PID Values Flashcards
(22 cards)
What is a plant?
System being controlled
What is the actuating signal?
Input
What is the controlled variable?
Output
What is the command variable?
The reference or desired value
What is the error term?
Difference between the command variable and the controlled variable
When is the error term 0?
When we have the desired output
What does the controller do?
Changes the error term to new input to eventually achieve output
What is controller gain?
Number multiplied by error term to get new input
Why doesn’t a single proportional controller always work?
Sometimes, it will create a constant error because the command variable never matches the controlled variable.
How can you fix a constant error?
Adding an integrator path, keeping a running total of past inputs.
What is an integrator?
Sums the input signal over time.
What is a steady state error represented as in the integrator?
For instance, a drone hovering at zero.
What happens as the integrator path increases?
Increases input in order to achieve 0 error
When the system reaches the command value, what stops working?
The proportional path.
What does the overshoot integral path create?
A negative error. This is overshooting.
What does the derivative do?
Produces a measure of the rate of changing. Saves how fast the error is changing, and can predict how to slow or decrease the input.
What will produce a negative value on the derivative?
Error decreasing. This goes vice versa.
What do past, present, and future represent in control systems?
Integral, Proportional, derivative
What is tuning?
Changing the weighting factor. This is Ki, Kp, and Kd
What will happen if one of the weighting factors is set to 0?
It will not be determined in the equation
What is PID?
A type of feedback control
