Types of Controllers Flashcards
What is the simplest controller?
On-Off Controller
How an On-Off Controller works?
When the measured variable is below the set point, the controller is ON and the output signal has maximum value. When the measured variable is above the set point, the controller is OFF and output is zero.
What are the most common used controllers in industry?
PID controllers
What PID means?
Proportional-Integral-Derivative
What is a Controller?
Wait
What is a Feedback Control System?
It’s a system where the system’s output is measured and fed back in order to influence the system input
What is the main component difference between an Open-Loop and a Closed-Loop Control System?
The block sensor that allows feedback information.
What is the purpose of the controller block?
It contains the control logic or “rules” required to turn feedback information into a control signal command that is sent to the plant.
What represents the Plant in a Control System Diagram?
The physical actuating device that is usually represented by one or more
transfer functions.
What is the error signal?
It’s the difference between the reference command (desired output) and the actual system output (feedback signal).
What is a SISO system?
It’s a system with a Single Input and a Single Output
What is a Proportional Controller?
It’s a controller where the control signal is proportional to the instantaneous error, where increasing the P-gain (Kp) will tend to speed up the system response.
It has a diminished effect as the feedback error goes to zero because it
preserves a steady-state error.
What is an Integral Controller?
It’s a controller where the control signal is proportional to the summation (integral) of all past error signals and therefore it’ll be nonzero even when the feedback error goes to zero.
It’s used to reduce the steady-state tracking error.
What is a Derivative Controller?
It’s a controller where the control signal is proportional to the instantaneous derivative of the error signal. Hence, it “anticipates” the system response because it is based on the derivative or time rate of the error signal.
In general, increasing the D-gain (Kd) reduces overshoot and adds damping to the closed-loop system.
When do we use a PI or PD Controller?
When the system dynamics already contain a component.
