adaptive pid controller full report

[seminar surveyer]

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SUBMITTED BYIPTIRANJAN SATAPATHY

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INTRODUCTION TO P CONTROLLER
The proportional controller output uses a ‘proportion’ of the system error to control the system. However, this introduces an off set error into the system.
Pterm= Kp* ERROR


INTRODUCTION TO I CONTROLLER
The integral controller output is proportional to the amount of time there is an error present in the system. The integral action removes the offset introduced by the proportional control but introduces a phase lag into the system.

INTRODUCTION TO D CONTROLLER
With derivative action, the controller output is proportional to the rate of change of the measurement or error. The controller output is calculated by the rate of change of the measurement with time.
Controller output=dm/dt
Where m is the measurement at time t.


CHARACTERISTIC OF PID CONTROLLER
A proportional controller (Kp) will have the effect of reducing the rise time.
An integral control (Ki) will have the effect of eliminating the steady-state error.
A derivative control (Kd) will have the effect of increasing the stability of the system, reducing the overshoot, and improving the transient response.

USEFULNES OF PID CONTROLLER
Most useful when a mathematical model of the plant is not available.


Many different PID tuning rules available.

ADVANTAGES
It reduces both the transient error & steady state error.
It reduces the overshoot time & settling time.
Hence the control signal produced by the PID controller minimize the deviation of the input and the desired out put to zero.
It produces noiseless signal.

TIPS FOR DESIGNING A PID CONTROLLER
Obtain an open loop response and determine what needs to be improved.
Add a proportional control to improve the rise time.
Add a derivative control to improve the over shoot.
Add a integral control to eliminate the steady state error.
Adjust each of Kp,Ki,Kd until you obtain a desired overall response.
SUMMARY
-PID control---most widely used control strategy today .

-Over 90% of control loops employ PID control, often the derivative gain set to zero (PI control).

-The three terms are intuitive---a non-specialist can grasp the essentials of the PID controller’s action. It does not require the operator to be familiar with advanced math to use PID controllers.

-Engineers prefer PID controls over untested solutions.

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