30-06-2012, 05:54 PM
CONTROL SYSTEM
[attachment=26382]
introduction
Plant: Input-output relationship (transfer function) may vary uncertainties (including time-varying) and Disturbances
Nominal Model G(s)=5/(s+1)
Actual Model G(s)=5.9/(s+1.3)
Sensor: output may be digital or analog. Its input: real “speed”, its output: “readable data” of speed
Actuator: Its input: “readable data” of the voltage of the power source.
Its output: voltage, with needed current
Purposes
Open-loop: speed varies with the motor and load for a given drive voltage
Closed-loop: Compensates for the influence of the variations in the motor and the load (uncertainties and disturbances) on the speed.
Types of Systems
Servo Systems: the desired speed (set-point) changes fast. Major requirement: to follow the changing “set-point” at an acceptable speed and accuracy.
Regulation Systems: the desired speed does not changes very fast. It may be constant. Major concern: substantial uncertainties/disturbances and high accuracy.
Controller
What does a controller do? Decides how to respond to the observed difference between the measured speed and the desired speed set-point.
How should the controller respond? Primarily based on the model, which describes the relationship between the input (voltage) and the output(speed) Robust Control: also largely based on the uncertainties
An important Step in System Design: Find the model (system identification)
Design: compromise between the uncertainties /disturbance and the response speed.
System Identification
End products: empirical models of systems
Model: description of relationship among related variables
Theoretical Models: from first principles
Empirical models:
Observations of system variables
==>Relationship among variables
==> Models linking the variables
Summary
Data Generation (Experiment Design)
Model Structure Determination
Parameters Estimation
Model Validation
[attachment=26382]
introduction
Plant: Input-output relationship (transfer function) may vary uncertainties (including time-varying) and Disturbances
Nominal Model G(s)=5/(s+1)
Actual Model G(s)=5.9/(s+1.3)
Sensor: output may be digital or analog. Its input: real “speed”, its output: “readable data” of speed
Actuator: Its input: “readable data” of the voltage of the power source.
Its output: voltage, with needed current
Purposes
Open-loop: speed varies with the motor and load for a given drive voltage
Closed-loop: Compensates for the influence of the variations in the motor and the load (uncertainties and disturbances) on the speed.
Types of Systems
Servo Systems: the desired speed (set-point) changes fast. Major requirement: to follow the changing “set-point” at an acceptable speed and accuracy.
Regulation Systems: the desired speed does not changes very fast. It may be constant. Major concern: substantial uncertainties/disturbances and high accuracy.
Controller
What does a controller do? Decides how to respond to the observed difference between the measured speed and the desired speed set-point.
How should the controller respond? Primarily based on the model, which describes the relationship between the input (voltage) and the output(speed) Robust Control: also largely based on the uncertainties
An important Step in System Design: Find the model (system identification)
Design: compromise between the uncertainties /disturbance and the response speed.
System Identification
End products: empirical models of systems
Model: description of relationship among related variables
Theoretical Models: from first principles
Empirical models:
Observations of system variables
==>Relationship among variables
==> Models linking the variables
Summary
Data Generation (Experiment Design)
Model Structure Determination
Parameters Estimation
Model Validation