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

3.2 Design and analysis of control system
There is different type of controllers used for temperature control of tempering furnace among 
those in the following section we discussed on PID and fuzzy-PID controllers. 
3.2.1 Design and analysis of PID
PID controller can be understood as a controller that takes the present, the past, and the future 
of the error into consideration. Tuning a control loop is the adjustment of its control 
parameters (proportional band/gain, integral gain/reset, derivative gain/rate) to the optimum 
values for the desired control response. Stability (bounded oscillation) is a basic requirement, 
but beyond that, different systems have different behavior, different applications have different 
requirements, and requirements may conflict one with another. The transfer function Gc(s) of 
the PID controller is [10-13]: 
( )
(
)---------------------------------------------------3.34 
( )
-------------------------------------------------------3.35 
3.2.1.1 Loop tuning mechanism
Tuning a control loop is the adjustment of its control parameters (proportional band/gain, 
integral gain/reset, derivative gain/rate) to the optimum values for the desired control 
response. Stability (no unbounded oscillation) is a basic requirement, but beyond that, different 

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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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systems have different behavior, different applications have different requirements, and 
requirements may conflict with one another [9] [15][16]. 
PID tuning is a difficult problem, even though there are only three parameters and in principle 
is simple to describe, because it must satisfy complex criteria within the limitations of PID 
control. There are accordingly various methods for loop tuning.