Difference Between PI, PID, Fuzzy Logic Controller, Disadvantages

May 21, 2021July 3, 2022 Rajasri Mundrathi

Hello guys, welcome back to our blog. In this article, we will discuss the difference between PI, PID, fuzzy logic controller, what is PI controller, what is PID controller, what is fuzzy logic controller, the advantages of PI controller, disadvantages of PI controller, advantages of PID controller, disadvantages of PID controller, what is fuzzy logic controller, advantages of the fuzzy logic controller, disadvantages of the fuzzy logic controller, etc.

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Difference Between PI, PID, Fuzzy Logic Controller

A controller is a device used in the system to modify the error signal and produce a control signal. The process in which the controller produces the control signal is called the control action. It modifies the transient response of the system. The controller must have zero settling time, steady state error, and low peak overshoot.

Depending on the control actions provided the controllers can be classified as:

Proportional controller
Integral controller
Proportional plus integral controller
Proportional plus derivative controller
Proportional plus integral plus derivative controller

Proportional + Integral Controller or PI Controller

The proportional plus integral controller or PI controller produces an output signal which consisting of two terms namely:

Proportional to an error signal
Proportional to the integral of the error signal

The output will be integral of the input. The effect of proportional integral controller on the system performance is that it increases the order of the system by one which results in reduction of steady state error. This controller is a feedback control loop which calculates an error signal.

It receives a voltage and current measurement which is used to calculate the power being drained by the battery. The error signal is calculated by taking the difference between the two points i.e., the set point and the power measured.

Advantages of PI controller:

“P” action increases the loop gain and makes the system less sensitive to variations of system parameters.
The “I” action eliminates or reduces the steady-state error.
The “I” action is adjusted by varying the integral time.
The change in the value of kp affects both the integral and proportional parts of control action.

Disadvantages of PI controller:

The system will become less stable.

Proportional + Integral + Derivative Controller or PID Controller

The PID Controller produces an output signal with a feedback loop control consisting of three terms:

Proportional to the error signal.
Proportional to integral of error signal error.
Proportional to the derivative of the error signal.

It is used to regulate pressure, speed, temperature, etc. it is an instrument that is used in industrial control applications. This controller has a feedback loop which is the most accurate and stable controller. It is a well-established way of driving a system towards its output.

It operates automatically to give an accurate and responsive correction to a control function. The PID Controller can be realized by an op-amp amplifier with integral and derivative action followed by a sign changer.

Advantages Of PID Controller:

The P Controller stabilizes the gain but produces a constant steady-state error.
The I Controller reduces or eliminates the steady-state error.
The D Controller reduces the rate of change of error.

Fuzzy Logic Controller (FLC)

A fuzzy logic controller is a system that is used to control the working of a physical system with the help of fuzzy logic. FLC is used to control washing machines, air conditioners, heater systems, fan regulators, traffic control, braking system controller, etc. we use FLC where an exact mathematical formulation of the problem is not possible.

These difficulties are due to the non-linearities, time-varying nature of the process. FLC logic is widely used in machine control. Fuzzy logic refers to the true or false. The fuzzy controller consists of three stages namely the input stage, processing stage, and output stage.

Advantages Of Fuzzy Logic Controller