CPE 043 Flashcards
reviewer
Control System examples
Man-made, Natural, Nonphysical
sample of Man-made control system
rockets fire, space shuttle, cooling water, self-guided vehicle
sample of Natural control system
blood sugar level, adrenaline rush
sample of Nonphysical control system
student’s study time and student performance
Purpose of Control Systems
(1) Power amplification (ex. rotating a huge radar antenna by a small knob)
(2) Remote control (ex. using robots in radioactive areas)
(3) Convenience of input form (ex. An aircon set to a temperature level produces cool air)
(4) Compensation for disturbances (ex. a wind or noise signal that passes through
an antenna is corrected by repositioning the antenna)
Example of Liquid-Level Control (300BC)
water clock by Ktesibios
oil lamp of Philon (figure 1) of Byzantium
What are the history of control system
*Liquid-Level Control (300BC)
*Steam Pressure and Temperature Controls (1681)
*Speed Control (1745)
*Stability, Stabilization and Steering (19th Century)
*20th Century Developments
*Contemporary Applications
Example of Steam Pressure and Temperature Controls (1681)
safety valve by Denis Papin
emperature control by Cornelis Drebel
Example of Speed Control (1745)
windmill by Edmund Lee and William Cubitt
flyball speed governor by James Watt
Example of Stability, Stabilization and Steering (19th Century)
the differential equation for the stability of motion by Maxwell, Routh and Lyapunov
Steering and stabilization of ships by Henry Bessemer
Example of 20th Century Developments
automatic steering of ships that led to what we call today proportional-plus-integral-plusderivative
(PID) by Nicholas Minorsky
Linear control systems analysis and control theory by Bode, Nyquist and Evans
Example of Contemporary Applications
Finishing mills, X-ray measures, digital computer, reaction control system, etc.
System Configurations
*Open-Loop Systems
*Closed-Loop (Feedback Control) Systems
*Computer-Controlled Systems
___________ convert the input to the form which the controller uses
Input transducer
The ________drives a process or a plant
controller
The _______ can be called controlled variable.
output
The ____ can be
called reference.
Input
_____________ cannot compensate for any disturbances that add
to the controller’s driving signal (Disturbance 1) and only depends on the input.
Open-Loop Systems
The ______________ measure the output and convert
it to the form used by the controller.
output transducer or sensor
___________ compensate for disturbances thus having a greater
accuracy than open loop system. A trade off would be its cost and complexity.
Closed-Loop (Feedback Control) Systems
The controller (or compensator) is a digital computer.
Adjustments of the compensator can be made by changing the software rather than the
hardware
Computer-Controlled Systems
Analysis and Design Objectives
*Dynamic control system
*Transient response (1st Objective)
*Steady-State Response (2nd Objective)
*Stability (3rd Objective)
___________ response of a system on the way the system dissipates or acquire
energy. In linear differential equations, it is called ____________.
Natural response, homogenous
_____________ response of a system depending on the input. In linear
differential equations, it is called ___________.
Forced Response, particular solution
_________ Upon reaching steady state, the natural response can go to zero or oscillate; or continue to
increase (which is _______). Thus, is required otherwise it would damage the system.
Stability (3rd Objective), unstable
_______ is usually used to place initial energy to the system and check the transient response.
Impulse input
_________ is used to compensate parameters shift due to external factors. (ex. due to temperature, pressure, etc.)
Sensitivity analysis
Explain in your own words how a water clock and oil lamp of Philon works.
Water Clock by Ktesibios: Ktesibios’s water clock, or clepsydra, used a float in a container that filled with water at a steady rate. The float was connected to a pointer that indicated the time on a scale, improving the accuracy of time measurement.
Oil Lamp by Philon: Philon’s oil lamp measured time by the steady consumption of oil. As the oil burned at a consistent rate, the level of oil decreased, and this decrease was used to indicate the passage of time.
Differentiate open-loop systems and close-loop systems.
An open-loop system operates without feedback.
A closed-loop system, also known as a feedback control system, uses feedback to compare the output with the desired input (reference) and makes adjustments to achieve the desired result.
The Design Process
Step 1: Transform requirements into a physical system
Step 2: Draw a functional diagram
Step 3: Create a schematic
Step 4: Develop a mathematical model (Block Diagram)
Step 5: Reduce the block diagram
Step 6: Analyze and design
