5 Control Techniques – Their Features & Applications

We have a number of control theories that have been put forward on how to design control laws to accomplish various purposes. Generally they can be classified as follows:

Classical Control

This control technique deals with the behaviour of dynamical systems, which typically have inputs and how their behaviour is modified by feedback, employing the Laplace transform as a primary tool to model such scheme. In a nutshell, we can say that the classical theory employs a mathematical model to define the relationships between the input and output of a system. Typical example of a controller based on classical control theory is the proportional integral derivative (PID) control, that is commonly used for control of industrial processes e.g. in chemical plants, commercial aeroplanes, etc.

Optimal Control

Optimal control theory aims to achieve certain optimal performance i.e. it seeks to find a control law for a given scheme such that a certain optimality standard is attained. Examples where this control theory is applied include H₂ control, linear quadratic regulator control, etc.

Robust Control

Robust control technique was developed to handle systems with uncertainties and disturbances and with high performances.  Areas where this control technique is used include military systems, etc.

Nonlinear Control

Developed to handle nonlinear systems with high performances examples military systems like aircraft, missiles.

Also read: Basic Steps to Consider in Designing a Control System

Intelligent Control

This is control technique is characterized as a knowledge-based control, adaptive control, neural and fuzzy control, etc. Was developed to handle systems with unknown models. Examples: economic systems, social systems, human systems.

Also read: Fuzzy Controller and its Industrial Applications