This article is just about PID controller explained and will hopefully provide some good background information on PID controllers basics level
What is PID Control meaning?
Why PID Control Use?
- First describe more generally what a controller is and one way to write an open-loop system is like this where inputs act on a plant or the system to be controlled and then some output a signal is generated
Here Take ROBOT as PID controller application:
- Often in these open-loop scenarios, the performance of the system isn’t good enough to meet your requirements let me give you an example of what I mean your task to
build a robot that needs to move from this spot here over to this GOAL
- you could figure out how fast the robot moves and then from that determine how long the robot needs to drive for before it gets to the GOAL this type of commanding is called open loop because the amount of time the robot drives is not adjusted based on the actual a position of the robot and open-loop commanding is perfectly fine for systems that don’t change much or where accuracy isn’t as important however
- what if there’s some dirt in one of the wheels and the robot veers off to the side or if the robot slightly faster than you had predicted in both of these cases the robot won’t stop on the GOAL because of it has no way of compensating for these errors and making adjustments on its own
- Now the solution then is feedback control which essentially means you’re sensing the output of the plant and feeding it back so that the system can make adjustments accordingly
- Now in a feedback system, there’s a reference signal and this is the desired value or the ultimate goal and you compare that to the measured value and what you’re left with is the error or the Delta between where you are and where you want
to be so…
- In the case of the robot, the error would be the difference between the reference position which is the distance x from the start to the GOAL in meters and the robot current position which is measured by the robot also in meters so at this point we need to figure out how
- to convert an error signal that has units the same as the output of the plant into an input signal that has units that may or may not be the same as the output and in addition to just changing the unit’s the error needs to be adjusted in such a way that the input into the robot causes it to eventually reach the GOAL and this is exactly what a controller does it takes the error signal and converts it into a command that is then sent to the plant and
- one of the goals of a control engineer is to design this controller so that as time progresses the error or the difference between the current location and the goal is driven to zero and zero error means that the measured position is exactly where you want it to be which means that the system meets all of its requirements