Lecture 32 : General procedure for dynamics equation forming and introduction to control
INTRODUCTION TO CONTROL
Control System :
Simply speaking, a control system provides an output or response for a given input or stimulus.
Figure 32.6 Block diagram of an industrial control system
An industrial control system typically consists of an automatic controller, an actuator, a plant and a sensor (measuring element).
Controller: It is an important element of Control system.It compares the actual value of the plant output with the reference input ( desired value), determines the deviation and produces a control signal that will reduce the deviation to zero or to a small value. The manner in which the controller produces the control signal is called the control action. Wise design of controller lead to substantial cost savings and performance improvement. It detects the actuating error signal, which is usually at a very low power level, and amplifies it to a sufficiently high level. The output of an automatic controller is fed to an actuator, such as an electric motor, a hydraulic motor or a pneumatic motor or a valve. We will see various types of controller & certain controllers in detail but later on.
Actuator: It is a power device that produces the input to the plant according to the control signal so that the output of plant will approach the refernce input.In case of Robot control system , actuator is generally electric motor.
Sensor or measuring element: It is a device that converts the output variable into another suitable variable such as a displacement pressure or voltage that can be used to compare the output to the refernce input signal. This element is in the feedback path of the closed loop system.
Plant:
It is the one whose output is to be controlled. e.g. In case of Robot control system, plant is the Robot Manipulator.
