Introduction to Feedback and Control Systems PDF

INTRODUCTION TO\ Feedback and Control System **What is Control System?** - **Control System** is the connectivity of different components yielding into a system arrangement that will give an ultimate system response. *(take all considerations)* - It consists of subsystems and processe...

INTRODUCTION TO\ Feedback and Control System **What is Control System?** - **Control System** is the connectivity of different components yielding into a system arrangement that will give an ultimate system response. *(take all considerations)* - It consists of subsystems and processes (or plants) assembled for the purpose of obtaining a desire output with desired performance given a specified input **TYPES OF CONTROL SYSTEM** 1. Open loop control system 2. Closed-loop or feedback control system **THREE MAIN COMPONENTS OF CONTROL SYSTEM** 1. Input 2. Process 3. Output +-----------------------------------+-----------------------------------+ | OPEN LOOP SYSTEM | CLOSED LOOP (FEEDBACK CONTROL) | +===================================+===================================+ | - A system where **feedback | - An **open loop** with | | portion** or component is | additional component = | | **not present** | **feedback** | | | | | - Direct system response | - A signal coming [from the | | | output] going | | - No chance to change the | back to the [input | | output since nakadepende sa | loop] | | input | | | | **Example**: [Sequential | | **Example**: [Combinational | Circuits], | | Circuits], | | | | Thermostat-controlled heating | | Microwave Oven, Turning on Lights | system, Split-type air | | | conditioner, Driving a car | | Disadvantage: Lack the precision | (feedback = environment, etc.) | | and adaptability of closed loop | | | systems | Advantage: can reject external | | | disturbances and improve | | | measurement noise attenuation | +-----------------------------------+-----------------------------------+ **OPEN LOOP CONTROL SYSTEM \>** - there's no feedback mechanism, and the system doesn't correct errors or adapt to changes - no change in output response; straighforward Ex: Human, Computer, Device (Controller) **CLOSED LOOP CONTROL SYSTEM \>** - also referred to as "Feedback Control System" - basically an **open loop** system **with feedback element** **\>\> TYPES OF CLOSED- LOOP SYSTEM** - Positive Feedback Control System - Negative Feedback Control System 1. **POSITIVE FEEDBACK CONTROL SYSTEM** - A type of feedback cs where **output is** **ADDED** from the input and the **SUM** is used as the input signal to the controller 2. **NEGATIVE FEEDBACK CONTROL SYSTEM** - Output is SUBTRACTED from input and the DIFFERENCE is used as the input signal to the controller Example: Operational Amplifier **OPEN AND CLOSED LOOP CONTROL SYSTEM** **MULTI-LOOP FEEDBACK CONTROL SYSTEM** - is the feedback system that contain more than one feedback loop. - ONE VARIABLE BUT MANY LOOPS  **MULTI-VARIABLE CONTROL SYSTEM** - is the control system where the interrelationship of many controlled variables are all considered in the control scheme. - MULTIPLE VARIABLE, ONE LOOP - "MIMO" (Multi Input Multi Output) Control System Design Processes **What is ENGINEERING DESIGN?** - Its objective is to create a system having specification, system configuration and identifying all system paraments [to realize the desirable system response.] **PROCEDURES OF BASIC CONTROL SYSTEM DESIGN** 1. Identify the goals and parameters to be controlled. Define the specifications (in metrics) against which to actual performance 2. Design the system modelling 3. Integration of system simulation and analysis to control system design process **\-\-\-\-\-\-\-\-\-\-\-\-- CONTROL SYSTEM DESIGN PROCESS** **\-\-\-\-\-\-\-\-\-\-- ENGINEERING DESIGN** - the central task of the engineer. - a complex process in which both creativity and analysis play major roles **\-\-\-\-\-\-\-\-\-\-- DESIGN** - to achieve a specific purpose - it is the process of conceiving or inventing the forms, parts, and details of a system **\-\-\-\-\-\-\-\-\-\-- DESIGN ACTIVITY** - planning for the emergence of a particular product or system **\-\-\-\-\-\-\-\-\-\-\-\-- STEPS IN DESIGNING (4) \-\-\-\-\-\-\-\-\-\-\-\-\-\--** 1. To determine a need arising from the values of various groups, covering the spectrum from public policy makers to the consumer 2. To specify in detail what the solution to that need must be and to embody these values 3. To develop and evaluate various alternative solutions to meet these specifications 4. To decide which one is to be designed in detail and fabricated. **\-\-\-\-\-\-- COMPONENTS OF A CONTROL SYSTEM DESIGN (6) \-\-\-\-\-\-\-\--** 1. Input 2. Controller 3. Actuator 4. Process 5. Output 6. Feedback Element **\-\-\-\-\-- Terms and concepts \-\-\-\-\--** **\-\-\-- AUTOMATION** - The control of a process by automatic means - No human intervention; automatic (microcontroller or microprocessor) **\-\-\-- Closed-Loop feedback control system** - A system that uses a measurement of the output and compares it with the desired output to control the process - Has feedback element **\-\-\-- COMPLEXITY OF DESIGN** - The intricate pattern of interwoven parts and knowledge required - Interconnectivity that considers maraming factors **\-\-\-- CONTROL SYSTEM \>\>** - Interconnection of components **forming a system configuration** that will provide a desired response **\-\-\-- DESIGN** - The process of conceiving or inventing the forms, parts, and details of a system to **achieve a specified purpose**. **\-\-\-- DESIGN GAP** - A gap between the complex physical system and the design model intrinsic to the progression from the initial concept to the final product. **\-\-\-- DISTURBANCE \>** - An unwanted input signal that affects the output signal. **\-\-\-- EMBEDDED CONTROL** - A feedback control system that employs on-board special-purpose digital computers as integral components of the feedback loop. **\-\-\-- ENGINEERING DESIGN** - The process of designing a technical system **\-\-\-- FEEDBACK SIGNAL** - A measure of the output of the system used for feedback to control the system - Signal coming from output to input, possibly add or subtract **\-\-\-- FLYBALL GOVERNOR** - A mechanical device for controlling the speed of a steam engine **\-\-\-- HYBRID FUEL AUTOMOBILE** - An automobile that uses a conventional internal combustion engine in combination with an energy storage device to provide a propulsion system. **\-\-\-- MEASUREMENT NOISE \>** - An unwanted input signal that affects the measured output signal **\-\-\-- MECHATRONICS** - The **synergistic integration** of mechanical, electrical, and computer system - Multi-discipline engineering **\-\-\-- MULTILOOP FEEDBACK CONTROL SYSTEM** - A feedback control system with more than one feedback control loop **\-\-\-- Multivariate control system** - A system with more than one input or output variable **\-\-\-- NegatIve feedback** - An output signal fed back so that it subtracts from the input signal **\-\-\-- OPEN-LOOP CONTROL SYSTEM** - A system that uses a device to control the process without using feedback. - the output has no effect upon the signal to the process. **\-\-\-- OPTIMIZATION** - The adjustment of the parameters to achieve the most favorable or advantageous design. **\-\-\-- POSITIVE FEEDBACK** - An output signal fed back so that it adds to the input signal. **\-\-\-- PROCESS** - The device, plant, or system under control. **\-\-\-- PRODUCTIVITY** - The ratio of physical output to physical input of an industrial process. **\-\-\-- RISK** - Uncertainties embodied in the unintended consequences of a design. **\-\-\-- ROBOT** - Programmable computers integrated with a manipulator - A re-programmable, multi-functional manipulator used for a variety of tasks **\-\-\-- SPECIFICATIONS** - Statements that explicitly state **what the device or product is to be and to do** - A set of prescribed performance criteria. **\-\-\-- SYNTHESIS** - The process by which new physical configurations are created - The combining of separate elements or devices to form a coherent whole. **\-\-\-- SYSTEM \>\>** - An interconnection of elements and devices **for a desired purpose**. **\-\-\-- TRADE-OFF** - The result of making a judgment about how to compromise **between conflicting criteria.** LAPLACE TRANSFORM - An integral transformation of a function f(t) from the time domain into the complex frequency domain, giving F(s). The **LINEAR SYSTEM** requires us of transformation of all mathematical differential equation into its Laplace transform equivalent. It allows complex differential equation to expressed and solved into simplify algebraic form. TO CONVERT THE TIME DOMAIN (T) INTO ITS FREQUENCY DOMAIN (S), THE FOLLOWING PROCEDURES MUST BE CONSIDERED: 1. Linearized the given differential equations. 2. Get the equivalent Laplace transform of the given differential equation. 3. Calculate the resulting algebraic expression. **DEFINITION OF LAPLACE TRANSFORM**  Given a function f(t), its Laplace transform, denoted by F(s) or [ℒ\[*f*(*t*)\], ]{.math.inline}*is defined by:* where s is a complex variable given by: **PROPERTIES OF LAPLACE TRANSFORM** **\-\-\--** THE INVERSE LAPLACE TRANSFORM **\-\-\--** - a mathematical operation that converts a function from the **Laplace domain (s-domain)** back to the **time domain (t-domain)**. It is the reverse process of the **Laplace transform** and is commonly used in engineering, physics, and control systems to analyze differential equations. NOTE: We use **PARTIAL FRACTION** expansion to break F(s) down into simple terms whose inverse transform we obtain from the original equation