Should I Use PID Regulator for My Control System?

[rasco]

Hi,
I have a very basic conceptual question. I have a system (eg. inverted pendulum) that I want to control. So I need to build a controller. That is clear. If I understand it well, I have minimally two separate options:
1 - use PID regulator/controller
2 - analyze the system, linearize it about a specific point so I create LTI system and based on this design my own closed loop controller.
3 - ?

But, when and why should I choose first or second option? What are advantages and disadvantages of each approach? What are other possible solutions?

Thank you in advance!

 

[timthereaper]

You've laid out the basic controller design steps in option 2 and you can use PID as the controller of the closed-loop system. Once you have an LTI system to deal with, you can determine from the transfer functions how big to make your PID parameters such that it approximates an ideal system. This is so you can control things like rise time, settling time, gain, etc.

 

[rasco]

So, I create LTI system in order to determine PID parameters. But I also have an option to create a simple controller based on closed loop formula u = -K*x, right? Or this formula is just a proportional controller, that means it is P letter from PID regulator?
And how is all this related to observer?
Thx

 

[timthereaper]

Sure, you can just have a proportional controller which would be like a u=-K*x formula, but the PID usually does better. You can control your system a lot more with PID. I'm not sure how exactly how this relates to observer.

 

[alphy]

I cannot give a definitive answer without knowing more about your specific system and its requirements. However, I can provide some general information to help you make an informed decision.

Firstly, let's discuss what a PID regulator is and how it works. PID stands for Proportional-Integral-Derivative, and it is a type of feedback controller that uses a combination of three terms (proportional, integral, and derivative) to adjust the control signal and keep the system at a desired setpoint. The proportional term responds to the current error between the setpoint and the actual output, the integral term takes into account past errors to eliminate steady-state error, and the derivative term anticipates future errors based on the rate of change of the error. This type of controller is commonly used in industrial and process control systems due to its simplicity and effectiveness.

On the other hand, designing your own closed-loop controller based on a linearized model of the system requires a deeper understanding of control theory and the dynamics of the system. This approach allows for more flexibility and customization in the design, but it also requires more time and effort to analyze and implement.

So, when should you choose one option over the other? A few factors to consider are the complexity of your system, the required control performance, and your level of expertise in control theory. If your system is relatively simple and does not require precise control, a PID controller may be sufficient and easier to implement. However, if your system is more complex and requires high accuracy and robustness, designing a custom controller may be a better option.

Additionally, there are other possible solutions such as using advanced control techniques like model predictive control or adaptive control. These approaches may offer better performance but also require more resources and expertise to implement.

In summary, the choice between using a PID controller or designing your own closed-loop controller depends on the specific requirements and constraints of your system. It is important to carefully consider all options and choose the one that best suits your needs.