high precision job, so the main objective of this thesis is to provide a design for controller system that keeps the performance of the CNC spindle speed. The performance of the CNC spindle motor speed effects on the quality of the product, machine life time, load changing, cutting depths changing, or feed rate of the CNC machine all of them might cause damages to the machine as well.
The main goal of the research in this thesis is the development of control algorithms for spindle motor of the CNC machines in the presence of large modeling uncertainties and external disturbances. Firstly, we apply the classical PID-type to the spindle motor of the CNC and from that, some limitations and drawbacks of classical PID-type were found especially when the system is objected to some errors, and overshoot. In order to solve this problem, we search about a method to solve overshoot problem of the classical PID-type controller automatically depending on the system performance at each iteration. So we design fuzzy control to solve overshoot problem. fuzzy has the problem of designing the fuzzy controller depending on expert’s experiences and there are
certain problems that are encountered for practical control problems during the design of the fuzzy controller, after apply fuzzy controller possess good results in transient state term, there’s no overshoot in the output but there is steady state error, to solve this problem we combine the conventional PID controller with the fuzzy controller in which is fuzzy+PID controller, the fuzzy+PID controller possess good results in all terms, the output of the system under variable reference are almost the same to the desired.
Practical tests are carried in different tasks without load and changing the reference for set-point speed and in other tests the systems loads are changing in different cutting depths (0, 2, 4 and 6 mm). Results of the fuzzy+PID controller show good and significant improvement in the performance over wide range of operating conditions. By comparing the practical results of the fuzzy+PID controller with those of open loop, PID and fuzzy controller using some performance indices such as the integral of absolute error (IAE), the integral of square error (ISE), the integral of time and absolute error (ITAE), the root mean square error (RMSE) and maximum error between desired input and actual output (E MAX%) criteria, it was found that the fuzzy+PID controller has the smallest values of all indices compared to all other controller that reflects the effectiveness, validity, and robustness of the proposed scheme fuzzy+PID controller.