What control is pid?

PID control is a feedback control mechanism that measures the error and calculates the control output to bring the controlled variable close to the set point. It is based on three basic operations of proportion, integral and differential, which are used to quickly respond to errors, eliminate steady state errors and improve system stability respectively. The PID controller includes an error calculator, a PID controller and an actuator, and parameters such as proportional gain, integral gain and differential gain need to be adjusted according to the controlled process. The advantages of PID control include high control accuracy, good stability, easy implementation and adaptability to various processes. However, the disadvantages are that it may oscillate, be sensitive to parameter changes, and is difficult to implement in nonlinear systems.

What is PID control

PID control, also known as proportional-integral-derivative control, is a Feedback control mechanism widely used in closed-loop control systems. It calculates the control output by measuring the error between the controlled variable (PV) and the set point (SP), with the aim of bringing the PV close to SP.

How to understand the PID control principle

The PID control algorithm is based on the following three basic operations:

• Proportion (P): It is proportional to the error and produces a control output proportional to the size of the error. This helps the system respond quickly to errors.
• Integral (I) : It reduces the steady state error. It accumulates errors over time and produces a control output proportional to the accumulated error. This helps eliminate long-term errors.
• Differential (D) : It predicts the change in error and produces a control output proportional to the rate of error change. This helps improve system stability and prevents oscillations.

Structure of PID controller

The PID controller consists of the following parts:

• Error Calculator: Calculate the error between PV and SP.
• PID controller: Calculate the PID control output based on the error.
• Actuator: Pass the PID control output to the controlled process.

Adjustment of PID controller

According to the characteristics of the controlled process, the three parameters of the PID controller (Kp, Ki and Kd) need to be adjusted. Adjustment:

• Kp (proportional gain) : affects the sensitivity of the control output.
• Ki (integral gain) : Affects the rate of eliminating long-term errors.
• Kd (differential gain) : Affects the response speed of the control output.

Advantages of PID controller

• High control accuracy
• Good stability
• Easy to implement and Maintenance
• Applicable to various controlled processes

Disadvantages of PID controller

• may occur under certain circumstances Oscillation
• is sensitive to parameter changes
• is difficult to implement in nonlinear systems

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