Fuzzy pid based Temperature Control of Electric Furnace for Glass Tempering Process

 
LIST OF APPENDIXES 
1. Appendix A: Rule viewer of fuzzy interface system 
2. Appendix B: MATLAB code for different tuning mechanisms of PID controller 

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ABSTRACT
 
Tempered glass is a safety glass processed by a controlled thermal or chemical treatment to 
increase its strength compared with the ordinary (or annealed) glass. In thermal tempering 
process, the glass is heated to a temperature just below the softening point and is then 
quenched rapidly in air. Thus, in thermal tempering manufacturing process temperature 
control of tempering furnace is the main task. Our country Ethiopia has some glass 
manufacturers hence we can use thermal tempering process to manufacture tempered glass. 
This thesis deals with the temperature control of electric furnace. The temperature of electric 
furnace is controlled to a desired value. In tempered glass furnace industry, the widely used 
controller for temperature control is conventional PI and PID controllers. Since electric 
furnaces are nonlinear and time varying processes, using PID controllers is difficult to meet the 
control requirement. Because they are not robust, haven’t good dynamic response and have 
large overshoot. Hence in this thesis, fuzzy logic controller which is fault tolerant and nonlinear 
controller is used to improve the PID and achieve steady state and transient requirements. 
Therefore, in this thesis a model of glass tempering furnace is prepared using 
MATLAB/SIMULINK and then fuzzy PID controller has been designed and simulated and its 
performance has been compared with conventional PID controllers. The performance of the 
controllers is compared in terms of disturbance rejection, transient and steady sate 
performance. 
It is observed from the simulation results that the average overshoot is 2.129%, rising time is 
44 seconds and the settling time is 170s seconds with the proposed fuzzy PID controller while 
overshoot is 16.129%, rise time is 45 second and settling time is 290 seconds with PID 
controller. Moreover, the robustness and disturbance rejection of the controllers is checked by 
parameter variation like time constant, delay time & DC gain and giving disturbance signal after 
settling time respectively. It is further observed that the proposed controller has better 
disturbance rejection and more robust.
Key words: Glass tempering furnace temperature control, Fuzzy PID controller, PID controller. 

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Fuzzy PID Based Temperature Control of Electric Furnace for Glass Tempering Process
M.Sc. Thesis, Addis Ababa University, December 2016 
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