What is a PID controller?

Introduction Anybody involved in automation and control engineering should understand the PID controllers.

1. The Components in a PID Controller

TComponent Proportional (P). This component produces an output that is proportional to error. The strength of response is determined by the proportional gain.

Component Integral (I). This component eliminates steady-state errors by addressing the sum total of previous errors. Integral gain (Ki), which determines the speed of correction, is a measure for how fast an accumulated error can be corrected1.

Component Derivative (D). This component is used to predict future errors by measuring the rate at which the error changes. The derivative gain Kd helps to mitigate overshoot, and improves stability.

2. Working Principle

PID controls operate by continuously computing the error. This is the difference between the setpoint desired and the process variable. The output is then adjusted based on proportional, integral and derivative components1.

Calculation of Error The PID controller calculates error continuously, i.e. the difference between desired setpoints and actual process variables.

Proportional Control : This component adjusts output according to the error.

Integral control: This component is a part that adjusts output according to the accumulation of errors over time.

Control Derivative: This component controls the output by adjusting it based on how fast the error rate changes.

                                                                                  

3. Using the PID Controller

To optimize performance, the PID controller must be tuned by adjusting its integral, proportional and derivative gains. Ziegler Nichols and Cohen Coon are two common tuning methods.

4. Application

The PID controller is used for a variety of applications including motor speed control and cruise control. They are indispensable for many industrial processes because of their versatility and efficiency.

 Understanding its working principles and components will allow you to implement PID controllers effectively and optimize their performance1.