Report Group One

FEEDBACK AND CONTROL SYSTEM

GROUP ONE BSECE IV-2

INTRODUCTION Fundamentals and Concepts of Feedback and Control System Angeles, Ma. Gina Rivera, Alvin M

INTRODUCTION TERMINOLOGIES System Control Engineering Control System Process Feedback

INTRODUCTION SYSTEM

a group of interacting, interrelated, or interdependent elements forming a complex whole segments of the environment

INTRODUCTION CONTROL ENGINEERING

based on the foundations of feedback theory and linear system analysis; integrates the concepts of network theory and communications theory

INTRODUCTION CONTROL SYSTEM

interconnection of components forming a system configuration that will provide a desired system response Twin goals of control system engineers: • Understanding • Control

INTRODUCTION CONTROL SYSTEM CLASSIFICATIONS • • • • • •

Method of Analysis and Design Type of Signal Type of Performance Control Number of Variables Type of System Components Main Purpose

INTRODUCTION METHOD OF ANALYSIS AND DESIGN • Linear System the principle of superposition can be applied

• Non-Linear System the principle of superposition cannot be applied

INTRODUCTION TYPE OF SIGNAL • Time Varying System physical systems have parameters changing with time

• Time Invariant System if the parameters are unaffected by the time

• Discrete Data System if the signal is not continuously varying with time but it is in the form of pulses.

• Continuous Data System If the signal obtained at various parts of the system are varying continuously with time

INTRODUCTION TYPE OF PERFORMANCE CONTROL • Adaptive Control System designing for the capability of continuously changing the compensation if the parameters are large or rapid

• Optimal Control System minimizing or maximizing the performance index

INTRODUCTION NUMBER OF VARIABLES • Single Variable Control System SISO—single input and single output

• Multivariable Control System MIMO—multiple input and multiple output

INTRODUCTION TYPE OF SYSTEM COMPONENTS • • • • •

Electromechanical Hydraulic Thermal Pneumatic control Etc.

INTRODUCTION TYPE OF SYSTEM COMPONENTS • • • •

Position Control Velocity Control Speed Control Etc.

INTRODUCTION PROCESS sequence of interdependent and linked procedures which, at every stage, consume one or more resources to convert inputs into outputs these outputs then serve as inputs for the next stage until a known goal or end result is reached

process to be controlled

INTRODUCTION FEEDBACK the return of a portion of the output of a process or system to the input, especially when used to maintain performance or to control a system or process

INTRODUCTION FEEDBACK SYSTEM feedback system difference

+ desired output response

-

Σ

Control Device

Actuator

Sensor / Measurement

Process

actual output response

INTRODUCTION EXAMPLES OF USES OF FEEDBACK Design of Improved Signal Amplifier by Harold s. Black feeding the amplifier output back to the input in reverse phase and keeping the device from oscillating to be a means of cancelling out the distortion in the input Gun Director by David b. Parkinson using a small potentiometer to control the antiaircraft gun through an actuator

INTRODUCTION EFFECTS OF FEEDBACK

INTRODUCTION EFFECTS OF FEEDBACK • Overall Gain positive feedback gain, reduced overall gain

• Stability ability of system to follow the input command signal

• Sensitivity insensitive to parameter changes, good control system

• Noise vibrations, brush and commutator noise, etc.

INTRODUCTION OPEN LOOP SYSTEM is a control system that utilizes a controller or control actuator to obtain the desired response. It also a system in which the output variable does not have any influence on the input variable and on the actuating device. It is a control system with a preprogrammed set of instructions to an actuator that has no feedback or error-detection process; consequently, the system is unable to make compensatory adjustments.

Desired output response

Actuating Device

Process

Output

INTRODUCTION CLOSED LOOP SYSTEM is one in which control action is dependent on the output. a system in which the value of some output quantity is controlled by feeding back the value of the controlled quantity and using it to manipulate an input quantity so as to bring the value of the controlled quantity closer to a desired value difference

+ desired output response

-

Σ

Control Device

Actuator

Sensor / Measurement

Process

actual output response

INTRODUCTION COMPARISON OF OPEN AND CLOSED LOOP OPEN LOOP SYSTEM

CLOSED LOOP SYSTEM

An open loop system has the ability A closed loop system has got the to perform accurately ability to perform accurately because of the feed back. It is easier to build

It is more difficult to build

In general, it is more stable

Less stable comparatively

If there is non-linearity in the Under the presence of non-linearity system, the performance will not be in the system, it operates better than good the open loop system Feedback is absence

Feedback is present

Examples: Traffic Control System, Washing Machine, Gas Stove

Examples: Temperature Control System, Robot Sensors,

INTRODUCTION MULTIVARIABLE CONTROL SYSTEM The control of systems characterized by multiple inputs or by multiple outputs, which are often the measured variables to be controlled, or by both multiple inputs and outputs

HISTORY Timeline of Evolution of Control Systems

Bautista, Ely

HISTORY 300BC The first applications of feedback control appeared in the development of float regulator mechanisms in Greece in the period 300 to 1 B.C. The water clock of Ktesibios used a float regulator.

HISTORY 250BC An oil lamp devised by Philon, used a float regulator in an oil lamp for maintaining a constant level of fuel oil. Heron of Alexandria, who lived in the first century A.D., published a book entitled Pneumatica, which outlined several forms of water-level mechanisms using float regulators.

HISTORY 1572 - 1633 The first feedback system to be invented in modern Europe was the temperature regulator of Cornelius Drebbel of Holland

HISTORY 1647 - 1712 Dennis Papin [1647–1712] invented the first pressure regulator for steam boilers in 1681. Papin’s pressure regulator was a form of safety regulator similar to a pressure-cooker valve.

Steam Digester

HISTORY 1765 The first historical feedback system, claimed by Russia, is the water-level float regulator said to have been invented by I. Polzunov

HISTORY 1769 The first automatic feedback controller used in an industrial process is generally agreed to be James Watt’s flyball governor, developed in 1769 for controlling the speed of a steam engine.

HISTORY SELECTED HISTORICAL DEVELOPMENTS 1769 James Watt’s steam engine and governor developed. The

Watt steam engine is often used to mark the beginning of the Industrial Revolution in Great Britain. During the Industrial Revolution, great strides were made in the development of mechanization, a technology preceding automation.

1800 Eli Whitney’s concept of interchangeable parts

manufacturing demonstrated in the production of muskets. Whitney’s development is often considered to be the beginning of mass production.

1868 J. C. Maxwell formulates a mathematical model for a governor control of a steam engine

1913 Henry Ford’s mechanized assembly machine introduced for automobile production.

1927 H.W. Bode analyzes feedback amplifiers.

HISTORY SELECTED HISTORICAL DEVELOPMENTS 1952 Numerical control (NC) developed at Massachusetts Institute of Technology for control of machine-tool axes.

1954 George Devol develops “programmed article transfer,” considered to be the first industrial robot design.

1960 First Unimate robot introduced based on Devol’s designs.

Unimate installed in 1961 for tending die-casting machines.

1970 State-variable models and optimal control developed. 1980 Robust control system design widely studied. 1990 Export-oriented manufacturing companies emphasize automation.

1994 Feedback control widely used in automobiles. Reliable, robust systems demanded in manufacturing.

HISTORY SELECTED HISTORICAL DEVELOPMENTS 1997 First ever autonomous rover vehicle, known as Sojourner, explores the Martian surface.

19982 Advances in micro- and nanotechnology. First intelligent 003 micromachines are developed and functioning nanomachines are created.

First Unimate robot by Devon

HISTORY

MODERN CONTROL SYSTEMS Conventional Control Systems and Computer Controlled Systems

Cayetano, Nedino Lester D

MODERN CONTROL SYSTEMS FEEDBACK Positive feedback seeks to increase the event that caused it, such as in a nuclear chain-reaction. It is also known as a self-reinforcing loop. An event influenced by positive feedback can increase or decrease its output until it hits a limiting constraint. Self-reinforcing loops can be a smaller part of a larger balancing loop, especially in biological systems such as regulatory circuits. Negative feedback seeks to reduce the input signal that caused it, is also known as a self-correcting or balancing loop. Such loops tend to be goal-seeking, as in a thermostat which compares actual temperature with desired temperature and seeks to reduce the difference.

MODERN CONTROL SYSTEMS CONVETIONAL CONTROLLED SYSTEM A manually controlled control system utilizes human intervention on regulating a system wherein an operator is instructed to maintain a certain level. The reference is memorized by the operator. The operator compares the actual level visually with the desired level and controls switches (actuator) to maintain the desired level . The power amplifier is the operator and the sensor is the visual.

MODERN CONTROL SYSTEMS COMPUTER CONTROLLED SYSTEM is defined as a control system where a computer replaces a group of single-loop analogue controllers. Its greater computational ability makes the substitution possible and also permits the application of more complex advanced-control techniques. The advantage offered by the digital computer over the conventional control system is that the computer can be programmed readily to carry out a wide variety of separate tasks. In addition, it is fairly easy to change the program so as to carry out a new or revised set of tasks.

MODERN CONTROL SYSTEMS CONVENTIONAL CONTROLLED SYSTEM

MODERN CONTROL SYSTEMS COMPUTER CONTROLLED SYSTEM is a control system where a computer replaces a group of single-loop analogue controllers. Its greater computational ability makes the substitution possible and also permits the application of more complex advanced-control techniques. The advantage offered by the digital computer over the conventional control system is that the computer can be programmed readily to carry out a wide variety of separate tasks. In addition, it is fairly easy to change the program so as to carry out a new or revised set of tasks.

MODERN CONTROL SYSTEMS COMPUTER CONTROLLED SYSTEM

MODERN CONTROL SYSTEMS TASK DIFFICULTY: Human vs. Automatic Machine

Tasks Difficult for a Machine

Task Difficult for a Human

Inspection and assessment of subjects in a certain condition

Inspection of a system in a hot, toxic environment

Drive a vehicle through a complex and rugged terrain

Repetitively assembling a device

Identify values (cost) of certain Precision and accuracy in objects movements specially when distracted.

MODERN CONTROL SYSTEMS EXAMPLES (Precision Temperature Controller)

MODERN CONTROL SYSTEMS CONTROL SYSTEM IN OUR DAILY LIFE Virtually daily activities is affected by some type of feedback control system. It is visible to the human body, in home, asemmbly lines, and robots. Other applications of control systems include transportation, space technology, chemical processes, machine tools, computer peripherals, power systems biotechnology, economic systems, ecological systems and government. An engineer with training in control system analysis and design will be able to design, build and analyze the devices and systems which provide automatic control.

AUTOMATED ASSEMBLY Automation and Future Evolutions

Bautista, Irene

AUTOMATIC ASSEMBLY

AUTOMATIC ASSEMBLY AUTOMATIC ASSEMBLY is a computerized production control technique used in the production of manufactured goods to balance output production with demand

AUTOMATIC ASSEMBLY DISCRETE PARTS MANUFACTUING •Mass Production •Batch Production •Job-Shop Manufacturing

AUTOMATIC ASSEMBLY PROCESS CONTROL MANUFACTURING •Development of analytical instruments to record what is happening as we as to analyze the chemical constituents of gases and fluids at hundreds of points inside a processing plant •Design and construction of much automatically controlled equipment •Use of large-scale analog computers to unravel complicated kinetic system problems •The devising of methods to achieve optimum performance in industrial technology

AUTOMATIC ASSEMBLY AUTOMATION Automation is basically the delegation of human control function to technical equipment for: • • • •

Increasing Productivity Increasing Quality Reducing Cost Increasing Safety in working conditions

AUTOMATIC ASSEMBLY AUTOMATION Automation is the use of control systems in concert with other applications of information technology to control industrial machinery and processes, reducing the need for human intervention. In the scope of industrialization, automation is a step beyond mechanization. Whereas mechanization provided human operators with machinery to assist them with the muscular requirements of work, automation greatly reduces the need for human sensory and mental requirements as well. Processes and systems can also be automated

AUTOMATIC ASSEMBLY SYSTEM FRAME OF AUTOMATION

Programmable Logic Controller Electronic Control using Logic Gates Hard wired logic Control Pneumatic Control Manual Control

AUTOMATIC ASSEMBLY MANUAL CONTROL All the actions related to process control are taken by the operators DRAWBACKS  Likely human errors and consequently its effect on quality of final product  The production, safety, energy consumption and usage of raw material are all subject to the correctness and accuracy of human action.

AUTOMATIC ASSEMBLY PNEUMATIC CONTROL The contactor and Relays together with hardware timers and counters were used in achieving the desired level of automation DRAWBACKS •Bulky and Complex System • Involves lot of rework to implement control logic • Longer project time

AUTOMATIC ASSEMBLY HARD-WIRED CONTROL The contactor and Relays together with hardware timers and counters were used in achieving the desired level of automation DRAWBACKS • Bulky panels • Complex wiring • Longer project time • Difficult maintenance and troubleshooting

AUTOMATIC ASSEMBLY ELECTRONIC CONTROL USING LOGIC GATES The hardware timers & counters were replaced by electronic timers ADVANTAGES •Reduced space requirements •Energy saving •Less maintenance & greater reliability DRAWBACKS • Changes in control logic not possible •More project time

AUTOMATIC ASSEMBLY PROGRAMMABLE LOGIC CONTROLLER Instead of achieving the desired control or automation through physical wiring of control devices, in PLC it is achieved through a program or say software. ADVANTAGES • Reduced space • Energy saving • Ease of maintenance • Economical • Greater life & reliability • Tremendous flexibility • Shorter project time • Easier storage, archiving and documentation

FUTURE EVOLUTION

DESIGN Engineering Design and Control System Design

Roque, Jeremias Jr P

DESIGN ENGINEERING DESIGN is the central task of an engineer wherein, DESIGN is defined as the process of conceiving or inventing the forms, parts, and details of a system to achieve a reasoned purpose. The design steps are: a) determine a need arising from values of groups, covering the spectrum from public policy makers to the consumer, b) specify in detail what the solution to that need must be and to embody these values, c) develop and evaluate various alternative solutions, and d) decide which is to be designed in detail and fabricated.

DESIGN Specifications are statements that explicitly state what the device or product is to be and do. Design specifications rests on four characteristics: • Complexity of Design, results from the wide range of tools, issues, and knowledge to be used in the process • Trade-Off, involves the need to make a judgment about how much of a compromise can be made between two conflicting criteria, both of which are desirable • Gaps, the void between what is intended (or visualized) as the product or device and the actual, practical form of the final design • Risk, uncertainties embodied in the unintended consequences of the design

DESIGN In engineering design, two types of thinking must takes place: analysis and synthesis Analysis Synthesis, the process where new physical configurations are created Engineering design is not a linear process, it is an iterative, nonlinear, creative process.

DESIGN CONTROL SYSTEM DESIGN is the arrangement or the plan of the system structure and the selection of its suitable components and parameters. 1. Establish control goals 2. Identify the variables to control 3. Write the specifications for the variables 4. Establish the system configuration and identify the actuator 5. Obtain a model of the process, the actuator, and the sensor 6. Describe a controller and select key parameters to be adjusted 7. Optimize the parameters and analyze the performance

EXAMPLES AND EXERCISES Applications of Concepts

EXAMPLES Sketch a block diagram of an open-loop system for dryer wherein the dryer is under the function of a given time.

Desired Output

Σ

Actual Output Control Device

Actuator

Process

Timer

Motor

Dryer

EXAMPLES Sketch a block diagram of a manual control system for regulating the level of fluid in a tank.

Desired Output

Σ

Actual Output Control Device

Actuator

Process

Human Operator

Valve

Fluid Input

Sensor Human Visual

EXAMPLES An automobile driver uses a control system to maintain the speed of the car at a prescribed level. Sketch the block diagram to illustrate this feedback system.

Desired Output

Σ

Actual Output Control Device

Actuator

Process

Gas

Engine

Steering Wheel

Sensor Speedometer

EXAMPLES Sketch the block diagram to illustrate this feedback system of a Temperature Control of Passenger Compartment Car wherein external factors are considered. Heat Sensor

Sun

Desired Output

Σ

Actual Output Control Device

Actuator

Process

Controller

Air Conditioner

Passenger Car

Sensor Thermometer/ Thermostat

EXERCISES Using the closed-loop pattern construct a feedback model of student-teacher learning process through examinations as the utility for measurement

Desired Output

Σ

Actual Output Control Device

Teacher

Actuator

Student

Sensor

Exam

Process

Learning

END Thank You Angeles, Ma. Gina Bautista, Ely Bautista, Irene Cayetano, Lester Rivera, Alvin M Roque, Jeremias Jr